title: Crystal structure of a novel prokaryotic Ser/Thr kinase and its implication in the Cpx stress response pathway.
abstract: The Cpx signalling system of Escherichia coli and Salmonella enterica senses extracytoplasmic stress and controls expression of factors that allow the bacterium to adapt to these stressors and thereby enhance survival. Many of the Cpx-responsive genes products are of unknown function. We determined the crystal structure of one of these gene products, called YihE in E. coli, which exhibits a eukaryotic kinase fold. Functional assays established that both YihE and the S. enterica YihE homologue, RdoA, undergo autophosphorylation and phosphorylate protein substrates at Ser/Thr residues in vitro, demonstrating that YihE/RdoA is a novel Ser/Thr protein kinase in prokaryotic cells. Phenotypic analysis of yihE/rdoA null strains indicates that this kinase is most abundant in stationary phase, and is important for long-term cell survival and for expression of surface appendages in both a Cpx-independent and -dependent manner. YihE/RdoA is therefore a previously unknown kinase component of a new type of bacterial phosphorelay mechanism, adding kinase activity as another response to the Cpx sensing system that functions to maintain cellular homeostasis.
authors.affiliation: Department of Biochemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
authors.forename: Jimin
authors.initials: J
authors.lastname: Zheng
authors.forename: Chunhua
authors.initials: C
authors.lastname: He
authors.forename: Vinay Kumar
authors.initials: VK
authors.lastname: Singh
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Martin
authors.forename: Zongchao
authors.initials: Z
authors.lastname: Jia
mesh_terms: D000222:Adaptation, Physiological; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D017353:Gene Deletion; D050296:Microbial Viability; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D019779:Salmonella enterica / Q000737:chemistry / Q000502:physiology*; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D029968:Escherichia coli Proteins; D000255:Adenosine Triphosphate; D017346:Protein Serine-Threonine Kinases; C523731:YihE protein, E coli