[Friend or Foe?--Psoriasin and Koebnerisin: multifunctional defence molecules in skin differentiation, tumorigenesis and inflammation]

Abstract

Psoriasin (S100A7) and koebnerisin (S100A15) were first identified in inflamed psoriatic skin. They have lately evolved by gene duplications within the Epidermal Differentiation Complex (chromosome 1q21) and form a novel S100 subfamily in human. Despite highest homology (> 90 %), psoriasin and koebnerisin are distinct in tissue distribution, regulation, and function. They act differently as antimicrobial peptides (AMP) and synergize to promote inflammation and cell migration as endogenous danger signals ("alarmines") and chemoattractants. Their different properties are compelling reasons to discriminate psoriasin and koebnerisin in epithelial homeostasis, inflammation and epithelial carcinogenesis.