title: Drosophila parkin requires PINK1 for mitochondrial translocation and ubiquitinates mitofusin.
abstract: Loss of the E3 ubiquitin ligase Parkin causes early onset Parkinson's disease, a neurodegenerative disorder of unknown etiology. Parkin has been linked to multiple cellular processes including protein degradation, mitochondrial homeostasis, and autophagy; however, its precise role in pathogenesis is unclear. Recent evidence suggests that Parkin is recruited to damaged mitochondria, possibly affecting mitochondrial fission and/or fusion, to mediate their autophagic turnover. The precise mechanism of recruitment and the ubiquitination target are unclear. Here we show in Drosophila cells that PINK1 is required to recruit Parkin to dysfunctional mitochondria and promote their degradation. Furthermore, PINK1 and Parkin mediate the ubiquitination of the profusion factor Mfn on the outer surface of mitochondria. Loss of Drosophila PINK1 or parkin causes an increase in Mfn abundance in vivo and concomitant elongation of mitochondria. These findings provide a molecular mechanism by which the PINK1/Parkin pathway affects mitochondrial fission/fusion as suggested by previous genetic interaction studies. We hypothesize that Mfn ubiquitination may provide a mechanism by which terminally damaged mitochondria are labeled and sequestered for degradation by autophagy.
authors.affiliation: Department of Biomedical Sciences, Medical Research Council Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield S10 2TN, United Kingdom.
authors.forename: Elena
authors.initials: E
authors.lastname: Ziviani
authors.forename: Ran N
authors.initials: RN
authors.lastname: Tao
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Whitworth
mesh_terms: D000818:Animals; D001343:Autophagy; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000201:enzymology*; D055785:Gene Knockdown Techniques; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology*; D009154:Mutation / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport; D044767:Ubiquitin-Protein Ligases; D054875:Ubiquitination; D000099202:PTEN-Induced Putative Kinase
chemical_list: D029721:Drosophila Proteins; D008565:Membrane Proteins; D017346:Protein Serine-Threonine Kinases; D044767:Ubiquitin-Protein Ligases; C527117:Marf protein, Drosophila; C534484:PINK1 protein, Drosophila; D000099202:PTEN-Induced Putative Kinase; C487430:park protein, Drosophila