Mechanisms for exporting large-sized cargoes from the endoplasmic reticulum.
Mechanisms for exporting large-sized cargoes from the endoplasmic reticulum.
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DOI：
10.1007/s00018-015-1952-9
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发表时间：
2015-10
期刊：
影响因子：
--
通讯作者：
Katada T
中科院分区：
文献类型：
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作者：
Saito K;Katada T
从内质网输出到高尔基体的货物蛋白通常在60-90 nm直径的外壳蛋白复合物II（COPII）包被的囊泡中转运。包括胶原蛋白和乳糜微粒在内的几种货物分子形成的结构太大而不能被这些囊泡容纳，但它们的分泌仍然需要COPII蛋白。在这里，我们首先回顾了最近的进展，特别是来自动物模型和人类疾病的大货物分泌物，这表明COPII蛋白的重要性。然后，我们讨论了最近分离的专门因素，调节COPII依赖的货物形成的过程中，以促进出口的大型货物从内质网。基于这些发现，我们提出了一个模型，描述了GTdR循环的分泌超大货物的重要性。接下来，我们总结了描述COPII蛋白质结构的报告，以及这些结果如何提供对大型货物载体组装机制的深入了解。最后，我们讨论了未来需要解决的问题。
Cargo proteins exported from the endoplasmic reticulum to the Golgi apparatus are typically transported in coat protein complex II (COPII)-coated vesicles of 60–90 nm diameter. Several cargo molecules including collagens and chylomicrons form structures that are too large to be accommodated by these vesicles, but their secretion still requires COPII proteins. Here, we first review recent progress on large cargo secretions derived especially from animal models and human diseases, which indicate the importance of COPII proteins. We then discuss the recent isolation of specialized factors that modulate the process of COPII-dependent cargo formation to facilitate the exit of large-sized cargoes from the endoplasmic reticulum. Based on these findings, we propose a model that describes the importance of the GTPase cycle for secretion of oversized cargoes. Next, we summarize reports that describe the structures of COPII proteins and how these results provide insight into the mechanism of assembly of the large cargo carriers. Finally, we discuss what issues remain to be solved in the future.