GYG1

This gene encodes a member of the glycogenin family. Glycogenin is a glycosyltransferase that catalyzes the formation of a short glucose polymer from uridine diphosphate glucose in an autoglucosylation reaction. This reaction is followed by elongation and branching of the polymer, catalyzed by glycogen synthase and branching enzyme, to form glycogen. This gene is expressed in muscle and other tissues. Mutations in this gene result in glycogen storage disease XV. This gene has pseudogenes on chromosomes 1, 8 and 13 respectively. Alternatively spliced transcript variants encoding different isoforms have been identified.

Full Name

glycogenin 1

Function

Self-glucosylates, via an inter-subunit mechanism, to form an oligosaccharide primer that serves as substrate for glycogen synthase.

Biological Process

Glycogen biosynthetic process Source: UniProtKB

Cellular Location

Cytosol; Extracellular region; Lysosomal lumen; Ficolin-1-rich granule lumen; Membrane; Secretory granule lumen

Involvement in disease

Glycogen storage disease 15 (GSD15):
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.
Polyglucosan body myopathy 2 (PGBM2):
A glycogen storage disease characterized by polyglucosan accumulation in muscle, and skeletal myopathy without cardiac involvement. Most patients manifest slowly progressive, hip girdle, shoulder girdle, and/or hand and leg muscle weakness. Polyglucosan contains abnormally long and poorly branched glucosyl chains and is variably resistant to digestion by alpha-amylase.

PTM

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.