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Interactions among the three adaptation systems of B acillus subtilis chemotaxis as revealed by an in vitro receptor‐kinase assay
Author(s) -
Walukiewicz Hanna E.,
Tohidifar Payman,
Ordal George W.,
Rao Christopher V.
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12721
Subject(s) - chemotaxis , biology , bacillus subtilis , receptor , sensory adaptation , microbiology and biotechnology , kinase , function (biology) , adaptation (eye) , methylation , signal transduction , biochemistry , genetics , neuroscience , sensory system , gene , bacteria
Summary The B acillus 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 .