Component of intercellular desmosome junctions. Involved in the interaction of plaque proteins and intermediate filaments mediating cell-cell adhesion. Coordinates the transition from proliferation to differentiation in hair follicle keratinocytes. Strongly expressed in the skin; during the anagen stage of hair follicles in the matrix, precortex and inner rooth sheath. Expressed in embryo at 7 to 17 dpc. Three calcium ions are usually bound at the interface of each cadherin domain and rigidify the connections, imparting a strong curvature to the full-length ectodomain. Defects in Dsg4 are the cause of an autosomal recessive phenotype lanceolate hair (lah). Lah mice pups develop only a few short hairs on the head and neck which form a lance head at the tip and disappear within a few month. They have thickened skin and do not exhibit any growth retardation.