title: Salmonella virulence effector SopE and Host GEF ARNO cooperate to recruit and activate WAVE to trigger bacterial invasion.
abstract: Salmonella virulence effectors elicit host cell membrane ruffling to facilitate pathogen invasion. The WAVE regulatory complex (WRC) governs the underlying membrane-localized actin polymerization, but how Salmonella manipulates WRC is unknown. We show that Rho GTPase activation by the Salmonella guanine nucleotide exchange factor (GEF) SopE efficiently triggered WRC recruitment but not its activation, which required host Arf GTPase activity. Invading Salmonella recruited and activated Arf1 to facilitate ruffling and uptake. Arf3 and Arf6 could also enhance invasion. RNAi screening of host Arf-family GEFs revealed a key role for ARNO in pathogen invasion and generation of pathogen-containing macropinosomes enriched in Arf1 and WRC. Salmonella recruited ARNO via Arf6 and the phosphoinositide phosphatase effector SopB-induced PIP3 generation. ARNO in turn triggered WRC recruitment and activation, which was dramatically enhanced when SopE and ARNO cooperated. Thus, we uncover a mechanism by which pathogen and host GEFs synergize to regulate WRC and trigger Salmonella invasion.
authors.affiliation: Department of Pathology, Cambridge University, Tennis Court Road, Cambridge, CB21QP, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Humphreys
authors.forename: Anthony
authors.initials: A
authors.lastname: Davidson
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Hume
authors.forename: Vassilis
authors.initials: V
authors.lastname: Koronakis
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000378:metabolism; D020727:ADP-Ribosylation Factors / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D004705:Endocytosis; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D012486:Salmonella typhimurium / Q000472:pathogenicity*; D013552:Swine; D037521:Virulence Factors / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D000199:Actins; D001426:Bacterial Proteins; D020690:GTPase-Activating Proteins; C103987:SopE protein, Salmonella; D037521:Virulence Factors; C102474:cytohesin-2; C116687:ARF3 protein, human; D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors; D020741:rho GTP-Binding Proteins