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Accueil > Départements > Biochimie, Biophysique et Biologie Structurale > Françoise OCHSENBEIN & Raphaël GUEROIS : Assemblage moléculaire et intégrité du génome

pubmed : ochsenbein, francois...

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NCBI : db=pubmed ; Term=Ochsenbein, Francoise[Full Author Name] or Guerois, Raphael[Full Author Name] or Andreani, Jessica[Full Author Name] or Plançon, Laure[Full Author Name]

Articles syndiqués

  • Rad52-Rad51 association is essential to protect Rad51 filaments against Srs2, but facultative for filament formation.

    10 juillet, par Ma E, Dupaigne P, Maloisel L, Guerois R, Le Cam E, Coïc E

    Rad52-Rad51 association is essential to protect Rad51 filaments against Srs2, but facultative for filament formation.

    Elife. 2018 Jul 09;7:

    Authors: Ma E, Dupaigne P, Maloisel L, Guerois R, Le Cam E, Coïc E

    Abstract
    Homology search and strand exchange mediated by Rad51 nucleoprotein filaments are key steps of the homologous recombination process. In budding yeast, Rad52 is the main mediator of Rad51 filament formation, thereby playing an essential role. The current model assumes that Rad51 filament formation requires the interaction between Rad52 and Rad51. However, we report here that Rad52 mutations that disrupt this interaction do not affect γ-ray- or HO endonuclease-induced gene conversion frequencies. In vivo and in vitro studies confirmed that Rad51 filaments formation is not affected by these mutations. Instead, we found that Rad52-Rad51 association makes Rad51 filaments toxic in Srs2-deficient cells after exposure to DNA damaging agents, independently of Rad52 role in Rad51 filament assembly. Importantly, we also demonstrated that Rad52 is essential for protecting Rad51 filaments against dissociation by the Srs2 DNA translocase. Our findings open new perspectives in the understanding of the role of Rad52 in eukaryotes.

    PMID: 29985128 [PubMed - as supplied by publisher]

  • Emerging fields in chaperone proteins : a French workshop.

    12 juin, par Mileo E, Ilbert M, Barducci A, Bordes P, Castanié-Cornet MP, Garnier C, Genevaux P, Gillet R, Goloubinoff P, Ochsenbein F, Richarme G, Iobbi-Nivol C, Giudici-Orticoni MT, Gontero B, Genest O

    Emerging fields in chaperone proteins: a French workshop.

    Biochimie. 2018 Jun 08;:

    Authors: Mileo E, Ilbert M, Barducci A, Bordes P, Castanié-Cornet MP, Garnier C, Genevaux P, Gillet R, Goloubinoff P, Ochsenbein F, Richarme G, Iobbi-Nivol C, Giudici-Orticoni MT, Gontero B, Genest O

    Abstract
    The "Bioénergétique et Ingénierie des Protéines (BIP)" laboratory, CNRS (France), organized its first French workshop on molecular chaperone proteins and protein folding in November 2017. The goal of this workshop was to gather scientists working in France on chaperone proteins and protein folding. This initiative was a great success with excellent talks and fruitful discussions. The highlights were on the description of unexpected functions and posttranslational regulation of known molecular chaperones (such as Hsp90, Hsp33, SecB, GroEL) and on state-of-the-art methods to tackle questions related to this theme, including Cryo-electron microscopy, Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR), simulation and modeling. We expect to organize a second workshop in two years that will include more scientists working in France in the chaperone field.

    PMID: 29890204 [PubMed - as supplied by publisher]

  • The trimeric coiled-coil HSBP1 protein promotes WASH complex assembly at centrosomes.

    31 mai, par Visweshwaran SP, Thomason PA, Guerois R, Vacher S, Denisov EV, Tashireva LA, Lomakina ME, Lazennec-Schurdevin C, Lakisic G, Lilla S, Molinie N, Henriot V, Mechulam Y, Alexandrova AY, Cherdyntseva NV, Bièche I, Schmitt E, Insall RH, Gautreau A
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    The trimeric coiled-coil HSBP1 protein promotes WASH complex assembly at centrosomes.

    EMBO J. 2018 May 29;:

    Authors: Visweshwaran SP, Thomason PA, Guerois R, Vacher S, Denisov EV, Tashireva LA, Lomakina ME, Lazennec-Schurdevin C, Lakisic G, Lilla S, Molinie N, Henriot V, Mechulam Y, Alexandrova AY, Cherdyntseva NV, Bièche I, Schmitt E, Insall RH, Gautreau A

    Abstract
    The Arp2/3 complex generates branched actin networks that exert pushing forces onto different cellular membranes. WASH complexes activate Arp2/3 complexes at the surface of endosomes and thereby fission transport intermediates containing endocytosed receptors, such as α5β1 integrins. How WASH complexes are assembled in the cell is unknown. Here, we identify the small coiled-coil protein HSBP1 as a factor that specifically promotes the assembly of a ternary complex composed of CCDC53, WASH, and FAM21 by dissociating the CCDC53 homotrimeric precursor. HSBP1 operates at the centrosome, which concentrates the building blocks. HSBP1 depletion in human cancer cell lines and in Dictyostelium amoebae phenocopies WASH depletion, suggesting a critical role of the ternary WASH complex for WASH functions. HSBP1 is required for the development of focal adhesions and of cell polarity. These defects impair the migration and invasion of tumor cells. Overexpression of HSBP1 in breast tumors is associated with increased levels of WASH complexes and with poor prognosis for patients.

    PMID: 29844016 [PubMed - as supplied by publisher]

  • InterEvDock2 : an expanded server for protein docking using evolutionary and biological information from homology models and multimeric inputs.

    10 mai, par Quignot C, Rey J, Yu J, Tufféry P, Guerois R, Andreani J
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    InterEvDock2: an expanded server for protein docking using evolutionary and biological information from homology models and multimeric inputs.

    Nucleic Acids Res. 2018 May 08;:

    Authors: Quignot C, Rey J, Yu J, Tufféry P, Guerois R, Andreani J

    Abstract
    Computational protein docking is a powerful strategy to predict structures of protein-protein interactions and provides crucial insights for the functional characterization of macromolecular cross-talks. We previously developed InterEvDock, a server for ab initio protein docking based on rigid-body sampling followed by consensus scoring using physics-based and statistical potentials, including the InterEvScore function specifically developed to incorporate co-evolutionary information in docking. InterEvDock2 is a major evolution of InterEvDock which allows users to submit input sequences - not only structures - and multimeric inputs and to specify constraints for the pairwise docking process based on previous knowledge about the interaction. For this purpose, we added modules in InterEvDock2 for automatic template search and comparative modeling of the input proteins. The InterEvDock2 pipeline was benchmarked on 812 complexes for which unbound homology models of the two partners and co-evolutionary information are available in the PPI4DOCK database. InterEvDock2 identified a correct model among the top 10 consensus in 29% of these cases (compared to 15-24% for individual scoring functions) and at least one correct interface residue among 10 predicted in 91% of these cases. InterEvDock2 is thus a unique protein docking server, designed to be useful for the experimental biology community. The InterEvDock2 web interface is available at http://bioserv.rpbs.univ-paris-diderot.fr/services/InterEvDock2/.

    PMID: 29741647 [PubMed - as supplied by publisher]

  • Sak4 of Phage HK620 Is a RecA Remote Homolog With Single-Strand Annealing Activity Stimulated by Its Cognate SSB Protein.

    10 mai, par Hutinet G, Besle A, Son O, McGovern S, Guerois R, Petit MA, Ochsenbein F, Lecointe F
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    Sak4 of Phage HK620 Is a RecA Remote Homolog With Single-Strand Annealing Activity Stimulated by Its Cognate SSB Protein.

    Front Microbiol. 2018;9:743

    Authors: Hutinet G, Besle A, Son O, McGovern S, Guerois R, Petit MA, Ochsenbein F, Lecointe F

    Abstract
    Bacteriophages are remarkable for the wide diversity of proteins they encode to perform DNA replication and homologous recombination. Looking back at these ancestral forms of life may help understanding how similar proteins work in more sophisticated organisms. For instance, the Sak4 family is composed of proteins similar to the archaeal RadB protein, a Rad51 paralog. We have previously shown that Sak4 allowed single-strand annealing in vivo, but only weakly compared to the phage λ Redβ protein, highlighting putatively that Sak4 requires partners to be efficient. Here, we report that the purified Sak4 of phage HK620 infecting Escherichia coli is a poorly efficient annealase on its own. A distant homolog of SSB, which gene is usually next to the sak4 gene in various species of phages, highly stimulates its recombineering activity in vivo. In vitro, Sak4 binds single-stranded DNA and performs single-strand annealing in an ATP-dependent way. Remarkably, the single-strand annealing activity of Sak4 is stimulated by its cognate SSB. The last six C-terminal amino acids of this SSB are essential for the binding of Sak4 to SSB-covered single-stranded DNA, as well as for the stimulation of its annealase activity. Finally, expression of sak4 and ssb from HK620 can promote low-level of recombination in vivo, though Sak4 and its SSB are unable to promote strand exchange in vitro. Regarding its homology with RecA, Sak4 could represent a link between two previously distinct types of recombinases, i.e., annealases that help strand exchange proteins and strand exchange proteins themselves.

    PMID: 29740405 [PubMed]

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