Salmonella Research Today is a free monthly online journal that collates and summarizes the latest research about Salmonella, including details on salmonella typhimurium, food poisoning, infection, treatment.

Chaperone release and unfolding of substrates in type III secretion.

Akeda Y, Galán JE

Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06536, USA.

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.

Published 6 October 2005 in Nature, 437(7060): 911-5.
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