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2014 |
Imler, Jean-Luc Overview of Drosophila immunity: a historical perspective Article de journal Developmental and Comparative Immunology, 42 (1), p. 3–15, 2014, ISSN: 1879-0089. Résumé | Liens | BibTeX | Étiquettes: Allergy and Immunology, Animal, Animals, Antimicrobial Cationic Peptides, Antimicrobial peptides, history, Humans, IMD pathway, imler, Immunity, Innate, innate immunity, M3i, Models, Pattern recognition receptors, Signal Transduction, Toll-Like Receptors @article{imler_overview_2014, title = {Overview of Drosophila immunity: a historical perspective}, author = {Jean-Luc Imler}, doi = {10.1016/j.dci.2013.08.018}, issn = {1879-0089}, year = {2014}, date = {2014-01-01}, journal = {Developmental and Comparative Immunology}, volume = {42}, number = {1}, pages = {3--15}, abstract = {The functional analysis of genes from the model organism Drosophila melanogaster has provided invaluable information for many cellular and developmental or physiological processes, including immunity. The best-understood aspect of Drosophila immunity is the inducible humoral response, first recognized in 1972. This pioneering work led to a remarkable series of findings over the next 30 years, ranging from the identification and characterization of the antimicrobial peptides produced, to the deciphering of the signalling pathways activating the genes that encode them and, ultimately, to the discovery of the receptors sensing infection. These studies on an insect model coincided with a revival of the field of innate immunity, and had an unanticipated impact on the biomedical field.}, keywords = {Allergy and Immunology, Animal, Animals, Antimicrobial Cationic Peptides, Antimicrobial peptides, history, Humans, IMD pathway, imler, Immunity, Innate, innate immunity, M3i, Models, Pattern recognition receptors, Signal Transduction, Toll-Like Receptors}, pubstate = {published}, tppubtype = {article} } The functional analysis of genes from the model organism Drosophila melanogaster has provided invaluable information for many cellular and developmental or physiological processes, including immunity. The best-understood aspect of Drosophila immunity is the inducible humoral response, first recognized in 1972. This pioneering work led to a remarkable series of findings over the next 30 years, ranging from the identification and characterization of the antimicrobial peptides produced, to the deciphering of the signalling pathways activating the genes that encode them and, ultimately, to the discovery of the receptors sensing infection. These studies on an insect model coincided with a revival of the field of innate immunity, and had an unanticipated impact on the biomedical field. |
2013 |
Fukuyama, Hidehiro; Verdier, Yann; Guan, Yongsheng; Makino-Okamura, Chieko; Shilova, Victoria; Liu, Xi; Maksoud, Elie; Matsubayashi, Jun; Haddad, Iman; Spirohn, Kerstin; Ono, Kenichiro; Hetru, Charles; Rossier, Jean; Ideker, Trey; Boutros, Michael; Vinh, Joëlle; Hoffmann, Jules A Landscape of protein-protein interactions in Drosophila immune deficiency signaling during bacterial challenge Article de journal Proc. Natl. Acad. Sci. U.S.A., 110 (26), p. 10717–10722, 2013, ISSN: 1091-6490. Résumé | Liens | BibTeX | Étiquettes: Amino Acid, Animals, Chromatin Assembly and Disassembly, Escherichia coli, functional proteomics, Genes, Genetically Modified, Histone Acetyltransferases, hoffmann, Host-Pathogen Interactions, Humans, IMD interactome, Insect, M3i, Models, Molecular, Protein Interaction Maps, Sequence Homology, Signal Transduction, small ubiquitin-like modifier @article{fukuyama_landscape_2013, title = {Landscape of protein-protein interactions in Drosophila immune deficiency signaling during bacterial challenge}, author = {Hidehiro Fukuyama and Yann Verdier and Yongsheng Guan and Chieko Makino-Okamura and Victoria Shilova and Xi Liu and Elie Maksoud and Jun Matsubayashi and Iman Haddad and Kerstin Spirohn and Kenichiro Ono and Charles Hetru and Jean Rossier and Trey Ideker and Michael Boutros and Joëlle Vinh and Jules A Hoffmann}, doi = {10.1073/pnas.1304380110}, issn = {1091-6490}, year = {2013}, date = {2013-06-01}, journal = {Proc. Natl. Acad. Sci. U.S.A.}, volume = {110}, number = {26}, pages = {10717--10722}, abstract = {The Drosophila defense against pathogens largely relies on the activation of two signaling pathways: immune deficiency (IMD) and Toll. The IMD pathway is triggered mainly by Gram-negative bacteria, whereas the Toll pathway responds predominantly to Gram-positive bacteria and fungi. The activation of these pathways leads to the rapid induction of numerous NF-κB-induced immune response genes, including antimicrobial peptide genes. The IMD pathway shows significant similarities with the TNF receptor pathway. Recent evidence indicates that the IMD pathway is also activated in response to various noninfectious stimuli (i.e., inflammatory-like reactions). To gain a better understanding of the molecular machinery underlying the pleiotropic functions of this pathway, we first performed a comprehensive proteomics analysis to identify the proteins interacting with the 11 canonical members of the pathway initially identified by genetic studies. We identified 369 interacting proteins (corresponding to 291 genes) in heat-killed Escherichia coli-stimulated Drosophila S2 cells, 92% of which have human orthologs. A comparative analysis of gene ontology from fly or human gene annotation databases points to four significant common categories: (i) the NuA4, nucleosome acetyltransferase of H4, histone acetyltransferase complex, (ii) the switching defective/sucrose nonfermenting-type chromatin remodeling complex, (iii) transcription coactivator activity, and (iv) translation factor activity. Here we demonstrate that sumoylation of the IκB kinase homolog immune response-deficient 5 plays an important role in the induction of antimicrobial peptide genes through a highly conserved sumoylation consensus site during bacterial challenge. Taken together, the proteomics data presented here provide a unique avenue for a comparative functional analysis of proteins involved in innate immune reactions in flies and mammals.}, keywords = {Amino Acid, Animals, Chromatin Assembly and Disassembly, Escherichia coli, functional proteomics, Genes, Genetically Modified, Histone Acetyltransferases, hoffmann, Host-Pathogen Interactions, Humans, IMD interactome, Insect, M3i, Models, Molecular, Protein Interaction Maps, Sequence Homology, Signal Transduction, small ubiquitin-like modifier}, pubstate = {published}, tppubtype = {article} } The Drosophila defense against pathogens largely relies on the activation of two signaling pathways: immune deficiency (IMD) and Toll. The IMD pathway is triggered mainly by Gram-negative bacteria, whereas the Toll pathway responds predominantly to Gram-positive bacteria and fungi. The activation of these pathways leads to the rapid induction of numerous NF-κB-induced immune response genes, including antimicrobial peptide genes. The IMD pathway shows significant similarities with the TNF receptor pathway. Recent evidence indicates that the IMD pathway is also activated in response to various noninfectious stimuli (i.e., inflammatory-like reactions). To gain a better understanding of the molecular machinery underlying the pleiotropic functions of this pathway, we first performed a comprehensive proteomics analysis to identify the proteins interacting with the 11 canonical members of the pathway initially identified by genetic studies. We identified 369 interacting proteins (corresponding to 291 genes) in heat-killed Escherichia coli-stimulated Drosophila S2 cells, 92% of which have human orthologs. A comparative analysis of gene ontology from fly or human gene annotation databases points to four significant common categories: (i) the NuA4, nucleosome acetyltransferase of H4, histone acetyltransferase complex, (ii) the switching defective/sucrose nonfermenting-type chromatin remodeling complex, (iii) transcription coactivator activity, and (iv) translation factor activity. Here we demonstrate that sumoylation of the IκB kinase homolog immune response-deficient 5 plays an important role in the induction of antimicrobial peptide genes through a highly conserved sumoylation consensus site during bacterial challenge. Taken together, the proteomics data presented here provide a unique avenue for a comparative functional analysis of proteins involved in innate immune reactions in flies and mammals. |
2011 |
Imler, Jean-Luc; Ferrandon, Dominique [Innate immunity crowned 2011 Nobel Prize winner] Article de journal Med Sci (Paris), 27 , p. 1019–24, 2011, ISSN: 0767-0974 (Print) 0767-0974 (Linking). Liens | BibTeX | Étiquettes: *Immunity, *Nobel Prize, Biological, ferrandon, Genetic Association Studies, Humans, imler, Immunotherapy/methods/trends, Innate/genetics, M3i, Models, Molecular Targeted Therapy/trends, Seasons, Structure-Activity Relationship, Toll-Like Receptors/chemistry/genetics/isolation & purification/physiology @article{imler_[innate_2011b, title = {[Innate immunity crowned 2011 Nobel Prize winner]}, author = {Jean-Luc Imler and Dominique Ferrandon}, url = {http://dx.doi.org.gate1.inist.fr/10.1051/medsci/20112711020}, doi = {10.1051/medsci/20112711020}, issn = {0767-0974 (Print) 0767-0974 (Linking)}, year = {2011}, date = {2011-11-01}, journal = {Med Sci (Paris)}, volume = {27}, pages = {1019--24}, keywords = {*Immunity, *Nobel Prize, Biological, ferrandon, Genetic Association Studies, Humans, imler, Immunotherapy/methods/trends, Innate/genetics, M3i, Models, Molecular Targeted Therapy/trends, Seasons, Structure-Activity Relationship, Toll-Like Receptors/chemistry/genetics/isolation & purification/physiology}, pubstate = {published}, tppubtype = {article} } |
Ogawa, Michinaga; Yoshikawa, Yuko; Kobayashi, Taira; Mimuro, Hitomi; Fukumatsu, Makoto; Kiga, Kotaro; Piao, Zhenzi; Ashida, Hiroshi; Yoshida, Mitsutaka; Kakuta, Shigeru; Koyama, Tomohiro; Goto, Yoshiyuki; Nagatake, Takahiro; Nagai, Shinya; Kiyono, Hiroshi; Kawalec, Magdalena; Reichhart, Jean-Marc; Sasakawa, Chihiro A Tecpr1-dependent selective autophagy pathway targets bacterial pathogens Article de journal Cell Host Microbe, 9 (5), p. 376–389, 2011, ISSN: 1934-6069. Résumé | Liens | BibTeX | Étiquettes: Animals, Autophagy, Biological, Cells, Cultured, M3i, Membrane Proteins, Mice, Microtubule-Associated Proteins, Models, Phagosomes, Protein Interaction Mapping, reichhart, Shigella, Two-Hybrid System Techniques @article{ogawa_tecpr1-dependent_2011, title = {A Tecpr1-dependent selective autophagy pathway targets bacterial pathogens}, author = {Michinaga Ogawa and Yuko Yoshikawa and Taira Kobayashi and Hitomi Mimuro and Makoto Fukumatsu and Kotaro Kiga and Zhenzi Piao and Hiroshi Ashida and Mitsutaka Yoshida and Shigeru Kakuta and Tomohiro Koyama and Yoshiyuki Goto and Takahiro Nagatake and Shinya Nagai and Hiroshi Kiyono and Magdalena Kawalec and Jean-Marc Reichhart and Chihiro Sasakawa}, doi = {10.1016/j.chom.2011.04.010}, issn = {1934-6069}, year = {2011}, date = {2011-05-01}, journal = {Cell Host Microbe}, volume = {9}, number = {5}, pages = {376--389}, abstract = {Selective autophagy of bacterial pathogens represents a host innate immune mechanism. Selective autophagy has been characterized on the basis of distinct cargo receptors but the mechanisms by which different cargo receptors are targeted for autophagic degradation remain unclear. In this study we identified a highly conserved Tectonin domain-containing protein, Tecpr1, as an Atg5 binding partner that colocalized with Atg5 at Shigella-containing phagophores. Tecpr1 activity is necessary for efficient autophagic targeting of bacteria, but has no effect on rapamycin- or starvation-induced canonical autophagy. Tecpr1 interacts with WIPI-2, a yeast Atg18 homolog and PI(3)P-interacting protein required for phagophore formation, and they colocalize to phagophores. Although Tecpr1-deficient mice appear normal, Tecpr1-deficient MEFs were defective for selective autophagy and supported increased intracellular multiplication of Shigella. Further, depolarized mitochondria and misfolded protein aggregates accumulated in the Tecpr1-knockout MEFs. Thus, we identify a Tecpr1-dependent pathway as important in targeting bacterial pathogens for selective autophagy.}, keywords = {Animals, Autophagy, Biological, Cells, Cultured, M3i, Membrane Proteins, Mice, Microtubule-Associated Proteins, Models, Phagosomes, Protein Interaction Mapping, reichhart, Shigella, Two-Hybrid System Techniques}, pubstate = {published}, tppubtype = {article} } Selective autophagy of bacterial pathogens represents a host innate immune mechanism. Selective autophagy has been characterized on the basis of distinct cargo receptors but the mechanisms by which different cargo receptors are targeted for autophagic degradation remain unclear. In this study we identified a highly conserved Tectonin domain-containing protein, Tecpr1, as an Atg5 binding partner that colocalized with Atg5 at Shigella-containing phagophores. Tecpr1 activity is necessary for efficient autophagic targeting of bacteria, but has no effect on rapamycin- or starvation-induced canonical autophagy. Tecpr1 interacts with WIPI-2, a yeast Atg18 homolog and PI(3)P-interacting protein required for phagophore formation, and they colocalize to phagophores. Although Tecpr1-deficient mice appear normal, Tecpr1-deficient MEFs were defective for selective autophagy and supported increased intracellular multiplication of Shigella. Further, depolarized mitochondria and misfolded protein aggregates accumulated in the Tecpr1-knockout MEFs. Thus, we identify a Tecpr1-dependent pathway as important in targeting bacterial pathogens for selective autophagy. |
Lee, Kwang-Zin; Ferrandon, Dominique Negative regulation of immune responses on the fly Article de journal EMBO J., 30 (6), p. 988–990, 2011, ISSN: 1460-2075. Liens | BibTeX | Étiquettes: *Gene Expression Regulation, *Homeostasis, Animals, bacteria, Bacteria/*immunology, Biological, Drosophila melanogaster/*immunology, Drosophila Proteins/biosynthesis/metabolism, ferrandon, Gene Expression Regulation, Homeostasis, M3i, Mitogen-Activated Protein Kinases, Mitogen-Activated Protein Kinases/metabolism, Models, NF-kappa B, NF-kappa B/metabolism, ras Proteins, ras Proteins/metabolism, Receptor Protein-Tyrosine Kinases, Receptor Protein-Tyrosine Kinases/metabolism @article{lee_negative_2011b, title = {Negative regulation of immune responses on the fly}, author = {Kwang-Zin Lee and Dominique Ferrandon}, doi = {10.1038/emboj.2011.47}, issn = {1460-2075}, year = {2011}, date = {2011-01-01}, journal = {EMBO J.}, volume = {30}, number = {6}, pages = {988--990}, keywords = {*Gene Expression Regulation, *Homeostasis, Animals, bacteria, Bacteria/*immunology, Biological, Drosophila melanogaster/*immunology, Drosophila Proteins/biosynthesis/metabolism, ferrandon, Gene Expression Regulation, Homeostasis, M3i, Mitogen-Activated Protein Kinases, Mitogen-Activated Protein Kinases/metabolism, Models, NF-kappa B, NF-kappa B/metabolism, ras Proteins, ras Proteins/metabolism, Receptor Protein-Tyrosine Kinases, Receptor Protein-Tyrosine Kinases/metabolism}, pubstate = {published}, tppubtype = {article} } |
2010 |
Silverman, Gary A; Whisstock, James C; Bottomley, Stephen P; Huntington, James A; Kaiserman, Dion; Luke, Cliff J; Pak, Stephen C; Reichhart, Jean-Marc; Bird, Phillip I Serpins flex their muscle: I. Putting the clamps on proteolysis in diverse biological systems Article de journal J. Biol. Chem., 285 (32), p. 24299–24305, 2010, ISSN: 1083-351X. Résumé | Liens | BibTeX | Étiquettes: Animals, Biological, Caenorhabditis elegans, Cell Death, Cell Differentiation, Cell Survival, Homeostasis, Humans, Immunity, Innate, M3i, Mice, Models, Phenotype, reichhart, Serpins, Transgenes, transgenic @article{silverman_serpins_2010, title = {Serpins flex their muscle: I. Putting the clamps on proteolysis in diverse biological systems}, author = {Gary A Silverman and James C Whisstock and Stephen P Bottomley and James A Huntington and Dion Kaiserman and Cliff J Luke and Stephen C Pak and Jean-Marc Reichhart and Phillip I Bird}, doi = {10.1074/jbc.R110.112771}, issn = {1083-351X}, year = {2010}, date = {2010-08-01}, journal = {J. Biol. Chem.}, volume = {285}, number = {32}, pages = {24299--24305}, abstract = {Serpins compose the largest superfamily of peptidase inhibitors and are well known as regulators of hemostasis and thrombolysis. Studies using model organisms, from plants to vertebrates, now show that serpins and their unique inhibitory mechanism and conformational flexibility are exploited to control proteolysis in molecular pathways associated with cell survival, development, and host defense. In addition, an increasing number of non-inhibitory serpins are emerging as important elements within a diversity of biological systems by serving as chaperones, hormone transporters, or anti-angiogenic factors.}, keywords = {Animals, Biological, Caenorhabditis elegans, Cell Death, Cell Differentiation, Cell Survival, Homeostasis, Humans, Immunity, Innate, M3i, Mice, Models, Phenotype, reichhart, Serpins, Transgenes, transgenic}, pubstate = {published}, tppubtype = {article} } Serpins compose the largest superfamily of peptidase inhibitors and are well known as regulators of hemostasis and thrombolysis. Studies using model organisms, from plants to vertebrates, now show that serpins and their unique inhibitory mechanism and conformational flexibility are exploited to control proteolysis in molecular pathways associated with cell survival, development, and host defense. In addition, an increasing number of non-inhibitory serpins are emerging as important elements within a diversity of biological systems by serving as chaperones, hormone transporters, or anti-angiogenic factors. |
Whisstock, James C; Silverman, Gary A; Bird, Phillip I; Bottomley, Stephen P; Kaiserman, Dion; Luke, Cliff J; Pak, Stephen C; Reichhart, Jean-Marc; Huntington, James A Serpins flex their muscle: II. Structural insights into target peptidase recognition, polymerization, and transport functions Article de journal J. Biol. Chem., 285 (32), p. 24307–24312, 2010, ISSN: 1083-351X. Résumé | Liens | BibTeX | Étiquettes: Animals, Biological, Biological Transport, Biophysics, Catalytic Domain, Hormones, Humans, Kinetics, M3i, Models, Peptide Hydrolases, Protein Binding, Protein Conformation, Protein Structure, reichhart, Serpins, Substrate Specificity, Tertiary, Thrombin @article{whisstock_serpins_2010, title = {Serpins flex their muscle: II. Structural insights into target peptidase recognition, polymerization, and transport functions}, author = {James C Whisstock and Gary A Silverman and Phillip I Bird and Stephen P Bottomley and Dion Kaiserman and Cliff J Luke and Stephen C Pak and Jean-Marc Reichhart and James A Huntington}, doi = {10.1074/jbc.R110.141408}, issn = {1083-351X}, year = {2010}, date = {2010-08-01}, journal = {J. Biol. Chem.}, volume = {285}, number = {32}, pages = {24307--24312}, abstract = {Inhibitory serpins are metastable proteins that undergo a substantial conformational rearrangement to covalently trap target peptidases. The serpin reactive center loop contributes a majority of the interactions that serpins make during the initial binding to target peptidases. However, structural studies on serpin-peptidase complexes reveal a broader set of contacts on the scaffold of inhibitory serpins that have substantial influence on guiding peptidase recognition. Structural and biophysical studies also reveal how aberrant serpin folding can lead to the formation of domain-swapped serpin multimers rather than the monomeric metastable state. Serpin domain swapping may therefore underlie the polymerization events characteristic of the serpinopathies. Finally, recent structural studies reveal how the serpin fold has been adapted for non-inhibitory functions such as hormone binding.}, keywords = {Animals, Biological, Biological Transport, Biophysics, Catalytic Domain, Hormones, Humans, Kinetics, M3i, Models, Peptide Hydrolases, Protein Binding, Protein Conformation, Protein Structure, reichhart, Serpins, Substrate Specificity, Tertiary, Thrombin}, pubstate = {published}, tppubtype = {article} } Inhibitory serpins are metastable proteins that undergo a substantial conformational rearrangement to covalently trap target peptidases. The serpin reactive center loop contributes a majority of the interactions that serpins make during the initial binding to target peptidases. However, structural studies on serpin-peptidase complexes reveal a broader set of contacts on the scaffold of inhibitory serpins that have substantial influence on guiding peptidase recognition. Structural and biophysical studies also reveal how aberrant serpin folding can lead to the formation of domain-swapped serpin multimers rather than the monomeric metastable state. Serpin domain swapping may therefore underlie the polymerization events characteristic of the serpinopathies. Finally, recent structural studies reveal how the serpin fold has been adapted for non-inhibitory functions such as hormone binding. |
Paquette, Nicholas; Broemer, Meike; Aggarwal, Kamna; Chen, Li; Husson, Marie; Ertürk-Hasdemir, Deniz; Reichhart, Jean-Marc; Meier, Pascal; Silverman, Neal Caspase-mediated cleavage, IAP binding, and ubiquitination: linking three mechanisms crucial for Drosophila NF-kappaB signaling Article de journal Mol. Cell, 37 (2), p. 172–182, 2010, ISSN: 1097-4164. Résumé | Liens | BibTeX | Étiquettes: Alleles, Amino Acid Motifs, Animals, Biological, Caspases, Inhibitor of Apoptosis Proteins, M3i, MAP Kinase Kinase Kinases, Models, NF-kappa B, reichhart, Sequence Alignment, Signal Transduction, Ubiquitin-Protein Ligases, Ubiquitination @article{paquette_caspase-mediated_2010, title = {Caspase-mediated cleavage, IAP binding, and ubiquitination: linking three mechanisms crucial for Drosophila NF-kappaB signaling}, author = {Nicholas Paquette and Meike Broemer and Kamna Aggarwal and Li Chen and Marie Husson and Deniz Ertürk-Hasdemir and Jean-Marc Reichhart and Pascal Meier and Neal Silverman}, doi = {10.1016/j.molcel.2009.12.036}, issn = {1097-4164}, year = {2010}, date = {2010-01-01}, journal = {Mol. Cell}, volume = {37}, number = {2}, pages = {172--182}, abstract = {Innate immune responses are critical for the immediate protection against microbial infection. In Drosophila, infection leads to the rapid and robust production of antimicrobial peptides through two NF-kappaB signaling pathways-IMD and Toll. The IMD pathway is triggered by DAP-type peptidoglycan, common to most Gram-negative bacteria. Signaling downstream from the peptidoglycan receptors is thought to involve K63 ubiquitination and caspase-mediated cleavage, but the molecular mechanisms remain obscure. We now show that PGN stimulation causes caspase-mediated cleavage of the imd protein, exposing a highly conserved IAP-binding motif (IBM) at its neo-N terminus. A functional IBM is required for the association of cleaved IMD with the ubiquitin E3-ligase DIAP2. Through its association with DIAP2, IMD is rapidly conjugated with K63-linked polyubiquitin chains. These results mechanistically connect caspase-mediated cleavage and K63 ubiquitination in immune-induced NF-kappaB signaling.}, keywords = {Alleles, Amino Acid Motifs, Animals, Biological, Caspases, Inhibitor of Apoptosis Proteins, M3i, MAP Kinase Kinase Kinases, Models, NF-kappa B, reichhart, Sequence Alignment, Signal Transduction, Ubiquitin-Protein Ligases, Ubiquitination}, pubstate = {published}, tppubtype = {article} } Innate immune responses are critical for the immediate protection against microbial infection. In Drosophila, infection leads to the rapid and robust production of antimicrobial peptides through two NF-kappaB signaling pathways-IMD and Toll. The IMD pathway is triggered by DAP-type peptidoglycan, common to most Gram-negative bacteria. Signaling downstream from the peptidoglycan receptors is thought to involve K63 ubiquitination and caspase-mediated cleavage, but the molecular mechanisms remain obscure. We now show that PGN stimulation causes caspase-mediated cleavage of the imd protein, exposing a highly conserved IAP-binding motif (IBM) at its neo-N terminus. A functional IBM is required for the association of cleaved IMD with the ubiquitin E3-ligase DIAP2. Through its association with DIAP2, IMD is rapidly conjugated with K63-linked polyubiquitin chains. These results mechanistically connect caspase-mediated cleavage and K63 ubiquitination in immune-induced NF-kappaB signaling. |
2009 |
Fraiture, Malou; Baxter, Richard H G; Steinert, Stefanie; Chelliah, Yogarany; Frolet, Cécile; Quispe-Tintaya, Wilber; Hoffmann, Jules A; Blandin, Stéphanie A; Levashina, Elena A Two mosquito LRR proteins function as complement control factors in the TEP1-mediated killing of Plasmodium Article de journal Cell Host Microbe, 5 (3), p. 273–284, 2009, ISSN: 1934-6069. Résumé | Liens | BibTeX | Étiquettes: Animals, Anopheles, APL1, Biological, blandin, Complement System Proteins, Hemolymph, hoffmann, Immunologic Factors, LRIM1, M3i, Models, Plasmodium, Protein Binding, Proteins, TEP1 @article{fraiture_two_2009, title = {Two mosquito LRR proteins function as complement control factors in the TEP1-mediated killing of Plasmodium}, author = {Malou Fraiture and Richard H G Baxter and Stefanie Steinert and Yogarany Chelliah and Cécile Frolet and Wilber Quispe-Tintaya and Jules A Hoffmann and Stéphanie A Blandin and Elena A Levashina}, doi = {10.1016/j.chom.2009.01.005}, issn = {1934-6069}, year = {2009}, date = {2009-03-01}, journal = {Cell Host Microbe}, volume = {5}, number = {3}, pages = {273--284}, abstract = {Plasmodium development within Anopheles mosquitoes is a vulnerable step in the parasite transmission cycle, and targeting this step represents a promising strategy for malaria control. The thioester-containing complement-like protein TEP1 and two leucine-rich repeat (LRR) proteins, LRIM1 and APL1, have been identified as major mosquito factors that regulate parasite loads. Here, we show that LRIM1 and APL1 are required for binding of TEP1 to parasites. RNAi silencing of the LRR-encoding genes results in deposition of TEP1 on Anopheles tissues, thereby depleting TEP1 from circulation in the hemolymph and impeding its binding to Plasmodium. LRIM1 and APL1 not only stabilize circulating TEP1, they also stabilize each other prior to their interaction with TEP1. Our results indicate that three major antiparasitic factors in mosquitoes jointly function as a complement-like system in parasite killing, and they reveal a role for LRR proteins as complement control factors.}, keywords = {Animals, Anopheles, APL1, Biological, blandin, Complement System Proteins, Hemolymph, hoffmann, Immunologic Factors, LRIM1, M3i, Models, Plasmodium, Protein Binding, Proteins, TEP1}, pubstate = {published}, tppubtype = {article} } Plasmodium development within Anopheles mosquitoes is a vulnerable step in the parasite transmission cycle, and targeting this step represents a promising strategy for malaria control. The thioester-containing complement-like protein TEP1 and two leucine-rich repeat (LRR) proteins, LRIM1 and APL1, have been identified as major mosquito factors that regulate parasite loads. Here, we show that LRIM1 and APL1 are required for binding of TEP1 to parasites. RNAi silencing of the LRR-encoding genes results in deposition of TEP1 on Anopheles tissues, thereby depleting TEP1 from circulation in the hemolymph and impeding its binding to Plasmodium. LRIM1 and APL1 not only stabilize circulating TEP1, they also stabilize each other prior to their interaction with TEP1. Our results indicate that three major antiparasitic factors in mosquitoes jointly function as a complement-like system in parasite killing, and they reveal a role for LRR proteins as complement control factors. |
Cronin, Shane J F; Nehme, Nadine T; Limmer, Stefanie; Liegeois, Samuel; Pospisilik, Andrew J; Schramek, Daniel; Leibbrandt, Andreas; de Simoes, Ricardo Matos; Gruber, Susanne; Puc, Urszula; Ebersberger, Ingo; Zoranovic, Tamara; Neely, Gregory G; von Haeseler, Arndt; Ferrandon, Dominique; Penninger, Josef M Genome-wide RNAi screen identifies genes involved in intestinal pathogenic bacterial infection Article de journal Science, 325 (5938), p. 340–343, 2009, ISSN: 1095-9203. Résumé | Liens | BibTeX | Étiquettes: *Genome, *RNA Interference, Animal, Animals, Cell Proliferation, Drosophila melanogaster/*genetics/immunology/*microbiology, Drosophila Proteins/genetics/metabolism, Epithelial Cells, Epithelial Cells/cytology/physiology, ferrandon, Genetically Modified, Genome, Hemocytes, Hemocytes/immunology/metabolism/microbiology, Homeostasis, Immunity, Innate, Innate/*genetics, Insect, Intestinal Mucosa, Intestinal Mucosa/cytology/immunology/metabolism/microbiology, Janus Kinases, Janus Kinases/genetics/metabolism, M3i, Models, RNA Interference, Serratia Infections, Serratia Infections/genetics/*immunology/microbiology, Serratia marcescens, Serratia marcescens/*immunology/physiology, Signal Transduction, STAT Transcription Factors, STAT Transcription Factors/genetics/metabolism, Stem Cells, Stem Cells/cytology/physiology @article{cronin_genome-wide_2009b, title = {Genome-wide RNAi screen identifies genes involved in intestinal pathogenic bacterial infection}, author = {Shane J F Cronin and Nadine T Nehme and Stefanie Limmer and Samuel Liegeois and Andrew J Pospisilik and Daniel Schramek and Andreas Leibbrandt and Ricardo Matos de Simoes and Susanne Gruber and Urszula Puc and Ingo Ebersberger and Tamara Zoranovic and Gregory G Neely and Arndt von Haeseler and Dominique Ferrandon and Josef M Penninger}, doi = {10.1126/science.1173164}, issn = {1095-9203}, year = {2009}, date = {2009-01-01}, journal = {Science}, volume = {325}, number = {5938}, pages = {340--343}, abstract = {Innate immunity represents the first line of defense in animals. We report a genome-wide in vivo Drosophila RNA interference screen to uncover genes involved in susceptibility or resistance to intestinal infection with the bacterium Serratia marcescens. We first employed whole-organism gene suppression, followed by tissue-specific silencing in gut epithelium or hemocytes to identify several hundred genes involved in intestinal antibacterial immunity. Among the pathways identified, we showed that the JAK-STAT signaling pathway controls host defense in the gut by regulating stem cell proliferation and thus epithelial cell homeostasis. Therefore, we revealed multiple genes involved in antibacterial defense and the regulation of innate immunity.}, keywords = {*Genome, *RNA Interference, Animal, Animals, Cell Proliferation, Drosophila melanogaster/*genetics/immunology/*microbiology, Drosophila Proteins/genetics/metabolism, Epithelial Cells, Epithelial Cells/cytology/physiology, ferrandon, Genetically Modified, Genome, Hemocytes, Hemocytes/immunology/metabolism/microbiology, Homeostasis, Immunity, Innate, Innate/*genetics, Insect, Intestinal Mucosa, Intestinal Mucosa/cytology/immunology/metabolism/microbiology, Janus Kinases, Janus Kinases/genetics/metabolism, M3i, Models, RNA Interference, Serratia Infections, Serratia Infections/genetics/*immunology/microbiology, Serratia marcescens, Serratia marcescens/*immunology/physiology, Signal Transduction, STAT Transcription Factors, STAT Transcription Factors/genetics/metabolism, Stem Cells, Stem Cells/cytology/physiology}, pubstate = {published}, tppubtype = {article} } Innate immunity represents the first line of defense in animals. We report a genome-wide in vivo Drosophila RNA interference screen to uncover genes involved in susceptibility or resistance to intestinal infection with the bacterium Serratia marcescens. We first employed whole-organism gene suppression, followed by tissue-specific silencing in gut epithelium or hemocytes to identify several hundred genes involved in intestinal antibacterial immunity. Among the pathways identified, we showed that the JAK-STAT signaling pathway controls host defense in the gut by regulating stem cell proliferation and thus epithelial cell homeostasis. Therefore, we revealed multiple genes involved in antibacterial defense and the regulation of innate immunity. |
2008 |
Geary, C; Baudrey, S; Jaeger, L Comprehensive features of natural and in vitro selected GNRA tetraloop-binding receptors Article de journal Nucleic Acids Res, 36 (4), p. 1138-52, 2008, (1362-4962 (Electronic) Journal Article Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S.). Résumé | BibTeX | Étiquettes: Acid, Adenine/chemistry, Analysis, Base, Conformation, Data, dimerization, directed, Evolution, KROL, Models, Molecular, Nucleic, RNA, RNA/*chemistry/classification, Sequence, Thermodynamics @article{, title = {Comprehensive features of natural and in vitro selected GNRA tetraloop-binding receptors}, author = { C. Geary and S. Baudrey and L. Jaeger}, year = {2008}, date = {2008-01-01}, journal = {Nucleic Acids Res}, volume = {36}, number = {4}, pages = {1138-52}, abstract = {Specific recognitions of GNRA tetraloops by small helical receptors are among the most widespread long-range packing interactions in large ribozymes. However, in contrast to GYRA and GAAA tetraloops, very few GNRA/receptor interactions have yet been identified to involve GGAA tetraloops in nature. A novel in vitro selection scheme based on a rigid self-assembling tectoRNA scaffold designed for isolation of intermolecular interactions with A-minor motifs has yielded new GGAA tetraloop-binding receptors with affinity in the nanomolar range. One of the selected receptors is a novel 12 nt RNA motif, (CCUGUG. AUCUGG), that recognizes GGAA tetraloop hairpin with a remarkable specificity and affinity. Its physical and chemical characteristics are comparable to those of the well-studied '11nt' GAAA tetraloop receptor motif. A second less specific motif (CCCAGCCC. GAUAGGG) binds GGRA tetraloops and appears to be related to group IC3 tetraloop receptors. Mutational, thermodynamic and comparative structural analysis suggests that natural and in vitro selected GNRA receptors can essentially be grouped in two major classes of GNRA binders. New insights about the evolution, recognition and structural modularity of GNRA and A-minor RNA-RNA interactions are proposed.}, note = {1362-4962 (Electronic) Journal Article Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S.}, keywords = {Acid, Adenine/chemistry, Analysis, Base, Conformation, Data, dimerization, directed, Evolution, KROL, Models, Molecular, Nucleic, RNA, RNA/*chemistry/classification, Sequence, Thermodynamics}, pubstate = {published}, tppubtype = {article} } Specific recognitions of GNRA tetraloops by small helical receptors are among the most widespread long-range packing interactions in large ribozymes. However, in contrast to GYRA and GAAA tetraloops, very few GNRA/receptor interactions have yet been identified to involve GGAA tetraloops in nature. A novel in vitro selection scheme based on a rigid self-assembling tectoRNA scaffold designed for isolation of intermolecular interactions with A-minor motifs has yielded new GGAA tetraloop-binding receptors with affinity in the nanomolar range. One of the selected receptors is a novel 12 nt RNA motif, (CCUGUG. AUCUGG), that recognizes GGAA tetraloop hairpin with a remarkable specificity and affinity. Its physical and chemical characteristics are comparable to those of the well-studied '11nt' GAAA tetraloop receptor motif. A second less specific motif (CCCAGCCC. GAUAGGG) binds GGRA tetraloops and appears to be related to group IC3 tetraloop receptors. Mutational, thermodynamic and comparative structural analysis suggests that natural and in vitro selected GNRA receptors can essentially be grouped in two major classes of GNRA binders. New insights about the evolution, recognition and structural modularity of GNRA and A-minor RNA-RNA interactions are proposed. |
2007 |
Ferrandon, Dominique Ubiquitin-proteasome: pallbearer carries the deceased to the grave Article de journal Immunity, 27 (4), p. 541–544, 2007, ISSN: 1074-7613. Résumé | Liens | BibTeX | Étiquettes: *Models, Animals, Apoptosis, Apoptosis/*physiology, ferrandon, Immunological, M3i, Macrophages, Macrophages/immunology/metabolism, Models, Phagocytosis, Phagocytosis/*physiology, Proteasome Endopeptidase Complex, Proteasome Endopeptidase Complex/*metabolism, ubiquitin, Ubiquitin/*metabolism @article{ferrandon_ubiquitin-proteasome:_2007b, title = {Ubiquitin-proteasome: pallbearer carries the deceased to the grave}, author = {Dominique Ferrandon}, doi = {10.1016/j.immuni.2007.10.003}, issn = {1074-7613}, year = {2007}, date = {2007-10-01}, journal = {Immunity}, volume = {27}, number = {4}, pages = {541--544}, abstract = {Phagocytosis is a complex process that involves multiple cellular functions. In this issue of Immunity, Silva et al. (2007) report that a protein ubiquitylation complex and the proteasome are required for the clearance of apoptotic cells in Drosophila.}, keywords = {*Models, Animals, Apoptosis, Apoptosis/*physiology, ferrandon, Immunological, M3i, Macrophages, Macrophages/immunology/metabolism, Models, Phagocytosis, Phagocytosis/*physiology, Proteasome Endopeptidase Complex, Proteasome Endopeptidase Complex/*metabolism, ubiquitin, Ubiquitin/*metabolism}, pubstate = {published}, tppubtype = {article} } Phagocytosis is a complex process that involves multiple cellular functions. In this issue of Immunity, Silva et al. (2007) report that a protein ubiquitylation complex and the proteasome are required for the clearance of apoptotic cells in Drosophila. |
Ferrandon, Dominique; Gottar, Marie; Gobert, Vanessa [New mechanism for detection of infections using the innate immune system of animals] Article de journal Med Sci (Paris), 23 (8-9), p. 707–709, 2007, ISSN: 0767-0974. Liens | BibTeX | Étiquettes: Animal, Animals, Drosophila/immunology, ferrandon, Gram-Positive Bacteria, Gram-Positive Bacteria/pathogenicity, Gram-Positive Bacterial Infections, Gram-Positive Bacterial Infections/immunology, Humans, Immune System, infection, Infection/*diagnosis/*immunology, M3i, Models @article{ferrandon_[new_2007b, title = {[New mechanism for detection of infections using the innate immune system of animals]}, author = {Dominique Ferrandon and Marie Gottar and Vanessa Gobert}, doi = {10.1051/medsci/20072389707}, issn = {0767-0974}, year = {2007}, date = {2007-09-01}, journal = {Med Sci (Paris)}, volume = {23}, number = {8-9}, pages = {707--709}, keywords = {Animal, Animals, Drosophila/immunology, ferrandon, Gram-Positive Bacteria, Gram-Positive Bacteria/pathogenicity, Gram-Positive Bacterial Infections, Gram-Positive Bacterial Infections/immunology, Humans, Immune System, infection, Infection/*diagnosis/*immunology, M3i, Models}, pubstate = {published}, tppubtype = {article} } |
2006 |
Gottar, Marie; Gobert, Vanessa; Matskevich, Alexey A; Reichhart, Jean-Marc; Wang, Chengshu; Butt, Tariq M; Belvin, Marcia; Hoffmann, Jules A; Ferrandon, Dominique Dual detection of fungal infections in Drosophila via recognition of glucans and sensing of virulence factors Article de journal Cell, 127 (7), p. 1425–1437, 2006, ISSN: 0092-8674. Résumé | Liens | BibTeX | Étiquettes: Animals, Antibody Formation, Beauveria, Candida albicans, Carrier Proteins, Cellular, ferrandon, Glucans, hoffmann, Immunity, Immunological, M3i, Metarhizium, Models, Polysaccharides, reichhart, Serine Endopeptidases, Signal Transduction, Virulence Factors @article{gottar_dual_2006, title = {Dual detection of fungal infections in Drosophila via recognition of glucans and sensing of virulence factors}, author = {Marie Gottar and Vanessa Gobert and Alexey A Matskevich and Jean-Marc Reichhart and Chengshu Wang and Tariq M Butt and Marcia Belvin and Jules A Hoffmann and Dominique Ferrandon}, doi = {10.1016/j.cell.2006.10.046}, issn = {0092-8674}, year = {2006}, date = {2006-12-01}, journal = {Cell}, volume = {127}, number = {7}, pages = {1425--1437}, abstract = {The Drosophila immune system discriminates between various types of infections and activates appropriate signal transduction pathways to combat the invading microorganisms. The Toll pathway is required for the host response against fungal and most Gram-positive bacterial infections. The sensing of Gram-positive bacteria is mediated by the pattern recognition receptors PGRP-SA and GNBP1 that cooperate to detect the presence of infections in the host. Here, we report that GNBP3 is a pattern recognition receptor that is required for the detection of fungal cell wall components. Strikingly, we find that there is a second, parallel pathway acting jointly with GNBP3. The Drosophila Persephone protease activates the Toll pathway when proteolytically matured by the secreted fungal virulence factor PR1. Thus, the detection of fungal infections in Drosophila relies both on the recognition of invariant microbial patterns and on monitoring the effects of virulence factors on the host.}, keywords = {Animals, Antibody Formation, Beauveria, Candida albicans, Carrier Proteins, Cellular, ferrandon, Glucans, hoffmann, Immunity, Immunological, M3i, Metarhizium, Models, Polysaccharides, reichhart, Serine Endopeptidases, Signal Transduction, Virulence Factors}, pubstate = {published}, tppubtype = {article} } The Drosophila immune system discriminates between various types of infections and activates appropriate signal transduction pathways to combat the invading microorganisms. The Toll pathway is required for the host response against fungal and most Gram-positive bacterial infections. The sensing of Gram-positive bacteria is mediated by the pattern recognition receptors PGRP-SA and GNBP1 that cooperate to detect the presence of infections in the host. Here, we report that GNBP3 is a pattern recognition receptor that is required for the detection of fungal cell wall components. Strikingly, we find that there is a second, parallel pathway acting jointly with GNBP3. The Drosophila Persephone protease activates the Toll pathway when proteolytically matured by the secreted fungal virulence factor PR1. Thus, the detection of fungal infections in Drosophila relies both on the recognition of invariant microbial patterns and on monitoring the effects of virulence factors on the host. |
Chen, Li-Ying; Wang, Juinn-Chin; Hyvert, Yann; Lin, Hui-Ping; Perrimon, Norbert; Imler, Jean-Luc; Hsu, Jui-Chou Weckle is a zinc finger adaptor of the toll pathway in dorsoventral patterning of the Drosophila embryo Article de journal Current biology: CB, 16 (12), p. 1183–1193, 2006, ISSN: 0960-9822. Résumé | Liens | BibTeX | Étiquettes: Adaptor Proteins, Animals, Antigens, Biological, Body Patterning, Cell Membrane, Differentiation, dimerization, DNA-Binding Proteins, Embryo, Epistasis, Genetic, imler, Immunity, Immunologic, Innate, M3i, Models, Mutation, Nonmammalian, Phenotype, Phosphoproteins, Receptors, Signal Transducing, Toll-Like Receptors, Transcription Factors, Zinc Fingers @article{chen_weckle_2006, title = {Weckle is a zinc finger adaptor of the toll pathway in dorsoventral patterning of the Drosophila embryo}, author = {Li-Ying Chen and Juinn-Chin Wang and Yann Hyvert and Hui-Ping Lin and Norbert Perrimon and Jean-Luc Imler and Jui-Chou Hsu}, doi = {10.1016/j.cub.2006.05.050}, issn = {0960-9822}, year = {2006}, date = {2006-06-01}, journal = {Current biology: CB}, volume = {16}, number = {12}, pages = {1183--1193}, abstract = {BACKGROUND: The Drosophila Toll pathway takes part in both establishment of the embryonic dorsoventral axis and induction of the innate immune response in adults. Upon activation by the cytokine Spätzle, Toll interacts with the adaptor proteins DmMyD88 and Tube and the kinase Pelle and triggers degradation of the inhibitor Cactus, thus allowing the nuclear translocation of the transcription factor Dorsal/Dif. weckle (wek) was previously identified as a new dorsal group gene that encodes a putative zinc finger transcription factor. However, its role in the Toll pathway was unknown. RESULTS: Here, we isolated new wek alleles and demonstrated that cactus is epistatic to wek, which in turn is epistatic to Toll. Consistent with this, Wek localizes to the plasma membrane of embryos, independently of Toll signaling. Wek homodimerizes and associates with Toll. Moreover, Wek binds to and localizes DmMyD88 to the plasma membrane. Thus, Wek acts as an adaptor to assemble/stabilize a Toll/Wek/DmMyD88/Tube complex. Remarkably, unlike the DmMyD88/tube/pelle/cactus gene cassette of the Toll pathway, wek plays a minimal role, if any, in the immune defense against Gram-positive bacteria and fungi. CONCLUSIONS: We conclude that Wek is an adaptor to link Toll and DmMyD88 and is required for efficient recruitment of DmMyD88 to Toll. Unexpectedly, wek is dispensable for innate immune response, thus revealing differences in the Toll-mediated activation of Dorsal in the embryo and Dif in the fat body of adult flies.}, keywords = {Adaptor Proteins, Animals, Antigens, Biological, Body Patterning, Cell Membrane, Differentiation, dimerization, DNA-Binding Proteins, Embryo, Epistasis, Genetic, imler, Immunity, Immunologic, Innate, M3i, Models, Mutation, Nonmammalian, Phenotype, Phosphoproteins, Receptors, Signal Transducing, Toll-Like Receptors, Transcription Factors, Zinc Fingers}, pubstate = {published}, tppubtype = {article} } BACKGROUND: The Drosophila Toll pathway takes part in both establishment of the embryonic dorsoventral axis and induction of the innate immune response in adults. Upon activation by the cytokine Spätzle, Toll interacts with the adaptor proteins DmMyD88 and Tube and the kinase Pelle and triggers degradation of the inhibitor Cactus, thus allowing the nuclear translocation of the transcription factor Dorsal/Dif. weckle (wek) was previously identified as a new dorsal group gene that encodes a putative zinc finger transcription factor. However, its role in the Toll pathway was unknown. RESULTS: Here, we isolated new wek alleles and demonstrated that cactus is epistatic to wek, which in turn is epistatic to Toll. Consistent with this, Wek localizes to the plasma membrane of embryos, independently of Toll signaling. Wek homodimerizes and associates with Toll. Moreover, Wek binds to and localizes DmMyD88 to the plasma membrane. Thus, Wek acts as an adaptor to assemble/stabilize a Toll/Wek/DmMyD88/Tube complex. Remarkably, unlike the DmMyD88/tube/pelle/cactus gene cassette of the Toll pathway, wek plays a minimal role, if any, in the immune defense against Gram-positive bacteria and fungi. CONCLUSIONS: We conclude that Wek is an adaptor to link Toll and DmMyD88 and is required for efficient recruitment of DmMyD88 to Toll. Unexpectedly, wek is dispensable for innate immune response, thus revealing differences in the Toll-mediated activation of Dorsal in the embryo and Dif in the fat body of adult flies. |
2005 |
Martinelli, Cosimo; Reichhart, Jean-Marc Evolution and integration of innate immune systems from fruit flies to man: lessons and questions Article de journal J. Endotoxin Res., 11 (4), p. 243–248, 2005, ISSN: 0968-0519. Résumé | Liens | BibTeX | Étiquettes: Animals, Biological Evolution, Cell Surface, Forecasting, Humans, Immunity, Immunological, Innate, M3i, Membrane Glycoproteins, Models, Receptors, reichhart, Signal Transduction, Toll-Like Receptor 5, Toll-Like Receptors @article{martinelli_evolution_2005, title = {Evolution and integration of innate immune systems from fruit flies to man: lessons and questions}, author = {Cosimo Martinelli and Jean-Marc Reichhart}, doi = {10.1179/096805105X37411}, issn = {0968-0519}, year = {2005}, date = {2005-01-01}, journal = {J. Endotoxin Res.}, volume = {11}, number = {4}, pages = {243--248}, abstract = {Despite broad differences in morphology, ecology and behavior, the fruit fly Drosophila melanogaster and humans show a remarkably high degree of conservation for many molecular, cellular, and developmental aspects of their biology. During the last decade, similarities have also been discovered in some of the mechanisms regulating their innate immune system. These parallels regard mainly the Toll-like receptor family and the intracellular signaling pathways involved in the control of the immune response. However, if the overall similarities are important, the detailed pathogen recognition mechanisms differ significantly between fly and humans, highlighting a complicated evolutionary history of the metazoan innate defenses. In this review, we will discuss the main similarities and differences between the two types of organisms. We hope that this current knowledge will be used as a starting point for a more comprehensive view of innate immunity within the broad variety of metazoan phyla.}, keywords = {Animals, Biological Evolution, Cell Surface, Forecasting, Humans, Immunity, Immunological, Innate, M3i, Membrane Glycoproteins, Models, Receptors, reichhart, Signal Transduction, Toll-Like Receptor 5, Toll-Like Receptors}, pubstate = {published}, tppubtype = {article} } Despite broad differences in morphology, ecology and behavior, the fruit fly Drosophila melanogaster and humans show a remarkably high degree of conservation for many molecular, cellular, and developmental aspects of their biology. During the last decade, similarities have also been discovered in some of the mechanisms regulating their innate immune system. These parallels regard mainly the Toll-like receptor family and the intracellular signaling pathways involved in the control of the immune response. However, if the overall similarities are important, the detailed pathogen recognition mechanisms differ significantly between fly and humans, highlighting a complicated evolutionary history of the metazoan innate defenses. In this review, we will discuss the main similarities and differences between the two types of organisms. We hope that this current knowledge will be used as a starting point for a more comprehensive view of innate immunity within the broad variety of metazoan phyla. |
2004 |
Leclerc, Vincent; Reichhart, Jean-Marc The immune response of Drosophila melanogaster Article de journal Immunol. Rev., 198 , p. 59–71, 2004, ISSN: 0105-2896. Résumé | BibTeX | Étiquettes: Animals, Cell Surface, Immunity, Immunological, Innate, M3i, Models, Receptors, reichhart, Signal Transduction, Toll-Like Receptors @article{leclerc_immune_2004, title = {The immune response of Drosophila melanogaster}, author = {Vincent Leclerc and Jean-Marc Reichhart}, issn = {0105-2896}, year = {2004}, date = {2004-04-01}, journal = {Immunol. Rev.}, volume = {198}, pages = {59--71}, abstract = {The response of the fruit fly Drosophila melanogaster to various microorganism infections relies on a multilayered defense. The epithelia constitute a first and efficient barrier. Innate immunity is activated when microorganisms succeed in entering the body cavity of the fly. Invading microorganisms are killed by the combined action of cellular and humoral processes. They are phagocytosed by specialized blood cells, surrounded by toxic melanin, or lysed by antibacterial peptides secreted into the hemolymph by fat body cells. During the last few years, research has focused on the mechanisms of microbial recognition by various pattern recognition receptors and of the subsequent induction of antimicrobial peptide expression. The cellular arm of the Drosophila innate immune system, which was somehow neglected, now constitutes the new frontier.}, keywords = {Animals, Cell Surface, Immunity, Immunological, Innate, M3i, Models, Receptors, reichhart, Signal Transduction, Toll-Like Receptors}, pubstate = {published}, tppubtype = {article} } The response of the fruit fly Drosophila melanogaster to various microorganism infections relies on a multilayered defense. The epithelia constitute a first and efficient barrier. Innate immunity is activated when microorganisms succeed in entering the body cavity of the fly. Invading microorganisms are killed by the combined action of cellular and humoral processes. They are phagocytosed by specialized blood cells, surrounded by toxic melanin, or lysed by antibacterial peptides secreted into the hemolymph by fat body cells. During the last few years, research has focused on the mechanisms of microbial recognition by various pattern recognition receptors and of the subsequent induction of antimicrobial peptide expression. The cellular arm of the Drosophila innate immune system, which was somehow neglected, now constitutes the new frontier. |
Burnouf, D Y; Olieric, V; Wagner, J; Fujii, S; Reinbolt, J; Fuchs, R P; Dumas, P Structural and biochemical analysis of sliding clamp/ligand interactions suggest a competition between replicative and translesion DNA polymerases Article de journal J Mol Biol, 335 (5), p. 1187-97, 2004, (0022-2836 Journal Article). Résumé | BibTeX | Étiquettes: *Binding, Antigen/metabolism, Bacterial/genetics, beta/*chemistry/genetics/*metabolism, Binding, Cell, coli/*enzymology, Competitive, Crystallization, DNA, DUMAS, Escherichia, Fragments/*metabolism, I/metabolism, III/metabolism, Kinetics, ligands, Models, Molecular, Nuclear, Peptide, Polymerase, Proliferating, Protein, Proteins/chemistry/metabolism, Recombinant, Replication/*genetics, Subunits @article{, title = {Structural and biochemical analysis of sliding clamp/ligand interactions suggest a competition between replicative and translesion DNA polymerases}, author = { D. Y. Burnouf and V. Olieric and J. Wagner and S. Fujii and J. Reinbolt and R. P. Fuchs and P. Dumas}, year = {2004}, date = {2004-01-01}, journal = {J Mol Biol}, volume = {335}, number = {5}, pages = {1187-97}, abstract = {Most DNA polymerases interact with their cognate processive replication factor through a small peptide, this interaction being absolutely required for their function in vivo. We have solved the crystal structure of a complex between the beta sliding clamp of Escherichia coli and the 16 residue C-terminal peptide of Pol IV (P16). The seven C-terminal residues bind to a pocket located at the surface of one beta monomer. This region was previously identified as the binding site of another beta clamp binding protein, the delta subunit of the gamma complex. We show that peptide P16 competitively prevents beta-clamp-mediated stimulation of both Pol IV and alpha subunit DNA polymerase activities, suggesting that the site of interaction of the alpha subunit with beta is identical with, or overlaps that of Pol IV. This common binding site for delta, Pol IV and alpha subunit is shown to be formed by residues that are highly conserved among many bacterial beta homologs, thus defining an evolutionarily conserved hydrophobic crevice for sliding clamp ligands and a new target for antibiotic drug design.}, note = {0022-2836 Journal Article}, keywords = {*Binding, Antigen/metabolism, Bacterial/genetics, beta/*chemistry/genetics/*metabolism, Binding, Cell, coli/*enzymology, Competitive, Crystallization, DNA, DUMAS, Escherichia, Fragments/*metabolism, I/metabolism, III/metabolism, Kinetics, ligands, Models, Molecular, Nuclear, Peptide, Polymerase, Proliferating, Protein, Proteins/chemistry/metabolism, Recombinant, Replication/*genetics, Subunits}, pubstate = {published}, tppubtype = {article} } Most DNA polymerases interact with their cognate processive replication factor through a small peptide, this interaction being absolutely required for their function in vivo. We have solved the crystal structure of a complex between the beta sliding clamp of Escherichia coli and the 16 residue C-terminal peptide of Pol IV (P16). The seven C-terminal residues bind to a pocket located at the surface of one beta monomer. This region was previously identified as the binding site of another beta clamp binding protein, the delta subunit of the gamma complex. We show that peptide P16 competitively prevents beta-clamp-mediated stimulation of both Pol IV and alpha subunit DNA polymerase activities, suggesting that the site of interaction of the alpha subunit with beta is identical with, or overlaps that of Pol IV. This common binding site for delta, Pol IV and alpha subunit is shown to be formed by residues that are highly conserved among many bacterial beta homologs, thus defining an evolutionarily conserved hydrophobic crevice for sliding clamp ligands and a new target for antibiotic drug design. |
Ferrandon, Dominique; Imler, Jean-Luc; Hoffmann, Jules A Sensing infection in Drosophila: Toll and beyond Article de journal Semin Immunol, 16 , p. 43–53, 2004, ISSN: 1044-5323. Résumé | BibTeX | Étiquettes: Animals, Carrier Proteins/chemistry/immunology/physiology, Cell Surface/immunology/*physiology, Drosophila Proteins/chemistry/immunology/*physiology, Drosophila/genetics/*immunology/microbiology, ferrandon, Fungi/immunology, Gene Expression Regulation, Gram-Negative Bacterial Infections/immunology, Gram-Positive Bacterial Infections/immunology, hoffmann, imler, Immunological, Insect Proteins/chemistry/immunology/physiology, M3i, Models, Non-U.S. Gov't, Receptors, Signal Transduction/immunology/physiology, Support @article{ferrandon_sensing_2004b, title = {Sensing infection in Drosophila: Toll and beyond}, author = {Dominique Ferrandon and Jean-Luc Imler and Jules A Hoffmann}, issn = {1044-5323}, year = {2004}, date = {2004-01-01}, journal = {Semin Immunol}, volume = {16}, pages = {43--53}, abstract = {Drosophila has evolved a potent immune system that is somewhat adapted to the nature of infections through the selective activation of either one of two NF-kappa B-like signalling pathways, the Toll and IMD (Immune deficiency) pathways. In contrast to the mammalian system, the Toll receptor does not act as a pattern recognition receptor (PRR) but as a cytokine receptor. The sensing of microbial infections is achieved by at least four PRRs that belong to two distinct families: the peptidoglycan recognition proteins (PGRPs) and the Gram-negative binding proteins (GNBPs)/beta-glucan recognition proteins (beta GRPs).}, keywords = {Animals, Carrier Proteins/chemistry/immunology/physiology, Cell Surface/immunology/*physiology, Drosophila Proteins/chemistry/immunology/*physiology, Drosophila/genetics/*immunology/microbiology, ferrandon, Fungi/immunology, Gene Expression Regulation, Gram-Negative Bacterial Infections/immunology, Gram-Positive Bacterial Infections/immunology, hoffmann, imler, Immunological, Insect Proteins/chemistry/immunology/physiology, M3i, Models, Non-U.S. Gov't, Receptors, Signal Transduction/immunology/physiology, Support}, pubstate = {published}, tppubtype = {article} } Drosophila has evolved a potent immune system that is somewhat adapted to the nature of infections through the selective activation of either one of two NF-kappa B-like signalling pathways, the Toll and IMD (Immune deficiency) pathways. In contrast to the mammalian system, the Toll receptor does not act as a pattern recognition receptor (PRR) but as a cytokine receptor. The sensing of microbial infections is achieved by at least four PRRs that belong to two distinct families: the peptidoglycan recognition proteins (PGRPs) and the Gram-negative binding proteins (GNBPs)/beta-glucan recognition proteins (beta GRPs). |
Blandin, Stephanie A; Shiao, Shin-Hong; Moita, Luis F; Janse, Chris J; Waters, Andrew P; Kafatos, Fotis C; Levashina, Elena A Complement-like protein TEP1 is a determinant of vectorial capacity in the malaria vector Anopheles gambiae Article de journal Cell, 116 (5), p. 661–670, 2004, ISSN: 0092-8674. Résumé | BibTeX | Étiquettes: Animals, Anopheles, blandin, Female, Genetic, Humans, Insect Proteins, Insect Vectors, M3i, Malaria, Models, Molecular, Plasmodium berghei, Polymorphism, Protein Structure, RNA, Sequence Alignment, Tertiary @article{blandin_complement-like_2004, title = {Complement-like protein TEP1 is a determinant of vectorial capacity in the malaria vector Anopheles gambiae}, author = {Stephanie A Blandin and Shin-Hong Shiao and Luis F Moita and Chris J Janse and Andrew P Waters and Fotis C Kafatos and Elena A Levashina}, issn = {0092-8674}, year = {2004}, date = {2004-01-01}, journal = {Cell}, volume = {116}, number = {5}, pages = {661--670}, abstract = {Anopheles mosquitoes are major vectors of human malaria in Africa. Large variation exists in the ability of mosquitoes to serve as vectors and to transmit malaria parasites, but the molecular mechanisms that determine vectorial capacity remain poorly understood. We report that the hemocyte-specific complement-like protein TEP1 from the mosquito Anopheles gambiae binds to and mediates killing of midgut stages of the rodent malaria parasite Plasmodium berghei. The dsRNA knockdown of TEP1 in adults completely abolishes melanotic refractoriness in a genetically selected refractory strain. Moreover, in susceptible mosquitoes this knockdown increases the number of developing parasites. Our results suggest that the TEP1-dependent parasite killing is followed by a TEP1-independent clearance of dead parasites by lysis and/or melanization. Further elucidation of the molecular mechanisms of TEP1-mediated parasite killing will be of great importance for our understanding of the principles of vectorial capacity in insects.}, keywords = {Animals, Anopheles, blandin, Female, Genetic, Humans, Insect Proteins, Insect Vectors, M3i, Malaria, Models, Molecular, Plasmodium berghei, Polymorphism, Protein Structure, RNA, Sequence Alignment, Tertiary}, pubstate = {published}, tppubtype = {article} } Anopheles mosquitoes are major vectors of human malaria in Africa. Large variation exists in the ability of mosquitoes to serve as vectors and to transmit malaria parasites, but the molecular mechanisms that determine vectorial capacity remain poorly understood. We report that the hemocyte-specific complement-like protein TEP1 from the mosquito Anopheles gambiae binds to and mediates killing of midgut stages of the rodent malaria parasite Plasmodium berghei. The dsRNA knockdown of TEP1 in adults completely abolishes melanotic refractoriness in a genetically selected refractory strain. Moreover, in susceptible mosquitoes this knockdown increases the number of developing parasites. Our results suggest that the TEP1-dependent parasite killing is followed by a TEP1-independent clearance of dead parasites by lysis and/or melanization. Further elucidation of the molecular mechanisms of TEP1-mediated parasite killing will be of great importance for our understanding of the principles of vectorial capacity in insects. |
2003 |
Luna, C; Hoa, N T; Zhang, J; Kanzok, S M; Brown, S E; Imler, Jean-Luc; Knudson, D L; Zheng, L Characterization of three Toll-like genes from mosquito Aedes aegypti Article de journal Insect Molecular Biology, 12 (1), p. 67–74, 2003, ISSN: 0962-1075. Résumé | BibTeX | Étiquettes: Aedes, Animals, Base Sequence, Cell Surface, Chimera, Cloning, Developmental, Female, Gene Expression Regulation, Genetic, imler, Insect Proteins, M3i, Male, messenger, Models, Molecular, Mutagenesis, Promoter Regions, Receptors, Reverse Transcriptase Polymerase Chain Reaction, RNA, Sequence Alignment, Signal Transduction, Site-Directed, Transfection @article{luna_characterization_2003, title = {Characterization of three Toll-like genes from mosquito Aedes aegypti}, author = {C Luna and N T Hoa and J Zhang and S M Kanzok and S E Brown and Jean-Luc Imler and D L Knudson and L Zheng}, issn = {0962-1075}, year = {2003}, date = {2003-02-01}, journal = {Insect Molecular Biology}, volume = {12}, number = {1}, pages = {67--74}, abstract = {Three Toll-related genes (AeToll1A, AeToll1B and AeToll5) were cloned and characterized from the yellow fever vector mosquito, Aedes aegypti. All three genes exhibited high levels of amino acid sequence similarity with Drosophila melanogaster (Dm)Toll1 and DmTehao (Toll5). AeToll1A and AeToll1B are 1124 and 1076 amino acid residues long, respectively. Both contain a carboxyl extension downstream of the Toll/interleukin-1 receptor (TIR) domain. AeToll5 is 1007 residues long and, like DmTehao, lacks the carboxyl terminal extension. Expression of these three genes was examined throughout development and after immune challenge. Both AeToll1A and AeToll5, like their Drosophila counterparts, activate transcription of drosomycin promoter in both Aedes and Drosophila cell lines. Deletion of the carboxyl extension of AeToll1A did not result in a further elevated level of the antifungal response. The intracellular signalling process appears to be species specific based on two observations. (1) DmToll is completely inactive in an Aedes cell line, suggesting a higher specificity requirement for DmToll in the intracellular signalling process. (2) Only one of three amino acid residues essential for DmToll function is required for AeToll1A function.}, keywords = {Aedes, Animals, Base Sequence, Cell Surface, Chimera, Cloning, Developmental, Female, Gene Expression Regulation, Genetic, imler, Insect Proteins, M3i, Male, messenger, Models, Molecular, Mutagenesis, Promoter Regions, Receptors, Reverse Transcriptase Polymerase Chain Reaction, RNA, Sequence Alignment, Signal Transduction, Site-Directed, Transfection}, pubstate = {published}, tppubtype = {article} } Three Toll-related genes (AeToll1A, AeToll1B and AeToll5) were cloned and characterized from the yellow fever vector mosquito, Aedes aegypti. All three genes exhibited high levels of amino acid sequence similarity with Drosophila melanogaster (Dm)Toll1 and DmTehao (Toll5). AeToll1A and AeToll1B are 1124 and 1076 amino acid residues long, respectively. Both contain a carboxyl extension downstream of the Toll/interleukin-1 receptor (TIR) domain. AeToll5 is 1007 residues long and, like DmTehao, lacks the carboxyl terminal extension. Expression of these three genes was examined throughout development and after immune challenge. Both AeToll1A and AeToll5, like their Drosophila counterparts, activate transcription of drosomycin promoter in both Aedes and Drosophila cell lines. Deletion of the carboxyl extension of AeToll1A did not result in a further elevated level of the antifungal response. The intracellular signalling process appears to be species specific based on two observations. (1) DmToll is completely inactive in an Aedes cell line, suggesting a higher specificity requirement for DmToll in the intracellular signalling process. (2) Only one of three amino acid residues essential for DmToll function is required for AeToll1A function. |
Imler, Jean-Luc; Hoffmann, Jules A Toll signaling: the TIReless quest for specificity Article de journal Nature Immunology, 4 (2), p. 105–106, 2003, ISSN: 1529-2908. Liens | BibTeX | Étiquettes: Animals, Cell Surface, Dendritic Cells, hoffmann, Humans, imler, Immunological, Interferon-beta, M3i, Membrane Glycoproteins, Mice, Models, Protein Structure, Receptors, Signal Transduction, Tertiary, Toll-Like Receptors @article{imler_toll_2003, title = {Toll signaling: the TIReless quest for specificity}, author = {Jean-Luc Imler and Jules A Hoffmann}, doi = {10.1038/ni0203-105}, issn = {1529-2908}, year = {2003}, date = {2003-02-01}, journal = {Nature Immunology}, volume = {4}, number = {2}, pages = {105--106}, keywords = {Animals, Cell Surface, Dendritic Cells, hoffmann, Humans, imler, Immunological, Interferon-beta, M3i, Membrane Glycoproteins, Mice, Models, Protein Structure, Receptors, Signal Transduction, Tertiary, Toll-Like Receptors}, pubstate = {published}, tppubtype = {article} } |
Heyman, T; Wilhelm, M; Wilhelm, F X The central PPT of the yeast retrotransposon Ty1 is not essential for transposition Article de journal J Mol Biol, 331 (2), p. 315-20, 2003, (0022-2836 Journal Article). Résumé | BibTeX | Étiquettes: Base, cerevisiae/genetics, Data, DNA/*biosynthesis, Genetic, Gov't, Models, Molecular, Mutation, Non-U.S., Purines/*chemistry, Retroelements/*genetics, Saccharomyces, Sequence, Support @article{, title = {The central PPT of the yeast retrotransposon Ty1 is not essential for transposition}, author = { T. Heyman and M. Wilhelm and F. X. Wilhelm}, year = {2003}, date = {2003-01-01}, journal = {J Mol Biol}, volume = {331}, number = {2}, pages = {315-20}, abstract = {The yeast retrotransposon Ty1 has structural and functional similarities to retroviruses. We report here that, as in retroviruses, the plus-strand DNA of Ty1 is synthesized as two segments. A central DNA flap is formed during reverse transcription consecutive to elongation (with strand displacement) of the upstream segment beyond the central polypurine tract (cPPT) until the replication machinery is stopped at the central termination sequence. Comparison of wild-type and cPPT-mutant Ty1 elements shows that the mutant element lacking the central DNA flap is only twofold defective in transposition.}, note = {0022-2836 Journal Article}, keywords = {Base, cerevisiae/genetics, Data, DNA/*biosynthesis, Genetic, Gov't, Models, Molecular, Mutation, Non-U.S., Purines/*chemistry, Retroelements/*genetics, Saccharomyces, Sequence, Support}, pubstate = {published}, tppubtype = {article} } The yeast retrotransposon Ty1 has structural and functional similarities to retroviruses. We report here that, as in retroviruses, the plus-strand DNA of Ty1 is synthesized as two segments. A central DNA flap is formed during reverse transcription consecutive to elongation (with strand displacement) of the upstream segment beyond the central polypurine tract (cPPT) until the replication machinery is stopped at the central termination sequence. Comparison of wild-type and cPPT-mutant Ty1 elements shows that the mutant element lacking the central DNA flap is only twofold defective in transposition. |
Wilhelm, F X; Wilhelm, M; Gabriel, A Extension and cleavage of the polypurine tract plus-strand primer by Ty1 reverse transcriptase Article de journal J Biol Chem, 278 (48), p. 47678-84, 2003, (0021-9258 Journal Article). Résumé | BibTeX | Étiquettes: Base, Calf, Data, DNA, DNA/chemistry, Genetic, Gov't, H, Messenger/metabolism, Models, Molecular, Non-U.S., P.H.S., Polymerase/*chemistry, Primers, Proteins/chemistry, Purines/*chemistry, Recombinant, Replication, Retroelements/*genetics, Ribonuclease, RNA, RNA-Directed, RNA/chemistry, Sequence, Support, Templates, Thymus/chemistry, U.S., Viral @article{, title = {Extension and cleavage of the polypurine tract plus-strand primer by Ty1 reverse transcriptase}, author = { F. X. Wilhelm and M. Wilhelm and A. Gabriel}, year = {2003}, date = {2003-01-01}, journal = {J Biol Chem}, volume = {278}, number = {48}, pages = {47678-84}, abstract = {Using hybrid RNA/DNA substrates containing the polypurine tract (PPT) plus-strand primer, we have examined the interaction between the Ty1 reverse transcriptase (RT) and the plus-strand initiation complex. We show here that, although the PPT sequence is relatively resistant to RNase H cleavage, it can be cleaved internally by the polymerase-independent RNase H activity of Ty1 RT. Alternatively, this PPT can be used to initiate plus-strand DNA synthesis. We demonstrate that cleavage at the PPT/DNA junction occurs only after at least 9 nucleotides are extended. Cleavage leaves a nick between the RNA primer and the nascent plus-strand DNA. We show that Ty1 RT has a strand displacement activity beyond a gap but that the PPT is not efficiently re-utilized in vitro for another round of DNA synthesis after a first plus-strand DNA has been synthesized and cleaved at the PPT/U3 junction.}, note = {0021-9258 Journal Article}, keywords = {Base, Calf, Data, DNA, DNA/chemistry, Genetic, Gov't, H, Messenger/metabolism, Models, Molecular, Non-U.S., P.H.S., Polymerase/*chemistry, Primers, Proteins/chemistry, Purines/*chemistry, Recombinant, Replication, Retroelements/*genetics, Ribonuclease, RNA, RNA-Directed, RNA/chemistry, Sequence, Support, Templates, Thymus/chemistry, U.S., Viral}, pubstate = {published}, tppubtype = {article} } Using hybrid RNA/DNA substrates containing the polypurine tract (PPT) plus-strand primer, we have examined the interaction between the Ty1 reverse transcriptase (RT) and the plus-strand initiation complex. We show here that, although the PPT sequence is relatively resistant to RNase H cleavage, it can be cleaved internally by the polymerase-independent RNase H activity of Ty1 RT. Alternatively, this PPT can be used to initiate plus-strand DNA synthesis. We demonstrate that cleavage at the PPT/DNA junction occurs only after at least 9 nucleotides are extended. Cleavage leaves a nick between the RNA primer and the nascent plus-strand DNA. We show that Ty1 RT has a strand displacement activity beyond a gap but that the PPT is not efficiently re-utilized in vitro for another round of DNA synthesis after a first plus-strand DNA has been synthesized and cleaved at the PPT/U3 junction. |
2002 |
Hoffmann, Jules A; Reichhart, Jean-Marc Drosophila innate immunity: an evolutionary perspective Article de journal Nat. Immunol., 3 (2), p. 121–126, 2002, ISSN: 1529-2908. Résumé | Liens | BibTeX | Étiquettes: Animals, Biological Evolution, Cell Surface, hoffmann, Immunity, Immunological, Innate, M3i, Membrane Glycoproteins, Models, Receptors, reichhart, Signal Transduction, Toll-Like Receptors @article{hoffmann_drosophila_2002, title = {Drosophila innate immunity: an evolutionary perspective}, author = {Jules A Hoffmann and Jean-Marc Reichhart}, doi = {10.1038/ni0202-121}, issn = {1529-2908}, year = {2002}, date = {2002-02-01}, journal = {Nat. Immunol.}, volume = {3}, number = {2}, pages = {121--126}, abstract = {In response to microbial infections, Drosophila mounts a multifaceted immune response involving humoral reactions that culminate in the destruction of invading organisms by lytic peptides. These defense mechanisms are activated via two distinct signaling pathways. One of these, the Toll pathway, controls resistance to fungal and Gram-positive bacterial infections, whereas the Imd pathway is responsible for defense against Gram-negative bacterial infections. Current evidence indicates that recognition of infectious nonself agents results from interactions between microbial wall components and extracellular pattern recognition proteins. We discuss here evolutionary perspectives on our present understanding of the antimicrobial defenses of Drosophila.}, keywords = {Animals, Biological Evolution, Cell Surface, hoffmann, Immunity, Immunological, Innate, M3i, Membrane Glycoproteins, Models, Receptors, reichhart, Signal Transduction, Toll-Like Receptors}, pubstate = {published}, tppubtype = {article} } In response to microbial infections, Drosophila mounts a multifaceted immune response involving humoral reactions that culminate in the destruction of invading organisms by lytic peptides. These defense mechanisms are activated via two distinct signaling pathways. One of these, the Toll pathway, controls resistance to fungal and Gram-positive bacterial infections, whereas the Imd pathway is responsible for defense against Gram-negative bacterial infections. Current evidence indicates that recognition of infectious nonself agents results from interactions between microbial wall components and extracellular pattern recognition proteins. We discuss here evolutionary perspectives on our present understanding of the antimicrobial defenses of Drosophila. |
Perederina, A; Nevskaya, N; Nikonov, O; Nikulin, A; Dumas, P; Yao, M; Tanaka, I; Garber, M; Gongadze, G; Nikonov, S Detailed analysis of RNA-protein interactions within the bacterial ribosomal protein L5/5S rRNA complex Article de journal RNA, 8 (12), p. 1548-57, 2002, (1355-8382 Journal Article). Résumé | BibTeX | Étiquettes: 5S/*chemistry/*metabolism, Acid, Amino, Bacterial, Base, Binding, Bonding, coli/genetics, Conformation, Data, Escherichia, Fragments/chemistry/metabolism, Gov't, Hydrogen, Models, Molecular, Non-U.S., Nucleic, Peptide, Protein, Proteins/*chemistry/*metabolism, Proteins/chemistry/metabolism, Ribosomal, RNA, Sequence, Sites, Support @article{, title = {Detailed analysis of RNA-protein interactions within the bacterial ribosomal protein L5/5S rRNA complex}, author = { A. Perederina and N. Nevskaya and O. Nikonov and A. Nikulin and P. Dumas and M. Yao and I. Tanaka and M. Garber and G. Gongadze and S. Nikonov}, year = {2002}, date = {2002-01-01}, journal = {RNA}, volume = {8}, number = {12}, pages = {1548-57}, abstract = {The crystal structure of ribosomal protein L5 from Thermus thermophilus complexed with a 34-nt fragment comprising helix III and loop C of Escherichia coli 5S rRNA has been determined at 2.5 A resolution. The protein specifically interacts with the bulged nucleotides at the top of loop C of 5S rRNA. The rRNA and protein contact surfaces are strongly stabilized by intramolecular interactions. Charged and polar atoms forming the network of conserved intermolecular hydrogen bonds are located in two narrow planar parallel layers belonging to the protein and rRNA, respectively. The regions, including these atoms conserved in Bacteria and Archaea, can be considered an RNA-protein recognition module. Comparison of the T. thermophilus L5 structure in the RNA-bound form with the isolated Bacillus stearothermophilus L5 structure shows that the RNA-recognition module on the protein surface does not undergo significant changes upon RNA binding. In the crystal of the complex, the protein interacts with another RNA molecule in the asymmetric unit through the beta-sheet concave surface. This protein/RNA interface simulates the interaction of L5 with 23S rRNA observed in the Haloarcula marismortui 50S ribosomal subunit.}, note = {1355-8382 Journal Article}, keywords = {5S/*chemistry/*metabolism, Acid, Amino, Bacterial, Base, Binding, Bonding, coli/genetics, Conformation, Data, Escherichia, Fragments/chemistry/metabolism, Gov't, Hydrogen, Models, Molecular, Non-U.S., Nucleic, Peptide, Protein, Proteins/*chemistry/*metabolism, Proteins/chemistry/metabolism, Ribosomal, RNA, Sequence, Sites, Support}, pubstate = {published}, tppubtype = {article} } The crystal structure of ribosomal protein L5 from Thermus thermophilus complexed with a 34-nt fragment comprising helix III and loop C of Escherichia coli 5S rRNA has been determined at 2.5 A resolution. The protein specifically interacts with the bulged nucleotides at the top of loop C of 5S rRNA. The rRNA and protein contact surfaces are strongly stabilized by intramolecular interactions. Charged and polar atoms forming the network of conserved intermolecular hydrogen bonds are located in two narrow planar parallel layers belonging to the protein and rRNA, respectively. The regions, including these atoms conserved in Bacteria and Archaea, can be considered an RNA-protein recognition module. Comparison of the T. thermophilus L5 structure in the RNA-bound form with the isolated Bacillus stearothermophilus L5 structure shows that the RNA-recognition module on the protein surface does not undergo significant changes upon RNA binding. In the crystal of the complex, the protein interacts with another RNA molecule in the asymmetric unit through the beta-sheet concave surface. This protein/RNA interface simulates the interaction of L5 with 23S rRNA observed in the Haloarcula marismortui 50S ribosomal subunit. |
2000 |
Imler, Jean-Luc; Tauszig, Servane; Jouanguy, Emmanuelle; Forestier, C; Hoffmann, Jules A LPS-induced immune response in Drosophila Article de journal Journal of Endotoxin Research, 6 (6), p. 459–462, 2000, ISSN: 0968-0519. Résumé | BibTeX | Étiquettes: Animals, Biological, Cell Line, Cell Surface, Defensins, Genes, Genetic, hoffmann, imler, Insect, Insect Proteins, Lipopolysaccharides, M3i, Membrane Glycoproteins, Models, Mutation, Promoter Regions, Receptors, Signal Transduction, Toll-Like Receptors @article{imler_lps-induced_2000, title = {LPS-induced immune response in Drosophila}, author = {Jean-Luc Imler and Servane Tauszig and Emmanuelle Jouanguy and C Forestier and Jules A Hoffmann}, issn = {0968-0519}, year = {2000}, date = {2000-01-01}, journal = {Journal of Endotoxin Research}, volume = {6}, number = {6}, pages = {459--462}, abstract = {The study of the regulation of the inducible synthesis of antimicrobial peptides in Drosophila melanogaster has established this insect as a powerful model in which to study innate immunity. In particular, the molecular characterization of the regulatory pathway controlling the antifungal peptide drosomycin has revealed the importance of Toll receptors in innate immunity. We report here that injection of LPS into flies induces an immune response, suggesting that LPS receptors are used in Drosophila to detect Gram-negative bacteria infection. We have identified in the recently sequenced genome of Drosophila eight genes coding for Toll-like receptors in addition to Toll, which may function as LPS receptors. However, overexpression of a selection of these genes in tissue-culture cells does not result in up-regulation of the antibacterial peptide genes. These results are discussed in light of the recent data from genetic screens aimed at identifying the genes controlling the antibacterial response in Drosophila.}, keywords = {Animals, Biological, Cell Line, Cell Surface, Defensins, Genes, Genetic, hoffmann, imler, Insect, Insect Proteins, Lipopolysaccharides, M3i, Membrane Glycoproteins, Models, Mutation, Promoter Regions, Receptors, Signal Transduction, Toll-Like Receptors}, pubstate = {published}, tppubtype = {article} } The study of the regulation of the inducible synthesis of antimicrobial peptides in Drosophila melanogaster has established this insect as a powerful model in which to study innate immunity. In particular, the molecular characterization of the regulatory pathway controlling the antifungal peptide drosomycin has revealed the importance of Toll receptors in innate immunity. We report here that injection of LPS into flies induces an immune response, suggesting that LPS receptors are used in Drosophila to detect Gram-negative bacteria infection. We have identified in the recently sequenced genome of Drosophila eight genes coding for Toll-like receptors in addition to Toll, which may function as LPS receptors. However, overexpression of a selection of these genes in tissue-culture cells does not result in up-regulation of the antibacterial peptide genes. These results are discussed in light of the recent data from genetic screens aimed at identifying the genes controlling the antibacterial response in Drosophila. |
1999 |
Hoffmann, Jules A; Kafatos, Fotis C; Janeway, Charles A; Ezekowitz, Alan R B Phylogenetic perspectives in innate immunity Article de journal Science, 284 (5418), p. 1313–1318, 1999, ISSN: 0036-8075. Résumé | BibTeX | Étiquettes: Active, Animals, Culicidae, hoffmann, Humans, Immunity, Immunological, infection, Innate, Insect Vectors, M3i, Mammals, Models, Phagocytosis, Phylogeny, Proteins @article{hoffmann_phylogenetic_1999, title = {Phylogenetic perspectives in innate immunity}, author = {Jules A Hoffmann and Fotis C Kafatos and Charles A Janeway and Alan R B Ezekowitz}, issn = {0036-8075}, year = {1999}, date = {1999-05-01}, journal = {Science}, volume = {284}, number = {5418}, pages = {1313--1318}, abstract = {The concept of innate immunity refers to the first-line host defense that serves to limit infection in the early hours after exposure to microorganisms. Recent data have highlighted similarities between pathogen recognition, signaling pathways, and effector mechanisms of innate immunity in Drosophila and mammals, pointing to a common ancestry of these defenses. In addition to its role in the early phase of defense, innate immunity in mammals appears to play a key role in stimulating the subsequent, clonal response of adaptive immunity.}, keywords = {Active, Animals, Culicidae, hoffmann, Humans, Immunity, Immunological, infection, Innate, Insect Vectors, M3i, Mammals, Models, Phagocytosis, Phylogeny, Proteins}, pubstate = {published}, tppubtype = {article} } The concept of innate immunity refers to the first-line host defense that serves to limit infection in the early hours after exposure to microorganisms. Recent data have highlighted similarities between pathogen recognition, signaling pathways, and effector mechanisms of innate immunity in Drosophila and mammals, pointing to a common ancestry of these defenses. In addition to its role in the early phase of defense, innate immunity in mammals appears to play a key role in stimulating the subsequent, clonal response of adaptive immunity. |
1998 |
Bergdoll, M; Eltis, L D; Cameron, A D; Dumas, P; Bolin, J T All in the family: structural and evolutionary relationships among three modular proteins with diverse functions and variable assembly Article de journal Protein Sci, 7 (8), p. 1661-70, 1998, (0961-8368 Journal Article). Résumé | BibTeX | Étiquettes: *Acetyltransferases, *Evolution, Acid, Amino, Bacterial, Burkholderia/*chemistry, Crystallography, Data, Genetic, Gov't, Homology, Human, Lactoylglutathione, Lyase/*chemistry, Models, Molecular, Non-U.S., Oxygenases/chemistry, P.H.S., Phylogeny, Protein, Proteins/*chemistry, Secondary, Sequence, structure, Support, U.S., X-Ray @article{, title = {All in the family: structural and evolutionary relationships among three modular proteins with diverse functions and variable assembly}, author = { M. Bergdoll and L. D. Eltis and A. D. Cameron and P. Dumas and J. T. Bolin}, year = {1998}, date = {1998-01-01}, journal = {Protein Sci}, volume = {7}, number = {8}, pages = {1661-70}, abstract = {The crystal structures of three proteins of diverse function and low sequence similarity were analyzed to evaluate structural and evolutionary relationships. The proteins include a bacterial bleomycin resistance protein, a bacterial extradiol dioxygenase, and human glyoxalase I. Structural comparisons, as well as phylogenetic analyses, strongly indicate that the modern family of proteins represented by these structures arose through a rich evolutionary history that includes multiple gene duplication and fusion events. These events appear to be historically shared in some cases, but parallel and historically independent in others. A significant early event is proposed to be the establishment of metal-binding in an oligomeric ancestor prior to the first gene fusion. Variations in the spatial arrangements of homologous modules are observed that are consistent with the structural principles of three-dimensional domain swapping, but in the unusual context of the formation of larger monomers from smaller dimers or tetramers. The comparisons support a general mechanism for metalloprotein evolution that exploits the symmetry of a homooligomeric protein to originate a metal binding site and relies upon the relaxation of symmetry, as enabled by gene duplication, to establish and refine specific functions.}, note = {0961-8368 Journal Article}, keywords = {*Acetyltransferases, *Evolution, Acid, Amino, Bacterial, Burkholderia/*chemistry, Crystallography, Data, Genetic, Gov't, Homology, Human, Lactoylglutathione, Lyase/*chemistry, Models, Molecular, Non-U.S., Oxygenases/chemistry, P.H.S., Phylogeny, Protein, Proteins/*chemistry, Secondary, Sequence, structure, Support, U.S., X-Ray}, pubstate = {published}, tppubtype = {article} } The crystal structures of three proteins of diverse function and low sequence similarity were analyzed to evaluate structural and evolutionary relationships. The proteins include a bacterial bleomycin resistance protein, a bacterial extradiol dioxygenase, and human glyoxalase I. Structural comparisons, as well as phylogenetic analyses, strongly indicate that the modern family of proteins represented by these structures arose through a rich evolutionary history that includes multiple gene duplication and fusion events. These events appear to be historically shared in some cases, but parallel and historically independent in others. A significant early event is proposed to be the establishment of metal-binding in an oligomeric ancestor prior to the first gene fusion. Variations in the spatial arrangements of homologous modules are observed that are consistent with the structural principles of three-dimensional domain swapping, but in the unusual context of the formation of larger monomers from smaller dimers or tetramers. The comparisons support a general mechanism for metalloprotein evolution that exploits the symmetry of a homooligomeric protein to originate a metal binding site and relies upon the relaxation of symmetry, as enabled by gene duplication, to establish and refine specific functions. |
1997 |
Meister, Marie; Lemaitre, Bruno; Hoffmann, Jules A Antimicrobial peptide defense in Drosophila Article de journal Bioessays, 19 (11), p. 1019–1026, 1997, ISSN: 0265-9247. Résumé | Liens | BibTeX | Étiquettes: Animals, Anti-Infective Agents, Gene Expression Regulation, Genetic, hoffmann, Insect Proteins, M3i, Models, Peptides, Promoter Regions, Signal Transduction @article{meister_antimicrobial_1997, title = {Antimicrobial peptide defense in Drosophila}, author = {Marie Meister and Bruno Lemaitre and Jules A Hoffmann}, doi = {10.1002/bies.950191112}, issn = {0265-9247}, year = {1997}, date = {1997-11-01}, journal = {Bioessays}, volume = {19}, number = {11}, pages = {1019--1026}, abstract = {Drosophila responds to a septic injury by the rapid synthesis of antimicrobial peptides. These molecules are predominantly produced by the fat body, a functional equivalent of mammalian liver, and are secreted into the hemolymph where their concentrations can reach up to 100 microM. Six distinct antibacterial peptides (plus isoforms) and one antifungal peptide have been characterized in Drosophila and their genes cloned. The induction of the gene encoding the antifungal peptide relies on the spätzle/Toll/cactus gene cassette, which is involved in the control of dorsoventral patterning in the embryo, and shows interesting structural and functional similarities with cytokine-induced activation of NF-kappa B in mammalian cells. An additional pathway, dependent on the as yet unidentified imd (for immune-deficiency) gene, is required for the full induction of the antibacterial peptide genes. Mutants deficient for the Toll and imd pathways exhibit a severely reduced survival to fungal and bacterial infections, respectively. Recent data on the molecular mechanisms underlying recognition of non-self are also discussed in this review.}, keywords = {Animals, Anti-Infective Agents, Gene Expression Regulation, Genetic, hoffmann, Insect Proteins, M3i, Models, Peptides, Promoter Regions, Signal Transduction}, pubstate = {published}, tppubtype = {article} } Drosophila responds to a septic injury by the rapid synthesis of antimicrobial peptides. These molecules are predominantly produced by the fat body, a functional equivalent of mammalian liver, and are secreted into the hemolymph where their concentrations can reach up to 100 microM. Six distinct antibacterial peptides (plus isoforms) and one antifungal peptide have been characterized in Drosophila and their genes cloned. The induction of the gene encoding the antifungal peptide relies on the spätzle/Toll/cactus gene cassette, which is involved in the control of dorsoventral patterning in the embryo, and shows interesting structural and functional similarities with cytokine-induced activation of NF-kappa B in mammalian cells. An additional pathway, dependent on the as yet unidentified imd (for immune-deficiency) gene, is required for the full induction of the antibacterial peptide genes. Mutants deficient for the Toll and imd pathways exhibit a severely reduced survival to fungal and bacterial infections, respectively. Recent data on the molecular mechanisms underlying recognition of non-self are also discussed in this review. |
Bergdoll, M; Remy, M H; Cagnon, C; Masson, J M; Dumas, P Proline-dependent oligomerization with arm exchange Article de journal Structure, 5 (3), p. 391-401, 1997, (0969-2126 Journal Article). Résumé | BibTeX | Étiquettes: *Acetyltransferases, *Dimerization, *Protein, Acid, Alignment, Amino, Aminotransferases/chemistry, Animals, Aspartate, ATPase/chemistry, Bacterial, Binding, Cattle, Chickens, Comparative, Conformation, Data, Folding, Heart/enzymology, Human, mitochondria, Models, Molecular, Mutagenesis, Na(+)-K(+)-Exchanging, Pancreatic/chemistry, Plant, Proline/*physiology, Protein, Proteins/chemistry, Pyrophosphatases/chemistry, Ribonuclease, Sequence, Site-Directed, Structural, Study, Viral, Viruses/chemistry @article{, title = {Proline-dependent oligomerization with arm exchange}, author = { M. Bergdoll and M. H. Remy and C. Cagnon and J. M. Masson and P. Dumas}, year = {1997}, date = {1997-01-01}, journal = {Structure}, volume = {5}, number = {3}, pages = {391-401}, abstract = {BACKGROUND: Oligomerization is often necessary for protein activity or regulation and its efficiency is fundamental for the cell. The quaternary structure of a large number of oligomers consists of protomers tightly anchored to each other by exchanged arms or swapped domains. However, nothing is known about how the arms can be kept in a favourable conformation before such an oligomerization. RESULTS: Upon examination of such quaternary structures, we observe an extremely frequent occurrence of proline residues at the point where the arm leaves the protomer. Sequence alignment and site-directed mutagenesis confirm the importance of these prolines. The conservation of these residues at the hinge regions can be explained by the constraints that they impose on polypeptide conformation and dynamics: by rigidifying the mainchain, prolines favour extended conformations of arms thus favouring oligomerization, and may prevent interaction of the arms with the core of the protomer. CONCLUSIONS: Hinge prolines can be considered as 'quaternary structure helpers'. The presence of a proline should be considered when searching for a determinant of oligomerization with arm exchange and could be used to engineer synthetic oligomers or to displace a monomers to oligomers equilibrium by mutation of this proline residue.}, note = {0969-2126 Journal Article}, keywords = {*Acetyltransferases, *Dimerization, *Protein, Acid, Alignment, Amino, Aminotransferases/chemistry, Animals, Aspartate, ATPase/chemistry, Bacterial, Binding, Cattle, Chickens, Comparative, Conformation, Data, Folding, Heart/enzymology, Human, mitochondria, Models, Molecular, Mutagenesis, Na(+)-K(+)-Exchanging, Pancreatic/chemistry, Plant, Proline/*physiology, Protein, Proteins/chemistry, Pyrophosphatases/chemistry, Ribonuclease, Sequence, Site-Directed, Structural, Study, Viral, Viruses/chemistry}, pubstate = {published}, tppubtype = {article} } BACKGROUND: Oligomerization is often necessary for protein activity or regulation and its efficiency is fundamental for the cell. The quaternary structure of a large number of oligomers consists of protomers tightly anchored to each other by exchanged arms or swapped domains. However, nothing is known about how the arms can be kept in a favourable conformation before such an oligomerization. RESULTS: Upon examination of such quaternary structures, we observe an extremely frequent occurrence of proline residues at the point where the arm leaves the protomer. Sequence alignment and site-directed mutagenesis confirm the importance of these prolines. The conservation of these residues at the hinge regions can be explained by the constraints that they impose on polypeptide conformation and dynamics: by rigidifying the mainchain, prolines favour extended conformations of arms thus favouring oligomerization, and may prevent interaction of the arms with the core of the protomer. CONCLUSIONS: Hinge prolines can be considered as 'quaternary structure helpers'. The presence of a proline should be considered when searching for a determinant of oligomerization with arm exchange and could be used to engineer synthetic oligomers or to displace a monomers to oligomers equilibrium by mutation of this proline residue. |
1996 |
Hoffmann, Jules A; Reichhart, Jean-Marc; Hetru, Charles Innate immunity in higher insects Article de journal Curr. Opin. Immunol., 8 (1), p. 8–13, 1996, ISSN: 0952-7915. Résumé | BibTeX | Étiquettes: Animals, Base Sequence, Cyclic, hoffmann, Immunity, Immunologic, Immunological, Innate, insects, M3i, Models, Peptide Hydrolases, Peptides, Receptors, reichhart @article{hoffmann_innate_1996, title = {Innate immunity in higher insects}, author = {Jules A Hoffmann and Jean-Marc Reichhart and Charles Hetru}, issn = {0952-7915}, year = {1996}, date = {1996-02-01}, journal = {Curr. Opin. Immunol.}, volume = {8}, number = {1}, pages = {8--13}, abstract = {The hallmark of the innate immune response of higher insects is the rapid and transient synthesis of a battery of broad spectrum antimicrobial peptides by the fat body. The control of the genes encoding these peptides involves cis-regulatory promoter elements homologous to sequences functional in mammalian acute-phase genes. Study of immune-deficient mutants of Drosophila has indicated that distinct pathways control the antibacterial and antifungal responses in this species. Novel receptors potentially involved in the initiation of the immune response have been recently characterized.}, keywords = {Animals, Base Sequence, Cyclic, hoffmann, Immunity, Immunologic, Immunological, Innate, insects, M3i, Models, Peptide Hydrolases, Peptides, Receptors, reichhart}, pubstate = {published}, tppubtype = {article} } The hallmark of the innate immune response of higher insects is the rapid and transient synthesis of a battery of broad spectrum antimicrobial peptides by the fat body. The control of the genes encoding these peptides involves cis-regulatory promoter elements homologous to sequences functional in mammalian acute-phase genes. Study of immune-deficient mutants of Drosophila has indicated that distinct pathways control the antibacterial and antifungal responses in this species. Novel receptors potentially involved in the initiation of the immune response have been recently characterized. |
1995 |
Cornet, B; Bonmatin, J M; Hetru, Charles; Hoffmann, Jules A; Ptak, M; Vovelle, F Refined three-dimensional solution structure of insect defensin A Article de journal Structure, 3 (5), p. 435–448, 1995, ISSN: 0969-2126. Résumé | BibTeX | Étiquettes: Amino Acid, Animals, Bacteriolysis, Chemistry, Defensins, Diptera, Gram-Positive Bacteria, hoffmann, Hydrogen Bonding, Insect Hormones, M3i, Magnetic Resonance Spectroscopy, Models, Molecular, Physical, Physicochemical Phenomena, Protein Conformation, Recombinant Proteins, Sequence Homology, Solutions, Structure-Activity Relationship @article{cornet_refined_1995, title = {Refined three-dimensional solution structure of insect defensin A}, author = {B Cornet and J M Bonmatin and Charles Hetru and Jules A Hoffmann and M Ptak and F Vovelle}, issn = {0969-2126}, year = {1995}, date = {1995-05-01}, journal = {Structure}, volume = {3}, number = {5}, pages = {435--448}, abstract = {BACKGROUND: Insect defensin A is a basic 4 kDa protein secreted by Phormia terranovae larvae in response to bacterial challenges or injuries. Previous biological tests suggest that the bacterial cytoplasmic membrane is the target of defensin A. The structural study of this protein is the first step towards establishing a structure-activity relationship and forms the basis for understanding its antibiotic activity at the molecular level. RESULTS: We describe a refined model of the three-dimensional structure of defensin A derived from an extensive analysis of 786 inter-proton nuclear Overhauser effects. The backbone fold involves an N-terminal loop and an alpha-helical fragment followed by an antiparallel beta-structure. The helix and the beta-structure are connected by two of the three disulphide bridges present in defensin A, forming a so-called 'cysteine-stabilized alpha beta' (CS alpha beta) motif. The N-terminal loop, which is locally well defined, can occupy different positions with respect to the other moieties of the molecule. CONCLUSIONS: The CS alpha beta motif, which forms the core of the defensin A structure, appears to be a common organization for several families of small proteins with toxic properties. The distribution of amino acid side chains in the protein structure creates several hydrophobic or hydrophilic patches. This leads us to propose that the initial step in the action of positively charged defensin A molecules with cytoplasmic membranes may involve interactions with acidic phospholipids.}, keywords = {Amino Acid, Animals, Bacteriolysis, Chemistry, Defensins, Diptera, Gram-Positive Bacteria, hoffmann, Hydrogen Bonding, Insect Hormones, M3i, Magnetic Resonance Spectroscopy, Models, Molecular, Physical, Physicochemical Phenomena, Protein Conformation, Recombinant Proteins, Sequence Homology, Solutions, Structure-Activity Relationship}, pubstate = {published}, tppubtype = {article} } BACKGROUND: Insect defensin A is a basic 4 kDa protein secreted by Phormia terranovae larvae in response to bacterial challenges or injuries. Previous biological tests suggest that the bacterial cytoplasmic membrane is the target of defensin A. The structural study of this protein is the first step towards establishing a structure-activity relationship and forms the basis for understanding its antibiotic activity at the molecular level. RESULTS: We describe a refined model of the three-dimensional structure of defensin A derived from an extensive analysis of 786 inter-proton nuclear Overhauser effects. The backbone fold involves an N-terminal loop and an alpha-helical fragment followed by an antiparallel beta-structure. The helix and the beta-structure are connected by two of the three disulphide bridges present in defensin A, forming a so-called 'cysteine-stabilized alpha beta' (CS alpha beta) motif. The N-terminal loop, which is locally well defined, can occupy different positions with respect to the other moieties of the molecule. CONCLUSIONS: The CS alpha beta motif, which forms the core of the defensin A structure, appears to be a common organization for several families of small proteins with toxic properties. The distribution of amino acid side chains in the protein structure creates several hydrophobic or hydrophilic patches. This leads us to propose that the initial step in the action of positively charged defensin A molecules with cytoplasmic membranes may involve interactions with acidic phospholipids. |
Keith, G; Dirheimer, G Postlabeling: a sensitive method for studying DNA adducts and their role in carcinogenesis Article de journal Curr Opin Biotechnol, 6 (1), p. 3-11, 1995, (0958-1669 Journal Article Review Review, Academic). Résumé | BibTeX | Étiquettes: *Cell, *Genome, Adducts/*analysis, and, Animals, Base, Cell, Conditions/genetics/pathology, Data, Dilution, Division, DNA, Genetic, Gov't, Human, Models, Molecular, Mutagenesis, Neoplasms/*genetics/pathology, Neoplastic, Non-U.S., Phosphorus, Precancerous, Radioisotope, Radioisotopes, Sensitivity, Sequence, Specificity, Support, Technique, Transformation, Xenobiotics @article{, title = {Postlabeling: a sensitive method for studying DNA adducts and their role in carcinogenesis}, author = { G. Keith and G. Dirheimer}, year = {1995}, date = {1995-01-01}, journal = {Curr Opin Biotechnol}, volume = {6}, number = {1}, pages = {3-11}, abstract = {The covalent binding of xenobiotics to DNA is an important trigger of the multistage process that leads to carcinogenesis. 32P-postlabeling represents a highly sensitive method for biomonitoring exposure to genotoxic agents and for cancer risk assessment; it is capable of detecting less than one DNA adduct per human genome. Recent improvements to the technique have shown that the resistance of adducted DNA to enzyme digestion may lead to an overestimation of the number of different adducts present in a sample.}, note = {0958-1669 Journal Article Review Review, Academic}, keywords = {*Cell, *Genome, Adducts/*analysis, and, Animals, Base, Cell, Conditions/genetics/pathology, Data, Dilution, Division, DNA, Genetic, Gov't, Human, Models, Molecular, Mutagenesis, Neoplasms/*genetics/pathology, Neoplastic, Non-U.S., Phosphorus, Precancerous, Radioisotope, Radioisotopes, Sensitivity, Sequence, Specificity, Support, Technique, Transformation, Xenobiotics}, pubstate = {published}, tppubtype = {article} } The covalent binding of xenobiotics to DNA is an important trigger of the multistage process that leads to carcinogenesis. 32P-postlabeling represents a highly sensitive method for biomonitoring exposure to genotoxic agents and for cancer risk assessment; it is capable of detecting less than one DNA adduct per human genome. Recent improvements to the technique have shown that the resistance of adducted DNA to enzyme digestion may lead to an overestimation of the number of different adducts present in a sample. |
1994 |
Meister, Marie; Braun, A; Kappler, Christine; Reichhart, Jean-Marc; Hoffmann, Jules A Insect immunity. A transgenic analysis in Drosophila defines several functional domains in the diptericin promoter Article de journal EMBO J., 13 (24), p. 5958–5966, 1994, ISSN: 0261-4189. Résumé | BibTeX | Étiquettes: Animals, Anti-Infective Agents, Base Sequence, beta-Galactosidase, DNA Mutational Analysis, Female, Gene Expression Regulation, Genetic, Genetically Modified, Germ Cells, hoffmann, Insect Hormones, Insect Proteins, M3i, Male, Models, Nucleic Acid, Promoter Regions, Recombinant Fusion Proteins, reichhart, Repetitive Sequences, Transformation @article{meister_insect_1994, title = {Insect immunity. A transgenic analysis in Drosophila defines several functional domains in the diptericin promoter}, author = {Marie Meister and A Braun and Christine Kappler and Jean-Marc Reichhart and Jules A Hoffmann}, issn = {0261-4189}, year = {1994}, date = {1994-12-01}, journal = {EMBO J.}, volume = {13}, number = {24}, pages = {5958--5966}, abstract = {Diptericins are antibacterial polypeptides which are strongly induced in the fat body and blood cells of dipteran insects in response to septic injury. The promoter of the single-copy, intronless diptericin gene of Drosophila contains several nucleotide sequences homologous to mammalian cis-regulatory motifs involved in the control of acute phase response genes. Extending our previous studies on the expression of the diptericin gene, we now report a quantitative analysis of the contribution of various putative regulatory elements to the bacterial inducibility of this gene, based on the generation of 60 transgenic fly lines carrying different elements fused to a reporter gene. Our data definitively identify two Kappa B-related motifs in the proximal promoter as the sites conferring inducibility and tissue-specific expression to the diptericin gene. These motifs alone, however, mediate only minimal levels of expression. Additional proximal regulatory elements are necessary to attain some 20% of the full response and we suspect a role for sequences homologous to mammalian IL6 response elements and interferon-gamma responsive sites in this up-regulation. The transgenic experiments also reveal the existence of a distal regulatory element located upstream of -0.6 kb which increases the level of expression by a factor of five.}, keywords = {Animals, Anti-Infective Agents, Base Sequence, beta-Galactosidase, DNA Mutational Analysis, Female, Gene Expression Regulation, Genetic, Genetically Modified, Germ Cells, hoffmann, Insect Hormones, Insect Proteins, M3i, Male, Models, Nucleic Acid, Promoter Regions, Recombinant Fusion Proteins, reichhart, Repetitive Sequences, Transformation}, pubstate = {published}, tppubtype = {article} } Diptericins are antibacterial polypeptides which are strongly induced in the fat body and blood cells of dipteran insects in response to septic injury. The promoter of the single-copy, intronless diptericin gene of Drosophila contains several nucleotide sequences homologous to mammalian cis-regulatory motifs involved in the control of acute phase response genes. Extending our previous studies on the expression of the diptericin gene, we now report a quantitative analysis of the contribution of various putative regulatory elements to the bacterial inducibility of this gene, based on the generation of 60 transgenic fly lines carrying different elements fused to a reporter gene. Our data definitively identify two Kappa B-related motifs in the proximal promoter as the sites conferring inducibility and tissue-specific expression to the diptericin gene. These motifs alone, however, mediate only minimal levels of expression. Additional proximal regulatory elements are necessary to attain some 20% of the full response and we suspect a role for sequences homologous to mammalian IL6 response elements and interferon-gamma responsive sites in this up-regulation. The transgenic experiments also reveal the existence of a distal regulatory element located upstream of -0.6 kb which increases the level of expression by a factor of five. |
Dumas, P; Bergdoll, M; Cagnon, C; Masson, J M Crystal structure and site-directed mutagenesis of a bleomycin resistance protein and their significance for drug sequestering Article de journal EMBO J, 13 (11), p. 2483-92, 1994, (0261-4189 Journal Article). Résumé | BibTeX | Étiquettes: *Acetyltransferases, &, Acid, Amino, Bacterial, Bacterial/*genetics, Base, Binding, Bleomycin/*metabolism/pharmacology, Conformation, Crystallization, Crystallography, Data, Drug, Fusion, Genes, Gov't, Microbial/genetics, Models, Molecular, Mutagenesis, Non-U.S., Protein, Proteins/*chemistry/genetics/isolation, Proteins/isolation, purification, purification/metabolism, Recombinant, Relationship, Resistance, Secondary, Sequence, Site-Directed, Sites, Structural, structure, Structure-Activity, Support, X-Ray @article{, title = {Crystal structure and site-directed mutagenesis of a bleomycin resistance protein and their significance for drug sequestering}, author = { P. Dumas and M. Bergdoll and C. Cagnon and J. M. Masson}, year = {1994}, date = {1994-01-01}, journal = {EMBO J}, volume = {13}, number = {11}, pages = {2483-92}, abstract = {The antibiotic bleomycin, a strong DNA cutting agent, is naturally produced by actinomycetes which have developed a resistance mechanism against such a lethal compound. The crystal structure, at 2.3 A resolution, of a bleomycin resistance protein of 14 kDa reveals a structure in two halves with the same alpha/beta fold despite no sequence similarity. The crystal packing shows compact dimers with a hydrophobic interface and involved in mutual chain exchange. Two independent solution studies (analytical centrifugation and light scattering) showed that this dimeric form is not a packing artefact but is indeed the functional one. Furthermore, light scattering also showed that one dimer binds two antibiotic molecules as expected. A crevice located at the dimer interface, as well as the results of a site-directed mutagenesis study, led to a model wherein two bleomycin molecules are completely sequestered by one dimer. This provides a novel insight into antibiotic resistance due to drug sequestering, and probably also into drug transport and excretion.}, note = {0261-4189 Journal Article}, keywords = {*Acetyltransferases, &, Acid, Amino, Bacterial, Bacterial/*genetics, Base, Binding, Bleomycin/*metabolism/pharmacology, Conformation, Crystallization, Crystallography, Data, Drug, Fusion, Genes, Gov't, Microbial/genetics, Models, Molecular, Mutagenesis, Non-U.S., Protein, Proteins/*chemistry/genetics/isolation, Proteins/isolation, purification, purification/metabolism, Recombinant, Relationship, Resistance, Secondary, Sequence, Site-Directed, Sites, Structural, structure, Structure-Activity, Support, X-Ray}, pubstate = {published}, tppubtype = {article} } The antibiotic bleomycin, a strong DNA cutting agent, is naturally produced by actinomycetes which have developed a resistance mechanism against such a lethal compound. The crystal structure, at 2.3 A resolution, of a bleomycin resistance protein of 14 kDa reveals a structure in two halves with the same alpha/beta fold despite no sequence similarity. The crystal packing shows compact dimers with a hydrophobic interface and involved in mutual chain exchange. Two independent solution studies (analytical centrifugation and light scattering) showed that this dimeric form is not a packing artefact but is indeed the functional one. Furthermore, light scattering also showed that one dimer binds two antibiotic molecules as expected. A crevice located at the dimer interface, as well as the results of a site-directed mutagenesis study, led to a model wherein two bleomycin molecules are completely sequestered by one dimer. This provides a novel insight into antibiotic resistance due to drug sequestering, and probably also into drug transport and excretion. |
1992 |
Bonmatin, J M; Bonnat, J L; Gallet, X; Vovelle, F; Ptak, M; Reichhart, Jean-Marc; Hoffmann, Jules A; Keppi, E; Legrain, M; Achstetter, T Two-dimensional 1H NMR study of recombinant insect defensin A in water: resonance assignments, secondary structure and global folding Article de journal J. Biomol. NMR, 2 (3), p. 235–256, 1992, ISSN: 0925-2738. Résumé | BibTeX | Étiquettes: Animals, Defensins, hoffmann, Hydrogen, Insect Hormones, insects, M3i, Magnetic Resonance Spectroscopy, Models, Molecular, Protein Conformation, Recombinant Proteins, reichhart, Saccharomyces cerevisiae, Thermodynamics @article{bonmatin_two-dimensional_1992, title = {Two-dimensional 1H NMR study of recombinant insect defensin A in water: resonance assignments, secondary structure and global folding}, author = {J M Bonmatin and J L Bonnat and X Gallet and F Vovelle and M Ptak and Jean-Marc Reichhart and Jules A Hoffmann and E Keppi and M Legrain and T Achstetter}, issn = {0925-2738}, year = {1992}, date = {1992-01-01}, journal = {J. Biomol. NMR}, volume = {2}, number = {3}, pages = {235--256}, abstract = {A 500 MHz 2D 1H NMR study of recombinant insect defensin A is reported. This defense protein of 40 residues contains 3 disulfide bridges, is positively charged and exhibits antibacterial properties. 2D NMR maps of recombinant defensin A were fully assigned and secondary structure elements were localized. The set of NOE connectivities, 3JNH-alpha H coupling constants as well as 1H/2H exchange rates and delta delta/delta T temperature coefficients of NH protons strongly support the existence of an alpha-helix (residues 14-24) and of an antiparallel beta-sheet (residues 27-40). Models of the backbone folding were generated by using the DISMAN program and energy refined by using the AMBER program. This was done on the basis of: (i) 133 selected NOEs, (ii) 21 dihedral restraints from 3JNH-alpha H coupling constants, (iii) 12 hydrogen bonds mostly deduced from 1H/2H exchange rates or temperature coefficients, in addition to 9 initial disulfide bridge covalent constraints. The two secondary structure elements and the two bends connecting them involve approximately 70% of the total number of residues, which impose some stability in the C-terminal part of the molecule. The remaining N-terminal fragment forms a less well defined loop. This spatial organization, in which a beta-sheet is linked to an alpha-helix by two disulfide bridges and to a large loop by a third disulfide bridge, is rather similar to that found in scorpion charybdotoxin and seems to be partly present in several invertebrate toxins.}, keywords = {Animals, Defensins, hoffmann, Hydrogen, Insect Hormones, insects, M3i, Magnetic Resonance Spectroscopy, Models, Molecular, Protein Conformation, Recombinant Proteins, reichhart, Saccharomyces cerevisiae, Thermodynamics}, pubstate = {published}, tppubtype = {article} } A 500 MHz 2D 1H NMR study of recombinant insect defensin A is reported. This defense protein of 40 residues contains 3 disulfide bridges, is positively charged and exhibits antibacterial properties. 2D NMR maps of recombinant defensin A were fully assigned and secondary structure elements were localized. The set of NOE connectivities, 3JNH-alpha H coupling constants as well as 1H/2H exchange rates and delta delta/delta T temperature coefficients of NH protons strongly support the existence of an alpha-helix (residues 14-24) and of an antiparallel beta-sheet (residues 27-40). Models of the backbone folding were generated by using the DISMAN program and energy refined by using the AMBER program. This was done on the basis of: (i) 133 selected NOEs, (ii) 21 dihedral restraints from 3JNH-alpha H coupling constants, (iii) 12 hydrogen bonds mostly deduced from 1H/2H exchange rates or temperature coefficients, in addition to 9 initial disulfide bridge covalent constraints. The two secondary structure elements and the two bends connecting them involve approximately 70% of the total number of residues, which impose some stability in the C-terminal part of the molecule. The remaining N-terminal fragment forms a less well defined loop. This spatial organization, in which a beta-sheet is linked to an alpha-helix by two disulfide bridges and to a large loop by a third disulfide bridge, is rather similar to that found in scorpion charybdotoxin and seems to be partly present in several invertebrate toxins. |
1988 |
Kappler, Christine; Kabbouh, M; Hetru, Charles; Durst, F; Hoffmann, Jules A Characterization of three hydroxylases involved in the final steps of biosynthesis of the steroid hormone ecdysone in Locusta migratoria (Insecta, Orthoptera) Article de journal J. Steroid Biochem., 31 (6), p. 891–898, 1988, ISSN: 0022-4731. Résumé | BibTeX | Étiquettes: Animals, Biological, Ecdysone, Grasshoppers, hoffmann, Kinetics, M3i, Mixed Function Oxygenases, Models, NAD, NADP, Subcellular Fractions @article{kappler_characterization_1988, title = {Characterization of three hydroxylases involved in the final steps of biosynthesis of the steroid hormone ecdysone in Locusta migratoria (Insecta, Orthoptera)}, author = {Christine Kappler and M Kabbouh and Charles Hetru and F Durst and Jules A Hoffmann}, issn = {0022-4731}, year = {1988}, date = {1988-12-01}, journal = {J. Steroid Biochem.}, volume = {31}, number = {6}, pages = {891--898}, abstract = {It is most generally accepted that the last three enzymatic reactions in the biosynthetic pathway of ecdysone are, in this order, the hydroxylations at positions C-25, C-22 and C-2. Using high specific activity tritiated ecdysone precursors (2,22,25-trideoxyecdysone, 2,22-dideoxyecdysone and 2-deoxyecdysone) we have characterized the hydroxylases involved in these reactions, in the major biosynthetic tissue of ecdysone, i.e. the prothoracic glands. We show that C-2 hydroxylase is a mitochondrial oxygenase which differs from conventional cytochrome P-450-dependent monooxygenases by its relative insensitivity to CO. In contrast, C-22 and C-25 hydroxylases appear as classical cytochrome P-450 monooxygenases; C-22 hydroxylase is a mitochondrial enzyme whereas our data point to a microsomal localization of the C-25 hydroxylase.}, keywords = {Animals, Biological, Ecdysone, Grasshoppers, hoffmann, Kinetics, M3i, Mixed Function Oxygenases, Models, NAD, NADP, Subcellular Fractions}, pubstate = {published}, tppubtype = {article} } It is most generally accepted that the last three enzymatic reactions in the biosynthetic pathway of ecdysone are, in this order, the hydroxylations at positions C-25, C-22 and C-2. Using high specific activity tritiated ecdysone precursors (2,22,25-trideoxyecdysone, 2,22-dideoxyecdysone and 2-deoxyecdysone) we have characterized the hydroxylases involved in these reactions, in the major biosynthetic tissue of ecdysone, i.e. the prothoracic glands. We show that C-2 hydroxylase is a mitochondrial oxygenase which differs from conventional cytochrome P-450-dependent monooxygenases by its relative insensitivity to CO. In contrast, C-22 and C-25 hydroxylases appear as classical cytochrome P-450 monooxygenases; C-22 hydroxylase is a mitochondrial enzyme whereas our data point to a microsomal localization of the C-25 hydroxylase. |