Chaperone release and unfolding of substrates in type III secretion

• Published in: Nature Vol. 437; no. 7060; pp. 911 - 915
• Main Authors: Galán, Jorge E, Akeda, Yukihiro
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 06-10-2005; Nature Publishing Group
• Subjects: Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Bacterial Proteins - secretion; Bacteriology; Biological and medical sciences; Cells; Chaperonin 60 - chemistry; Chaperonin 60 - metabolism; Fundamental and applied biological sciences. Psychology; Microbiology; Molecular Chaperones - chemistry; Molecular Chaperones - metabolism; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Pathogens; Protein Folding; Protein Tyrosine Phosphatases - chemistry; Protein Tyrosine Phosphatases - metabolism; Proteins; Proton-Translocating ATPases - metabolism; Salmonella enterica - chemistry; Salmonella enterica - enzymology; Salmonella enterica - metabolism; Salmonella enterica - pathogenicity; Substrate Specificity; Substrates; Virulence Factors - chemistry; Virulence Factors - metabolism; Salmonella; Bacteria; Type III secretion system; Chaperone; Enterobacteriaceae
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature03992

Type III protein secretion systems are essential virulence factors of many bacteria pathogenic to humans, animals and plants. These systems mediate the transfer of bacterial virulence proteins directly into the host cell cytoplasm. Proteins are thought to travel this pathway in a largely unfolded manner, and a family of customized cytoplasmic chaperones, which specifically bind cognate secreted proteins, are essential for secretion. Here we show that InvC, an ATPase associated with a Salmonella enterica type III secretion system, has a critical function in substrate recognition. Furthermore, InvC induces chaperone release from and unfolding of the cognate secreted protein in an ATP-dependent manner. Our results show a similarity between the mechanisms of substrate recognition by type III protein secretion systems and AAA + ATPase disassembly machines.