Molecular Mechanism of Mitochondrial Protein Import and Sorting

线粒体蛋白输入和分选的分子机制

• 批准号: 10680659
• 负责人: ONO Hideyu
• 金额: $ 2.18万
• 依托单位: YAMAGATA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680659/
• 关键词: mitochondria; protein targeting; protein translocation; mitochondrial outer membrane; mitochondrial inner membrane; プレシークエンス

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.

在线粒体蛋白输入过程中，多种胞质因子发挥着重要作用。我们在大鼠肝细胞质中发现了新的细胞质因子，该因子对N-乙基马来酰亚胺不敏感，表明这与MSF并非完全不同。我们试图纯化这个因素并进行部分表征。根据我们的研究，该因子很可能在线粒体蛋白前体和线粒体表面之间的识别过程中起作用。我们还检查了粪卟啉原氧化酶（CPO，线粒体膜间间隙酶）的输入和短路。 CPO的前序列同时具有基质靶向和分选信号，前体在转化为成熟形式并定位到膜间隙之前被加工成中间形式。观察到两种类型的中间体。基质加工肽酶可能通过切割前体的两个识别位点形成两种类型的中间体。此外，我们观察到血红素抑制前体转运至大鼠线粒体，这表明前体的输入受血红素浓度调节。