O-Mannose and O-N-acetyl galactosamine glycosylation of mammalian α-dystroglycan is conserved in a region-specific manner

Defects in the O-linked glycosylation of the peripheral membrane protein alpha-dystroglycan (alpha-DG) are the main cause of several forms of congenital muscular dystrophies and thus the characterization of the glycosylation of alpha-DG is of great medical importance. A detailed investigation of the glycosylation pattern of the native alpha-DG protein is essential for the understanding of the biological processes related to human disease in which the protein is involved. To date, several studies have reported novel O-glycans and attachment sites on the mucin-like domain of mammalian alpha-DG with both similar and contradicting glycosylation patterns, indicating the species-specific O-glycosylation of mammalian alpha-DG. By applying a standardized purification scheme and subsequent glycoproteomic analysis of native alpha-DG from rabbit and human skeletal muscle biopsies and from cultured mouse C2C12 myotubes, we show that the O-glycosylation patterns of the mucin-like domain of native alpha-DG are conserved among mammalians in a region-specific manner.