S100A9

S100A9

A gene on chromosome 1q21 that encodes a member of the S100 family of proteins, which contain 2 EF-hand calcium-binding motifs and as a group regulate cell cycle progression and differentiation and other cellular processes. S100A9 has antimicrobial activity against bacteria and fungi and provides resistance to invasion by pathogenic bacteria, and it upregulates transcription of genes under the control of NF-kappa-B; it is linked to the endotoxic shock response to bacterial lipopolysaccharide. S100A9 promotes tubulin polymerisation and macrophage and granulocyte migration and infiltration into wound sites; it is a pro-inflammatory mediator and upregulates IL8 release and cell surface expression of ICAM1. Extracellular S100A9 (calprotectin) binds to target cells and promotes apoptosis.
 
Molecular pathology
Altered expression of S100A9 is linked to cystic fibrosis.
References in periodicals archive ?
Calprotectin is a calcium and zinc binding protein complex formed by S100A8 and S100A9 proteins.
The students discovered that both groups of mice had similar levels of fibrosis and number of scar forming cells but the livers of S100A9 knockout mice had fewer neutrophils, suggesting that neutrophils are not important for promoting liver fibrosis (scarring).
Alterations of circulating endogenous secretory RAGE and S100A9 levels indicating dysfunction of the AGE-RAGE axis in autism.
To shed more light on the possible alterations of the AGEs-RAGE axis in autism, these researchers measured plasma levels of endogenous secretory RAGE (esRAGE) and its proinflammatory ligand S100A9 in 18 young adults with an ASD diagnosis and 18 age- and gender-matched healthy comparison subjects.
Of these proteins, S100A8 (also known as myeloid-related protein 8 and calgranulin A), S100A9 (myeloid-related protein 14, calgranulin B), and S100A12 (calgranulin C) have prompted particular interest among rheumatologists because they are valuable markers of phagocyte activation (2).
S100A12 is produced mainly by granulocytes upon inflammatory activation and acts independently of S100A8 and S100A9 (17).
In the absence of ELISAs specific for the monomeric forms of S100A8 and S100A9 and of a commercially available test for S100A12, we have hypothesized that mass spectrometry (MS) might be a possible approach for detecting these proteins (22).
TASQ (tasquinimod, ABR-215050) binds to a molecule called S100A9 which is expressed in the white blood cells involved in the regulation of immune responses.
The masses of the 2 S100A9 proteins (13152 and 12 689 Da) corresponded to a form missing the N-terminal methionine and an added acetylation of threonine 2, and a form missing the 1st 5 N-terminal residues and an added acetylation of serine 6, as reported elsewhere (21).
Immunoblotting with an anti-S100A9 antibody likewise identified both S100A9 and A9 *, and relative quantification of blot signals correlated strongly with the respective SELDI-TOF peak intensity signals (r = 0.
Human S100A8 and S100A9 were purchased from Bachem AG.
Biochemical characterization of the murine S100A9 (MRP14) protein suggests that it is functionally equivalent to its human counterpart despite its low degree of sequence homology.