title: A peptide derived from cyclin-dependent kinase activator (p35) specifically inhibits Cdk5 activity and phosphorylation of tau protein in transfected cells.
abstract: Cyclin-dependent kinase-5 (Cdk5) is a serine/threonine kinase activated by its neuron-specific activator, p35, or its truncated form, p25. It has been proposed that the deregulation of Cdk5 activity by association with p25 in human brain tissue disrupts the neuronal cytoskeleton and may be involved in neurodegenerative diseases such as Alzheimer's disease. In this study, we demonstrate that a short peptide (amino acid residues 154-279; Cdk5 inhibitory peptide; CIP), derived from p35, specifically inhibits Cdk5 activity in vitro and in HEK293 cells cotransfected with the peptide and Cdk5/p25, but had no effect on endogenous cdc2 kinase activity. Moreover, we demonstrate that the phosphorylation of tau in HEK293 cells, cotransfected with Cdk5/p25 and CIP, is effectively reduced. These results suggest that CIP specifically inhibits both Cdk5/p25 complex activity and the tau hyperphosphorylation induced by Cdk5/p25. The elucidation of the molecular basis of p25 activation and CIP inhibition of Cdk5 activity may provide insight into mechanisms underlying the pathology of Alzheimer's disease and contribute to therapeutic strategies.
authors.affiliation: Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda 20892, USA.
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Zheng
authors.forename: Bing-Sheng
authors.initials: BS
authors.lastname: Li
authors.forename: Niranjana D
authors.initials: ND
authors.lastname: Amin
authors.forename: Wayne
authors.initials: W
authors.lastname: Albers
authors.forename: Harish C
authors.initials: HC
authors.lastname: Pant
mesh_terms: D000595:Amino Acid Sequence; D016203:CDC2 Protein Kinase / Q000378:metabolism; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D006801:Humans; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D014162:Transfection; D016875:tau Proteins / Q000378:metabolism*
chemical_list: C000588766:Cdk5 inhibitory peptide, human; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C089495:neuronal Cdk5 activator (p25-p35); D016875:tau Proteins; D051360:Cyclin-Dependent Kinase 5; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; C495905:CDK5 protein, human; D018844:Cyclin-Dependent Kinases