Gaynor E C, Graham T R, Emr S D
Department of Biology, The Division of Cellular and Molecular Medicine, and the Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093-0668, USA.
Biochim Biophys Acta. 1998 Aug 14;1404(1-2):33-51. doi: 10.1016/s0167-4889(98)00045-7.
Coat complexes facilitate the formation of transport vesicles which are essential for proper trafficking of protein and lipids through the secretory pathway. Since its initial identification in the mid-1980s, the COPI coat complex has been credited with mediating multiple distinct transport events and intracellular processes in the exocytic pathway. Not surprisingly, the diversity of these functions has led to significant debate concerning the primary function of COPI. Specifically, within the ER/Golgi and intra-Golgi systems, does COPI mediate anterograde protein transport, retrograde protein transport, or both? This review will focus on the in vivo roles of COPI, primarily examining data from studies of yeast COPI mutants but also including evidence from mammalian systems as appropriate. Some of the current controversies surrounding whether COPI acts directly or indirectly in anterograde and retrograde transport will also be addressed. Because recruitment of COPI to membranes requires the small GTP-binding protein ARF, we will also discuss ARF and proteins that regulate ARF function, and how these proteins might modulate both COPI-driven events and overall membrane composition. Finally, we will point out some of the links still missing from our understanding of COPI-driven events and discuss possible future directions for studies of COPI function.
衣被复合体促进运输小泡的形成，而运输小泡对于蛋白质和脂质通过分泌途径的正常运输至关重要。自20世纪80年代中期首次被鉴定以来，COPI衣被复合体被认为介导了胞吐途径中的多种不同运输事件和细胞内过程。毫不奇怪，这些功能的多样性引发了关于COPI主要功能的激烈争论。具体而言，在内质网/高尔基体和高尔基体内系统中，COPI介导顺行性蛋白质运输、逆行性蛋白质运输，还是两者都介导？本综述将聚焦于COPI在体内的作用，主要研究来自酵母COPI突变体研究的数据，但也会酌情纳入来自哺乳动物系统的证据。还将讨论当前围绕COPI在顺行性和逆行性运输中是直接还是间接起作用的一些争议。由于COPI募集到膜上需要小GTP结合蛋白ARF，我们还将讨论ARF以及调节ARF功能的蛋白质，以及这些蛋白质如何调节由COPI驱动的事件和整体膜组成。最后，我们将指出在我们对由COPI驱动的事件的理解中仍然缺失的一些联系，并讨论COPI功能研究未来可能的方向。
