Salmonella modulation of the phagosome membrane, role of SseJ

Salmonellae have the ability to invade, persist and replicate within an intracellular phagosome termed the Salmonella-containing vacuole (SCV). Salmonellae alter lipid and protein content of the SCV membrane and manipulate cytoskeletal elements in contact with the SCV using the Salmonella pathogenicity island 1 (SPI-2) type III secretion system effectors. These modifications result in microtubular-based movement and morphological changes, which include endosomal tubulation of the SCV membrane. SseJ is a SPI-2 effector that localizes to the cytoplasmic face of the SCV and esterifies cholesterol through its glycerophospholipid : cholesterol acyltransferase activity. SseJ enzymatic activity as well as localization to the SCV are determined by binding to the small mammalian GTPase, RhoA. This review will focus on current knowledge about the role of SseJ in SCV membrane modification and will discuss how the hypothesis that a major role of SPI-2 effectors is to modify SCV protein and lipid content to promote bacterial intracellular survival.