Cadherin-15 is a 124kD type I transmembrane glycoprotein of the Cadherin superfamily of calcium-dependent homotypic adhesion molecules. Like other classical Cadherins, the 814aa human Cadherin-15 contains a signal sequence (21aa), a propeptide (29aa), an extracellular domain with five Cadherin domain repeats (ECD, 556aa), a transmembrane segment (20aa) and a cytoplasmic domain (188aa). The Cadherin repeats are responsible for cell-cell adhesion by homophilic binding on opposing cells. Intracellularly, Cadherin-15 binds beta-catenin or plakoglobin (gamma-catenin), which in turn bind alpha-catenin. Cadherin-15 also binds p120 catenin. Cadherin-15 is present during early stages of skeletal muscle development and is thought to align myoblasts for fusion. It is also present in muscle satellite cells and participates in muscle regeneration. It is expressed in the granule cell layer of the cerebellar glomerulus. Deletion of mouse Cadherin-15 has little effect in vivo, most likely due to compensation by N-Cadherin. However, Cadherin-15 upregulation and adhesion between myoblasts during induction of differentiation in vitro is required for their fusion. Human Cadherin-15 ECD shows 88% aa identity with mouse, rat, or bovine and 85% aa identity with canine Cadherin-15 ECD. Cadherin-15 is an outlier among classical Cadherins, with 40% aa identity or less in the ECD.