Department of Biochemistry, Ajou University School of Medicine, Suwon, South Korea.
Cell Div. 2012 Dec 20;7(1):25. doi: 10.1186/1747-1028-7-25.
Mitochondria exhibit a dynamic morphology in cells and their biogenesis and function are integrated with the nuclear cell cycle. In mitotic cells, the filamentous network structure of mitochondria takes on a fragmented form. To date, however, whether mitochondrial fusion activity is regulated in mitosis has yet to be elucidated.
Here, we report that mitochondria were found to be fragmented in G2 phase prior to mitotic entry. Mitofusin 1 (Mfn1), a mitochondrial fusion protein, interacted with cyclin B1, and their interactions became stronger in G2/M phase. In addition, MARCH5, a mitochondrial E3 ubiquitin ligase, reduced Mfn1 levels and the MARCH5-mediated Mfn1 ubiquitylation were enhanced in G2/M phase.
Mfn1 is degraded through the MARCH5-mediated ubiquitylation in G2/M phase and the cell cycle-dependent degradation of Mfn1 could be facilitated by interaction with cyclin B1/Cdk1 complexes.
线粒体在细胞中呈现出动态的形态，其生物发生和功能与核细胞周期相整合。在有丝分裂细胞中，线粒体的丝状网络结构呈现出碎片化的形式。然而，迄今为止，线粒体融合活性是否在有丝分裂中受到调节仍不清楚。
在这里，我们报告说，在进入有丝分裂之前，线粒体在 G2 期就已经碎片化。线粒体融合蛋白 Mfn1 与细胞周期蛋白 B1 相互作用，并且它们在 G2/M 期的相互作用更强。此外，线粒体 E3 泛素连接酶 MARCH5 降低了 Mfn1 的水平，并且在 G2/M 期，MARCH5 介导的 Mfn1 泛素化增强。
Mfn1 在 G2/M 期通过 MARCH5 介导的泛素化降解，并且 Mfn1 的细胞周期依赖性降解可以通过与细胞周期蛋白 B1/Cdk1 复合物的相互作用来促进。
