Anti-Mouse S100A8 (Clone: ABM4A69)

S100A8 is a low molecular weight (10 kDa) secreted cytoplasmic protein belonging to S100 family of calcium- and zinc-binding protein. S100A8 regulates a number of cellular processes, such as, inflammation, antimicrobial, oxidant-scavenging and apoptosis-inducing activities, cell cycle progression and differentiation, leukocyte arachidonic acid trafficking and metabolism. S100A8 is a homodimer but predominantly remains as heterodimer with S100A9 and the S100A8/S100A9 complex is called as Calprotectin. S100A8 is generally expressed in myeloid cells, neutrophils, monocytes and keratinocytes but high levels are found in the serum sample of patients with inflammatory diseases, such as, rheumatoid, cystic fibrosis, inflammatory bowel disease, systemic lupus erythematosus, progressive systemic sclerosis and many other inflammatory diseases. S100A8 is also associated with Psoriasis (an inflammatory skin disorder characterized by keratinocyte hyperproliferation and altered differentiation). Protein function: S100A8 is a calcium- and zinc-binding protein which plays a prominent role in the regulation of inflammatory processes and immune response. It can induce neutrophil chemotaxis and adhesion. Predominantly found as calprotectin (S100A8/A9) which has a wide plethora of intra- and extracellular functions. The intracellular functions include: facilitating leukocyte arachidonic acid trafficking and metabolism, modulation of the tubulin-dependent cytoskeleton during migration of phagocytes and activation of the neutrophilic NADPH-oxidase. Activates NADPH- oxidase by facilitating the enzyme complex assembly at the cell membrane, transferring arachidonic acid, an essential cofactor, to the enzyme complex and S100A8 contributes to the enzyme assembly by directly binding to NCF2/P67PHOX. The extracellular functions involve proinflammatory, antimicrobial, oxidant-scavenging and apoptosis-inducing activities. Its proinflammatory activity includes recruitment of leukocytes, promotion of cytokine and chemokine production, and regulation of leukocyte adhesion and migration. Acts as an alarmin or a danger associated molecular pattern (DAMP) molecule and stimulates innate immune cells via binding to pattern recognition receptors such as Toll-like receptor 4 (TLR4) and receptor for advanced glycation endproducts (AGER). Binding to TLR4 and AGER activates the MAP-kinase and NF- kappa-B signaling pathways resulting in the amplification of the proinflammatory cascade. Has antimicrobial activity towards bacteria and fungi and exerts its antimicrobial activity probably via chelation of Zn(2+) which is essential for microbial growth. Can induce cell death via autophagy and apoptosis and this occurs through the cross-talk of mitochondria and lysosomes via reactive oxygen species (ROS) and the process involves BNIP3. Can regulate neutrophil number and apoptosis by an anti-apoptotic effect, regulates cell survival via ITGAM/ITGB and TLR4 and a signaling mechanism involving MEK-ERK. Its role as an oxidant scavenger has a protective role in preventing exaggerated tissue damage by scavenging oxidants. The iNOS-S100A8/A9 transnitrosylase complex is proposed to direct selective inflammatory stimulus-dependent S- nitrosylation of multiple targets such as GAPDH, ANXA5, EZR, MSN and VIM by recognizing a [IL]-x-C-x-x-[DE] motif, S100A8 seems to contribute to S-nitrosylation site selectivity. [The UniProt Consortium]