COPG2: Proteins and Enzymes

Coatomer proteins are involved in regulating transport between the endoplasmic reticulum (ER) and the Golgi complex and in intra-Golgi transport. There exist two Coatomer-Protein mechanisms (COPI and COPII) and although they have mechanistic parallels, they are molecularly distinct. The COPI coat is comprised of seven subunits (alpha-, beta-, beta'-, gamma-, delta-, epsilon-, and zeta-COP) in a complex called coatomer. Assembly of the coatomer (COPI) onto non-clathrin coated vesicles is regulated by ADP-ribosylation factor (ARF). Vesicle formation, budding, fusion, and disassembly is dependent on GDP-GTP exchange, COPI, and ARF. COPI has been shown to facilitate retrograde intracellular transport from the ER to the Golgi complex. By contrast, COPII facilitates anterograde transport between these subcellular organelles. COPII has been shown to be independently and selectively recruited to the ER relative to COPI subunits.