Anti-a3 antibodies are used in antigen-specific immunodetection in biological samples. The target a3 is a known alias name of the protein T cell immune regulator 1, ATPase H+ transporting V0 subunit a3, encoded by the TCIRG1 gene in humans. This 830-amino acid residue 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). It is localized to the membrane of the cell. It is reported to be widely expressed in many tissue types.