title: Interactions among the three adaptation systems of Bacillus subtilis chemotaxis as revealed by an in vitro receptor-kinase assay.
abstract: The Bacillus subtilis chemotaxis pathway employs three systems for sensory adaptation: the methylation system, the CheC/CheD/CheYp system, and the CheV system. Little is known in general about how these three adaptation systems contribute to chemotaxis in B. subtilis and whether they interact with one another. To further understand these three adaptation systems, we employed a quantitative in vitro receptor-kinase assay. Using this assay, we were able to determine how CheD and CheV affect receptor-kinase activity as a function of the receptor modification state. CheD was found to increase receptor-kinase activity, where the magnitude of the increase depends on the modification state of the receptor. The principal new findings concern CheV. Little was known about this protein before now. Our data suggest that this protein has two roles depending on the modification state of the receptor, one for sensory adaptation when the receptors are modified (methylated) and the other for signal amplification when they are unmodified (unmethylated). In addition, our data suggest that methylation of site 630 tunes the strength of the CheV adaptation system. Collectively, our results provide new insight regarding the integrated function of the three adaptation systems in B. subtilis.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
authors.forename: Hanna E
authors.initials: HE
authors.lastname: Walukiewicz
authors.forename: Payman
authors.initials: P
authors.lastname: Tohidifar
authors.forename: George W
authors.initials: GW
authors.lastname: Ordal
authors.forename: Christopher V
authors.initials: CV
authors.lastname: Rao
mesh_terms: D000222:Adaptation, Physiological; D001412:Bacillus subtilis / Q000201:enzymology* / Q000502:physiology; D001426:Bacterial Proteins / Q000378:metabolism*; D002630:Chemotactic Factors / Q000378:metabolism*; D002633:Chemotaxis; D015964:Gene Expression Regulation, Bacterial; D008745:Methylation; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C446292:CheD protein, Bacillus subtilis; D002630:Chemotactic Factors; C087011:cheV protein, bacteria; D011494:Protein Kinases