Inhibiting serine/threonine protein kinases, such as glycogen synthase kinase-3β (GSK-3β), cyclin-dependent kinase-5 (CDK-5), and extracellular signal-regulated kinase 1/2 (ERK1/2), can ameliorate tau hyperphosphorylation and pathologies in AD.1 However, kinases inhibitors showed poor selectivity in reducing tau phosphorylation. Here, CDK5 is linked to Alzheimer disease.