Immunodetection of partially glycosylated isoforms of α-dystroglycan by a new monoclonal antibody against its β-dystroglycan-binding epitope

The α/β dystroglycan (DG) complex links the extracellular matrix to the actin cytoskeleton. The extensive glycosylation of α-DG is believed to be crucial for the interaction with its extracellular matrix-binding partners. We characterized a monoclonal antibody, directed against the β-DG-binding epitope (≈positions 550-565), which recognizes preferentially hypoglycosylated α-DG. In Western blot, the antibody was able to detect a number of partially glycosylated α-DG isoforms from rat brain and chicken skeletal muscle tissue samples. In addition, we demonstrated its inhibitory effect on the interaction between α- and β-DG in vitro and preliminary immunostaining experiments suggest that such hypoglycosylated α-DG isoforms could play a role within cells.