The Salmonella enterica serovar typhimurium translocated effectors SseJ and SifB are targeted to the Salmonella-containing vacuole.
The Salmonella enterica serovar Typhimurium type III secretion system (TTSS) encoded in Salmonella pathogenicity island 2 (SPI-2) promotes replication within host cells and systemic infection of mice. The SPI-2 TTSS is expressed following Salmonella internalization into host cells and translocates effectors across the membrane of the Salmonella-containing vacuole (SCV). Two effectors with similar amino-terminal domains, SseJ and SifB, localize to the SCV membrane in infected HEp-2 cells and subsequently traffic away from the SCV along Salmonella-induced-filaments (Sifs). Following infection of RAW cells, SseJ and SifB localize to the SCV as well as LAMP-1-positive, vesicular-appearing structures distant from the SCV. Trafficking of SseJ and SifB away from the SCV requires the SPI-2 effector SifA. Deletion of sseJ, but not sifB, leads to attenuation of Salmonella replication in mice following intraperitoneal inoculation. The contribution of SseJ to in vivo replication is identical in wild-type and sifA deletion backgrounds, suggesting that SseJ trafficking away from the SCV along Sifs is unnecessary for its virulence function.
Freeman
Jeremy A
JA
Department of Microbiology, University of Washington, Seattle, Washington 98195, USA.
Ohl
Michael E
ME
Miller
Samuel I
SI
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D017353:Gene Deletion; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D021381:Protein Transport; D012481:Salmonella Infections, Animal / Q000382:microbiology; D012486:Salmonella typhimurium / Q000254:growth & development / Q000472:pathogenicity*; D014617:Vacuoles / Q000378:metabolism*; D014774:Virulence
D001426:Bacterial Proteins; D006023:Glycoproteins; C421862:SifA protein, Salmonella