Recombinant Mouse High mobility group protein B1 (Hmgb1), partial

Function

In the extracellular compartment (following either active secretion or passive release) involved in regulation of the inflammatory response. Fully reduced HGMB1 (which subsequently gets oxidized after release) in association with CXCL12 mediates the recruitment of inflammatory cells during the initial phase of tissue injury; the CXCL12:HMGB1 complex triggers CXCR4 homodimerization (PubMed:22370717). Induces the migration of monocyte-derived immature dendritic cells and seems to regulate adhesive and migratory functions of neutrophils implicating AGER/RAGE and ITGAM (PubMed:17268551). Can bind to various types of DNA and RNA including microbial unmethylated CpG-DNA to enhance the innate immune response to nucleic acids. Proposed to act in promiscuous DNA/RNA sensing which cooperates with subsequent discriminative sensing by specific pattern recognition receptors (PubMed:19890330). Promotes extracellular DNA-induced AIM2 inflammasome activation implicating AGER/RAGE. Disulfide HMGB1 binds to transmembrane receptors, such as AGER/RAGE, TLR2, TLR4 and probably TREM1, thus activating their signal transduction pathways (PubMed:17568691, PubMed:19264983, PubMed:21419643). Mediates the release of cytokines/chemokines such as TNF, IL-1, IL-6, IL-8, CCL2, CCL3, CCL4 and CXCL10 (PubMed:12110890, PubMed:17548579). Promotes secretion of interferon-gamma by macrophage-stimulated natural killer (NK) cells in concert with other cytokines like IL-2 or IL-12. TLR4 is proposed to be the primary receptor promoting macrophage activation and signaling through TLR4 seems to implicate LY96/MD-2. In bacterial LPS- or LTA-mediated inflammatory responses binds to the endotoxins and transfers them to CD14 for signaling to the respective TLR4:LY96 and TLR2 complexes (By similarity). Contributes to tumor proliferation by association with ACER/RAGE (By similarity). Can bind to IL1-beta and signals through the IL1R1:IL1RAP receptor complex (By similarity). Binding to class A CpG activates cytokine production in plasmacytoid dendritic cells implicating TLR9, MYD88 and AGER/RAGE and can activate autoreactive B cells. Via HMGB1-containing chromatin immune complexes may also promote B cell responses to endogenous TLR9 ligands through a B-cell receptor (BCR)-dependent and ACER/RAGE-independent mechanism (By similarity). Inhibits phagocytosis of apoptotic cells by macrophages; the function is dependent on poly-ADP-ribosylation and involves binding to phosphatidylserine on the cell surface of apoptotic cells (PubMed:18768881, PubMed:22204001). In adaptive immunity may be involved in enhancing immunity through activation of effector T-cells and suppression of regulatory T (TReg) cells (PubMed:21419643). In contrast, without implicating effector or regulatory T-cells, required for tumor infiltration and activation of T-cells expressing the lymphotoxin LTA:LTB heterotrimer thus promoting tumor malignant progression (PubMed:23108142). Also reported to limit proliferation of T-cells (By similarity). Released HMGB1:nucleosome complexes formed during apoptosis can signal through TLR2 to induce cytokine production (By similarity). Involved in induction of immunological tolerance by apoptotic cells; its pro-inflammatory activities when released by apoptotic cells are neutralized by reactive oxygen species (ROS)-dependent oxidation specifically on Cys-106 (By similarity). During macrophage activation by activated lymphocyte-derived self apoptotic DNA (ALD-DNA) promotes recruitment of ALD-DNA to endosomes (PubMed:25660970)

Subcellular Location

Nucleus; Cytoplasm; Chromosome; Cell membrane (Peripheral membrane protein); Endosome; Endoplasmic reticulum-Golgi intermediate compartment; Secreted

Tissue Specificity

Serum levels are found elevated in mice with modeled systemic lupus erythematosus (SLE) and are correlated with SLE disease activity (PubMed:26078984)

Subunit

Interacts (fully reduced HMGB1) with CXCL12; probably in a 1:2 ratio involving two molecules of CXCL12, each interacting with one HMG box of HMGB1; inhibited by glycyrrhizin (PubMed:22370717). Associates with the TLR4:LY96 receptor complex (By similarity). Component of the RAG complex composed of core components RAG1 and RAG2, and associated component HMGB1 or HMGB2 (PubMed:9184213). Interacts (in cytoplasm upon starvation) with BECN1; inhibits the interaction of BECN1 and BCL2 leading to promotion of autophagy (PubMed:20819940). Interacts with KPNA1; involved in nuclear import (PubMed:17114460). Interacts with SREBF1, TLR2, TLR4, TLR9, APEX1, FEN1, POLB, TERT (PubMed:16040616, PubMed:16267105, PubMed:17548579, PubMed:17803946, PubMed:22544226). Interacts with AGER, PTPRZ1, IL1B, MSH2, XPA, XPC, HNF1A, TP53 (By similarity). Interacts with CD24; the probable CD24:SIGLEC10 complex is proposed to inhibit HGMB1-mediated tissue damage immune response (PubMed:19264983). Interacts with THBD; prevents HGMB1 interaction with ACER/RAGE and inhibits HGMB1 pro-inflammatory activity (By similarity). Interacts with HAVCR2; impairs HMGB1 binding to B-DNA and likely HMGB1-mediated innate immune response (PubMed:22842346). Interacts with XPO1; mediating nuclear export (By similarity). Interacts with receptor RAGE/AGER (By similarity)

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