Targeting of a polytopic membrane protein to the inner envelope membrane of chloroplasts in vivo involves multiple transmembrane segments.
Targeting of a polytopic membrane protein to the inner envelope membrane of chloroplasts in vivo involves multiple transmembrane segments.
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DOI：
10.1093/jxb/eru290
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发表时间：
2014-10
影响因子：
6.9
通讯作者：
Inaba T
中科院分区：
文献类型：
--
作者：
Okawa K;Inoue H;Adachi F;Nakayama K;Ito-Inaba Y;Schnell DJ;Uehara S;Inaba T
这项工作表明，体内多面体膜蛋白靶向叶绿体内膜涉及多个跨膜片段，包括不可缺少的跨膜片段。叶绿体的内膜（IEM）在形成渗透屏障和控制细胞器与细胞质之间的代谢物交换方面发挥着至关重要的作用。因此，IEM 含有许多膜蛋白，并且需要导入和整合这些核编码蛋白以实现其生物发生。最近的研究表明，单跨 IEM 蛋白的跨膜片段在确定其 IEM 定位方面发挥着关键作用。然而，很少有研究关注多胞膜蛋白靶向 IEM 的分子机制。在本研究中，我们使用 Cor413im1 蛋白作为模型底物研究了多位 IEM 蛋白的靶向机制。 Cor413im1 不利用可溶性中间体来靶向 IEM。此外，我们表明 Cor413im1 的假定第五跨膜片段对于其靶向 IEM 是必需的。含有该跨膜片段的 C 端部分也能够将 Cor413im1 蛋白递送至 IEM。然而，Cor413im1 的第五个跨膜片段本身不足以将融合蛋白靶向 IEM。这些数据表明，多胞体膜蛋白在体内靶向叶绿体IEM涉及多个跨膜片段，并且叶绿体已经进化出一种将多胞体蛋白整合到IEM的独特机制。
This work demonstrated that the targeting of a polytopic membrane protein to the inner envelope membrane of chloroplasts in vivo involves multiple transmembrane segments including the indispensable transmembrane segment. The inner envelope membrane (IEM) of the chloroplast plays crucial roles in forming an osmotic barrier and controlling metabolite exchange between the organelle and the cytosol. The IEM therefore harbours a number of membrane proteins and requires the import and integration of these nuclear-encoded proteins for its biogenesis. Recent studies have demonstrated that the transmembrane segment of single-spanning IEM proteins plays key roles in determining their IEM localization. However, few studies have focused on the molecular mechanisms by which polytopic membrane proteins are targeted to the IEM. In this study, we investigated the targeting mechanism of polytopic IEM proteins using the protein Cor413im1 as a model substrate. Cor413im1 does not utilize a soluble intermediate for its targeting to the IEM. Furthermore, we show that the putative fifth transmembrane segment of Cor413im1 is necessary for its targeting to the IEM. The C-terminal portion containing this transmembrane segment is also able to deliver Cor413im1 protein to the IEM. However, the fifth transmembrane segment of Cor413im1 itself is insufficient to target a fusion protein to the IEM. These data suggest that the targeting of polytopic membrane proteins to the chloroplast IEM in vivo involves multiple transmembrane segments and that chloroplasts have evolved a unique mechanism for the integration of polytopic proteins to the IEM.
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影响因子：
7.2
作者：
Clough, SJ;Bent, AF
通讯作者：
Bent, AF
DOI：
10.1111/j.1365-313x.2008.03638.x
发表时间：
2008-12
期刊：
The Plant journal : for cell and molecular biology
影响因子：
--
作者：
Chiu CC;Li HM
通讯作者：
Li HM
DOI：
10.1083/jcb.200104022
发表时间：
2001-07-23
期刊：
The Journal of cell biology
影响因子：
--
作者：
Hiltbrunner A;Bauer J;Vidi PA;Infanger S;Weibel P;Hohwy M;Kessler F
通讯作者：
Kessler F
影响因子：
3.3
作者：
Davis, AJ;Ryan, KR;Jensen, RE
通讯作者：
Jensen, RE
影响因子：
7.2
作者：
Froehlich, John E.;Keegstra, Kenneth
通讯作者：
Keegstra, Kenneth