Anti-(a)3 antibodies are protein reagents that detect specific antigens. The (a)3 antigen is another term for the human protein T cell immune regulator 1, ATPase H+ transporting V0 subunit a3, encoded by the TCIRG1 gene. The protein is a known subunit of the V0 complex of vacuolar(H+)-ATPase (V-ATPase), a multisubunit enzyme composed of a peripheral complex (V1) that hydrolyzes ATP and a membrane integral complex (V0) that translocates protons (By similarity). Canonically, it has an amino acid length of 830 residues and a mass of 93 kilodaltons. Its subcellular localization is in the membrane and it is widely expressed in many tissue types. The (a)3 protein is a member of the V-ATPase 116 kDa subunit protein family. Other alias names for (a)3 include ATP6N1C, ATP6V0A3, and Atp6i.