Glycosylation of the c-Myc Transactivation Domain

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 92; no. 10; pp. 4417 - 4421
• Main Authors: Chou, Teh-Ying, Dang, Chi V., Hart, Gerald W.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 09-05-1995; National Acad Sciences; National Academy of Sciences
• Subjects: Acetylglucosamine - analysis; Acetylglucosamine - metabolism; Amidohydrolases; Animals; Binding Sites; Biochemistry; Cattle; Cell Line; CHO Cells; Chromatography; Chromatography, Affinity; Cloning, Molecular; Complementary DNA; Cricetinae; Elution; Gels; Glycoside Hydrolases; Glycosylation; Helix-Loop-Helix Motifs; Humans; Lectins; Leucine Zippers; Macromolecular Substances; Nuclear pore; Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; Protein Biosynthesis; Protein Processing, Post-Translational; Proteins; Proto-Oncogene Proteins c-myc - biosynthesis; Proto-Oncogene Proteins c-myc - isolation & purification; Proto-Oncogene Proteins c-myc - metabolism; Rats; Recombinant Proteins - biosynthesis; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Sequence Deletion; Serine; Spodoptera; Sugars; Threonine; Transcriptional Activation; Transfection
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.92.10.4417

O-linked N-acetylglucosamine (O-GlcNAc) is an abundant and dynamic posttranslational modification 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.