The OMM-severed and IMM-ubiquitinated mitochondria are intermediates of mitochondrial proteotoxicity-induced autophagy in PRKN/parkin-deficient cells.
The OMM-severed and IMM-ubiquitinated mitochondria are intermediates of mitochondrial proteotoxicity-induced autophagy in PRKN/parkin-deficient cells.
复制标题
OMM 切断和 IMM 泛素化线粒体是 PRKN/parkin 缺陷细胞中线粒体蛋白毒性诱导自噬的中间体。
DOI：
10.1080/15548627.2021.1964887
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发表时间：
2021
期刊：
影响因子：
13.3
通讯作者：
Karbowski,Mariusz
中科院分区：
文献类型：
--
作者：
Oshima,Yumiko;Verhoeven,Nicolas;Cartier,Etienne;Karbowski,Mariusz
除其他机制外，线粒体膜动力学（包括线粒体裂变和融合）以及泛素 (Ub)-蛋白酶体系统 (UPS) 的活性对于维持线粒体功能都至关重要。为了加深我们对线粒体裂变、UPS 的作用以及它们如何协调影响线粒体对蛋白毒性反应的了解，我们分析了 E3 Ub 连接酶 PRKN/parkin 表达和缺陷细胞中的线粒体泛素化和线粒体特异性自噬（线粒体自噬）。通过成像、生化和遗传分析，我们发现在线粒体翻译保真度 (MTF) 急剧降低的模型中，单个细胞内的一些线粒体群富集，而一些线粒体群则显示 CYCS（细胞色素 c，体细胞）和 CPOX（粪卟啉原氧化酶）蛋白水平降低，这两种蛋白均位于膜间空间 （IMS）；此后称为“马赛克分布”。镶嵌线粒体的形成需要线粒体裂变和活跃的线粒体翻译。在缺乏 PRKN 活性的细胞系中，该过程随后是线粒体外膜 (OMM) 的切断和线粒体内膜 (IMM) 蛋白（包括 TRAP1 和 CPOX）的泛素化、自噬受体的募集以及线粒体自噬体的形成。相反，在表达 PRKN 的细胞中，PRKN 优先靶向具有高 CYCS 和 CPOX 水平的线粒体，导致 OMM 泛素化和典型的 PRKN-PINK1 介导的自噬。
Among other mechanisms, mitochondrial membrane dynamics including mitochondrial fission and fusion, and the activity of the ubiquitin (Ub)-proteasome system (UPS) both are critical for maintaining mitochondrial function. To advance our knowledge of the role of mitochondrial fission, the UPS, and how they coordinatively affect mitochondrial response to proteotoxicity, we analyzed mitochondrial ubiquitination and mitochondria-specific autophagy (mitophagy) in E3 Ub ligase PRKN/parkin-expressing and -deficient cells. Through imaging, biochemical, and genetic analyses, we found that in a model of acute reduction of mitochondrial translation fidelity (MTF) some population of mitochondria within a single cell are enriched, while some showed reduced levels of CYCS (cytochrome c, somatic) and CPOX (coproporphyrinogen oxidase) proteins, both located in the intermembrane space (IMS); henceforth called “mosaic distribution”. Formation of mosaic mitochondria requires mitochondrial fission and active mitochondrial translation. In cell lines deficient in PRKN activity, this process is followed by severing the outer mitochondrial membrane (OMM) and ubiquitination of the inner mitochondrial membrane (IMM) proteins (including TRAP1 and CPOX), recruitment of autophagy receptors, and formation of mito-autophagosomes. In contrast, in PRKN-expressing cells, mitochondria with high CYCS and CPOX levels are preferentially targeted by PRKN, leading to OMM ubiquitination and canonical PRKN-PINK1-mediated autophagy.