S100A7A protein

S100 proteins are a large family of calcium-binding proteins that act as antimicrobial peptides regulating basic cellular and extracellular processes such as cell proliferation and differentiation, cell migration, and antimicrobial host defense.

Psoriasin (S100A7) is a calcium-binding EF-hand protein that is overexpressed in psoriatic keratinocytes. S100A7 is a member of the S100 gene family located in the S100 gene cluster on chromosome 1q21 and shares the typical calcium binding domains that define this protein family.

Psoriasin (S100A7) was first detected in psoriatic skin susceptible to inflammation, suggesting involvement in the lesional phenotype of the disease, the Köbner phenomenon. Furthermore, the protein plays a role due to its role in antimicrobial defense (antimicrobial peptide - AMP), innate immunity, epidermal cell maturation, and epithelial tumorigenesis.

By RT-PCR of psoriatic skin, Wolf et al (2003) cloned 2 splice variants of S100A7A, which they named S100A15 . Both splice variants encode identical 101-amino acid proteins with a calculated molecular mass of 11.3 kD. S100A15 has an N-terminal S100-type EF-hand motif and a C-terminal canonical EF-hand motif, a bipartite core target sequence, and an N-myristoylation site.

S100A15 is 93% identical to S100A7. In mice, the functions that are distributed between the two proteins in humans are clustered in a single one: the S100A7/A15 protein.

Diseases associated with S100A7A include psoriasis and macular degeneration, age-related. Related metabolic pathways include defensins and the innate immune system.

1. Al-Sudany NK et al. (2019) Downregulation of S100a7a antimicrobial peptide in acne vulgaris patients after isotretinoin therapy. Dermatol Ther 32:e13136.
2. Marenholz I et al. (2001) Identification of human epidermal differentiation complex (EDC)-encoded genes by subtractive hybridization of entire YACs to a gridded keratinocyte cDNA library. Genome Res 11: 341-355.
3. Nasser MW et al (2015) RAGE mediates S100A7-induced breast cancer growth and metastasis by modulating the tumor microenvironment. Cancer Res 75: 974-985.
4. Wolf R et al (2003) Molecular cloning and characterization of alternatively spliced mRNA isoforms from psoriatic skin encoding a novel member of the S100 family. FASEB J 17: 1969-1979.
5. Wolf R et al. (2011) Novel S100A7 (psoriasin)/S100A15 (koebnerisin) subfamily: highly homologous but distinct in regulation and function. Amino Acids 41: 789-796.