Chemotactic-signal transducers respond to changes in the concentration of attractants and repellents in the environment, transduce a signal from the outside to the inside of the cell, and facilitate sensory adaptation through the variation of the level of methylation. All amino acids serve as attractants in B.subtilis, they appear to cause an increase in the turnover methyl groups, leading to methylation of an unidentified acceptor, while repellents have been shown to cause a decrease in methyl group turnover. The methyl groups are added by a methyltransferase and removed by a methylesterase. McpB is required for taxis towards asparagine, aspartate, glutamine, and histidine. Interacts with FloT. Present in detergent-resistant membrane (DRM) fractions that may be equivalent to eukaryotic membrane rafts; these rafts include proteins involved in signaling, molecule trafficking and protein secretion. Some glutamine residues are deamidated to glutamate by CheD and subsequently methylated. The demethylation is selective. Gln-371 is demethylated only upon asparagine addition whereas Glu-637 is demethylated only upon asparagine removal. Glu-630 appears indiscriminate and is demethylated upon both addition and removal of asparagine. Only chemotaxis towards asparagine is completely deficient in the absence of McpB. Belongs to the methyl-accepting chemotaxis (MCP) protein family.