title: Chaperone release and unfolding of substrates in type III secretion.
abstract: 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.
authors.affiliation: Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Akeda
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Galán
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D018834:Chaperonin 60 / Q000737:chemistry / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D017510:Protein Folding; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism; D019779:Salmonella enterica / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism* / Q000472:pathogenicity; D013379:Substrate Specificity; D037521:Virulence Factors / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D018834:Chaperonin 60; D018832:Molecular Chaperones; D037521:Virulence Factors; D017027:Protein Tyrosine Phosphatases; C439890:sptP protein, Salmonella typhimurium; D006180:Proton-Translocating ATPases