Anti-centromere protein Q antibodies are used in the immunodetection of the protein encoded by the CENPQ gene. In humans, the canonical protein has a reported length of 268 amino acid residues and a mass of 30.6 kDa. Its subcellular localization is in the nucleus. A member of the CENP-Q/OKP1 protein family, it is a known component of the CENPA-CAD (nucleosome distal) complex, a complex recruited to centromeres which is involved in assembly of kinetochore proteins, mitotic progression and chromosome segregation. Post-translational modifications have been described, including phosphorylation. Other names for this target antigen include C6orf139.