Ultrastructural analysis of IpaD at the tip of the nascent MxiH type III secretion apparatus of Shigella flexneri.

ABSTRACT: Shigella flexneri is a Gram-negative enteric pathogen that is the predominant cause of bacillary dysentery. Shigella uses a type III secretion system to deliver effector proteins that alter normal target cell functions to promote pathogen invasion. The type III secretion apparatus (T3SA) consists of a basal body, an extracellular needle, and a tip complex that is responsible for delivering effectors into the host cell cytoplasm. IpaD [Ipa (invasion plasmid antigen)] is the first protein to localize to the T3SA needle tip, where it prevents premature effector secretion and serves as an environmental sensor for triggering recruitment of the translocator protein IpaB to the needle tip. Thus, IpaD would be expected to form a stable structure whose overall architecture supports its functions. I

SUBMITTER: Epler CR 

PROVIDER: S-EPMC3367090 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature