S100 protein is a family of low molecular weight protein found in vertebrates characterized by two EF-hand calcium-binding motifs. There are at least 21 different S100 proteins, and the name is derived from the fact that the protein is 100% soluble in ammonium sulfate at neutral pH. Most S100 proteins are disulfide-linked homodimer, and is normally present in cells derived from theneural crest, chondrocytes, macrophages, dendritic cells, etc. S100 proteins have been implicated in a variety of intracellular and extracellular functions. They are involved in regulation of protein phosphorylation, transcription factors, the dynamics of cytoskeleton constituents, enzyme activities, cell growth and differentiation, and the inflammatory response. Protein S100-A14, also known as S100 calciumbinding protein A14, S114 and S100A14, is a cytoplasm protein which belongs to the S-100 family. It is expressed at highest levels in colon and at moderate levels in thymus, kidney, liver, small intestine, and lung. Low expression in heart and no expression is seen in brain, skeletal muscle, spleen, placenta and peripheral blood leukocytes.

Koebnerisin is also known as protein S100-A7A (S100A7A), S100 calcium-binding protein A7-like 1 (S100A7L1) or S100 calcium-binding protein A15 (S100A15). Human S100A7A / S100A15 is a novel member of the S100 family of EF-hand calcium-binding proteins and was recently identified in psoriasis, where it is significantly upregulated in lesional skin. S100A7 is expressed by both normal cultured and malignant keratinocytes and malignant breast epithelial cells within ductal carcinoma in situ, suggesting an association with abnormal pathways of differentiation. S100A7 plays a role in the pathogenesis of inflammatory skin disease, as a chemotactic factor for hematopoietic cells. It also plays a role in early stages of breast tumor progression in association with the development of the invasive phenotype. The association of the 11.2 kDa S100A7A / S100A15 with psoriasis suggests that it contributes to the pathogenesis of the disease and could provide a molecular target for therapy.