Molecular Mechanism of Mitochondrial Protein Import and Sorting

点击翻译按钮获取中文摘要

In the process of mitochondrial protein import, various cytosolic factors play an important role. We found new cytosolic factor in rat liver cytosol and this factor was insensitive to N-ethylmaleimide, suggesting that this was not completely different from MSF. We tried to purify this factor and partiually characterized. From our research, it is likely that this factor works in the process of recognition between mitochondorial protein precursor and mitochondirial surface.We also examined import and shorting of coproporphyrinogen oxidase (CPO, mitochondrial intermembrane space enzyme). The presequence of CPO had both matrix targeting and sorting signal and the precursor was processed to the intermediate form before converting to mature form and localization to the intermembrane space. Two types of intermediates were observed. Matrix processing peptidase might form the two types of intermediates by cutting the two recognition site of the precursor. Moreover, we observed hemin inhibition of transport of the precursor into rat mitochondria, suggesting that import of the precursor was regulated by heme concentration.