title: Yersinia protein kinase YopO is activated by a novel G-actin binding process.
abstract: Pathogenic bacteria of the genus Yersinia employ a type III secretion system to inject effector proteins (Yops) into host cells. The Yops down-regulate host cell functions through unique biochemical activities. YopO, a serine/threonine kinase required for Yersinia virulence, is activated by host cell actin via an unknown process. Here we show that YopO kinase is activated by formation of a 1:1 complex with monomeric (G) actin but is unresponsive to filamentous (F) actin. Two separate G-actin binding sites, one in the N-terminal kinase region (amino acids 89-440) and one in the C-terminal guanine nucleotide dissociation inhibitor-like region (amino acids 441-729) of YopO, were identified. Actin binding to both of these sites was necessary for effective autophosphorylation of YopO on amino acids Ser-90 and Ser-95. A S90A/S95A YopO mutant was strongly reduced in substrate phosphorylation, suggesting that autophosphorylation activates YopO kinase activity. In cells the kinase activity of YopO regulated rounding/arborization and was specifically required for inhibition of Yersinia YadA-dependent phagocytosis. Thus, YopO kinase is activated by a novel G-actin binding process, and this appears to be crucial for its anti-host cell functions.
authors.affiliation: Institut für Medizinische Mikrobiologie, Virologie, und Hygiene, Universitätsklinikum Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Trasak
authors.forename: Gerhardt
authors.initials: G
authors.lastname: Zenner
authors.forename: Annette
authors.initials: A
authors.lastname: Vogel
authors.forename: Gülnihal
authors.initials: G
authors.lastname: Yüksekdag
authors.forename: René
authors.initials: R
authors.lastname: Rost
authors.forename: Ilka
authors.initials: I
authors.lastname: Haase
authors.forename: Markus
authors.initials: M
authors.lastname: Fischer
authors.forename: Lars
authors.initials: L
authors.lastname: Israel
authors.forename: Axel
authors.initials: A
authors.lastname: Imhof
authors.forename: Stefan
authors.initials: S
authors.lastname: Linder
authors.forename: Michael
authors.initials: M
authors.lastname: Schleicher
authors.forename: Martin
authors.initials: M
authors.lastname: Aepfelbacher
mesh_terms: D000199:Actins / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002460:Cell Line; D004789:Enzyme Activation; D006801:Humans; D009154:Mutation; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D015854:Up-Regulation; D015007:Yersinia / Q000201:enzymology* / Q000472:pathogenicity; D015009:Yersinia Infections / Q000378:metabolism / Q000382:microbiology*
chemical_list: D000199:Actins; D001426:Bacterial Proteins; C415206:YopO protein, Yersinia enterocolitica; D017346:Protein Serine-Threonine Kinases