Adhesion molecules in keratinocytes.

Adhesion molecules are proteins on the cell surface that are involved in the interactions between lymphocytes and antigen-presenting cells, especially in inflammatory skin diseases and autoimmune bullous disorders. Adhesion molecules include cadherins (subgroups E, N, P, M), integrins, selectins, and the immunoglobulin gene family. Cadherins E in the epidermis including desmocollin 1 and 2 and desmoglein 1 and 3 are essential transmembrane components of desmosome glycoproteins, which play a major role in bullous diseases, pemphigus in particular. Also important are integrin beta 1 alpha 1 and other integrins, which connect ligands of the collagen, laminin, and fibronectin. Selectins (E, P) are important for leukocyte migration on endothelial cells. Adhesion molecules from the immunoglobulin superfamily (intercellular adhesion molecule-1, 3 [ICAM-1,3]; vascular adhesion molecule-1 [VCAM-1]) have significant roles in the immune and inflammatory mechanisms.