title: Signaling by the Escherichia coli aspartate chemoreceptor Tar with a single cytoplasmic domain per dimer.
abstract: Many transmembrane receptors are oligomeric proteins. Binding of a ligand may alter the oligomeric state of the receptor, induce structural changes within the oligomer, or both. The bacterial aspartate chemoreceptor Tar forms a homodimer in the presence or absence of ligands. Tar mediates attractant and repellent responses by modulating the activity of the cytoplasmic kinase CheA. In vivo intersubunit suppression was used to show that certain combinations of full-length and truncated mutant Tar proteins complemented each other to restore attractant responses to aspartate. These results suggest that heterodimers with only one intact cytoplasmic domain are functional. The signaling mechanism may require interactions between dimers or conformational changes within a single cytoplasmic domain.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-01, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Tatsuno
authors.forename: M
authors.initials: M
authors.lastname: Homma
authors.forename: K
authors.initials: K
authors.lastname: Oosawa
authors.forename: I
authors.initials: I
authors.lastname: Kawagishi
mesh_terms: D001224:Aspartic Acid / Q000378:metabolism* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002628:Chemoreceptor Cells; D002633:Chemotaxis; D003593:Cytoplasm / Q000378:metabolism; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D029968:Escherichia coli Proteins; D005990:Glycerol / Q000494:pharmacology; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000072236:Methyl-Accepting Chemotaxis Proteins; D008745:Methylation; D009154:Mutation; D011487:Protein Conformation; D011494:Protein Kinases / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013489:Suppression, Genetic
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D011956:Receptors, Cell Surface; C057331:Tar protein, E coli; D001224:Aspartic Acid; D011494:Protein Kinases; D000071677:Histidine Kinase; C000607608:cheA protein, E coli; D005990:Glycerol