CitB family of transcription factors consists of response regulators of two-component systems controlling transport and catabolism of tricarboxylates or dicarboxylates such as citrate, malate etc. [9973351, 19376865]. [22101843, 18997424]. Members of CitB family of response regulators and their cognate sensor kinases were found both in Gram-positive and Gram-negative bacteria . Activity of two-component response regulators is controlled via phosphorylation with phosphoryl group donated by cognate histidine kinase (e.g. CitA). Histidine kinases of CitB-family regulators, in their turn, undergo autophosphorylation process in response to binding of citrate , succinate, fumarate, malate, aspartate, and L- and D-tartrate .
CitB-family response regulators (COG4565) are composed of an N-terminal receiver domain and a characteristic C-terminal winged HTH DNA binding domain (SSF46785).