intercalated discs are three types of junctions: adherens junctions, desmosomes and gap junctions; Cadherin-2 is an essential component in adherens junctions, which enables cell–cell adhesion and force transmission across the sarcolemma. Cadherin-2 complexed to catenins has been described as a master regulator of intercalated disc function. Cadherin-2 appears at cell–cell junctions prior to gap junction formation, and is critical for normal myofibrillogenesis. Expression of a mutant form of Cadherin-2 harboring a large deletion in the extracellular domain inhibited the function of endogenous Cadherin-2 in adult ventricular cardiomyocytes, and neighboring cardiomyocytes lost cell–cell contact and gap junction plaques as well. Mouse models employing transgenesis have highlighted the function of N-cadherin in cardiac muscle. Mice with altered expression of N-cadherin and/or E-cadherin showed a dilated cardiomyopathy phenotype, likely due to malfunction of intercalated discs. In agreement with this, mice with ablation of N-cadherin in adult hearts via a cardiac-specific tamoxifen-inducible Cre N-cadherin transgene showed disrupted assembly of intercalated discs, dilated cardiomyopathy, impaired cardiac function, decreased sarcomere length, increased Z-line thickness, decreases in connexin 43, and a loss in muscular tension. Mice died within two months of transgene expression, mainly due to spontaneous Ventricular tachycardia. Further analysis of N-cadherin knockout mice revealed that the arrhythmias were likely due to ion channel remodeling and aberrant Kv1.5 channel function. These animals showed a prolonged action potential duration, reduced density of inward rectifier potassium channel and decreased expression of Kv1.5, KCNE2 and cortactin combined with disrupted actin cytoskeleton at the sarcolemma. Role in neurons In neural cells, at certain central nervous system synapses, presynaptic to postsynaptic adhesion is mediated at least in part by Cadherin-2. N-cadherins interact with catenins to play an important role in learning and memory (For full article see Cadherin-catenin complex in learning and memory). Loss of N-cadherin is also associated with attention-deficit hyperactivity disorder in humans, and impaired synaptic functioning. Role in cancer metastasis Cadherin-2 is commonly found in cancer cells and provides a mechanism for transendothelial migration. When a cancer cell adheres to the endothelial cells of a blood vessel it up-regulates the src kinase pathway, which phosphorylates beta-catenins attached to both Cadherin-2 (this protein) and E-cadherins. This causes the intercellular connection between two adjacent endothelial cells to fail and allows the cancer cell to slip through. Clinical significance Variants in CDH2 have been identified to cause a syndromic neurodevelopmental disorder characterized by Corpus callosum, axon, cardiac, ocular, and genital differences.