2012 Fiscal Year Final Research Report

The molecular mechanism underlying PINK1-madiated mitochondrial maintenance

Research Project

Project/Area Number	23890206
Research Category	Grant-in-Aid for Research Activity Start-up
Allocation Type	Single-year Grants
Research Field	General medical chemistry
Research Institution	Juntendo University
Principal Investigator	KANAO Tomoko 順天堂大学, 大学院・医学系研究科, 研究員 (00614083)
Project Period (FY)	2010 – 2012
Keywords	パーキンソン病 / PINK1 / Parkin / PGAM5 / 神経変性
Research Abstract	We have reported that PGAM5 acts between PINK1 and Parkin. To understand the molecular roles of PAGM5 in the PINK1-Parkin pathway further, we searched for PGAM5-binding proteins using mass spectrometric analysis and screened genes encoding these binding proteins using Drosophila PINK1 models. We found that Rictor modulates the phenotypes caused by PINK1 inactivation in Drosophila. However, PINK1 did not modify the phosphorylation status of Rictor in cultured cells, suggesting that Rictor is not a direct substrate of PINK1. To isolate physiological substrates of PINK1, we performed phospho-proteomics analysis and subsequent in vitro kinase assay using normal and PINK1 mutant cells. We then found that Ser65 in the ubiquitin-like domain (Ubl) of Parkin is phosphorylated in a PINK1-dependent manner upon depolarization of mitochondrial membrane potential. We further showed that the phosphorylation of Parkin is required for the activation of its ubiquitin-ligase activity.