CDK5 and Alzheimer disease: Previous studies have revealed that dysregulation of CDK5 and its activators p35 and p25 contribute to the abnormal accumulation of hyperphosphorylated CDK5 substrates and eventual mature neuronal cell death in AD, HIV-associated neuroinflammatory conditions such as HIV encephalitis (HIVE), and prion-related disorders such as scrapie [4-6].