Cell-cell and cell-matrix interactions are of fundamental importance for the development and the maintenance of tissues and organs in multicellular organisms. Adhesive processes are mediated and controlled by an increasingly large and complex number of cell adhesion molecules that are anchored to the cell surface membrane by transmembrane domains. According to their structural and functional features, cell adhesion molecules have been classified into at least four major families: the integrins, selectins, cadherins and members of the immunoglobulin superfamily. Apart from linking cells to...