Tom22 is a multifunctional organizer of the mitochondrial preprotein translocase
Tom22 is a multifunctional organizer of the mitochondrial preprotein translocase
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DOI：
10.1038/46802
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发表时间：
1999-09-30
期刊：
影响因子：
64.8
通讯作者：
Pfanner, N
中科院分区：
文献类型：
--
作者：
van Wilpe, S;Ryan, MT;Pfanner, N
线粒体前蛋白由外膜多亚基移位酶（TOM）输入，包括受体蛋白和一般输入孔（1-5）。中央受体Tom 22通过其胞质结构域和膜间空间结构域结合前蛋白（6-10），并与通道蛋白Tom 40稳定结合（参考文献11-13）。在这里，我们报告了一个意想不到的观察结果，即酵母菌株可以在没有Tom 22的情况下生存，尽管它的生长和线粒体蛋白的输入大大减少。Tom 22是一种多功能蛋白质，是TOM机制更高层次组织所必需的。在没有Tom 22的情况下，移位酶解离成核心复合物，代表基本的输入单元，但缺乏对通道门控的严格控制。Tom 22的单膜锚是核心复合物之间稳定相互作用所需的，而其胞质结构域用作外周受体Tom 20和Tom 70的对接点。因此，前蛋白移位酶可以将联合收割机受体功能与多结构域蛋白中的不同组织作用结合起来。
Mitochondrial preproteins are imported by a multisubunit translocase of the outer membrane (TOM), including receptor proteins and a general import pore(1-5). The central receptor Tom22 binds preproteins through both its cytosolic domain and its intermembrane space domain(6-10) and is stably associated with the channel protein Tom40 (refs 11-13). Here we report the unexpected observation that a yeast strain can survive without Tom22, although it is strongly reduced in growth and the import of mitochondrial proteins. Tom22 is a multifunctional protein that is required for the higher-level organization of the TOM machinery. In the absence of Tom22, the translocase dissociates into core complexes, representing the basic import units, but lacks a tight control of channel gating. The single membrane anchor of Tom22 is required for a stable interaction between the core complexes, whereas its cytosolic domain, serves as docking point for the peripheral receptors Tom20 and Tom70. Thus a preprotein translocase can combine receptor functions with distinct organizing roles in a multidomain protein.