Anti-H2AC1 antibodies are used in the immunodetection of the protein H2A clustered histone 1. In humans, the canonical protein has a reported length of 131 amino acid residues and a mass of 14.2 kDa. Its subcellular localization is in the nucleus and chromosomes. It is notably widely expressed in many tissue types. A member of the Histone H2A protein family, H2AC1 is an important component of nucleosome. Post-translational modifications have been described, including ubiquitination, acetylation and phosphorylation. Synonyms for this target antigen include H2A histone family, member R, histone 1, H2aa, histone H2A/r, histone cluster 1 H2A family member a, histone cluster 1, H2aa, and histone H2A type 1-A. H2AC1 gene orthologs have been reported in the mouse, rat, bovine and chimpanzee species.