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.
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References in periodicals archive ?
Response group: (a) percentages of CD66b+ neutrophils in the peripheral blood of patients with active CD (n =15) before and after IFX treatment; (b) expression of CD66b mRNA in the peripheral blood neutrophils from patients with active CD (n =15) before and after IFX treatment by qRT-PCR; (c) expression of CD66b mRNA in intestinal mucosa from patients with active CD (n = 13) before and after IFX treatment by qRT-PCR; (d) immunohistochemical staining of CD66b in the intestinal mucosa of active CD (n = 10) before and after IFX treatment; and (e) expression of S100A8, (f) S100A9, and (g) MPO in the intestinal mucosa of patients with active CD (n = 13) before and after IFX treatment.
Myeloid-related proteins (MRP), also called S100A8 (MRP8) and S100A9 (MRP14), are two calcium-binding proteins linked to innate immunity, and they are expressed in neutrophils and monocytes.
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).
Calprotectin, a heterocomplex of the two calcium-binding proteins S100A8 and S100A9, is one of the most common skin-derived AMPs [41].
S100A9 belongs to a large [Ca.sup.2+]-binding protein family, which has a wide range of functions.
S100 proteins are part of the inflammatory response and a number of these proinflammatory cytokines (S100B, S100A6, S100A7, S100A1, S100A9, and S100A12) have been implicated in neurodegenerative disorders, such as AD.
Furthermore, as exercise does not increase calprotectin levels in neutrophils [6], the likely source is skeletal muscle, since S100A8 and S100A9 mRNA rates increase in skeletal muscle during exercise [16].
HDM-DP, as an allergen from our environment, could induce the secretion of myeloid-related protein 8 (MRP8, S100A8) and MRP14 (S100A9).
Human S100A8 and S100A9 were purchased from Bachem AG.
Calprotectin is a group of protein heterocomplexes: MRP-8/MRP-14 or S100A8/A9 (calcium-binding proteins, similar to migration-inhibiting factors: MRP-8 (S100A8) and MRP-14 (S100A9)).
Abbreviations SEM: Scanning electron microscopy TEM: Transmission electron microscopy MPO: Myeloperoxidase Lf: Lactoferrin NGAL: Neutrophil gelatinase-associated lipocalin GAPDH: Glyceraldehyde-3-phosphate dehydrogenase S100A8, S100A9: The S100 calcium-binding proteins, known also as calgranulins A and B or myeloid-related proteins MRP8 and MRP14, or cystic fibrosis antigen S100A8/A9: Calprotectin MMP-9: Matrix metalloproteinase 9 or gelatinase B, 92 kDa HNP 1-3: Human neutrophil peptides 1-3 or defensins CAP37: Cationic antimicrobial protein 37 LPS: Lipopolysaccharide from Salmonella enterica serovar Typhimurium fMLP: N-Formylmethionyl-leucyl-phenylalanine PMA: Phorbol 12-miristate 13-acetate CDT: Clostridium difficile binary toxin.