Description
HMGB1 is a nuclear protein that is released passively by necrotic cells, retained by apoptotic cells, and secreted actively by inflammatory cells.
HMGB1 is essential for life: HMGB1 knockout mice die shortly after birth. Just recently, the two different activities of HMGB1 as a chemoattractant of motile cells and as inducer of cytokines have been attributed to different biochemical forms. Chemokine-HMGB1 (the form with chemoattractant activity) is completely reduced, while Cytokine-HMGB1 contains a disulfide bond between C23 and C45 (Yang et al. Redox modification of cysteine residues regulates the cytokine activity of HMGB1. Mol Med. 2012 Mar 30;18(3):250-259). Chemokine-HMGB1 behaves as a trigger of inflammation, attracting inflammatory cells, and of tissue repair, attracting stem cells and promoting their proliferation. Also, Chemokine-HMGB1 activates dendritic cells and promotes their functional maturation and migration to lymph nodes. However, and contrary to early reports, pure Chemokine-HMGB1 does not promote cytokine secretion; it does only so when it interacts with other molecules, like LPS, single-stranded DNA, or IL-1beta (see Sha et al. HMGB1 develops enhanced proinflammatory activity by binding to cytokines. J Immunol 2008, 180:2531-7, and Youn et al. High Mobility Group Box 1 Protein Binding to Lipopolysaccharide Facilitates Transfer of Lipopolysaccharide to CD14 and Enhances Lipopolysaccharide-Mediated TNF-alpha Production in Human Monocytes. J Immunol. 2008, 180:5067-74). Cytokine secretion is only promoted by cytokine-HMGB1 (see related products above). The Chemokine-HMGB1 we provide is the natural protein, with no tags or additional amino acids. It is produced in E.coli from an expression plasmid coding for the rat protein (Müller et al. Thermodynamics of HMGB1 interaction with duplex DNA. Biochemistry 2001, 40: 10254-61).