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The Salmonella type III secretion translocon protein SspC is inserted into the epithelial cell plasma membrane upon infection
Author(s) -
Scherer Christina A.,
Cooper Emily,
Miller Samuel I.
Publication year - 2000
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2000.02066.x
Subject(s) - effector , biology , secretion , cytoplasm , chromosomal translocation , microbiology and biotechnology , mutant , translocon , membrane , type three secretion system , cell membrane , membrane protein , biochemistry , gene
Salmonella species translocate effector proteins into the host cell cytoplasm using a type III secretion system (TTSS). The translocation machinery probably contacts the eukaryotic cell plasma membrane to effect protein transfer. Data presented here demonstrate that both SspB and SspC, components of the translocation apparatus, are inserted into the epithelial cell plasma membrane 15 min after Salmonella typhimurium infection. In addition, a yeast two‐hybrid interaction between SspC and an eukaryotic intermediate filament protein was identified. Three individual carboxyl‐terminal point mutations within SspC that disrupt the yeast two‐hybrid interaction were isolated. Strains expressing the mutant SspC alleles were defective for invasion, translocation of effector molecules and membrane localization of SspC. These data indicate that insertion of SspC into the plasma membrane of target cells is required for invasion and effector molecule translocation and that the carboxyl terminus of SspC is essential for these functions.