Attenuation of sensory receptor signaling by covalent modification.
The Tar receptor is a transmembrane protein that regulates bacterial chemotaxis in response to changes in the level of aspartic acid in the medium. The extracellular portion of the protein can bind aspartate, and the cytoplasmic portion modulates CheA kinase activity. The receptor can either activate or inhibit the kinase. The cytoplasmic portion of the receptor can be modified by carboxymethylation of specific glutamic acid residues. To test the effects of differential methylation on receptor function, we prepared membranes from cells that have specifically modified forms of the receptor and tested the relative ability of each of these forms to activate or inhibit CheA kinase. Completely demethylated receptor was a potent inhibitor and poor activator of the kinase, while the fully modified receptor was an excellent activator but an inefficient inhibitor. Partially modified receptor could act both as an effective inhibitor and as an activator. Reversible modification provides a mechanism that allows the cell to accumulate a population of receptor molecules capable of generating a wide range of signaling intensities.[1]References
- Attenuation of sensory receptor signaling by covalent modification. Borkovich, K.A., Alex, L.A., Simon, M.I. Proc. Natl. Acad. Sci. U.S.A. (1992) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg