Self-glucosylates, via an inter-subunit mechanism, to form an oligosaccharide primer that serves as substrate for glycogen synthase.
Glycan biosynthesis; glycogen biosynthesis.
Involvement in disease
Defects in GYG1 are the cause of glycogen storage disease type 15 (GSD15) [MIM:613507]. It is a metabolic disorder resulting in muscle weakness, associated with the glycogen depletion in skeletal muscle, and cardiac arrhythmia, associated with the accumulation of abnormal storage material in the heart. The skeletal muscle shows a marked predominance of slow-twitch, oxidative muscle fibers and mitochondrial proliferation.
Belongs to the glycogenin family.
Self-glycosylated by the transfer of glucose residues from UDP-glucose to itself, forming an alpha-1,4-glycan of around 10 residues attached to Tyr-195. Phosphorylated.