A Genome-Wide siRNA Screen Implicates Spire1/2 in SipA-Driven Salmonella Typhimurium Host Cell Invasion.

摘要: Salmonella Typhimurium (S. Tm) is a leading cause of diarrhea. The disease triggered by pathogen invasion into the gut epithelium. Invasion attributed to SPI-1 type 3 secretion system (T1). T1 injects effector proteins epithelial cells and thereby elicits rearrangements host cellular actin cytoskeleton invasion. SopE, SopB, SopE2 SipA are contributing this. However, cell factors still not completely understood. To address this question comprehensively, we used Hela tissue culture cells, genome-wide siRNA library, modified gentamicin protection assay S. TmSipA, sopBsopE2sopE mutant which strongly relies on protein invade cells. We found that TmSipA does elicit membrane ruffles, nor promote entry non-invasive bacteria "in trans". SipA-mediated infection involved SPIRE family nucleators, besides well-established (WRC, ARP2/3, RhoGTPases, COPI). Stage-specific follow-up assays knockout fibroblasts indicated SPIRE1 SPIRE2 in different steps Tm process. Whereas interferes with bacterial binding, influences intracellular replication Tm. Hence, these two might fulfill non-redundant functions pathogen-host interaction. lack co-localization hints short, direct interaction between or an indirect effect.