Dataset Information

Stoichiometry of the bacterial type III secretion export apparatus

ABSTRACT: Bacterial type III secretion systems are cell envelope-spanning effector protein-delivery machines essential for colonization and survival of many Gram-negative pathogens and symbionts. The membrane-embedded core unit of these secretion systems is termed needle complex. The needle complex is composed of a base that anchors the machinery to the inner and outer membranes, a hollow filament formed by inner rod and needle subunits that serves as conduit for substrate proteins, and a membrane-embedded export apparatus facilitating substrate translocation. While the stoichiometry of the base and of the major export apparatus protein have been revealed by structural analyses, the stoichiometries of the other export apparatus components and of the inner rod remain unknown. We employed peptide concatenated standard and absolute quantification-based strategies to analyze the stoichiometry of the entire needle complex by mass spectrometry. Here we provide evidence that the export apparatus of the type III secretion system encoded on Salmonella pathogenicity island 1 contains 5 SpaP, 1 SpaQ, 1 SpaR, and 1 SpaS. We have corroborated the previously suggested stoichiometry of 9 InvA per needle complex and describe a loose association of InvA with other needle complex components that may reflect its function. These numbers indicate that the inner membrane patch of the needle complex base houses 104 transmembrane domains in total, a dense assembly whose function in the secretion process we merely understand. Furthermore, we present evidence that not more than 6 PrgJ form the inner rod of the needle complex.

INSTRUMENT(S): LTQ Orbitrap Elite, Q Exactive

ORGANISM(S): Salmonella Enterica Subsp. Enterica Serovar Typhimurium Str. Sl1344

SUBMITTER: Nicolas Nalpas

LAB HEAD: Samuel Wagner

PROVIDER: PXD003113 | Pride | 2016-02-25

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	20140225_CO_0339SaWa_R19R22_01.raw	Raw
	20140225_CO_0339SaWa_R20R24_01.raw	Raw
	20140314_CO_0339SaWa_R27R29.raw	Raw
	20140314_CO_0339SaWa_R28R30.raw	Raw
	20140611_CO_0339SaWa_R35R37_03.raw	Raw

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Publications

Determination of the Stoichiometry of the Complete Bacterial Type III Secretion Needle Complex Using a Combined Quantitative Proteomic Approach.

Zilkenat Susann S Franz-Wachtel Mirita M Stierhof York-Dieter YD Galán Jorge E JE Macek Boris B Wagner Samuel S

Molecular & cellular proteomics : MCP 20160221 5

Precisely knowing the stoichiometry of their components is critical for investigating structure, assembly, and function of macromolecular machines. This has remained a technical challenge in particular for large, hydrophobic membrane-spanning protein complexes. Here, we determined the stoichiometry of a type III secretion system of Salmonella enterica serovar Typhimurium using two complementary protocols of gentle complex purification combined with peptide concatenated standard and synthetic sta ...[more]

PMID: 26900162

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