Identification, Expression, and Import of Components 17 and 23 of the Inner Mitochondrial Membrane Translocase from Arabidopsis
Identification, Expression, and Import of Components 17 and 23 of the Inner Mitochondrial Membrane Translocase from Arabidopsis
复制标题
拟南芥内线粒体膜转位酶组分 17 和 23 的鉴定、表达和导入
DOI：
--
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
J. Whelan
中科院分区：
文献类型：
--
作者：
M. Murcha;R. Lister;A. Ho;J. Whelan
对拟南芥线粒体内膜转位酶（TIM17:23）组分17和23的特征分析表明，TIM17和TIM23有3个基因，TIM44有2个基因。AtTIM17与酵母（酿酒酵母）和哺乳动物同源物的不同之处在于，两个基因编码的蛋白质较长，一个基因编码的蛋白质较短。与酵母TIM23相比，所有拟南芥TIM23预测蛋白都缺少前34个氨基酸。AtTIM17和AtTIM23基因均有表达，但表现出不同的组织和发育特征。酵母中缺失突变体的互补表明，对于AtTIM17，必须去除酵母中不存在的C端延伸才能实现互补，而对于TIM23，必须存在前蛋白和氨基酸转运体结构域才能实现互补。AtTIM17和AtTIM23的进口分析表明，它们都含有以膜电位依赖的方式整合到线粒体内膜的内部信号。进口AtTIM17-2的C端易被外部添加的线粒体完整的蛋白酶降解。85个c端氨基酸的去除导致了截断蛋白的输入和完全保护。这表明，AtTIM17-2的C末端的新延伸以类似于酵母TIM23的方式连接内外膜。
Characterization of components 17 and 23 of the inner mitochondrial membrane translocase (TIM17:23) from Arabidopsis indicated that there were three genes present for TIM17 and TIM23 and two for TIM44. AtTIM17 differed from the yeast (Saccharomyces cerevisiae) and mammalian homologs in that two genes encoded proteins that were longer and one gene encoded a shorter protein. All Arabidopsis TIM23 predicted proteins appeared to lack the first 34 amino acids compared with yeast TIM23. All AtTIM17 and AtTIM23 genes were expressed but displayed different tissue and developmental profiles. Complementation of deletion mutants in yeast indicated that for AtTIM17, the extension at the C terminus not present in yeast had to be removed to achieve complementation, whereas for TIM23, a preprotein and amino acid transporter domain had to be present for complementation. Import assays with AtTIM17 and AtTIM23 indicated that they both contained internal signals for integration into the inner mitochondrial membrane in a membrane potential-dependent manner. The C terminus of imported AtTIM17-2 was susceptible to degradation by externally added protease with intact mitochondria. Removal of the 85 C-terminal amino acids resulted in import and full protection of the truncated protein. This suggests that the novel extension at the C terminus of AtTIM17-2 links the outer and inner membrane in a manner analogous to yeast TIM23.
影响因子：
56.9
作者：
Winzeler, EA;Shoemaker, DD;Davis, RW
通讯作者：
Davis, RW
影响因子：
56.9
作者：
Kolesnikova, OA;Entelis, NS;Tarassov, IA
通讯作者：
Tarassov, IA