Ubiquitous and temporal glycosylation of nuclear and cytoplasmic proteins

Abstract

We have described a novel form of nuclear and cytoplasmic protein glycosylation (O-GlcNAc), which is as abundant and as transient on intracellular proteins as protein phosphorylation. O-GlcNAc consists of single, non-modified N~ acetylglucosamine residues O-glycosidically attached to Ser(Thr) hydroxyl moieties at sites similar to those used by growth-factor kinases. O-GlcNAc occurs on ‘hundreds’ of intracellular proteins in all eukaryotes. Proteins bearing O-GlcNAc include cytoskeletal-, viral-, nuclear pore-, heat shock-, and transcriptional regulatory proteins. Available data suggest that O-GlcNAc is a regulatory modification that mediates subunit-subunit interactions, and in many cases blocks phosphorylation. © 1995 IUPAC