The coatomer is a cytosolic protein complex that binds to dilysine motifs and reversibly associates with Golgi non-clathrin-coated vesicles, which further mediate biosynthetic protein transport from the ER, via the Golgi up to the trans Golgi network. Coatomer complex is required for budding from Golgi membranes, and is essential for the retrograde Golgi-to-ER transport of dilysine-tagged proteins. Required for mitochondrial morphology. Oligomeric complex that consists of at least the alpha, beta, beta', gamma, delta, epsilon and zeta subunits. The complex interacts with ARF1 and PAB1. The coatomer is cytoplasmic or polymerized on the cytoplasmic side of the Golgi, as well as on the vesicles/buds originating from it. The N-terminus is blocked. Causes a block in ER to Golgi transport. Exhibits exaggerated ER structures displaying interconnected networks of ER cisternae. Cells arrest at all stages of the vegetative cycle. Present with 26000 molecules/cell in log phase SD medium.