Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA.
Center for Computational Biology & Bioinformatics, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
Sci Rep. 2020 May 22;10(1):8499. doi: 10.1038/s41598-020-65438-7.
Parkin is an E3 ubiquitin ligase well-known for facilitating clearance of damaged mitochondria by ubiquitinating proteins on the outer mitochondrial membrane. However, knowledge of Parkin's functions beyond mitophagy is still limited. Here, we demonstrate that Parkin has functions in the nucleus and that Parkinson's disease-associated Parkin mutants, ParkinR42P and ParkinG430D, are selectively excluded from the nucleus. Further, Parkin translocates to the nucleus in response to hypoxia which correlates with increased ubiquitination of nuclear proteins. The serine-threonine kinase PINK1 is responsible for recruiting Parkin to mitochondria, but translocation of Parkin to the nucleus occurs independently of PINK1. Transcriptomic analyses of HeLa cells overexpressing wild type or a nuclear-targeted Parkin revealed that during hypoxia, Parkin contributes to both increased and decreased transcription of genes involved in regulating multiple metabolic pathways. Furthermore, a proteomics screen comparing ubiquitinated proteins in hearts from Parkin and Parkin transgenic mice identified the transcription factor estrogen-related receptor α (ERRα) as a potential Parkin target. Co-immunoprecipitation confirmed that nuclear-targeted Parkin interacts with and ubiquitinates ERRα. Further analysis uncovered that nuclear Parkin increases the transcriptional activity of ERRα. Overall, our study supports diverse roles for Parkin and demonstrates that nuclear Parkin regulates transcription of genes involved in multiple metabolic pathways.
Parkin 是一种 E3 泛素连接酶，以通过泛素化线粒体外膜上的蛋白质来促进清除受损线粒体而闻名。然而，Parkin 的功能超越自噬的知识仍然有限。在这里，我们证明 Parkin 具有核内功能，并且帕金森病相关的 Parkin 突变体 ParkinR42P 和 ParkinG430D 被选择性地排除在核外。此外，Parkin 在缺氧时易位到核内，这与核内蛋白质的泛素化增加有关。丝氨酸-苏氨酸激酶 PINK1 负责将 Parkin 募集到线粒体，但 Parkin 向核内的易位独立于 PINK1 发生。在过表达野生型或核靶向 Parkin 的 HeLa 细胞中转录组分析显示，在缺氧期间，Parkin 有助于参与调节多种代谢途径的基因的转录增加和减少。此外，比较 Parkin 和 Parkin 转基因小鼠心脏中泛素化蛋白质的蛋白质组学筛选鉴定了转录因子雌激素相关受体 α (ERRα) 作为潜在的 Parkin 靶标。免疫共沉淀证实核靶向 Parkin 与 ERRα 相互作用并泛素化 ERRα。进一步分析揭示了核内 Parkin 增加了 ERRα 的转录活性。总的来说，我们的研究支持 Parkin 的多种作用，并表明核内 Parkin 调节参与多种代谢途径的基因的转录。
