FIGURE 10.

Phospho-sites on Tau preceded by basic residues display resistance to dephosphorylation by PP2A. A, amino acid sequences surrounding proline-directed phospho-sites (numbered) in human (h) Tau. Basic residues are underlined. B, wild type GST-Tau was phosphorylated in vitro by Cdk5 and GSK3β, then different amounts of PP2A were added for 1 h. Reactions were terminated by the addition of SDS loading buffer, then subjected to Western blot analysis using a total Tau antibody (Tau-5) and several phospho-specific Tau antibodies as indicated. mU, milliunits.