title: Src, cortactin and Arp2/3 complex are required for E-cadherin-mediated internalization of Listeria into cells.
abstract: Listeria monocytogenes is a food-borne pathogen able to invade non-phagocytic cells. InlA, a L. monocytogenes surface protein, interacts with human E-cadherin to promote bacterial entry. L. monocytogenes internalization is a dynamic process involving co-ordinated actin cytoskeleton rearrangements and host cell membrane remodelling at the site of bacterial attachment. Interaction between E-cadherin and catenins is required to promote Listeria entry, and for the establishment of adherens junctions in epithelial cells. Although several molecular factors promoting E-cadherin-mediated Listeria internalization have been identified, the proteins regulating the transient actin polymerization required at the bacterial entry site are unknown. Here we show that the Arp2/3 complex acts as an actin nucleator during the InlA/E-cadherin-dependent internalization. Using a variety of approaches including siRNA, expression of dominant negative derivatives and pharmacological inhibitors, we demonstrate the crucial role of cortactin in the activation of the Arp2/3 complex during InlA-mediated entry. We also show the requirement of the small GTPase Rac1 and that of Src-tyrosine kinase activity to promote Listeria internalization. Together, these data suggest a model in which Src tyrosine kinase and Rac1 promote recruitment of cortactin and activation of Arp2/3 at Listeria entry site, mimicking events that occur during adherens junction formation.
authors.affiliation: Institut Pasteur, Unité des Interactions Bactéries-Cellules; Inserm, U604; and INRA, USC2020, Paris F-75015, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Sousa
authors.forename: Didier
authors.initials: D
authors.lastname: Cabanes
authors.forename: Laurence
authors.initials: L
authors.lastname: Bougnères
authors.forename: Marc
authors.initials: M
authors.lastname: Lecuit
authors.forename: Philippe
authors.initials: P
authors.lastname: Sansonetti
authors.forename: Guy
authors.initials: G
authors.lastname: Tran-Van-Nhieu
authors.forename: Pascale
authors.initials: P
authors.lastname: Cossart
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism* / Q000502:physiology; D001426:Bacterial Proteins / Q000378:metabolism / Q000502:physiology; D018938:Caco-2 Cells; D015820:Cadherins / Q000378:metabolism*; D051356:Cortactin / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005455:Fluorescent Antibody Technique; D006801:Humans; D047468:Immunoprecipitation; D008089:Listeria monocytogenes / Q000254:growth & development / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism / Q000502:physiology; D020830:rac1 GTP-Binding Protein / Q000378:metabolism / Q000502:physiology; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D001426:Bacterial Proteins; D015820:Cadherins; D051356:Cortactin; D034741:RNA, Small Interfering; C114864:WASF1 protein, human; D051300:Wiskott-Aldrich Syndrome Protein Family; D019061:src-Family Kinases; D020830:rac1 GTP-Binding Protein