Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany.
Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany.
Biol Chem. 2020 May 26;401(6-7):709-721. doi: 10.1515/hsz-2020-0101.
Mitochondrial precursor proteins with amino-terminal presequences are imported via the presequence pathway, utilizing the TIM23 complex for inner membrane translocation. Initially, the precursors pass the outer membrane through the TOM complex and are handed over to the TIM23 complex where they are sorted into the inner membrane or translocated into the matrix. This handover process depends on the receptor proteins at the inner membrane, Tim50 and Tim23, which are critical for efficient import. In this review, we summarize key findings that shaped the current concepts of protein translocation along the presequence import pathway, with a particular focus on the precursor handover process from TOM to the TIM23 complex. In addition, we discuss functions of the human TIM23 pathway and the recently uncovered pathogenic mutations in TIM50.
线粒体前体蛋白带有 N 端前导序列，通过前导序列途径进行输入，利用 TIM23 复合物进行内膜转位。最初，前体蛋白通过 TOM 复合物穿过外膜，然后被递交给 TIM23 复合物，在那里它们被分拣到内膜或转运到基质中。这个交接过程依赖于内膜上的受体蛋白 Tim50 和 Tim23，它们对于有效的输入至关重要。在这篇综述中，我们总结了形成目前前导序列输入途径中蛋白质转运的概念的关键发现，特别关注从 TOM 到 TIM23 复合物的前体蛋白交接过程。此外，我们还讨论了人类 TIM23 途径的功能以及最近发现的 Tim50 致病突变。
