SseA is required for translocation of Salmonella pathogenicity island-2 effectors into host cells.
The Salmonella pathogenicity island-2 (SPI2) is a virulence locus on the bacterial chromosome required for intracellular proliferation and systemic infection in mice. Cell culture models and a murine model of systemic infection were used to address the role of an uncharacterized SPI2 open reading frame, designated as sseA, in Salmonella virulence. A Salmonella strain with an unmarked internal deletion of sseA displayed a phenotype that was similar to an SPI2-encoded type III secretion system apparatus mutant. Moreover, SseA was required for survival and replication within epithelial cells and macrophages. Murine infection studies confirmed that the DeltasseA strain was severely attenuated for virulence. Using immunofluorescence microscopy, the virulence defect in the DeltasseA strain was attributed to an inability to translocate SPI2 effector proteins into host cells. These data demonstrate that SseA is essential for SPI2-mediated translocation of effector proteins.
Coombes
Brian K
BK
Biotechnology Laboratory and Department of Biochemistry and Molecular Biology, 237-6174 University Boulevard, University of British Columbia, BC, V6T 1Z3, Vancouver, Canada.
Brown
Nat F
NF
Kujat-Choy
Sonya
S
Vallance
Bruce A
BA
Finlay
B Brett
BB
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005798:Genes, Bacterial; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D018832:Molecular Chaperones / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D021381:Protein Transport; D012475:Salmonella / Q000378:metabolism / Q000472:pathogenicity*; D012481:Salmonella Infections, Animal / Q000382:microbiology; D037521:Virulence Factors / Q000502:physiology
D001426:Bacterial Proteins; D008565:Membrane Proteins; D018832:Molecular Chaperones; C440638:SPI-2 protein, Salmonella; C474474:SseA protein, Salmonella typhimurium; D037521:Virulence Factors