title: Yersinia enterocolitica invasin triggers phagocytosis via beta1 integrins, CDC42Hs and WASp in macrophages.
abstract: The Yersinia outer surface protein invasin binds to beta1 integrins on target cells and has been shown to trigger phagocytic uptake by macrophages. Here, we investigated the role of the actin regulator Wiskott-Aldrich syndrome protein (WASp), its effector the Arp2/3 complex and the Rho-GTPases CDC42Hs, Rac and Rho in invasin/beta1 integrin-triggered phagocytosis. During uptake of invasin-coated latex beads, the alpha5beta1 integrin, WASp and the Arp2/3 complex were recruited to the developing actin-rich phagocytic cups in primary human macrophages. Blockage of beta1 integrins by specific antibodies, inhibition of Arp2/3 function by microinjection of inhibitors or the use of WASp knockout macrophages inhibited phagocytic cup formation and uptake. Furthermore, microinjection of the dominant negative GTPase mutants N17CDC42Hs, N17Rac or the Rho-specific inhibitor C3-transferase into macrophages greatly attenuated invasin-induced formation of cups. These data suggest that during invasin-triggered phagocytosis beta1 integrins activate actin polymerization via CDC42Hs, its effector WASp and the Arp2/3 complex. The contribution of Rac and Rho to phagocytic cup formation also suggests a complex interplay between different Rho GTPases during phagocytosis of pathogens.
authors.affiliation: Max von Pettenkofer-Institut für Medizinische Mikrobiologie, Pettenkoferstrasse 9a, Ludwig-Maximilians-Universität, 80336 München, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Wiedemann
authors.forename: S
authors.initials: S
authors.lastname: Linder
authors.forename: G
authors.initials: G
authors.lastname: Grassl
authors.forename: M
authors.initials: M
authors.lastname: Albert
authors.forename: I
authors.initials: I
authors.lastname: Autenrieth
authors.forename: M
authors.initials: M
authors.lastname: Aepfelbacher
mesh_terms: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000378:metabolism; D018829:Adhesins, Bacterial; D001426:Bacterial Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D008264:Macrophages / Q000502:physiology*; D008856:Microscopy, Fluorescence; D008863:Microspheres; D010587:Phagocytosis / Q000502:physiology*; D011506:Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D051316:Wiskott-Aldrich Syndrome Protein; D015008:Yersinia enterocolitica / Q000502:physiology*; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*
chemical_list: C495926:ACTR2 protein, human; C495928:ACTR3 protein, human; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D019012:Integrin beta1; D011506:Proteins; D011993:Recombinant Fusion Proteins; C495767:WAS protein, human; D051316:Wiskott-Aldrich Syndrome Protein; C053476:invasin, Yersinia; D020764:cdc42 GTP-Binding Protein