Cadherins are the major cell adhesion molecules at adherens junctions (AJs). Classical cadherins are Ca2+-dependent, homophilic adhesion molecules that link adjacent cells (Gumbiner, 2005; Halbleib and Nelson, 2006; Pokutta and Weis, 2007). The extracellular domain of classical cadherins consists of five cadherin-type repeats (called "extracellular cadherin" (EC) -domains). In the presence of Ca2+, the monomers form parallel cis-dimers resulting in a rod-like structure (Gumbiner, 2005). The cis-dimers undergo trans homophilic interactions to mediate homotypic cell-cell interactions. The cytoplasmic tails of classical cadherins interact with different proteins (primarily catenins) to regulate cell surface expression levels, linkage to the actin cytoskeleton, and cell signaling. Non-classical cadherins (Atypical cadherins, Proto-cadherins, cadherin-related proteins) have a variable number of cadherin-type repeats, do not associate with catenins, and are not associated with AJs (Halbleib and Nelson, 2006).