vesicle coat COPI vesicle coat GO:0017167 GO:0030126 One of two multimeric complexes that forms a membrane vesicle coat. The mammalian COPI subunits are called alpha-, beta-, beta'-, gamma-, delta-, epsilon- and zeta-COP. Vesicles with COPI coats are found associated with Golgi membranes at steady state. cellular_component coatomer go.owl pro.owl Golgi apparatus part