Loss of MARCH5 mitochondrial E3 ubiquitin ligase induces cellular senescence through dynamin-related protein 1 and mitofusin 1
Loss of MARCH5 mitochondrial E3 ubiquitin ligase induces cellular senescence through dynamin-related protein 1 and mitofusin 1
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DOI：
10.1242/jcs.061481
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发表时间：
2010-02-15
影响因子：
4
通讯作者：
Cho, Hyeseong
中科院分区：
文献类型：
--
作者：
Park, Yong-Yea;Lee, Seungmin;Cho, Hyeseong
线粒体通过分裂和融合活动不断分裂和联合收割机结合。MARCH 5是一种线粒体E3泛素连接酶，已被鉴定为结合线粒体分裂1蛋白（hFis 1）、动力蛋白相关蛋白1（Drp 1）和线粒体融合蛋白2（Mfn 2）的分子，这些蛋白是控制线粒体分裂和融合的关键蛋白。然而，这些相互作用如何控制线粒体动力学和细胞功能仍然不清楚。在这里，我们表明，shRNA介导的MARCH 5敲低促进了高度互连和延长的线粒体的积累。用MARCH 5 shRNA或MARCH 5 RING结构域突变体转染的细胞显示出细胞增大和变平，伴随着衰老相关的β-半乳糖苷酶（SA-β-Gal）活性增加，表明这些细胞已经经历了细胞衰老。值得注意的是，Mfn 1水平的显着增加，但没有Mfn 2，Drp 1或hFis 1水平，在MARCH 5-耗尽的细胞中观察到，表明Mfn 1是一个主要的泛素化底物。将Mfn 1（T109 A）（Mfn 1的GTP酶缺陷突变形式）引入MARCH 5-RNAi细胞中不仅破坏了线粒体延伸，而且消除了SA-β-Gal活性的增加。此外，异常的线粒体表型在MARCH 5-RNAi细胞逆转异位表达的Drp 1，但不是由hFis 1，和逆转的线粒体形态在MARCH 5耗尽的细胞伴随着减少SA-β-Gal活性。总的来说，我们的数据表明，缺乏MARCH 5导致线粒体延长，这通过阻断Drp 1活性和/或促进线粒体Mfn 1的积累来促进细胞衰老。
Mitochondria constantly divide and combine through fission and fusion activities. MARCH5, a mitochondrial E3 ubiquitin ligase, has been identified as a molecule that binds mitochondrial fission 1 protein (hFis1), dynamin-related protein 1 (Drp1) and mitofusin 2 (Mfn2), key proteins in the control of mitochondrial fission and fusion. However, how these interactions control mitochondrial dynamics, and cellular function has remained obscure. Here, we show that shRNA-mediated MARCH5 knockdown promoted the accumulation of highly interconnected and elongated mitochondria. Cells transfected with MARCH5 shRNA or a MARCH5 RING domain mutant displayed cellular enlargement and flattening accompanied by increased senescence-associated beta-galactosidase (SA-beta-Gal) activity, indicating that these cells had undergone cellular senescence. Notably, a significant increase in Mfn1 level, but not Mfn2, Drp1 or hFis1 levels, was observed in MARCH5-depleted cells, indicating that Mfn1 is a major ubiquitylation substrate. Introduction of Mfn1(T109A), a GTPase-deficient mutant form of Mfn1, into MARCH5-RNAi cells not only disrupted mitochondrial elongation, but also abolished the increase in SA-beta-Gal activity. Moreover, the aberrant mitochondrial phenotypes in MARCH5-RNAi cells were reversed by ectopic expression of Drp1, but not by hFis1, and reversion of the mitochondria morphology in MARCH5-depleted cells was accompanied by a reduction in SA-beta-Gal activity. Collectively, our data indicate that the lack of MARCH5 results in mitochondrial elongation, which promotes cellular senescence by blocking Drp1 activity and/or promoting accumulation of Mfn1 at the mitochondria.