title: Structural basis for the inhibition of host protein ubiquitination by Shigella effector kinase OspG.
abstract: Shigella invasion of its human host is assisted by T3SS-delivered effector proteins. The OspG effector kinase binds ubiquitin and ubiquitin-loaded E2-conjugating enzymes, including UbcH5b and UbcH7, and attenuates the host innate immune NF-kB signaling. We present the structure of OspG bound to the UbcH7∼Ub conjugate. OspG has a minimal kinase fold lacking the activation loop of regulatory kinases. UbcH7∼Ub binds OspG at sites remote from the kinase active site, yet increases its kinase activity. The ubiquitin is positioned in the "open" conformation with respect to UbcH7 using its I44 patch to interact with the C terminus of OspG. UbcH7 binds to OspG using two conserved loops essential for E3 ligase recruitment. The interaction of the UbcH7∼Ub with OspG is remarkably similar to the interaction of an E2∼Ub with a HECT E3 ligase. OspG interferes with the interaction of UbcH7 with the E3 parkin and inhibits the activity of the E3.
authors.affiliation: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada.
authors.forename: Andrey M
authors.initials: AM
authors.lastname: Grishin
authors.affiliation: Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada.
authors.forename: Tara E C
authors.initials: TE
authors.lastname: Condos
authors.affiliation: Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada.
authors.forename: Kathryn R
authors.initials: KR
authors.lastname: Barber
authors.affiliation: Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France; INSERM, U786, 75015, Paris, France.
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Campbell-Valois
authors.affiliation: Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France; INSERM, U786, 75015, Paris, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Parsot
authors.affiliation: Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada.
authors.forename: Gary S
authors.initials: GS
authors.lastname: Shaw
authors.affiliation: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada; Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada. Electronic address: miroslaw.cygler@usask.ca.
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Cygler
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D054884:Host-Pathogen Interactions / Q000502:physiology*; D006801:Humans; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D016328:NF-kappa B / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D059748:Proteolysis; D012763:Shigella flexneri / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D015398:Signal Transduction; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000378:metabolism; D054875:Ubiquitination
chemical_list: D001426:Bacterial Proteins; D046912:Multiprotein Complexes; D016328:NF-kappa B; D000255:Adenosine Triphosphate; C079437:UBE2L3 protein, human; D044763:Ubiquitin-Conjugating Enzymes; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein