Glycogen synthase kinase-3 beta (GSK3β) and cyclin-dependent protein kinase-5 (CDK5), proline-directed kinases, are well-known enzymes linked to neurofibrillary pathology in AD, both of which were suggested to cause phosphorylation of tau on pathogenic sites in AD [50, 51]. The gene discussed is CDK5; the disease is Alzheimer disease.