Tyrosine Phosphorylation Regulates the Proteolytic Activation of Protein Kinase Cδ in Dopaminergic Neuronal Cells

• Published in: The Journal of biological chemistry Vol. 280; no. 31; p. 28721
• Main Authors: Siddharth Kaul, Vellareddy Anantharam, Yongjie Yang, Christopher J. Choi, Arthi Kanthasamy, Anumantha G. Kanthasamy
• Format: Journal Article
• Language: English
• Published: American Society for Biochemistry and Molecular Biology 05.08.2005
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M501092200

Oxidative stress is a key apoptotic stimulus in neuronal cell death and has been implicated in the pathogenesis of many neurodegenerative disorders, including Parkinson disease (PD). Recently, we demonstrated that protein kinase C-δ (PKCδ) is an oxidative stress-sensitive kinase that can be activated by caspase-3-dependent proteolytic cleavage to induce apoptotic cell death in cell culture models of Parkinson disease (Kaul, S., Kanthasamy, A., Kitazawa, M., Anantharam, V., and Kanthasamy, A. G. (2003) Eur. J. Neurosci. 18, 1387-1401 and Kanthasamy, A. G., Kitazawa, M., Kanthasamy, A., and Anantharam, V. (2003) Antioxid. Redox. Signal. 5, 609-620). Here we showed that the phosphorylation of a tyrosine residue in PKCδ can regulate the proteolytic activation of the kinase during oxidative stress, which consequently influences the apoptotic cell death in dopaminergic neuronal cells. Exposure of a mesencephalic dopaminergic neuronal cell line (N27 cells) to H 2 O 2 (0-300 μ m ) induced a dose-dependent increase in cytotoxicity, caspase-3 activation and PKCδ cleavage. H 2 O 2 -induced proteolytic activation of PKC was δ mediated by the activation of caspase-3. Most interestingly, both the general Src tyrosine kinase inhibitor genistein (25 μ m ) and the p60 Src tyrosine-specific kinase inhibitor (TSKI; 5 μ m ) dramatically inhibited H 2 O 2 and the Parkinsonian toxin 1-methyl-4-phenylpyridinium-induced PKCδ cleavage, kinase activation, and apoptotic cell death. H 2 O 2 treatment also increased phosphorylation of PKCδ at tyrosine site 311, which was effectively blocked by co-treatment with TSKI. Furthermore, N27 cells overexpressing a PKCδ Y311F mutant protein exhibited resistance to H 2 O 2 -induced PKCδ cleavage, caspase activation, and apoptosis. To our knowledge, these data demonstrate for the first time that phosphorylation of Tyr-311 on PKCδ can regulate the proteolytic activation and proapoptotic function of the kinase in dopaminergic neuronal cells.