The essential function of the skin is that of a barriere against the outside. The epidermis is the tissue which assures the solidity and the resistance of the skin against forces of traction. The desmosomes, allowing the adhesion of epidermal cells, the keratinocytes, between them, are the structures of resistance of the epidermis. This adhesion function is possible thanks to the interactions between the desmosomial molecules and cytosqueletal filaments. Currently fifteen desmosomal proteins implicated in this process have been characterized. The role of desmosome in integrity of epidermis is demonstrated by the existence of the auto immune dermatosis, the pemphigus, in which the inflammatory reaction against desmosomal proteins results in the loss of the cohesion of keratinocytes.