title: CheC is related to the family of flagellar switch proteins and acts independently from CheD to control chemotaxis in Bacillus subtilis.
abstract: Chemotaxis by Bacillus subtilis requires the inter-acting chemotaxis proteins CheC and CheD. In this study, we show that CheD is absolutely required for a behavioural response to proline mediated by McpC but is not required for the response to asparagine mediated by McpB. We also show that CheC is not required for the excitation response to asparagine stimulation but is required for adaptation while asparagine remains complexed with the McpB chemoreceptor. CheC displayed an interaction with the histidine kinase CheA as well as with McpB in the yeast two-hybrid assay, suggesting that the mechanism by which CheC affects adaptation may result from an interaction with the receptor-CheA complex. Furthermore, CheC was found to be related to the family of flagellar switch proteins comprising FliM and FliY but is not present in many proteobacterial genomes in which CheD homologues exist. The distinct physiological roles for CheC and CheD during B. subtilis chemotaxis and the observation that CheD is present in bacterial genomes that lack CheC indicate that these proteins can function independently and may define unique pathways during chemotactic signal transduction. We speculate that CheC interacts with flagellar switch components and dissociates upon CheY-P binding and subsequently interacts with the receptor complex to facilitate adaptation.
authors.affiliation: Department of Biochemistry, College of Medicine, University of Illinois, Urbana, IL 61801, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Kirby
authors.forename: C J
authors.initials: CJ
authors.lastname: Kristich
authors.forename: M M
authors.initials: MM
authors.lastname: Saulmon
authors.forename: M A
authors.initials: MA
authors.lastname: Zimmer
authors.forename: L F
authors.initials: LF
authors.lastname: Garrity
authors.forename: I B
authors.initials: IB
authors.lastname: Zhulin
authors.forename: G W
authors.initials: GW
authors.lastname: Ordal
mesh_terms: D000595:Amino Acid Sequence; D001216:Asparagine / Q000494:pharmacology; D001412:Bacillus subtilis / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D011392:Proline / Q000494:pharmacology; D016415:Sequence Alignment; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; C446291:CheC protein, Bacillus subtilis; C446292:CheD protein, Bacillus subtilis; C077389:FliN protein, Bacteria; D001216:Asparagine; D011392:Proline