Bollmann Franziska, Dohrke Jan-Niklas, Wurm Christian A, Jans Daniel C, Jakobs Stefan
Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
Clinic of Neurology, University of Göttingen, 37073 Göttingen, Germany.
Biology (Basel). 2021 Jun 23;10(7):572. doi: 10.3390/biology10070572.
Mitochondria are highly dynamic organelles that interchange their contents mediated by fission and fusion. However, it has previously been shown that the mitochondria of cultured human epithelial cells exhibit a gradient in the relative abundance of several proteins, with the perinuclear mitochondria generally exhibiting a higher protein abundance than the peripheral mitochondria. The molecular mechanisms that are required for the establishment and the maintenance of such inner-cellular mitochondrial protein abundance gradients are unknown. We verified the existence of inner-cellular gradients in the abundance of clusters of the mitochondrial outer membrane protein Tom20 in the mitochondria of kidney epithelial cells from an African green monkey (Vero cells) using STED nanoscopy and confocal microscopy. We found that the Tom20 gradients are established immediately after cell division and require the presence of microtubules. Furthermore, the gradients are abrogated in hyperfused mitochondrial networks. Our results suggest that inner-cellular protein abundance gradients from the perinuclear to the peripheral mitochondria are established by the trafficking of individual mitochondria to their respective cellular destination.
线粒体是高度动态的细胞器，通过裂变和融合来交换其内容物。然而，先前已经表明，培养的人上皮细胞的线粒体在几种蛋白质的相对丰度上呈现出梯度，核周线粒体的蛋白质丰度通常高于外周线粒体。建立和维持这种细胞内线粒体蛋白质丰度梯度所需的分子机制尚不清楚。我们使用受激发射损耗（STED）纳米显微镜和共聚焦显微镜，验证了非洲绿猴肾上皮细胞（Vero细胞）线粒体中，线粒体外膜蛋白Tom20簇丰度的细胞内梯度的存在。我们发现，Tom20梯度在细胞分裂后立即建立，并且需要微管的存在。此外，在过度融合的线粒体网络中，这些梯度会被消除。我们的结果表明，从核周线粒体到外周线粒体的细胞内蛋白质丰度梯度是通过单个线粒体运输到其各自的细胞目的地而建立的。
