ABSTRACT
Adhesion molecules mediate cell-to-cell contact, and participate in the regulation of the development of tissues. Cell adhesion molecules can be classified into four families: immunoglobin-like proteins, integrins, selectins, and cadherins (1). In general, cadherins are membrane-bound glycoprotein receptors that function in cell-to-cell adhesion at adherens junctions, where cytoskeleton components are assembled intracellularly (2). The cadherin superfamily members are grouped as a family of proteins by virtue of tandem repeats of an extracellular cadherin-specific motif referred to as the EC domain, and are distinguished from each other by their unique structural features (3). The cadherin superfamily includes the classical cadherins, desmosomal cadherins, protocadherins, and cadherin-related proteins (3, 4); They are classified into these specific subgroups based on the motifs of their cytoplasmic domain, the number of membrane-spanning regions, or the number of EC domains (5). The majority of cadherins have a single membranespanning domain, and a cytoplasmic domain involved in linkage to the cytoskeleton (1, 6, 7). Each extracellular EC domain is approximately 110 amino acids in length and contains highly conserved amino acid motifs (DXD, LDRE, and DXNDNXPXF), which are involved in Ca2+-mediated intermolecular association among cadherins on the same cell as well as adjacent cells (1, 3).
