Structure of the mammalian oligosaccharyltransferase complex in the native ER protein translocon
Structure of the mammalian oligosaccharyltransferase complex in the native ER protein translocon
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DOI：
10.1038/ncomms4072
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发表时间：
2014-01-01
影响因子：
16.6
通讯作者：
Foerster, Friedrich
中科院分区：
文献类型：
--
作者：
Pfeffer, Stefan;Dudek, Johanna;Foerster, Friedrich
在哺乳动物细胞中，蛋白质通常通过内质网（ER）蛋白质易位子以共翻译模式跨内质网（ER）膜易位，ER蛋白质易位子包含蛋白质传导通道Sec 61和参与新生链加工和易位的另外的复合物。寡糖基转移酶复合物（OST）作为转位子的组成部分，催化共翻译N-糖基化，这是真核细胞中最常见的蛋白质修饰之一。在这里，我们使用冷冻电子断层扫描，冷冻电子显微镜单粒子分析和小干扰RNA介导的基因沉默，以确定的整体结构，寡聚状态和位置的OST在天然ER蛋白易位的哺乳动物细胞前所未有的细节。所观察到的OST定位在Sec 61附近提供了一个基础，了解蛋白质易位到ER和糖基化的新生蛋白质是如何在结构上耦合。本机易位的整体空间组织，在这里确定的，作为一个可靠的框架，进一步的假设驱动的研究。
In mammalian cells, proteins are typically translocated across the endoplasmic reticulum (ER) membrane in a co-translational mode by the ER protein translocon, comprising the protein-conducting channel Sec61 and additional complexes involved in nascent chain processing and translocation. As an integral component of the translocon, the oligosaccharyl-transferase complex (OST) catalyses co-translational N-glycosylation, one of the most common protein modifications in eukaryotic cells. Here we use cryoelectron tomography, cryoelectron microscopy single-particle analysis and small interfering RNA-mediated gene silencing to determine the overall structure, oligomeric state and position of OST in the native ER protein translocon of mammalian cells in unprecedented detail. The observed positioning of OST in close proximity to Sec61 provides a basis for understanding how protein translocation into the ER and glycosylation of nascent proteins are structurally coupled. The overall spatial organization of the native translocon, as determined here, serves as a reliable framework for further hypothesis-driven studies.