Cytoskeletal architecture and epithelial differentiation: molecular determinants of cell interaction and cytoskeletal filament anchorage.

Desmosomes are morphologically well defined junctions between epithelial cells and also some other cells such as myocardiocytes, meningeal cells and dendritic reticulum cells of lymphatic follicles. Besides their function in cell coupling, desmosomes anchor components of the cytoskeleton, i.e. intermediate-sized filaments (IFs), through their cytoplasmic plaques, thereby contributing to cytoskeletal and tissue architecture. In molecular terms, desmosomes are specific assemblies of transmembrane glycoproteins of the cadherin family, desmoglein(s) and desmocollin(s), that contribute to cell adhesion via their extracellular, aminoterminal domains and to plaque formation and IF coupling through their cytoplasmic, carboxyterminal "tails". Using transfection assays, we analyzed the function of different tail domains in plaque assembly and IF anchorage. Furthermore, we present evidence that both desmogleins and desmocollins represent multigene subfamilies showing cell type specific expression and that a desmosomal plaque protein occurring in stratified and complex epithelia, the "band 6 protein", is related to the plakoglobin family.