Mihara K
Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka, Fukuoka 812-8582, Japan.
Bioessays. 2000 Apr;22(4):364-71. doi: 10.1002/(SICI)1521-1878(200004)22:4<364::AID-BIES6>3.0.CO;2-N.
Most mitochondrial proteins are synthesized in the cytosol as preproteins with a cleavable presequence and are delivered to the import receptors on the mitochondria by cytoplasmic import factors. The proteins are then imported to the intramitochondrial compartments by the import systems of the outer and inner membranes, TOM and TIM. Mitochondrial outer membrane proteins are synthesized without a cleavable presequence and most of them contain hydrophobic transmembrane domains, which, in conjunction with the flanking segments, function as the mitochondria import signals. Some of the proteins are inserted into the outer membrane by the TOM machinery; the import signal probably arrests further translocation and is released from the translocation channel to the lipid bilayer. The other proteins are inserted into the membrane by a novel pathway independent of the TOM machinery. This article reviews recent developments in the biogenesis of mitochondrial outer membrane proteins.
大多数线粒体蛋白在细胞质中作为具有可裂解前序列的前体蛋白合成，并通过细胞质导入因子传递到线粒体上的导入受体。然后，这些蛋白通过外膜和内膜的导入系统TOM和TIM导入到线粒体内腔室。线粒体外膜蛋白在合成时没有可裂解的前序列，其中大多数含有疏水跨膜结构域，这些结构域与侧翼片段一起作为线粒体导入信号。一些蛋白通过TOM机制插入外膜；导入信号可能会阻止进一步的转运，并从转运通道释放到脂质双层中。其他蛋白则通过一条独立于TOM机制的新途径插入膜中。本文综述了线粒体外膜蛋白生物发生的最新进展。
