ANALYSIS OF PHOSPHORYLATION OF TAU WITH ANTIBODIES SPECIFIC FOR PHOSPHORYLATION SITES

Previously, we determined sites of tau protein phosphorylation by tau protein kinase (TPK) I/glycogen synthase kinase 3 beta (GSK-3 beta) an d TPKII/(cyclin-dependent kinase 5 (CDK5) + p23). We prepared antibodi es specific for these sites of tau phosphorylated by TPKI and TPKII, u sing chemically synthesized phosphopeptides as antigens. Each antibody specifically reacts with each phosphorylation site. With these antibo dies, it was confirmed that TPKI and TPKII are responsible for these p hosphorylation sites, as reported previously, except that Ser404 is al so weakly phosphorylated by TPKI alone. It was also observed that TPKI I-phosphorylation enhances TPKI-phosphorylation. These results indicat e that these antibodies are useful tools for investigation of the phos phorylation of tau by TPKI and TPKII.