Oxa1 directly interacts with Atp9 and mediates its assembly into the mitochondrial F1Fo-ATP synthase complex
Oxa1 directly interacts with Atp9 and mediates its assembly into the mitochondrial F1Fo-ATP synthase complex
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DOI：
10.1091/mbc.e06-10-0925
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发表时间：
2007-05-01
影响因子：
3.3
通讯作者：
Stuart, Rosemary A.
中科院分区：
文献类型：
--
作者：
Jia, Lixia;Dienhart, Mary K.;Stuart, Rosemary A.
酵母 Oxa1 蛋白参与线粒体氧化磷酸化 (OXPHOS) 机制的生物发生。 Oxa1 参与细胞色素氧化酶 (COX) 复合物的组装，促进线粒体编码的 COX 亚基的共翻译膜插入，这一点已有充分记录。在这项研究中，我们探讨了 Oxa1 及其序列相关蛋白 Cox18/Oxa2 在 F1Fo-ATP 合酶复合物的生物合成中的作用。我们证明 Oxa1（而非 Cox18/Oxa2）直接支持 ATP 合酶膜嵌入 F-o 区段的组装。发现 Oxa1 以翻译后方式与新合成的线粒体编码的 Atp9 蛋白发生物理相互作用，并且以不依赖于 Oxa1 C 端基质定位区域的方式发生物理相互作用。 Atp9-Oxa1 相互作用的稳定方式与之前观察到的线粒体编码的 COX 亚基与 Oxa1 的共翻译和瞬时相互作用相反。在不存在 Oxa1 的情况下，观察到 Atp9 组装成包含 F-1 亚基的寡聚复合物，但其与 F-o 区亚基 6 (Atp6) 的进一步组装受到干扰。我们提出，通过以翻译后方式直接与新合成的 Atp9 相互作用，Oxa1 需要维持 Atp9-F-1-亚复合物与 Atp6 关联的组装能力。
The yeast Oxa1 protein is involved in the biogenesis of the mitochondrial oxidative phosphorylation (OXPHOS) machinery. The involvement of Oxa1 in the assembly of the cytochrome oxidase (COX) complex, where it facilitates the cotranslational membrane insertion of mitochondrially encoded COX subunits, is well documented. In this study we have addressed the role of Oxa1, and its sequence-related protein Cox18/Oxa2, in the biogenesis of the F1Fo-ATP synthase complex. We demonstrate that Oxa1, but not Cox18/Oxa2, directly supports the assembly of the membrane embedded F-o-sector of the ATP synthase. Oxa1 was found to physically interact with newly synthesized mitochondrially encoded Atp9 protein in a posttranslational manner and in a manner that is not dependent on the C-terminal, matrix-localized region of Oxa1. The stable manner of the Atp9-Oxa1 interaction is in contrast to the cotranslational and transient interaction previously observed for the mitochondrially encoded COX subunits with Oxa1. In the absence of Oxa1, Atp9 was observed to assemble into an oligomeric complex containing F-1-subunits, but its further assembly with subunit 6 (Atp6) of the F-o-sector was perturbed. We propose that by directly interacting with newly synthesized Atp9 in a posttranslational manner, Oxa1 is required to maintain the assembly competence of the Atp9-F-1-subcomplex for its association with Atp6.