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    Critical role of a sheath phosphorylation site on the assembly and function of an atypical type VI secretion system

    Ziveri, J. and Chhuon, C. and Jamet, A. and Rytter, H. and Prigent, G. and Tros, F. and Barel, M. and Coureuil, M. and Lays, C. and Henry, T. and Keep, Nicholas H. and Guerrera, I.C. and Charbit, A. (2019) Critical role of a sheath phosphorylation site on the assembly and function of an atypical type VI secretion system. Molecular and Cellular Proteomics 18 (12), pp. 2418-2432. ISSN 1535-9476.

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    The bacterial pathogen Francisella tularensis possesses a non-canonical type VI secretion system (T6SS) that is required for phagosomal escape in infected macrophages. KCl stimulation has been previously used to trigger assembly and secretion of the T6SS in culture. By differential proteomics, we found here that the amounts of the T6SS proteins remained unchanged upon KCl stimulation, suggesting involvement of post-translational modifications in T6SS assembly. A phosphoproteomic analysis indeed identified a unique phosphorylation site on IglB, a key component of the T6SS sheath. Substitutions of Y139 with alanine or phosphomimetics prevented T6SS formation and abolished phagosomal escape whereas substitution with phenylalanine delayed but did not abolish phagosomal escape in J774-1 macrophages. Altogether our data demonstrated that the Y139 site of IglB plays a critical role in T6SS biogenesis, suggesting that sheath phosphorylation could participate to T6SS dynamics.


    Item Type: Article
    Additional Information: This research was originally published in Molecular & Cellular Proteomics. © the American Society for Biochemistry and Molecular Biology or © the Author(s).
    School: Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences
    Research Centres and Institutes: Structural Molecular Biology, Institute of (ISMB)
    Depositing User: Nick Keep
    Date Deposited: 07 Oct 2019 13:32
    Last Modified: 02 Aug 2023 17:54


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