MAPT and Alzheimer disease: GSK3β plays also a key role in AD pathogenesis in which it contributes to several phosphorylation sites found in hyperphosphorylated PHF-Tau (Hanger et al., 1992; Morishima-Kawashima et al., 1995; Reynolds et al., 2002; Avila et al., 2010; Hernandez et al., 2012; Llorens-Maritin et al., 2014).