Dystroglycan is one of the dystrophin-associated glycoproteins,which is encoded by a 5.5 kb transcript in human. The proteinproduct is cleaved into two non-covalently associated subunits,[alpha] (N-terminal) and [beta] (C-terminal). In skeletalmuscle the dystroglycan complex works as a transmembrane linkagebetween the extracellular matrix and the cytoskeleton.[alpha]-dystroglycan is extracellular and binds to merosin([alpha]-2 laminin) in the basement membrane, while[beta]-dystroglycan is a transmembrane protein and binds todystrophin, which is a large rod-like cytoskeletal protein,absent in Duchenne muscular dystrophy patients. Dystrophin bindsto intracellular actin cables. In this way, the dystroglycancomplex, which links the extracellular matrix to theintracellular actin cables, is thought to provide structuralintegrity in muscle tissues. The dystroglycan complex is alsoknown to serve as an agrin receptor in muscle, where it mayregulate agrin-induced acetylcholine receptor clustering at theneuromuscular junction. There is also evidence which suggeststhe function of dystroglycan as a part of the signaltransduction pathway because it is shown that Grb2, a mediatorof the Ras-related signal pathway, can interact with thecytoplasmic domain of dystroglycan. In general, aberrantexpression of dystrophin-associated protein complex underliesthe pathogenesis of Duchenne muscular dystrophy, Becker musculardystrophy and severe childhood autosomal recessive musculardystrophy. Interestingly, no genetic disease has been describedfor either [alpha]- or [beta]-dystroglycan. Dystroglycan iswidely distributed in non-muscle tissues as well as in muscletissues. During epithelial morphogenesis of kidney, thedystroglycan complex is shown to act as a receptor for thebasement membrane. Dystroglycan expression in mouse brain andneural retina has also been reported. However, the physiologicalrole of dystroglycan in non-muscle tissues has remained unclear[1]. Dystroglycan (Dystrophin-associated glycoprotein 1) DAG1