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Overview

Uniprot IDP05109
Protein NameProtein S100-A8
Gene NameS100A8
OrganismHomo sapiens

Kla Sites from experimental identification

Position Flanking peptide
18 SIIDVYHKYSLIKGN
23 YHKYSLIKGNFHAVY
36 VYRDDLKKLLETECP
49 CPQYIRKKGADVWFK
7 *MLTELEKALNSIID
85 MGVAAHKKSHEESHK
92 KSHEESHKE******

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. Also participates in regulatory T-cell differentiation together with CD69 (PubMed:26296369). 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 pro-inflammatory, antimicrobial, oxidant-scavenging and apoptosis-inducing activities. Its pro-inflammatory 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 pro-inflammatory 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. Can act as a potent amplifier of inflammation in autoimmunity as well as in cancer development and tumor spread. The iNOS-S100A8/A9 transnitrosylase complex directs selective inflammatory stimulus-dependent S-nitrosylation of GAPDH and probably multiple targets such as ANXA5, EZR, MSN and VIM by recognizing a [IL]-x-C-x-x-[DE] motif; S100A8 seems to contribute to S-nitrosylation site selectivity

Protein Sequence

10 MLTELEKALN 20 SIIDVYHKYS 30 LIKGNFHAVY 40 RDDLKKLLET 50 ECPQYIRKKG 60 ADVWFKELDI 70 NTDGAVNFQE 80 FLILVIKMGV 90 AAHKKSHEES HKE

Gene Ontology

Classification GO ID Description
Molecular Function GO:0035662 Toll-like receptor 4 binding
Cellular Component GO:0005737 cytoplasm
Cellular Component GO:0005856 cytoskeleton
Cellular Component GO:0005829 cytosol
Cellular Component GO:0070062 extracellular exosome
Cellular Component GO:0031012 extracellular matrix
Cellular Component GO:0005576 extracellular region
Cellular Component GO:0005615 extracellular space
Cellular Component GO:0045111 intermediate filament cytoskeleton
Cellular Component GO:0005634 nucleus
Cellular Component GO:0005886 plasma membrane
Cellular Component GO:0034774 secretory granule lumen
Molecular Function GO:0050544 arachidonate binding
Molecular Function GO:0005509 calcium ion binding
Molecular Function GO:0048306 calcium-dependent protein binding
Molecular Function GO:0008017 microtubule binding
Molecular Function GO:0050786 RAGE receptor binding
Molecular Function GO:0008270 zinc ion binding
Biological Process GO:0006915 apoptotic process
Biological Process GO:0035425 autocrine signaling
Biological Process GO:0006914 autophagy
Biological Process GO:0002544 chronic inflammatory response
Biological Process GO:0042742 defense response to bacterium
Biological Process GO:0050832 defense response to fungus
Biological Process GO:0043542 endothelial cell migration
Biological Process GO:0006954 inflammatory response
Biological Process GO:0045087 innate immune response
Biological Process GO:0002523 leukocyte migration involved in inflammatory response
Biological Process GO:0070488 neutrophil aggregation
Biological Process GO:0030593 neutrophil chemotaxis
Biological Process GO:0018119 peptidyl-cysteine S-nitrosylation
Biological Process GO:0030307 positive regulation of cell growth
Biological Process GO:0050729 positive regulation of inflammatory response
Biological Process GO:2001244 positive regulation of intrinsic apoptotic signaling pathway
Biological Process GO:0051493 regulation of cytoskeleton organization
Biological Process GO:0034121 regulation of toll-like receptor signaling pathway
Biological Process GO:0045471 response to ethanol
Biological Process GO:0032496 response to lipopolysaccharide
Biological Process GO:0010043 response to zinc ion

Reference

[1] Yang Z, Yan C, Ma J, Peng P, Ren X et al.. Lactylome analysis suggests lactylation-dependent mechanisms of metabolic adaptation in hepatocellular carcinoma.. Nat Metab 5(1):61-79. 2023 Jan. PMID: 36593272.

[2] Yang YH, Wang QC, Kong J, Yang JT, Liu JF. Global profiling of lysine lactylation in human lungs.. Proteomics 23(15):e2200437. 2023 Aug. PMID: 37170646.