The structure of the COPI coat determined within the cell.
The structure of the COPI coat determined within the cell.
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DOI：
10.7554/elife.32493
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发表时间：
2017-11-17
期刊：
影响因子：
7.7
通讯作者：
Briggs JA
中科院分区：
文献类型：
--
作者：
Bykov YS;Schaffer M;Dodonova SO;Albert S;Plitzko JM;Baumeister W;Engel BD;Briggs JA
COPI包被的囊泡介导高尔基体内和从高尔基体到内质网的运输。膜蛋白涂层的结构，包括COPI，已被广泛研究与体外重建系统，使用纯化的成分。先前我们已经确定了体外重构COPI包衣的完整结构模型（Dodonova等人，2017年）。在这里，我们应用冷冻聚焦离子束铣削，冷冻电子断层扫描和subtomogram平均，以确定天然结构的COPI涂层内玻璃化莱茵衣藻细胞。天然藻类结构类似于体外哺乳动物结构，但另外揭示了在β ′-COP下结合的货物。我们发现，所有的外套组件同时解体，并在萌芽后相对较快。原位结构分析，保持高尔基拓扑结构，表明囊泡改变其大小，膜厚度和货物的内容，因为它们的进展从顺式到反式，但结构的外套机械保持不变。
COPI-coated vesicles mediate trafficking within the Golgi apparatus and from the Golgi to the endoplasmic reticulum. The structures of membrane protein coats, including COPI, have been extensively studied with in vitro reconstitution systems using purified components. Previously we have determined a complete structural model of the in vitro reconstituted COPI coat (Dodonova et al., 2017). Here, we applied cryo-focused ion beam milling, cryo-electron tomography and subtomogram averaging to determine the native structure of the COPI coat within vitrified Chlamydomonas reinhardtii cells. The native algal structure resembles the in vitro mammalian structure, but additionally reveals cargo bound beneath β’–COP. We find that all coat components disassemble simultaneously and relatively rapidly after budding. Structural analysis in situ, maintaining Golgi topology, shows that vesicles change their size, membrane thickness, and cargo content as they progress from cis to trans, but the structure of the coat machinery remains constant.