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.

• PMID: 9714721
• DOI full text
• PubMed
• PubTator

Reference Type

Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, Non-P.H.S. | Research Support, U.S. Gov't, P.H.S. | Review

Authors

Gaynor EC, Graham TR, Emr SD

Primary Lit For

Additional Lit For

ARF1 | ARF2

Review For