title: Ku70, a component of DNA-dependent protein kinase, is a mammalian receptor for Rickettsia conorii.
abstract: Rickettsia conorii, a strictly intracellular and category C priority bacterial pathogen (NIAID), invades different mammalian cells. Although some signaling events involved in bacterial entry have been documented, the bacterial and host proteins mediating entry were not known. We report the identification of the Ku70 subunit of DNA-dependent protein kinase (DNA-PK) as a receptor involved in R. conorii internalization. Ku70 is recruited to R. conorii entry sites, and inhibition of Ku70 expression impairs R. conorii internalization. Bacterial invasion is dependent on the presence of cholesterol-enriched microdomains containing Ku70. R. conorii infection stimulates the ubiquitination of Ku70. In addition, the ubiquitin ligase c-Cbl is recruited to R. conorii entry foci, and downregulation of endogenous c-Cbl blocks bacterial invasion and Ku70 ubiquitination. An affinity chromatography approach identified the rickettsial protein rOmpB as a ligand for Ku70. This is the first report of a receptor-ligand interaction involved in the internalization of any rickettsial species.
authors.affiliation: Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris F-75015, France.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Martinez
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Seveau
authors.forename: Esteban
authors.initials: E
authors.lastname: Veiga
authors.forename: Shigemi
authors.initials: S
authors.lastname: Matsuyama
authors.forename: Pascale
authors.initials: P
authors.lastname: Cossart
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D034961:Antigens, Nuclear / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D051243:Caveolin 2 / Q000032:analysis; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D002522:Chlorocebus aethiops; D002784:Cholesterol / Q000378:metabolism / Q000494:pharmacology; D024161:Collagen Type XI / Q000378:metabolism; D051747:DNA-Activated Protein Kinase / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects; D005347:Fibroblasts / Q000382:microbiology; D006367:HeLa Cells; D006801:Humans; D000072200:Ku Autoantigen; D021962:Membrane Microdomains / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011485:Protein Binding; D050721:Proto-Oncogene Proteins c-cbl / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D020114:Rickettsia conorii / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D014709:Vero Cells; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D034961:Antigens, Nuclear; D001425:Bacterial Outer Membrane Proteins; C499319:COL11A2 protein, human; D051243:Caveolin 2; D024161:Collagen Type XI; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D025801:Ubiquitin; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D002784:Cholesterol; D050721:Proto-Oncogene Proteins c-cbl; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D051747:DNA-Activated Protein Kinase; C000606509:Xrcc6 protein, human; C000606510:Xrcc6 protein, mouse; D000072200:Ku Autoantigen; C067419:CBL protein, human