MAPT and Alzheimer disease: The first group contains proteins such as glycogen synthetase kinase-3 beta (GSK3β), that phosphorylates tau at different sites (specifically at 42 sites, 29 of them phosphorylated in AD brains) and casein kinase 1 delta (CK1δ), a non-proline-directed protein kinase (non-PDPK) that regulates the microtubule dynamics through tau phosphorylation at 46 sites (25 of them phosphorylated in AD brains).