O-linked β-N-acetylglucosamine (O-GlcNAc) is a post-translational modification (i.e., O-GlcNAcylation) on serine/threonine residues of proteins. Distinct from the traditional glycosylation (i.e., N-glycosylation, O-glycosylation, and GPI-anchored glycosylation), O-GlcNAcylation is a unique intracellular monosaccharide modification without being further elongated into complex sugar structures.
O-GlcNAcylation has been documented in all metazoans (including animals, insects and plants), some bacteria, fungi and virus. O-GlcNAcylation is catalyzed by a discrete set of enzymes: O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). OGT transfers the GlcNAc moiety from UDP-GlcNAc to specific serine/threonine residues of target proteins while OGA removes it. O-GlcNAcylation occurs on myriad of nuclear, cytosolic and mitochondrial proteins. Protein O-GlcNAcylation plays important roles in almost all biochemical processes examined (including transcription, translation, cell cycle, metabolism and signaling). Aberrant O-GlcNAcylation is underlying the etiologies of a number of chronic diseases (including cancer, diabetes, and neurodegenerative disease).
O-GlcNAcAtlas is the first comprehensive and curated database encapsulating experimentally identified O-GlcNAc sites and proteins in the past 35 years (since its discovery in the early 1980s). We hope it will serve as a great resource to facilitate protein O-GlcNAcylation studies for both basic and translational biomedical research.