Regulations of energy metabolism and cellular fate via mitochondrial porin

线粒体孔蛋白一直被认为只是外丝裂细胞膜上的一个“孔”。然而，最近的研究表明，线粒体！Porin还调节细胞的能量代谢和命运。在本研究中，我们对线粒体孔蛋白进行了研究，得到了以下结果：1)在肿瘤细胞中，线粒体上附着着大量的己糖激酶。然而，当线粒体可结合的己糖激酶被添加到肝脏线粒体时，只有一小部分可以附着在线粒体上。这一事实表明，肝线粒体和肿瘤线粒体在己糖激酶结合部位(即孔蛋白)上可能存在差异。在这项研究中，我们对编码在恶性肿瘤细胞中表达的孔蛋白(S)的信息进行了表征。因此，肝线粒体的己糖激酶结合量低于肿瘤线粒体的原因可以用肝细胞和肿瘤细胞之间孔蛋白表达水平的差异来解释。2)基于简并引物的聚合酶链式反应鉴定出一个与1型孔蛋白结构相似的信息。这一结果表明线粒体孔蛋白的第四个成员可能存在。我们目前正在对这一信息进行特征描述。3)关于孔蛋白的信息已经得到了很好的描述，但存在于线粒体外膜的孔蛋白还没有得到研究。我们提高了针对孔蛋白的抗体，并分析了线粒体部分中存在的孔蛋白。结果发现，线粒体膜外膜中主要存在2型孔蛋白亚型。

Mitochondrial porin has been regarded just a "pore" in the outer mitbchohdrial membrane. However, recent studies indicated that mitochondria! porin also regulates cellular energy metabolism and fate. In this study, we characterized mitochondrial porin and obtained following results.1) In tumor cells, a large amount of hexokinase is attached to the mitochondria. However, when mitochondria-bindable hexokinase was added to liver mitochondria, only a small portion can be attached to the mitochondria. This fact indicates the possible differences in the hexokinase binding sites (i.e. porin) between liver mitochondria and tumor mitochondria. In, this study, we characterized messages encoding porin(s) expressed in malignant tumor cells. As a result, the reason why liver mitochondria show lower hexokinase binding capacity than tumor mitochondria was clearly explained by the differences in the expression levels of porin between liver and tumor cells.2) A message showing structural similarity to type 1 porin was identified by degenerated primer based PCR. This result indicates possible existence of fourth member of mitochondrial porin. We are currently characterizing this message.3) Messages of porin have been well characterized but porin protein present in the mitochondrial outer membrane has not yet investigated. We raised antibody against porin protein and analyzed porin protein present in the mitochondrial fraction. As a result, type 2 isoform was found to be major porin isoform present in the outer mitochondrial membrane.