May be involved in the regulation of capsular polysaccharide biosynthesis. Autophosphorylates in vitro. Phosphorylates and activates in vitro two UDP-glucose dehydrogenases, YwqF and TuaD, as well as the DNA-binding proteins Ssb and SsbB. ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Autophosphorylated in vitro, which inhibits ATPase activity. Dephosphorylated by YwqE in vitro. Belongs to the CpsD/CapB family.