The intracellular pathogen Salmonella translocates a multitude of proteins, termed effectors, into the host cell to affect host cell processes and establish a safe replicative niche. We have identified two of these effectors, PipB and PipB2. PipB and PipB2 share some sequence similarity, primarily limited to their C-termini which are composed of tandem pentapeptide repeat domains. Both effectors are translocated by bacteria across the Salmonella -containing vacuole, the vacuole within which intracellular Salmonella reside, and are targeted to remodeled host cell structures, Salmonella-induced filaments. These tubular structures are formed from the aggregation of host cell enodosomal compartments. In the case of PipB2, it is additionally targeted to vesicles that accumulate at the host cell periphery and are positive for markers of late endosomes. Both effectors are enriched in lipid rafts in host cell membranes, regions that act as important signaling platforms. Our studies suggest that these proteins can interact with, and modulate the activity of, host proteins involved in membrane trafficking.
| Knodler, Leigh A; Vallance, Bruce A; Hensel, Michael et al. (2003) Salmonella type III effectors PipB and PipB2 are targeted to detergent-resistant microdomains on internal host cell membranes. Mol Microbiol 49:685-704 |
