S100 calcium-binding protein A8 (S100A8)

S100 calcium-binding protein A8 (S100A8) is a member of the S100 family of EF-hand calcium-binding proteins predominantly expressed in neutrophils and monocytes. It functions both intra- and extracellularly, mainly as a regulator and effector in inflammation and innate immune responses. S100A8 forms heterodimers (and higher-order complexes) with S100A9 (calprotectin), which are critical for chemotaxis, cytoskeletal reorganization, regulation of NADPH oxidase, and ROS production, as well as modulation of inflammatory signaling via receptors such as RAGE and TLR4. Its expression is elevated in a range of inflammatory and infectious diseases and certain cancers, and it serves as a biomarker for disease activity in several immune-mediated conditions. Structural studies show that it binds both calcium and zinc, which regulate its oligomerization and function[1][2][4][5][6][7].

Other names

Protein S100-A8Calgranulin AMRP8p8Cystic fibrosis antigenLeukocyte L1 complex light chainMigration inhibitory factor-related protein 8Calprotectin L1L subunitUrinary stone protein band ACAGACFAGCGLACP-10L1AgMA387MIFNIF60B8AG

Immune modulation; Inhibition of S100A8/A9–receptor interactions (e.g., TLR4, RAGE) to reduce inflammatory signaling[2][5]; Modulation of myeloid cell activity and migration