The role of Cdk5-mediated apurinic/apyrimidinic endonuclease 1 phosphorylation in neuronal death

• Published in: Nature cell biology Vol. 12; no. 6; pp. 563 - 571
• Main Authors: Haque, M. Emdadul, Woulfe, John M, Slack, Ruth S, Rousseaux, Maxime W.C, Park, David S, Qu, Dianbo, Zhang, Yi, Huang, En, Venderova, Katerina
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2010; Nature Publishing Group
• Subjects: 631/337/1427/1429; 631/80/458/1733; 631/80/82; 692/699/375/365; Alzheimer's disease; Animals; Antibodies; Biomedical and Life Sciences; Brain research; Cancer Research; Cell Biology; Cell death; Cyclin-Dependent Kinase 5 - metabolism; Cyclin-Dependent Kinase 5 - physiology; Cyclin-dependent kinases; Deoxyribonucleic acid; Developmental Biology; DNA; DNA Damage; DNA-(Apurinic or Apyrimidinic Site) Lyase - metabolism; DNA-(Apurinic or Apyrimidinic Site) Lyase - physiology; Endonucleases - metabolism; Humans; Kinases; Life Sciences; Male; Mass spectrometry; Medical research; Mice; Mice, Knockout; Mortality; Neurons - metabolism; Nucleases; Pathogenesis; Phosphorylation; Physiological aspects; Protein kinases; Proteins; Scientific imaging; Stem Cells; Canada; South Korea; Ottawa Ontario Canada
• ISSN: 1465-7392; 1476-4679
• DOI: 10.1038/ncb2058

Cyclin-dependent kinase 5 phosphorylates Ape1, a regulator of base excision repair, to reduce its endonuclease activity and increase neuronal death following treatment with neurotoxins. Interestingly, increase in Ape1 phosphorylation is also observed in patients with neurodegenerative diseases. Accumulating evidence suggests that deregulated cyclin-dependent kinase 5 (Cdk5) plays a critical part in neuronal death. However, the pathogenic targets of Cdk5 are not fully defined. Here we demonstrate that the Cdk5 activator p35 interacts directly with apurinic/apyrimidinic endonuclease 1 (Ape1), a protein crucial for base excision repair (BER) following DNA damage. Cdk5 complexes phosphorylate Ape1 at Thr 232 and thereby reduces its apurinic/apyrimidinic (AP) endonuclease activity. Ape1 phosphorylation is dependent on Cdk5 in in vitro and in vivo . The reduced endonuclease activity of phosphorylated Ape1 results in accumulation of DNA damage and contributes to neuronal death. Overexpression of Ape1 WT and Ape1 T232A , but not the phosphorylation mimic Ape1 T232E , protects neurons against MPP + /MPTP. Loss of Ape1 sensitizes neurons to death. Importantly, increased phosphorylated Ape1 was also observed in post-mortem brain tissue from patients with Parkinson's and Alzheimer's diseases, suggesting a potential link between Ape1 phosphorylation and the pathogenesis of neurodegenerative diseases.