title: The C terminus of SipC binds and bundles F-actin to promote Salmonella invasion.
abstract: Salmonella enterica serovar Typhimurium invade non-phagocytic cells by injecting bacterial effector proteins to exploit the host actin cytoskeleton network. SipC is such a Salmonella effector known to nucleate actin, bundle F-actin, and translocate type III effectors. The molecular mechanism of how SipC bundles F-actin and SipC domains responsible for these activities are not well characterized. We successfully separated these activities through a series of genetic deletion/insertions in SipC. We found that the C terminus (amino acids 200-409) of SipC bundled actin filaments using in vitro biochemical assays. We further demonstrated that amino acid residues 221-260 and 381-409 of full-length SipC were indispensable for its actin binding and bundling activities. Furthermore, Salmonella mutant strains lacking the actin bundling activity were less invasive into HeLa cells. These studies indicate that the C terminus of SipC bundles F-actin to promote Salmonella invasion.
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Sebenzile K
authors.initials: SK
authors.lastname: Myeni
authors.forename: Daoguo
authors.initials: D
authors.lastname: Zhou
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D017434:Protein Structure, Tertiary; D012480:Salmonella Infections / Q000235:genetics / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D017384:Sequence Deletion
chemical_list: D000199:Actins; D001426:Bacterial Proteins; C094578:Salmonella invasion protein C