title: Regulation of p53 by activated protein kinase C-delta during nitric oxide-induced dopaminergic cell death.
abstract: Selective cell death of dopaminergic neurons in the substantia nigra is the major cause of Parkinson disease. Current evidence suggests that this cell death could be mediated by nitric oxide by-products such as nitrate and peroxynitrite. Because protein kinase C (PKC)-delta is implicated in apoptosis of various cell types, we studied its roles and activation mechanisms in nitric oxide (NO)-induced apoptosis of SN4741 dopaminergic cells. When cells were treated with sodium nitroprusside (SNP), a NO donor, endogenous PKC-delta was nitrated and activated. Immunoprecipitation revealed that p53 co-immunoprecipitated with PKC-delta and was phosphorylated at the 15th serine residue in SNP-treated cells. An in vitro kinase assay revealed that p53 was directly phosphorylated by SNP-activated PKC-delta. The p53 Ser-15 phosphorylation was suppressed in SNP-treated cells when the NO-mediated activation of PKC-delta was inhibited by rottlerin or (-)-epigallocatechin gallate. Within 3 h of p53 phosphorylation, its protein levels increased because of decreased ubiquitin-dependent proteosomal proteolysis, whereas the protein levels of MDM2, ubiquitin-protein isopeptide ligase, were down-regulated in a p53 phosphorylation-dependent fashion. Taken together, these results demonstrate that nitration-mediated activation of PKC-delta induces the phosphorylation of the Ser-15 residue in p53, which increases its protein stability, thereby contributing to the nitric oxide-mediated apoptosis-like cell death pathway. These findings may be expanded to provide new insight into the cellular mechanisms of Parkinson disease.
authors.affiliation: Systems Bio-Dynamics NCRC, Division of Molecular and Life Science, POSTECH, Pohang 790-784, Korea.
authors.forename: Sung-Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Dong-Chan
authors.initials: DC
authors.lastname: Kim
authors.forename: Bo-Hwa
authors.initials: BH
authors.lastname: Choi
authors.forename: Hyunjung
authors.initials: H
authors.lastname: Ha
authors.forename: Kyong-Tai
authors.initials: KT
authors.lastname: Kim
mesh_terms: D000818:Animals; D017209:Apoptosis; D002392:Catechin / Q000031:analogs & derivatives / Q000737:chemistry; D016923:Cell Death; D002460:Cell Line; D002470:Cell Survival; D018920:Coculture Techniques; D004298:Dopamine / Q000378:metabolism*; D004789:Enzyme Activation; D015151:Immunoblotting; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D020287:In Situ Nick-End Labeling; D051379:Mice; D017628:Microglia / Q000378:metabolism; D008954:Models, Biological; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism*; D009573:Nitrites; D009599:Nitroprusside / Q000494:pharmacology; D010300:Parkinson Disease / Q000378:metabolism; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D051745:Protein Kinase C-delta / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D009573:Nitrites; D016159:Tumor Suppressor Protein p53; D009599:Nitroprusside; D009569:Nitric Oxide; D012694:Serine; D002392:Catechin; C045651:epigallocatechin gallate; D051736:Proto-Oncogene Proteins c-mdm2; D051745:Protein Kinase C-delta; D046988:Proteasome Endopeptidase Complex; D004298:Dopamine