S100 calcium-binding protein A7 (S100A7), also known as psoriasin, is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

that in humans is encoded by the ''S100A7''

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

Function

S100A7 is a member of the S100 family of proteins containing 2

EF-hand The EF hand is a helix–loop–helix structural domain or ''motif'' found in a large family of calcium-binding proteins. The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in ...

calcium-binding motifs. S100 proteins are localized in the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

and/or

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucle ...

of a wide range of cells, and involved in the regulation of a number of cellular processes such as

cell cycle The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subs ...

progression and differentiation. S100 genes include at least 13 members which are located as a cluster on chromosome 1q21. This protein differs from the other S100 proteins of known structure in its lack of calcium binding ability in one EF-hand at the

N-terminus The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...

. The protein functions as a prominent antimicrobial peptide mainly against ''

E. coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...

''. S100A7 also displays antimicrobial properties. It is secreted by epithelial cells of the skin and is a key antimicrobial protein against ''Escherichia coli'' by disrupting their cell membranes. This is the reason that in countries with poor sanitation, human skin is exposed to ''E. coli'' strains from faecal matter but it does not usually result in an infection.Bulet, P., et al. 2004. Anti-microbial peptides: from invertebrates to vertebrates. Immunology Review 198:169–184. S100A7 is highly homologous to

S100A15 S100 calcium-binding protein A15 (S100A15), also known as koebnerisin and S100 calcium-binding protein A7A (S100A7A), is a protein that in humans is encoded by the ''S100A7A'' (alias:''S100A15'') gene. S100 proteins are a diverse calcium-bindin ...

(

koebnerisin S100 calcium-binding protein A15 (S100A15), also known as koebnerisin and S100 calcium-binding protein A7A (S100A7A), is a protein that in humans is encoded by the ''S100A7A'' (alias:''S100A15'') gene. S100 proteins are a diverse calcium-binding ...

) but distinct in expression, tissue distribution and function.

Clinical significance

This protein is markedly over-expressed in the skin lesions of

psoriatic Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complete ...

patients, but is excluded as a candidate gene for familial psoriasis susceptibility. The expression of psoriasin is induced in skin wounds through activation of the

epidermal growth factor receptor The epidermal growth factor receptor (EGFR; ErbB-1; HER1 in humans) is a transmembrane protein that is a receptor for members of the epidermal growth factor family (EGF family) of extracellular protein ligands. The epidermal growth factor recept ...

Interactions

S100A7 has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...

with

COP9 constitutive photomorphogenic homolog subunit 5 COP9 constitutive photomorphogenic homolog subunit 5 (Arabidopsis), also known as COPS5 or Csn5, is a gene conserved from humans to Saccharomyces cerevisiae. Function The protein encoded by this gene is one of the eight subunits of COP9 signal ...

FABP5 Fatty acid-binding protein, epidermal is a protein that in humans is encoded by the ''FABP5'' gene. Function This gene encodes the fatty acid binding protein found in epidermal cells, and was first identified as being upregulated in psoriasis ...

and

RANBP9 Ran-binding protein 9 is a protein that in humans is encoded by the ''RANBP9'' gene. Function This gene encodes a protein that binds RAN, a small GTP binding protein belonging to the RAS superfamily that is essential for the translocation of RN ...

. S100A7 interacts with RAGE (receptor of advanced glycated end products).

Function

Clinical significance

Interactions

References

Further reading