Alain DEFONTAINE
Maître de conférences Université
section 65
Équipe : |
Thèmes de recherche
Expression des protéines recombinantes ; mutagénèse
Publications
2 publications
Pillot, Aline; Defontaine, Alain; Fateh, Amina; Lambert, Annie; Prasanna, Maruthi; Fanuel, Mathieu; Pipelier, Muriel; Csaba, Noemi; Violo, Typhaine; Camberlein, Emilie; Grandjean, Cyrille Site-Specific Conjugation for Fully Controlled Glycoconjugate Vaccine Preparation Article Frontiers in Chemistry, 7 (November), p. 1–9, 2019, ISSN: 22962646. @article{Pillot2019, title = {Site-Specific Conjugation for Fully Controlled Glycoconjugate Vaccine Preparation}, author = {Aline Pillot and Alain Defontaine and Amina Fateh and Annie Lambert and Maruthi Prasanna and Mathieu Fanuel and Muriel Pipelier and Noemi Csaba and Typhaine Violo and Emilie Camberlein and Cyrille Grandjean}, doi = {10.3389/fchem.2019.00726}, issn = {22962646}, year = {2019}, date = {2019-01-01}, journal = {Frontiers in Chemistry}, volume = {7}, number = {November}, pages = {1--9}, abstract = {Glycoconjugate vaccines are formed by covalently link a carbohydrate antigen to a carrier protein whose role is to achieve a long lasting immune response directed against the carbohydrate antigen. The nature of the sugar antigen, its length, its ratio per carrier protein and the conjugation chemistry impact on both structure and the immune response of a glycoconjugate vaccine. In addition it has long been assumed that the sites at which the carbohydrate antigen is attached can also have an impact. These important issue can now be addressed owing to the development of novel chemoselective ligation reactions as well as techniques such as site-selective mutagenesis, glycoengineering, or extension of the genetic code. The preparation and characterization of homogeneous bivalent pneumococcal vaccines is reported. The preparation and characterization of homogeneous bivalent pneumococcal vaccines is reported. A synthetic tetrasaccharide representative of the serotype 14 capsular polysaccharide of Streptococcus pneumoniae has been linked using the thiol/maleimide coupling chemistry to four different Pneumococcal surface adhesin A (PsaA) mutants, each harboring a single cysteine mutation at a defined position. Humoral response of these 1 to 1 carbohydrate antigen/PsaA conjugates have been assessed in mice. Our results showed that the carbohydrate antigen-PsaA connectivity impacts the anti-carrier response and raise questions about the design of glycoconjugate vaccine whereby the protein plays the dual role of immunogen and carrier.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Glycoconjugate vaccines are formed by covalently link a carbohydrate antigen to a carrier protein whose role is to achieve a long lasting immune response directed against the carbohydrate antigen. The nature of the sugar antigen, its length, its ratio per carrier protein and the conjugation chemistry impact on both structure and the immune response of a glycoconjugate vaccine. In addition it has long been assumed that the sites at which the carbohydrate antigen is attached can also have an impact. These important issue can now be addressed owing to the development of novel chemoselective ligation reactions as well as techniques such as site-selective mutagenesis, glycoengineering, or extension of the genetic code. The preparation and characterization of homogeneous bivalent pneumococcal vaccines is reported. The preparation and characterization of homogeneous bivalent pneumococcal vaccines is reported. A synthetic tetrasaccharide representative of the serotype 14 capsular polysaccharide of Streptococcus pneumoniae has been linked using the thiol/maleimide coupling chemistry to four different Pneumococcal surface adhesin A (PsaA) mutants, each harboring a single cysteine mutation at a defined position. Humoral response of these 1 to 1 carbohydrate antigen/PsaA conjugates have been assessed in mice. Our results showed that the carbohydrate antigen-PsaA connectivity impacts the anti-carrier response and raise questions about the design of glycoconjugate vaccine whereby the protein plays the dual role of immunogen and carrier. |
Chabot, Thomas; Defontaine, Alain; Marquis, Damien; Renodon-Corniere, Axelle; Courtois, Emmanuelle; Fleury, Fabrice; Cheraud, Yvonnick New phosphorylation sites of rad51 by c-met modulates presynaptic filament stability Article Cancers, 11 (3), 2019, ISSN: 20726694. @article{Chabot2019a, title = {New phosphorylation sites of rad51 by c-met modulates presynaptic filament stability}, author = {Thomas Chabot and Alain Defontaine and Damien Marquis and Axelle Renodon-Corniere and Emmanuelle Courtois and Fabrice Fleury and Yvonnick Cheraud}, doi = {10.3390/cancers11030413}, issn = {20726694}, year = {2019}, date = {2019-01-01}, journal = {Cancers}, volume = {11}, number = {3}, abstract = {Genomic instability through deregulation of DNA repair pathways can initiate cancer and subsequently result in resistance to chemo and radiotherapy. Understanding these biological mechanisms is therefore essential to overcome cancer. RAD51 is the central protein of the Homologous Recombination (HR) DNA repair pathway, which leads to faithful DNA repair of DSBs. The recombinase activity of RAD51 requires nucleofilament formation and is regulated by post-translational modifications such as phosphorylation. In the last decade, studies have suggested the existence of a relationship between receptor tyrosine kinases (RTK) and Homologous Recombination DNA repair. Among these RTK the c-MET receptor is often overexpressed or constitutively activated in many cancer types and its inhibition induces the decrease of HR. In this study, we show for the first time that c-MET is able to phosphorylate the RAD51 protein. We demonstrate in vitro that c-MET phosphorylates four tyrosine residues localized mainly in the subunit-subunit interface of RAD51. Whereas these post-translational modifications do not affect the presynaptic filament formation, they strengthen its stability against the inhibitor effect of the BRC peptide obtained from BRCA2. Taken together, these results confirm the role of these modifications in the regulation of the BRCA2-RAD51 interaction and underline the importance of c-MET in DNA damage response.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Genomic instability through deregulation of DNA repair pathways can initiate cancer and subsequently result in resistance to chemo and radiotherapy. Understanding these biological mechanisms is therefore essential to overcome cancer. RAD51 is the central protein of the Homologous Recombination (HR) DNA repair pathway, which leads to faithful DNA repair of DSBs. The recombinase activity of RAD51 requires nucleofilament formation and is regulated by post-translational modifications such as phosphorylation. In the last decade, studies have suggested the existence of a relationship between receptor tyrosine kinases (RTK) and Homologous Recombination DNA repair. Among these RTK the c-MET receptor is often overexpressed or constitutively activated in many cancer types and its inhibition induces the decrease of HR. In this study, we show for the first time that c-MET is able to phosphorylate the RAD51 protein. We demonstrate in vitro that c-MET phosphorylates four tyrosine residues localized mainly in the subunit-subunit interface of RAD51. Whereas these post-translational modifications do not affect the presynaptic filament formation, they strengthen its stability against the inhibitor effect of the BRC peptide obtained from BRCA2. Taken together, these results confirm the role of these modifications in the regulation of the BRCA2-RAD51 interaction and underline the importance of c-MET in DNA damage response. |
2 publications
Forato, Florian; Liu, Hao; Benoit, Roland; Fayon, Franck; Charlier, Cathy; Fateh, Amina; Defontaine, Alain; Tellier, Charles; Talham, Daniel R; Queffélec, Clémence; Bujoli, Bruno Langmuir, 32 (22), p. 5480–5490, 2016, ISSN: 15205827. @article{Forato2016, title = {Comparison of Zirconium Phosphonate-Modified Surfaces for Immobilizing Phosphopeptides and Phosphate-Tagged Proteins}, author = {Florian Forato and Hao Liu and Roland Benoit and Franck Fayon and Cathy Charlier and Amina Fateh and Alain Defontaine and Charles Tellier and Daniel R Talham and Clémence Queffélec and Bruno Bujoli}, doi = {10.1021/acs.langmuir.6b01020}, issn = {15205827}, year = {2016}, date = {2016-01-01}, journal = {Langmuir}, volume = {32}, number = {22}, pages = {5480--5490}, abstract = {Different routes for preparing zirconium phosphonate-modified surfaces for immobilizing biomolecular probes are compared. Two chemical-modification approaches were explored to form self-assembled monolayers on commercially available primary amine-functionalized slides, and the resulting surfaces were compared to well-characterized zirconium phosphonate monolayer-modified supports prepared using Langmuir-Blodgett methods. When using POCl3 as the amine phosphorylating agent followed by treatment with zirconyl chloride, the result was not a zirconium-phosphonate monolayer, as commonly assumed in the literature, but rather the process gives adsorbed zirconium oxide/hydroxide species and to a lower extent adsorbed zirconium phosphate and/or phosphonate. Reactions giving rise to these products were modeled in homogeneous-phase studies. Nevertheless, each of the three modified surfaces effectively immobilized phosphopeptides and phosphopeptide tags fused to an affinity protein. Unexpectedly, the zirconium oxide/hydroxide modified surface, formed by treating the amine-coated slides with POCl3/Zr4+, afforded better immobilization of the peptides and proteins and efficient capture of their targets.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Different routes for preparing zirconium phosphonate-modified surfaces for immobilizing biomolecular probes are compared. Two chemical-modification approaches were explored to form self-assembled monolayers on commercially available primary amine-functionalized slides, and the resulting surfaces were compared to well-characterized zirconium phosphonate monolayer-modified supports prepared using Langmuir-Blodgett methods. When using POCl3 as the amine phosphorylating agent followed by treatment with zirconyl chloride, the result was not a zirconium-phosphonate monolayer, as commonly assumed in the literature, but rather the process gives adsorbed zirconium oxide/hydroxide species and to a lower extent adsorbed zirconium phosphate and/or phosphonate. Reactions giving rise to these products were modeled in homogeneous-phase studies. Nevertheless, each of the three modified surfaces effectively immobilized phosphopeptides and phosphopeptide tags fused to an affinity protein. Unexpectedly, the zirconium oxide/hydroxide modified surface, formed by treating the amine-coated slides with POCl3/Zr4+, afforded better immobilization of the peptides and proteins and efficient capture of their targets. |
Goux, Marine; Fateh, Amina; Defontaine, Alain; Cinier, Mathieu; Tellier, Charles In vivo phosphorylation of a peptide tag for protein purification Article Biotechnology Letters, 38 (5), p. 767–772, 2016, ISSN: 1573-6776. @article{Goux2016, title = {In vivo phosphorylation of a peptide tag for protein purification}, author = {Marine Goux and Amina Fateh and Alain Defontaine and Mathieu Cinier and Charles Tellier}, url = {https://doi.org/10.1007/s10529-016-2040-4}, doi = {10.1007/s10529-016-2040-4}, issn = {1573-6776}, year = {2016}, date = {2016-01-01}, journal = {Biotechnology Letters}, volume = {38}, number = {5}, pages = {767--772}, abstract = {To design a new system for the in vivo phosphorylation of proteins in Escherichia coli using the co-expression of the α-subunit of casein kinase II (CKIIα) and a target protein, (Nanofitin) fused with a phosphorylatable tag.}, keywords = {}, pubstate = {published}, tppubtype = {article} } To design a new system for the in vivo phosphorylation of proteins in Escherichia coli using the co-expression of the α-subunit of casein kinase II (CKIIα) and a target protein, (Nanofitin) fused with a phosphorylatable tag. |