Mitochondrial porin can be translocated across both endoplasmic reticulum and mitochondrial membranes.
Mitochondrial porin can be translocated across both endoplasmic reticulum and mitochondrial membranes.
复制标题
线粒体孔蛋白可以跨内质网和线粒体膜易位。
DOI：
--
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
T. Omura
中科院分区：
文献类型：
--
作者：
M. Sakaguchi;N. Hachiya;K. Mihara;T. Omura
线粒体孔蛋白是外膜的主要膜蛋白。为了评估酵母孔蛋白分子（P）中的终止转移序列，我们构建了以下嵌合蛋白。(i)将分泌蛋白白细胞介素2的信号序列融合到孔蛋白（SP）的氨基端。(ii)将细胞色素c氧化酶亚基IV的基质靶向前序列融合到孔蛋白（CP）的氨基端。(iii)将酵母线粒体“70 kDa蛋白”的42个氨基酸残基的氨基末端片段引入白细胞介素2（IL 70）的中间部分。这些嵌合蛋白在体外转录-翻译系统中表达，并检测其整合到微粒体膜或线粒体膜中。当在粗糙微粒体膜（RM）存在下用小麦胚无细胞系统体外合成蛋白质时，SP完全跨膜易位，被信号肽酶加工，并被糖基化。IL 70分子在RM中的转运在引入的70 kDa蛋白的氨基端区段处停止。真实的孔蛋白不与微粒体膜相互作用。为了评估与线粒体的相互作用，用网织红细胞裂解物系统合成孔蛋白和CP，并与分离的大鼠肝线粒体进行翻译后输入反应。真正的孔蛋白以耐碱性的方式整合到外膜中。CP被输入到线粒体中，其前序列被基质中的加工蛋白酶切割。（250字处删节）
Mitochondrial porin is a major integral membrane protein of the outer membrane. To assess the stop-transfer sequence in the yeast porin molecule (P), we constructed the following chimeric proteins. (i) The signal sequence of interleukin 2, a secretory protein, was fused to the amino-terminus of porin (SP). (ii) The matrix targeting presequence of cytochrome c oxidase subunit IV was fused to the amino-terminus of porin (CP). (iii) The amino-terminal segment consisting of 42 amino acid residues of "70 kDa protein" of yeast mitochondria, a major membrane protein of the outer membrane, was introduced into the middle portion of interleukin 2 (IL70). These chimeric proteins were expressed with an in vitro transcription-translation system and their integration into microsomal membrane or mitochondrial membranes was examined. When the proteins were synthesized in vitro with wheat germ cell-free system in the presence of rough microsomal membrane (RM), SP was completely translocated across the membrane, processed by the signal peptidase, and glycosylated. The translocation of IL70 molecule across RM was stopped at the introduced amino-terminal segment of 70 kDa protein. The authentic porin did not interact with the microsomal membrane. To assess the interaction with mitochondria, porin and CP were synthesized with the reticulocyte lysate system and subjected to posttranslational import reaction with isolated rat liver mitochondria. The authentic porin was integrated into the outer membrane in an alkali-resistant fashion. CP was imported into the mitochondria and its presequence was cleaved by the processing protease in the matrix.(ABSTRACT TRUNCATED AT 250 WORDS)