Dystroglycan Glycosylation and Its Involvement in Muscular Dystrophy

Abstract

Dystroglycan is a highly glycosylated peripheral membrane protein that functions as a cell surface receptor for proteins in the extracellular matrices and synapses. O-Mannosyl glycosylation is necessary for the ligand-binding activities of dystroglycan and a unique “post-phosphoryl moiety” modified via a phosphodiester linkage on the O-mannose likely forms the ligand-binding domain. Several proteins are involved in the process of this modification, the mechanism for which appears highly ordered. In various tissues, dystroglycan plays important physiological roles such as maintenance of muscle cell viability and structural development of the brain. Conversely, abnormal glycosylation causes a group of muscular dystrophy, collectively called “dystroglycanopathy,” which is often associated with brain abnormalities including type II lissencephaly and mental retardation. Here, we will be reviewing the structure, modification pathway, and physiological roles of dystroglycan glycosylation as well as their involvement in human diseases.