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SpaP and SpaR interaction partner identification

ABSTRACT: Bacterial type III protein secretion systems inject effector proteins into eukaryotic host cells in order to promote survival and colonization of Gram-negative pathogens and symbionts. Secretion across the bacterial cell envelope and injection into host cells is facilitated by a so-called needle complex. Its small hydrophobic export apparatus components SpaP and SpaR were shown to nucleate assembly of the needle complex and to form the central “cup” substructure of a Salmonella Typhimurium secretion system, however, the in vivo placement of these components in the needle complex and their function during the secretion process remained poorly defined. Here we show that a SpaP pentamer forms a 15 Å wide pore and present a detailed map of SpaP interactions with the export apparatus components SpaQ, SpaR, and SpaS. We further demonstrate the formation of a continuous conduit for substrate translocation and injection by intimate interactions of the periplasmic domains of SpaP and SpaR with the inner rod protein PrgJ, refine the current view of export apparatus assembly and consolidate transmembrane topology models for SpaP and SpaR.

INSTRUMENT(S): LTQ Orbitrap Elite, Q Exactive

ORGANISM(S): Salmonella Enterica Subsp. Enterica Serovar Typhimurium

SUBMITTER: Nicolas Nalpas

LAB HEAD: Samuel Wagner

PROVIDER: PXD005028 | Pride | 2016-11-29

REPOSITORIES: Pride

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SpaP and SpaR interaction partner identification

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