title: The Salmonella pathogenicity island 1 secretion system directs cellular cholesterol redistribution during mammalian cell entry and intracellular trafficking.
abstract: The bacterial pathogen Salmonella triggers its own uptake into non-phagocytic mammalian cells. Entry is induced by the delivery of bacterial effector pro-teins that subvert signalling and promote cytoskeletal rearrangement, although the molecular mechanisms that co-ordinate initial pathogen-host cell recognition remain poorly characterized. Here we show that cholesterol is essential for Salmonella uptake. Depletion and chelation of plasma membrane cholesterol specifically inhibited bacterial internalization but not adherence. Cholesterol accumulated at bacterial entry sites in cultured cells, and was retained by Salmonella-containing vacuoles following pathogen internalization. Cellular cholesterol redistribution required bacterial effector protein delivery mediated by the Salmonella pathogenicity island (SPI) 1 type III secretion system, but was independent of the SPI2-encoded system.
authors.affiliation: University of Cambridge, Department of Pathology, Tennis Court Road, Cambridge, CB2 1QP, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Garner
authors.forename: Richard D
authors.initials: RD
authors.lastname: Hayward
authors.forename: Vassilis
authors.initials: V
authors.lastname: Koronakis
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018613:Microscopy, Confocal; D012486:Salmonella typhimurium / Q000378:metabolism / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; C419942:Spi1 protein, Salmonella; D002784:Cholesterol