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 limiting lipid storage in lipid droplets. Oligomeric complex that consists of at least the alpha, beta, beta', gamma, delta, epsilon and zeta subunits. The coatomer is cytoplasmic or polymerized on the cytoplasmic side of the Golgi, as well as on the vesicles/buds originating from it (By similarity). Present within the clusters of tubulo-vesicular structures of Golgi membrane and cis-Golgi membranes. During oogenesis and spermatogenesis, expressed in ovariole, germarium, testis tip and testis. Before the first zygotic nuclear division, seen in membrane structures confined in the embryonic cortex. This cortical distribution is maintained through stage 6. In cycles 10 and 11, the presence in the Golgi membranes between hexagonally arranged nuclei is readily observed in tangential optical sections through the embryonic surface. In stage 14, present in a thin vitelloplasmic layer below the plane that represents the basal borders of the cells separating the cellularized cortex from the rest of the embryo, and also within cells. Within the cells, appear to be more abundant in the cytoplasmic region between the nucleus and the embryonic surface. In early embryos, a large proportion appears randomly diffused, but in the later stages of embryogenesis, a larger proportion is associated with the membranes. In early embryos, expressed in the ovary. During embryogenesis, up-regulated in regions 2 and 3 of the germarium in meiotic cysts and in follicle cells. Expressed in testis tip starting in early meiotic spermatocytes. Also detected in paragonia. During embryogenesis, appears to be expressed ubiquitously at low levels and markedly up-regulated in the cells of the presumptive proventriculus and the salivary glands starting at stage 10. Brefeldin A induces dissociation from the Golgi of betaCOP and presumably the other coatomer subunits.