CheY acetylation is required for ordinary adaptation time in Escherichia coli chemotaxis

Recent studies demonstrated the dependence of speed adaptation in Escherichia coli on acetylation of the chemotaxis signaling molecule CheY. Here, we examined whether CheY acetylation is involved in chemotactic adaptation. A mutant lacking the acetylating enzyme acetyl-CoA synthetase (Acs) requires more time to adapt to attractant stimulation, and vice versa to repellent stimulation. This effect is avoided by conditions that favor production of acetyl-CoA, thus enabling Acs-independent CheY autoacetylation, or reversed by expressing Acs from a plasmid. These findings suggest that CheY should be acetylated for ordinary adaptation time, and that the function of this acetylation in adaptation is to enable the motor to shift its rotation to clockwise. We further identify the enzyme phosphotransacetylase as a third deacetylase of CheY in E. coli.