title: PINK1-mediated phosphorylation of Parkin boosts Parkin activity in Drosophila.
abstract: Two genes linked to early onset Parkinson's disease, PINK1 and Parkin, encode a protein kinase and a ubiquitin-ligase, respectively. Both enzymes have been suggested to support mitochondrial quality control. We have reported that Parkin is phosphorylated at Ser65 within the ubiquitin-like domain by PINK1 in mammalian cultured cells. However, it remains unclear whether Parkin phosphorylation is involved in mitochondrial maintenance and activity of dopaminergic neurons in vivo. Here, we examined the effects of Parkin phosphorylation in Drosophila, in which the phosphorylation residue is conserved at Ser94. Morphological changes of mitochondria caused by the ectopic expression of wild-type Parkin in muscle tissue and brain dopaminergic neurons disappeared in the absence of PINK1. In contrast, phosphomimetic Parkin accelerated mitochondrial fragmentation or aggregation and the degradation of mitochondrial proteins regardless of PINK1 activity, suggesting that the phosphorylation of Parkin boosts its ubiquitin-ligase activity. A non-phosphorylated form of Parkin fully rescued the muscular mitochondrial degeneration due to the loss of PINK1 activity, whereas the introduction of the non-phosphorylated Parkin mutant in Parkin-null flies led to the emergence of abnormally fused mitochondria in the muscle tissue. Manipulating the Parkin phosphorylation status affected spontaneous dopamine release in the nerve terminals of dopaminergic neurons, the survivability of dopaminergic neurons and flight activity. Our data reveal that Parkin phosphorylation regulates not only mitochondrial function but also the neuronal activity of dopaminergic neurons in vivo, suggesting that the appropriate regulation of Parkin phosphorylation is important for muscular and dopaminergic functions.
authors.affiliation: Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Kahori
authors.initials: K
authors.lastname: Shiba-Fukushima
authors.affiliation: Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Inoshita
authors.affiliation: Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan; Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Hattori
authors.affiliation: Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Imai
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D042967:Electron Transport Complex I / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000294:innervation / Q000473:pathology; D010300:Parkinson Disease / Q000235:genetics; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination; D014921:Wings, Animal / Q000294:innervation / Q000473:pathology; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D000099202:PTEN-Induced Putative Kinase
chemical_list: D029721:Drosophila Proteins; D042967:Electron Transport Complex I; D008565:Membrane Proteins; D017346:Protein Serine-Threonine Kinases; D044767:Ubiquitin-Protein Ligases; D020741:rho GTP-Binding Proteins; C527117:Marf protein, Drosophila; C534484:PINK1 protein, Drosophila; D000099202:PTEN-Induced Putative Kinase; C504427:Miro protein, Drosophila; C487430:park protein, Drosophila