Desmosomes are the most common type of intercellular junction in vertebrate epithelial cells. They are characterized by 2 forms of interaction with other cellular structures. First, they form membrane anchorage sites for intermediate-size filaments, which are seen as electron-dense plaques evident beneath the plasma membrane. Second, a specific membrane core domain interacts with a corresponding domain of the plasma membrane of an adjacent cell, apparently mediating intercellular adhesion in a stable way. The desmosome intermediate filament complex is thought to impart tensile strength and resilience to the epithelium. Desmosomal proteins can be divided into 2 groups based on whether they fractionate with the urea-insoluble 'core' or the urea-soluble 'plaque' components. Desmoglein is, for example, a protein of the core. The main proteins of the plaque comprise the desmoplakins and plakoglobin.