Required for the extracellular polysaccharide colanic acid synthesis. The autophosphorylated form is inactive. Probably involved in the export of colanic acid from the cell to medium (By similarity). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Dephosphorylated and activated by wzb. Glycan metabolism; exopolysaccharide biosynthesis. Autophosphorylated. Seems to be phosphorylated through a cooperative two-step mechanism. First, Tyr-568 is phosphorylated in an intramolecular reaction that generates a significant increase of protein kinase activity. Then Tyr-707, Tyr-709, Tyr-710, Tyr-712 and Tyr-714 are phosphorylated in an intermolecular Tyr-568-dependent reaction (By similarity). Belongs to the etk/wzc family.