Member of the two-component regulatory system UvrY/BarA involved in the regulation of carbon metabolism via the CsrA/CsrB regulatory system. Phosphorylates UvrY, probably via a four-step phosphorelay (By similarity). ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. Activation requires a sequential transfer of a phosphate group from a His in the primary transmitter domain, to an Asp in the receiver domain and to a His in the secondary transmitter domain.