title: A Cdk5 inhibitory peptide reduces tau hyperphosphorylation and apoptosis in neurons.
abstract: The extracellular aggregation of amyloid beta (Abeta) peptides and the intracellular hyperphosphorylation of tau at specific epitopes are pathological hallmarks of neurodegenerative diseases such as Alzheimer's disease (AD). Cdk5 phosphorylates tau at AD-specific phospho-epitopes when it associates with p25. p25 is a truncated activator, which is produced from the physiological Cdk5 activator p35 upon exposure to Abeta peptides. We show that neuronal infections with Cdk5 inhibitory peptide (CIP) selectively inhibit p25/Cdk5 activity and suppress the aberrant tau phosphorylation in cortical neurons. Furthermore, Abeta(1-42)-induced apoptosis of these cortical neurons was also reduced by coinfection with CIP. Of particular importance is our finding that CIP did not inhibit endogenous or transfected p35/Cdk5 activity, nor did it inhibit the other cyclin-dependent kinases such as Cdc2, Cdk2, Cdk4 and Cdk6. These results, therefore, provide a strategy to address, and possibly ameliorate, the pathology of neurodegenerative diseases that may be a consequence of aberrant p25 activation of Cdk5, without affecting 'normal' Cdk5 activity.
authors.affiliation: Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-4130, USA.
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Zheng
authors.forename: Sashi
authors.initials: S
authors.lastname: Kesavapany
authors.forename: Maneth
authors.initials: M
authors.lastname: Gravell
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Hamilton
authors.forename: Manfred
authors.initials: M
authors.lastname: Schubert
authors.forename: Niranjana
authors.initials: N
authors.lastname: Amin
authors.forename: Wayne
authors.initials: W
authors.lastname: Albers
authors.forename: Philip
authors.initials: P
authors.lastname: Grant
authors.forename: Harish C
authors.initials: HC
authors.lastname: Pant
mesh_terms: D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D016203:CDC2 Protein Kinase / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000033:anatomy & histology; D006801:Humans; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D019636:Neurodegenerative Diseases / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010446:Peptide Fragments / Q000378:metabolism; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016875:tau Proteins / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D010455:Peptides; D011993:Recombinant Fusion Proteins; C075222:amyloid beta-protein (1-42); C089495:neuronal Cdk5 activator (p25-p35); D016875:tau Proteins; D051360:Cyclin-Dependent Kinase 5; D016203:CDC2 Protein Kinase; C495905:CDK5 protein, human; C495907:Cdk5 protein, rat; D018844:Cyclin-Dependent Kinases; C505407:CASP3 protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases