This chemotaxis protein stimulates methylation of MCP proteins [1]. The chemotaxis machinery of Bacillus subtilis is similar to that of the well characterised system of Escherichia coli. However, B. subtilis contains several chemotaxis genes not found in the E. coli genome, such as CheC and CheD, indicating that the B. subtilis chemotactic system is more complex. CheD plays an important role in chemotactic sensory transduction for many organisms. CheD deamidates other B. subtilis chemoreceptors including McpB and McpC. Deamidation by CheD is required for B. subtilis chemoreceptors to effectively transduce signals to the CheA kinase [2]. The structure of a complex between the signal-terminating phosphatase, CheC, and the receptor-modifying deamidase, CheD, reveals how CheC mimics receptor substrates to inhibit CheD and how CheD stimulates CheC phosphatase activity. CheD resembles other cysteine deamidases from bacterial pathogens that inactivate host Rho-GTPases. Phospho-CheY, the intracellular signal and CheC target, stabilises the CheC-CheD complex and reduces availability of CheD [3]. A model is proposed whereby CheC acts as a CheY-P-induced regulator of CheD; CheY-P would cause CheC to sequester CheD from the chemoreceptors, inducing adaptation of the chemotaxis system [4].

1: CheC and CheD interact to regulate methylation of Bacillus subtilis methyl-accepting chemotaxis proteins. Rosario MM, Ordal GW; Mol Microbiol 1996;21:511-518. PMID:8866475

2: Bacillus subtilis CheD is a chemoreceptor modification enzyme required for chemotaxis. Kristich CJ, Ordal GW; J Biol Chem. 2002;277:25356-25362. PMID:12011078

3: A receptor-modifying deamidase in complex with a signaling phosphatase reveals reciprocal regulation. Chao X, Muff TJ, Park SY, Zhang S, Pollard AM, Ordal GW, Bilwes AM, Crane BR; Cell. 2006;124:561-571. PMID:16469702

4: The CheC phosphatase regulates chemotactic adaptation through CheD. Muff TJ, Ordal GW; J Biol Chem. 2007;282:34120-34128. PMID:17908686