wzc, as a tyrosine autokinase, plays an important role in the synthesis, maturation and transport of capsular polysaccharides. The switch between phosphorylation and dephosphorylation of wzc determines the opening and closing of capsular polysaccharide transport channels. The point mutation of wzc gene significantly changed the viscosity of bacteria. Phosphorylated proteome was determined to investigate whether the change of bacterial viscosity was related to the change of wzc phosphorylation state.