title: Phosphorylation and dephosphorylation of a bacterial transcriptional activator by a transmembrane receptor.
abstract: Signal transduction in the bacterial Omp, Che, and Ntr systems involves the phosphorylation and dephosphorylation of response regulators (OmpR, CheY and CheB, NRI) that share a homologous domain. We show that in the Omp system, the transmembrane sensor EnvZ, catalyzes both the phosphorylation of OmpR and the dephosphorylation of OmpR-P. The phosphorylation reaction proceeds by a mechanism shared with the Ntr and Che kinases, NRII, and CheA. EnvZ can phosphorylate NRI and can stimulate transcription from the glnAp2 promoter, and similarly, CheA can phosphorylate OmpR and can stimulate transcription from the ompF promoter. OmpR-P formed by either CheA or EnvZ is much more stable than CheY-P and NRI-P, but is rapidly hydrolyzed to OmpR and Pi by EnvZ in the presence of ATP, ADP, or nonhydrolyzable analogs of ATP. Because EnvZ is normally a transmembrane receptor with a periplasmic sensory domain, our results suggest that the role of EnvZ may be to control the intracellular concentration of OmpR-P in response to environmental signals.
authors.affiliation: Department of Molecular Biology, Princeton University, New Jersey 08544-1014.
authors.forename: M M
authors.initials: MM
authors.lastname: Igo
authors.forename: A J
authors.initials: AJ
authors.lastname: Ninfa
authors.forename: J B
authors.initials: JB
authors.lastname: Stock
authors.forename: T J
authors.initials: TJ
authors.lastname: Silhavy
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins; D002630:Chemotactic Factors / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D029968:Escherichia coli Proteins; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000378:metabolism; D000072236:Methyl-Accepting Chemotaxis Proteins; D009097:Multienzyme Complexes; D051922:PII Nitrogen Regulatory Proteins; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000378:metabolism; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002630:Chemotactic Factors; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D009097:Multienzyme Complexes; D051922:PII Nitrogen Regulatory Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C000607606:cheY protein, E coli; C497876:glnG protein, E coli; D011494:Protein Kinases; D000071677:Histidine Kinase; C000607608:cheA protein, E coli; C057843:envZ protein, E coli; D010749:Phosphoprotein Phosphatases