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The type III secretion system of Pseudomonas aeruginosa: infection by injection
Alan R. Hauser
Abstract | The Gram-negative bacterium Pseudomonas aeruginosa uses a complex type III secretion apparatus to inject effector proteins into host cells. The configuration of this secretion machinery, the activities of the proteins that are injected by it and the consequences of this process for infection are now being elucidated. This Review summarizes our current knowledge of P. aeruginosa type III secretion, including the secretion and translocation machinery, the regulation of this machinery, and the associated chaperones and effector proteins. The features of this interesting secretion system have important implications for the pathogenesis of P. aeruginosa infections and for other type III secretion systems.
http://www.ncbi.nlm.nih.gov/sites/entrez?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=12339
Web End =Pseudomonas aeruginosa is a major cause of health care-associated infections, including pneumonia and infections involving the urinary tract, wounds, burns and the bloodstream1. Patients with http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=219700
Web End =cystic fibrosis (CF) are also prone to acquiring P. aeruginosa infection2. Like many other Gram-negative bacteria, P. aeruginosa manipulates eukaryotic host cells by using a type III secretion system (T3SS). This T3SS forms complex, needle-like machines on the bacterial surface, which function in a highly regulated manner to transport proteins into host cells.
In this Review, I describe our current knowledge of the components of the T3SS of P. aeruginosa, with particular emphasis on the effector proteins that it injects into the host. Recent studies in humans and progress in the development of therapeutic agents that are designed to inhibit the P. aeruginosa T3SS are also summarized.
The P. aeruginosa type III secretion system
P. aeruginosa uses a broad arsenal of virulence determinants to establish infections3, one of which, its T3SS, has been the focus of much recent attention4. Thirty-six genes encoded in five operons that are clustered together in the P. aeruginosa chromosome are involved in the bio-genesis and regulation of the type III secretory machine. At least six other genes, scattered around the chromo-some, encode the effector proteins and their chaperones that are important for the T3SS. This complex regulon can be divided into five parts (FIG. 1a, b): proteins that
constitute the needle complex that transports substrates from the bacterial cytosol to the extracellular
environment, proteins that translocate secreted proteins into host...