Fig. 2.
Site-specific effects of prephosphorylation of tau by PKA on the subsequent phosphorylation by GSK-3β and cdk5. Recombinant tau441 was first phosphorylated by PKA, and then the phosphorylated tau (P-tau) and the control-treated tau (Tau) were further incubated with GSK-3β or cdk5/p25 for 150 min. The phosphorylation of tau and P-tau at various phosphorylation sites was examined by Western blots developed with phosphorylation-dependent and site-specific tau antibodies, as indicated under each blot.