Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
Biol Chem. 2020 May 26;401(6-7):677-686. doi: 10.1515/hsz-2019-0440.
Mitochondria harbor in their outer membrane (OM) proteins of different topologies. These proteins are encoded by the nuclear DNA, translated on cytosolic ribosomes and inserted into their target organelle by sophisticated protein import machineries. Recently, considerable insights have been accumulated on the insertion pathways of proteins into the mitochondrial OM. In contrast, little is known regarding the early cytosolic stages of their biogenesis. It is generally presumed that chaperones associate with these proteins following their synthesis in the cytosol, thereby keeping them in an import-competent conformation and preventing their aggregation and/or mis-folding and degradation. In this review, we outline the current knowledge about the biogenesis of different mitochondrial OM proteins with various topologies, and highlight the recent findings regarding their import pathways starting from early cytosolic events until their recognition on the mitochondrial surface that lead to their final insertion into the mitochondrial OM.
线粒体的外膜（OM）中含有不同拓扑结构的蛋白质。这些蛋白质由核 DNA 编码，在细胞质核糖体上翻译，并通过复杂的蛋白输入机制插入到其靶细胞器中。最近，人们对蛋白质插入线粒体 OM 的途径有了相当多的了解。相比之下，对于它们生物发生的早期细胞质阶段知之甚少。一般认为，伴侣蛋白在细胞质中合成后与这些蛋白质结合，从而使它们保持在可输入的构象，防止它们聚集和/或错误折叠和降解。在这篇综述中，我们概述了不同拓扑结构的线粒体 OM 蛋白质生物发生的最新知识，并强调了它们从早期细胞质事件开始的输入途径的最新发现，直到它们在线粒体表面被识别，最终插入线粒体 OM。
