EXPRESSION AND FUNCTION OF THE KERATINOCYTE INTEGRINS

Human keratinocytes express several adhesive receptors of the integrin family. Expression is normally confined to the basal (proliferative) layer of keratinocytes, both in mature epidermis and during developmen t. Altered expression patterns are observed during wound healing, in p soriasis and in squamous cell carcinomas, Keratinocyte integrins are s ubject to both transcriptional and post-translational regulation and l igand binding ability can be modulated independently of expression. St udies with cultured keratinocytes suggest a variety of functions for t he receptors: adhesion to extracellular matrix proteins, intercellular adhesion, stratification, lateral migration and the regulation of ter minal differentiation. Three distinct subpopulations of basal keratino cytes, with characteristics of stem cells, transit amplifying cells an d cells committed to differentiate, can be distinguished on the basis of differences in integrin expression and function.