Anti-HMGB1 antibodies are used in the immunodetection of the protein high mobility group box 1. In humans, the canonical protein has a reported length of 215 amino acid residues and a mass of 24.9 kDa. Its subcellular localization is in the cell membrane, nucleus, ER, cytoplasm, and is secreted. It is ubiquitously expressed across many tissue types. A member of the HMGB protein family, HMGB1 is known to be involved with the apoptotic pathway and autophagy pathways. Post-translational modifications have been described, including acetylation, protein cleavage and phosphorylation. Synonyms for this target antigen include HMG1, HMG3, SBP-1, high mobility group protein B1, Amphoterin, and HMG-1. HMGB1 gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.