title: Glycosylation of the c-Myc transactivation domain.
abstract: O-linked N-acetylglucosamine (O-GlcNAc) is an abundant and dynamic posttranslational modification composed of a single monosaccharide, GlcNAc, glycosidically composed of a single monosaccharide, GlcNAc, glycosidically linked to the side-chain hydroxyl of serine or threonine residues. Although O-GlcNAc occurs on a myriad of nuclear and cytoplasmic proteins, only a few have thus far been identified. These O-GlcNAc-bearing proteins are also modified by phosphorylation and form reversible multimeric complexes. Here we present evidence for O-GlcNAc glycosylation of the oncoprotein c-Myc, a helix-loop-helix/leucine zipper phosphoprotein that heterodimerizes with Max and participates in the regulation of gene transcription in normal and neoplastic cells. O-GlcNAc modification of c-Myc is shown by three different methods: (i) demonstration of lectin binding to in vitro translated protein using a protein-protein interaction mobility-shift assay; (ii) glycosidase or glycosyltransferase treatment of in vitro translated protein analyzed by lectin affinity chromatography; and (iii) direct characterization of the sugar moieties on purified recombinant protein overexpressed in either insect cells or Chinese hamster ovary cells. Analyses of serial deletion mutants of c-Myc further suggest that the O-GlcNAc site(s) are located within or near the N-terminal transcription activation/malignant transformation domain, a region where mutations of c-Myc that are frequently found in Burkitt and AIDS-related lymphomas cluster.
authors.affiliation: Biochemistry, Cellular and Molecular Biology Training Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: T Y
authors.initials: TY
authors.lastname: Chou
authors.forename: C V
authors.initials: CV
authors.lastname: Dang
authors.forename: G W
authors.initials: GW
authors.lastname: Hart
mesh_terms: D000117:Acetylglucosamine / Q000032:analysis / Q000378:metabolism; D000581:Amidohydrolases; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002417:Cattle; D002460:Cell Line; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D006224:Cricetinae; D006026:Glycoside Hydrolases; D006031:Glycosylation; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D016350:Leucine Zippers; D046911:Macromolecular Substances; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D017384:Sequence Deletion; D012694:Serine; D018411:Spodoptera; D013912:Threonine; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: D046911:Macromolecular Substances; D016271:Proto-Oncogene Proteins c-myc; D011994:Recombinant Proteins; D013912:Threonine; D012694:Serine; D006026:Glycoside Hydrolases; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D000117:Acetylglucosamine