Mitofusin 1 and mitofusin 2 are ubiquitinated in a PINK1/parkin-dependent manner upon induction of mitophagy
Mitofusin 1 and mitofusin 2 are ubiquitinated in a PINK1/parkin-dependent manner upon induction of mitophagy
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DOI：
10.1093/hmg/ddq419
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发表时间：
2010-12-15
影响因子：
3.5
通讯作者：
Taanman, Jan-Willem
中科院分区：
文献类型：
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作者：
Gegg, Matthew E.;Cooper, J. Mark;Taanman, Jan-Willem
线粒体功能障碍和蛋白质降解紊乱与帕金森病（PD）的发病机制有关。Parkin和PINK 1基因突变是家族性PD的原因之一。PINK 1是一种推定的与线粒体相关的激酶，PINK 1表达的缺失导致线粒体功能障碍，其随时间增加。Parkin被认为是PINK 1的下游，并且还介导通过大自噬（mitophagy）去除受损的线粒体。我们研究了通过RNAi降低PINK 1表达后多巴胺能SH-SY 5 Y细胞中的线粒体功能障碍是否部分是由于线粒体自噬的抑制。发现通过大自噬途径的通量减少与PINK 1沉默12天后ATP合成的抑制一致。parkin在这些细胞中的过表达恢复了自噬通量和ATP合成。过表达和RNAi研究还表明，PINK 1和parkin是CCCP诱导的线粒体损伤后线粒体自噬所必需的。在CCCP处理后3 h内检测到几种线粒体蛋白的泛素化，包括mitofusin 1和mitofusin 2。这些翻译后修饰在parkin或PINK 1沉默后减少。线粒体蛋白的泛素化似乎可以识别线粒体的降解并促进线粒体自噬。因此，PINK 1和parkin是清除多巴胺能细胞中受损线粒体所必需的，抑制该途径可能导致有缺陷线粒体的积累，这可能有助于PD发病机制。
Mitochondrial dysfunction and perturbed degradation of proteins have been implicated in Parkinson's disease (PD) pathogenesis. Mutations in the Parkin and PINK1 genes are a cause of familial PD. PINK1 is a putative kinase associated with mitochondria, and loss of PINK1 expression leads to mitochondrial dysfunction, which increases with time. Parkin is suggested to be downstream of PINK1 and also mediates the removal of damaged mitochondria by macroautophagy (mitophagy). We investigated whether mitochondrial dysfunction in dopaminergic SH-SY5Y cells following decreased PINK1 expression by RNAi may in part be due to the inhibition of mitophagy. Reduced flux through the macroautophagy pathway was found to be coincident with the inhibition of ATP synthesis following 12 days of PINK1 silencing. Overexpression of parkin in these cells restored both autophagic flux and ATP synthesis. Overexpression and RNAi studies also indicated that PINK1 and parkin were required for mitophagy following CCCP-induced mitochondrial damage. The ubiquitination of several mitochondrial proteins, including mitofusin 1 and mitofusin 2, were detected within 3 h of CCCP treatment. These post-translational modifications were reduced following the silencing of parkin or PINK1. The ubiquitination of mitochondrial proteins appears to identify mitochondria for degradation and facilitate mitophagy. PINK1 and parkin are thus required for the removal of damaged mitochondria in dopaminergic cells, and inhibition of this pathway may lead to the accumulation of defective mitochondria which may contribute to PD pathogenesis.