Intercellular adhesion and its role in epidermal differentiation.

The differentiation of epidermal keratinocytes is accompanied by a regular sequence of changes in the nature of their adhesive interactions. The basis of these changes is discussed with reference to the more detailed studies of intercellular adhesion of other tissue types. In the early stages, desmosome formation predominates. A sequence of molecular events which may underlie desmosome formation and junctional stability is constructed. At the later stages of differentiation, adhesive interactions between non-junctional membranes are of increasing importance, and cells undergo pronounced flattening. The involvement of the cytoskeleton in these processes is considered. Possibilities for further studies on keratinocyte adhesion in normal and pathological epidermis are suggested.