Dystroglycan

Dystroglycan is a is_associated_with::protein that in humans is encoded by the DAG1 is_associated_with::gene.

Dystroglycan is one of the is_associated_with::dystrophin-associated is_associated_with::glycoproteins, which is encoded by a 5.5 kb transcript in is_associated_with::Homo sapiens on is_associated_with::chromosome 3. There are two is_associated_with::exons that are separated by a large is_associated_with::intron. The spliced exons code for a protein product that is finally cleaved into two non-covalently associated subunits, [alpha] (N-terminal) and [beta] (C-terminal).

Function
In skeletal muscle the dystroglycan complex works as a transmembrane linkage between 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 is_associated_with::transmembrane protein and binds to dystrophin, which is a large rod-like is_associated_with::cytoskeletal protein, absent in is_associated_with::Duchenne muscular dystrophy patients. Dystrophin binds to intracellular is_associated_with::actin cables. In this way, the dystroglycan complex, which links the extracellular matrix to the intracellular actin cables, is thought to provide structural integrity in muscle tissues. The dystroglycan complex is also known to serve as an is_associated_with::agrin receptor in muscle, where it may regulate agrin-induced is_associated_with::acetylcholine receptor clustering at the neuromuscular junction. There is also evidence which suggests the function of dystroglycan as a part of the signal transduction pathway because it is shown that is_associated_with::Grb2, a mediator of the Ras-related signal pathway, can interact with the cytoplasmic domain of dystroglycan.

Expression
Dystroglycan is widely distributed in non-muscle tissues as well as in muscle tissues. During epithelial morphogenesis of kidney, the dystroglycan complex is shown to act as a receptor for the basement membrane. Dystroglycan expression in Mus musculus brain and neural retina has also been reported. However, the physiological role of dystroglycan in non-muscle tissues has remained unclear

Interactions
Dystroglycan has been shown to interact with is_associated_with::FYN, is_associated_with::C-src tyrosine kinase, Src, is_associated_with::NCK1, is_associated_with::Grb2, is_associated_with::Caveolin 3 and is_associated_with::SHC1.