HMGB1 belongs to the HMGB family and contains 2 HMG box DNA-binding domains. HMGB1 is a DNA binding proteins that associates with chromatin and has the ability to bend DNA. This nuclear protein organizes the DNA and regulates transcription. After binding HMGB1 bends the DNA, which conducts to the binding of other proteins. HMGB1 suports transcription of many genes in interactions with many transcription factors or cooperation nucleosoms looses packed DNA and increases the chromatin remodeling, contact with core histones changes the structure of nucleosoms. it involved in V(D)J recombination by acting as a cofactor of the RAG complex. The presence of HMGB1 in the nucleus depends on posttranslational modifications. When the protein is not acetylated, stays in the nucleus, but hyperacetylation on lysine residues occurs to translocation into the cytosol. Synonyms: High-mobility group protein B1, high-mobility group protein 1, HMG-1, amphoterin and HMGB1.