Phosphorylation of OmpR by the osmosensor EnvZ modulates expression of the ompF and ompC genes in Escherichia coli.

Abstract

EnvZ and OmpR, the regulatory proteins for ompF and ompC expression in Escherichia coli, belong to a modulator-effector family of regulatory proteins which are essential for the response to environmental signals. We show that the soluble cytoplasmic domain of the transmembrane modulator protein EnvZ is phosphorylated in vitro by [7-32P]

Lipid-Mediated Regulation of Embedded Receptor Kinases via Parallel Allosteric Relays

“…The EnvZ/OmpR system is a prototypical TCS in which EnvZ senses changes in environmental osmolality and transmits the signal to its response regulator, OmpR. OmpR is a transcription factor that regulates the transcription of the outer-membrane porin genes ompF and ompC (6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Phosphorylation of OmpR changes its affinity for promoters of outer membrane porin genes, resulting in altered porin expression (16).…”

Tuning of the porin expression under anaerobic growth conditions by His‐to‐Asp cross‐phosphorelay through both the EnvZ‐osmosensor and ArcB‐anaerosensor in Escherichia coli

“…1). The EnvZ osmosensor exhibits a typical His-kinase activity speci®c towards the OmpR transcriptional activator (Aiba et al 1989a,b;Forst et al 1989;Igo et al 1989). The resulting phospho-OmpR is an active form of DNA-binding transcriptional activator for both the ompC and ompF promoters (Aiba et al 1989c).…”

The Critical Role of the Conserved Thr247 Residue in the Functioning of the Osmosensor EnvZ, a Histidine Kinase/Phosphatase, in Escherichia coli

“…After another 3-h incubation, the cells were harvested and broken with a French press. The EnvZc and EnvZc(T247X) mutant proteins were purified by 40% ammonium sulfate fractionation and subsequent Sephacryl S-100HR gel-filtration column chromatography (15). Proteins were quantified using the Bio-Rad protein assay reagent.…”

“…The mutant envZ genes thus constructed were confirmed by nucleotide sequencing. Plasmid pZcT247R, carrying the EnvZc(T247R) mutant, was created earlier in the laboratory by sitedirected mutagenesis of envZ using M13 as described previously (15) and subsequent cloning into plasmid pET11a-EnvZc. 2 Construction of Plasmids Used in the in Vivo ␤-Galactosidase Assays-The pTazT247X plasmids (X ϭ Ala, Glu, Lys, Cys, Ser, Tyr, Arg, Asn, or Gln) carrying mutations of the taz1-1 gene were constructed by ligating the NdeI-HindIII fragment from pTJ003 (24) and the NdeIHindIII fragments from the pZcT247X plasmids (created for the in vitro assays in this study).…”