Coatomer_g_Cpla is the very C-terminal domain of the eukaryotic Coatomer subunit gamma-1 proteins. It acts as a platform domain to the C-terminal appendage. It carries one single protein/protein interaction site, which is the binding site for ARFGAP2 or ADP-ribosylation factor GTPase-activating protein. COPI-coated vesicles mediate retrograde transport from the Golgi back to the ER and intra-Golgi transport. The gamma-COPI is part of one of two subcomplexes that make up the heptameric coatomer complex along with the beta, delta and zeta subunits [1].

1: Gamma-COP appendage domain - structure and function. Watson PJ, Frigerio G, Collins BM, Duden R, Owen DJ; Traffic. 2004;5:79-88. PMID:14690497