S100 protein

S100/ICaBP type calcium binding domain

Structure of the S100B protein. Based on PyMOL rendering of PDB 1b4c.
Identifiers
Symbol S_100
Pfam PF01023
InterPro IPR013787
PROSITE PDOC00275
SCOP 1cnp
SUPERFAMILY 1cnp

The S100 proteins are a family of low-molecular-weight proteins found in vertebrates and characterized by two calcium-binding sites that have helix-loop-helix ("EF-hand type") conformation. There are at least 21 different S100 proteins.[1] They are encoded by a family of genes whose symbols use the S100 prefix, for example, S100A1, S100A2, S100A3.

Structure

Most S100 proteins are homodimeric, consisting of two identical polypeptides, which are held together by non-covalent bonds. S100 proteins are structurally similar to calmodulin. On the other hand they differ from calmodulin on the other features. For instance, their expression pattern is cell-specific, i.e. they are expressed in particular cell types. Their expression depends on environmental factors. To contrast, calmodulin is a ubiquitous and universal intracellular Ca2+ receptor widely expressed in many cells.

Normal function

S100 proteins are normally present in cells derived from the neural crest (Schwann cells, and melanocytes), chondrocytes, adipocytes, myoepithelial cells, macrophages, Langerhans cells,[2][3] dendritic cells,[4] and keratinocytes. It may be present in some breast epithelial cells.

S100 proteins have been implicated in a variety of intracellular and extracellular functions.[5] S100 proteins are involved in regulation of protein phosphorylation, transcription factors, Ca2+ homeostasis, the dynamics of cytoskeleton constituents, enzyme activities, cell growth and differentiation, and the inflammatory response. S100A7 (psoriasin) and S100A15 have been found to act as cytokines in inflammation, particularly in autoimmune skin conditions such as psoriasis.[6]

Pathology

S100 immunostain marking the sustentacular cells in a paraganglioma.

Several members of the S100 protein family are useful as markers for certain tumors and epidermal differentiation. It can be found in melanomas,[7] 100% of schwannomas, 100% of neurofibromas (weaker than schwannomas), 50% of malignant peripheral nerve sheath tumors (may be weak and/or focal), paraganglioma stromal cells, histiocytoma and clear cell sarcomas. Further, S100 proteins are markers for inflammatory diseases and can mediate inflammation and act as antimicrobials.[8]

S100 proteins have been used in the lab as cell markers for anatomic pathology.

Human genes

CRNN; FLG; FLG2; HRNR; RPTN; S100G; TCHH; THHL1;

Nomenclature

The "S100" symbol prefix is derived from the fact that these proteins are soluble in 100%, i.e. saturated, ammonium sulfate at neutral pH. The symbol has often been hyphenated,[9] but current gene and protein nomenclature, such as HGNC nomenclature, does not use hyphens in symbols.

See also

References

  1. ↑ Marenholz I, Heizmann CW, Fritz G (October 2004). "S100 proteins in mouse and man: from evolution to function and pathology (including an update of the nomenclature)". Biochem. Biophys. Res. Commun. 322 (4): 1111–22. doi:10.1016/j.bbrc.2004.07.096. PMID 15336958.
  2. ↑ Wilson, AJ; Maddox, PH; Jenkins, D (January 1991). "CD1a and S100 antigen expression in skin Langerhans cells in patients with breast cancer.". The Journal of pathology 163 (1): 25–30. PMID 2002421.
  3. ↑ Coppola, D; Fu, L; Nicosia, SV; Kounelis, S; Jones, M (May 1998). "Prognostic significance of p53, bcl-2, vimentin, and S100 protein-positive Langerhans cells in endometrial carcinoma.". Human pathology 29 (5): 455–62. PMID 9596268.
  4. ↑ Shinzato, M; Shamoto, M; Hosokawa, S; Kaneko, C; Osada, A; Shimizu, M; Yoshida, A (May 1995). "Differentiation of Langerhans cells from interdigitating cells using CD1a and S-100 protein antibodies.". Biotechnic & histochemistry : official publication of the Biological Stain Commission 70 (3): 114–8. PMID 7548432.
  5. ↑ Donato R (April 2003). "Intracellular and extracellular roles of S100 proteins". Microsc. Res. Tech. 60 (6): 540–51. doi:10.1002/jemt.10296. PMID 12645002.
  6. ↑ Wolf R, Howard OM, Dong HF, Voscopoulos C, Boeshans K, Winston J et al. (2008). "Chemotactic activity of S100A7 (Psoriasin) is mediated by the receptor for advanced glycation end products and potentiates inflammation with highly homologous but functionally distinct S100A15.". J Immunol 181 (2): 1499–506. doi:10.4049/jimmunol.181.2.1499. PMC 2435511. PMID 18606705.
  7. ↑ Nonaka D, Chiriboga L, Rubin BP (November 2008). "Differential expression of S100 protein subtypes in malignant melanoma, and benign and malignant peripheral nerve sheath tumors". J. Cutan. Pathol. 35 (11): 1014–9. doi:10.1111/j.1600-0560.2007.00953.x. PMID 18547346.
  8. ↑ Wolf R, Ruzicka T, Yuspa SH (July 2010). "Novel S100A7 (psoriasin)/S100A15 (koebnerisin) subfamily: highly homologous but distinct in regulation and function". Amino Acids 41 (4): 789–96. doi:10.1007/s00726-010-0666-4. PMID 20596736.
  9. ↑ Elsevier, Dorland's Illustrated Medical Dictionary, Elsevier.

Further reading

External links