Anti-COPI coat complex subunit alpha antibodies are used for the immunodetection of the protein encoded by the COPA gene. In humans, the canonical protein has a reported length of 1224 amino acid residues and a mass of 138.3 kDa. Its subcellular localization is in the membrane, cytoplasmic vesicles, Golgi, and cytoplasm. Alternative splicing is reported to yield 2 different isoforms for this protein. It is noted to be involved in Golgi transport and intracellular protein transport. The gene encoding this protein is implicated in Autoimmune interstitial lung, joint, and kidney disease. Other names for this target antigen include HEP-COP, alpha-COP, coatomer subunit alpha, alpha coat protein, coatomer protein complex subunit alpha, and AILJK. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.