About HMG / High-Mobility Group:
High mobility group (HMG) proteins are the largest class of nonhistone proteins found in the nucleus of cells in humans. They are often found in association with regions of active transcription in chromatin, making them essential in the regulation of DNA-dependent processes. HMG proteins are known to contain various post-translational modifications, including méthylation, acétylation, phosphorylation, ADP-ribosylation, and glycosylation.
HMG proteins can play a significant role in various human health conditions and disorders. Disruptions and rearrangements in the genes coding for some of the HMG proteins are associated with some common benign tumors, and antibodies for HMG proteins are often found in those living with autoimmune diseases. HMGB1, a common HMG protein, has also been shown to have an extracellular activity as a chemokine. This attracts neutrophils and mononuclear inflammatory cells to an infected liver. The SRY gene on the Y Chromosome contains an HMG-Box domain.
High-Mobility Group Structure
HMG proteins are subdivided into three superfamilies containing their own functional domain. HMGA contains an AT-hook domain and includes HMGA1 and HMGA2. HMGB contains an HMG-box domain, with HMGB1, HMGB2, HMGB3, and HMGB4 being members of the family. Finally, HMGN contains a nucleosomal binding domain. This group includes HMGN1, HMGN2, HMGN3, HMGN4. Each of these groups was originally isolated in mammalian cells and has been named according to their electrophoretic mobility in polyacrylamide gels.