GSK3B and Alzheimer disease: Although many kinases can phosphorylate tau proteins in vitro, we limited our analysis to Dyrk1a, Cdk5, and GSK3β because they can phosphorylate tau in vivo (in the mouse brain) and are altered in late-onset AD brains (Lee et al., 2001; Ferrer et al., 2005; Schmid et al., 2006; Ballatore et al., 2007; Ryoo et al., 2007; Hooper et al., 2008).