Anti-H2A.X variant histone antibodies are used for the immunodetection of the protein encoded by the H2AX gene. In humans, the canonical protein has a reported length of 143 amino acid residues and a mass of 15.1 kDa. Its subcellular localization is in the nucleus. A member of the Histone H2A protein family, it is known to be involved with nervous system development and DNA damage pathways. Post-translational modifications have been described, including ubiquitination, acetylation and phosphorylation. Other names for this target antigen include H2AFX, histone H2AX, H2A histone family member X, H2AX histone, histone H2A.x, and H2A.X. Gene orthologs have been identified in the mouse, rat, bovine, chimpanzee and chicken species.