The SseC translocon component in Salmonella enterica serovar Typhimurium is chaperoned by SscA
1 Michael G. DeGroote Institute for Infectious Disease Research, Hamilton, Ontario L8N 3Z5, Canada
2 Department of Biochemistry and Biomedical Sciences, McMaster University, Health Sciences Centre Room 4H17, Hamilton, Ontario L8S 4K1, Canada
3 Department of Molecular and Cellular Biology, University of Guelph, 488 Gordon Street, Science Complex, Room 4202, Guelph, Ontario N1G 2W1, Canada
BMC Microbiology 2013, 13:221 doi:10.1186/1471-2180-13-221Published: 4 October 2013
Salmonella enterica is a causative agent of foodborne gastroenteritis and the systemic disease known as typhoid fever. This bacterium uses two type three secretion systems (T3SSs) to translocate protein effectors into host cells to manipulate cellular function. Salmonella pathogenicity island (SPI)-2 encodes a T3SS required for intracellular survival of the pathogen. Genes in SPI-2 include apparatus components, secreted effectors and chaperones that bind to secreted cargo to coordinate their release from the bacterial cell. Although the effector repertoire secreted by the SPI-2 T3SS is large, only three virulence-associated chaperones have been characterized.
Here we report that SscA is the chaperone for the SseC translocon component. We show that SscA and SseC interact in bacterial cells and that deletion of sscA results in a loss of SseC secretion, which compromises intracellular replication and leads to a loss of competitive fitness in mice.
This work completes the characterization of the chaperone complement within SPI-2 and identifies SscA as the chaperone for the SseC translocon.