Of the two isoforms of GSK-3, GSK-3α and GSK-3β, GSK-3β is the major tau kinase (Ishiquro et al., 1993; Takashima et al., 1996) which can phosphorylate tau at multiple AD-related sites, including Ser-46, Thr-50, Thr-175, Thr-181, Ser-199, Ser-202, Thr-205, Thr-212, Thr-217, Thr-231, Ser-235, Ser-396, Ser-400, Ser-404, and Ser-413 (Wang and Liu, 2008; Hanger et al., 2009). Here, GSK3B is linked to Alzheimer disease.