title: Parkin prevents mitochondrial swelling and cytochrome c release in mitochondria-dependent cell death.
abstract: Parkin gene mutations have been implicated in autosomal-recessive early-onset parkinsonism and lead to specific degeneration of dopaminergic neurons in midbrain. To investigate the role of Parkin in neuronal cell death, we overproduced this protein in PC12 cells in an inducible manner. In this cell line, neuronally differentiated by nerve growth factor, Parkin overproduction protected against cell death mediated by ceramide, but not by a variety of other cell death inducers (H(2)O(2), 4-hydroxynonenal, rotenone, 6-OHDA, tunicamycin, 2-mercaptoethanol and staurosporine). Protection was abrogated by the proteasome inhibitor epoxomicin and disease-causing variants, indicating that it was mediated by the E3 ubiquitin ligase activity of Parkin. Interestingly, Parkin acted by delaying mitochondrial swelling and subsequent cytochrome c release and caspase-3 activation observed in ceramide-mediated cell death. Subcellular fractionation demonstrated enrichment of Parkin in the mitochondrial fraction and its association with the outer mitochondrial membrane. Together, these results suggest that Parkin may promote the degradation of substrates localized in mitochondria and involved in the late mitochondrial phase of ceramide-mediated cell death. Loss of this function may underlie the degeneration of nigral dopaminergic neurons in patients with Parkin mutations.
authors.affiliation: INSERM U289, Hôpital de la Salpêtrière, 75013 Paris, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Darios
authors.forename: Olga
authors.initials: O
authors.lastname: Corti
authors.forename: Christoph B
authors.initials: CB
authors.lastname: Lücking
authors.forename: Cornelia
authors.initials: C
authors.lastname: Hampe
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Muriel
authors.forename: Nacer
authors.initials: N
authors.lastname: Abbas
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Gu
authors.forename: Etienne C
authors.initials: EC
authors.lastname: Hirsch
authors.forename: Thomas
authors.initials: T
authors.lastname: Rooney
authors.forename: Merle
authors.initials: M
authors.lastname: Ruberg
authors.forename: Alexis
authors.initials: A
authors.lastname: Brice
mesh_terms: D000818:Animals; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D016923:Cell Death / Q000502:physiology; D002518:Ceramides / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism*; D006801:Humans; D008025:Ligases / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D051381:Rats; D044767:Ubiquitin-Protein Ligases
chemical_list: D002518:Ceramides; D003574:Cytochrome c Group; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein; C505407:CASP3 protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D008025:Ligases