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The Salmonella effector SopB affects phospholipid content of Salmonella‐induced membrane ruffles
Author(s) -
SteeleMortimer Olivia
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1030.5
Subject(s) - salmonella enterica , effector , microbiology and biotechnology , biology , salmonella , pi3k/akt/mtor pathway , protein kinase b , secretion , type three secretion system , signal transduction , mutant , biochemistry , bacteria , genetics , gene
Salmonella enterica serovars are pathogenic Gram‐negative bacteria that can cause disease in a variety of eukaryotic hosts. Central to pathogenesis is the ability to invade non‐phagocytic cells within the intestinal epithelium, a process that involves massive actin rearrangements and membrane ruffle formation on the plasma membrane. This is absolutely dependent on a type III secretion system (T3SS), which translocates a number of bacterial effector proteins directly into the host cell. One of these effectors, SopB/SigD, is an inositol phosphatase that is absolutely required for activation of Akt/PKB in infected epithelial cells. We have previously shown that the SopB/Akt pathway can protect infected cells against the onset of apoptosis. Here we have further delineated the mechanism of Akt activation in Salmonella‐infected cells. Unlike the canonical Akt pathway this process is Wortmannin‐insensitive and is prolonged, being detectable for at least 8 hrs. Using PH‐domain GFP fusions we have performed semi‐quantitative analysis of the phospholipids present in Salmonella induced ruffles and demonstrate a role for SopB in ruffle formation. This activity is absolutely dependent on the phosphatase activity of SopB since a catalytically inactive SopB mutant is unable to affect the phospholipid content of Salmonella‐induced ruffles. Conclusions The T3SS effector protein SopB modulates the phospholipid content of Salmonella‐induced membrane ruffles.