Hierarchical effector protein transport by the Salmonella Typhimurium SPI-1 type III secretion system.
BACKGROUND: Type III secretion systems (TTSS) are employed by numerous pathogenic and symbiotic bacteria to inject a cocktail of different "effector proteins" into host cells.These effectors subvert host cell signaling to establish symbiosis or disease.METHODOLOGY/PRINCIPAL FINDINGS: We have studied the injection of SipA and SptP, two effector prot