Mutations in the PTEN-induced putative kinase1 (PINK1) represent the second most frequent cause of autosomal recessive Parkinson's disease. The PINK1 protein mainly localizes to mitochondria and interacts with a variety of proteins, including the pro-autophagy protein beclin1 and the ubiquitin-ligase parkin. Upon stress conditions, PINK1 is known to recruit parkin at the surface of dysfunctional mitochondria and to activate the mitophagy cascade. Aim of this study was to use a simple and highly reproducible catecholamine cell model and transmission electron microscopy to characterize whether PINK1 could affect mitochondrial homeostasis, the recruitment of specific proteins at mitochondria, mitophagy and apoptosis. Samples were analyzed both in baseline conditions and following treatment with methamphetamine (METH), a neurotoxic compound which strongly activates autophagy and produces mitochondrial damage. Our data provide robust sub-cellular evidence that the modulation of PINK1 levels dramatically affects the morphology and number of mitochondria and the amount of cell death. In particular, especially upon METH exposure, PINK1 is able to increase the total number of mitochondria, concurrently recruit beclin1, parkin and ubiquitin and enhance the clearance of damaged mitochondria. In the absence of functional PINK1 and upon autophagy stress, we observe a failure of the autophagy system at large, with marked accumulation of dysfunctional mitochondria and dramatic increase of apoptotic cell death. These findings highlight the strong neuroprotective role of PINK1 as a key protein in the surveillance and regulation of mitochondrial homeostasis.

中文翻译：

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PINK1 基因调控对线粒体改变、自噬和细胞死亡的亚细胞分析。

PTEN 诱导的推定激酶 1 (PINK1) 中的突变是常染色体隐性帕金森病的第二大常见原因。PINK1 蛋白主要定位于线粒体并与多种蛋白质相互作用，包括促自噬蛋白 beclin1 和泛素连接酶 parkin。在压力条件下，已知 PINK1 会在功能失调的线粒体表面募集 Parkin 并激活线粒体自噬级联反应。本研究的目的是使用简单且高度可重复的儿茶酚胺细胞模型和透射电子显微镜来表征 PINK1 是否会影响线粒体稳态、线粒体中特定蛋白质的募集、线粒体自噬和细胞凋亡。在基线条件下和用甲基苯丙胺 (METH) 处理后对样品进行分析，一种神经毒性化合物，可强烈激活自噬并产生线粒体损伤。我们的数据提供了强有力的亚细胞证据，表明 PINK1 水平的调节显着影响线粒体的形态和数量以及细胞死亡的数量。特别是在 METH 暴露后，PINK1 能够增加线粒体总数，同时招募 beclin1、parkin 和泛素，并增强受损线粒体的清除率。在没有功能性 PINK1 和自噬应激的情况下，我们观察到自噬系统总体上失败，功能失调的线粒体显着积累，凋亡细胞死亡显着增加。这些发现突出了 PINK1 作为监测和调节线粒体稳态的关键蛋白质的强大神经保护作用。