Integrins of normal human epidermis: differential expression, synthesis and molecular structure.

The expression of integrin cell surface receptors in normal skin and their synthesis and molecular structure in keratinocyte cultures was investigated. The reactivity of four different polypeptides of the integrin family (alpha 2-, alpha 3-, alpha 6- and beta 1-chains) was demonstrated in the basal cell layer of normal epidermis. Studies of labelled keratinocyte cell lines showed that the polypeptides were expressed as alpha 2 beta 1, alpha 3 beta 1 and alpha 6 beta 4 integrins. Only the alpha 6 beta 4 integrin showed polarization towards the basement membrane attachment site of basal layer keratinocytes, and was preferentially expressed at microvillous projections. In contrast, alpha 2 beta 1 and alpha 3 beta 1 integrins were equally expressed throughout the basal cell plasma membrane.