DrXiujun Yu

Upon infection of mammalian host cells, Salmonella Typhimurium resides within acidic membrane-bound compartments known as Salmonella-containing vacuoles (SCVs). In this environment, the type three secretion apparatus (T3SA) encoded by Salmonella pathogenicity island 2 (SPI-2) is assembled, and secretes translocator proteins. An SsaL/SsaM/SpiC regulatory complex is required to form a translocon pore on the membrane of SCV. Once the translocon pore is formed, the neutral pH of host cell cytosol is sensed by the bacterium through an unknown mechanism to dissociate the SsaL/SsaM/SpiC complex and allow secretion and translocation of effector proteins into the host cell. I am interested in understanding how the neutral pH of host cell cytosol is sensed and transduced into the bacterial cytosolic side to dissociate the SsaL/SsaM/SpiC complex, and how the acidic pH triggers the assembly of SPI-2 T3SA.