CDK5 and Alzheimer disease: In AD, several kinases, including A-kinase, C-kinase, cyclin-dependent kinase-5 (CDK-5), CaM kinase II, glycogen synthase kinase-3β (GSK-3β), and MAPKs [32,37] lead to hyperphosphorylation of Tau, resulting in its dissociation from MTs and the formation of NFT [38].