CDK5 and Alzheimer disease: Intracerebroventricular infusions of the CDK5 inhibitory peptide (CIP), a 125 aa peptide generated from p35 by C- and N-terminal cleavage inhibits CDK5/p25 activity and reduces Tau hyperphosphorylation, the number of NFTs and neurodegeneration in the p25-overpressing transgenic mouse model of AD [409].