A5043863262- Glycosylation and Glycoproteins Research
- Carbohydrate Chemistry and Synthesis
- Galectins and Cancer Biology
- Proteoglycans and glycosaminoglycans research
- Ubiquitin and proteasome pathways
- Enzyme Production and Characterization
- Trypanosoma species research and implications
- Lysosomal Storage Disorders Research
- Protein Tyrosine Phosphatases
- Monoclonal and Polyclonal Antibodies Research
- RNA and protein synthesis mechanisms
- RNA modifications and cancer
- Genetics, Bioinformatics, and Biomedical Research
- Cellular transport and secretion
- Advanced Proteomics Techniques and Applications
- Pancreatic function and diabetes
- Metabolism, Diabetes, and Cancer
- Peptidase Inhibition and Analysis
- Research on Leishmaniasis Studies
- Chemical Synthesis and Analysis
- Enzyme Catalysis and Immobilization
- Biochemical and Molecular Research
- Enzyme Structure and Function
- Chromosomal and Genetic Variations
- Microbial Metabolites in Food Biotechnology
University of Georgia
2019-2024
Okanagan University College
2024
University of British Columbia
2024
Johns Hopkins University
2012-2023
Johns Hopkins Medicine
2012-2023
University of Missouri–Kansas City
2023
University of Utah
2023
Alzheimer’s Disease Neuroimaging Initiative
2023
Union Bank of Switzerland
2023
Defence Science and Technology Laboratory
2022
Bovine milk galactosyltransferase has been used, in conjunction with UDP-[3H]galactose, as an impermeant probe for accessible GlcNAc residues on the surfaces of lymphocytes. Galactosylation living thymic lymphocytes is dependent upon cell number, enzyme concentration, UDP-galactose and Mn2+ concentration. Kinetics labeling are biphasic, leveling off at approximately 30 min. The data strongly indicate vectorial surface covalent attachment galactose. Thymocytes, T-lymphocytes, B-lymphocytes...
Author(s): Varki, Ajit; Cummings, Richard D; Aebi, Markus; Packer, Nicole H; Seeberger, Peter Esko, Jeffrey Stanley, Pamela; Hart, Gerald; Darvill, Alan; Kinoshita, Taroh; Prestegard, James J; Schnaar, Ronald L; Freeze, Hudson Marth, Jamey Bertozzi, Carolyn R; Etzler, Marilynn E; Frank, Martin; Vliegenthart, Johannes Fg; Lutteke, Thomas; Perez, Serge; Bolton, Evan; Rudd, Pauline; Paulson, James; Kanehisa, Minoru; Toukach, Philip; Aoki-Kinoshita, Kiyoko F; Dell, Anne; Narimatsu, Hisashi;...
Nuclear and cytoplasmic protein glycosylation is a widespread reversible posttranslational modification in eukaryotic cells. Intracellular by the addition of N- acetylglucosamine (GlcNAc) to serine threonine catalyzed O-GlcNAc transferase (OGT). This “O-GlcNAcylation” intracellular proteins can occur on phosphorylation sites, has been implicated controlling gene transcription, neurofilament assembly, emergence diabetes neurologic disease. To study OGT function vivo , we have used...
Dynamic modification of cytoplasmic and nuclear proteins by O-linked N-acetylglucosamine (O-GlcNAc) on Ser/Thr residues is ubiquitous in higher eukaryotes analogous to protein phosphorylation. The enzyme for the addition this modification, O-GlcNAc transferase, has been cloned from several species. Here, we have a human brain O-GlcNAcase that cleaves off proteins. cDNA encodes polypeptide 916 amino acids with predicted molecular mass 103 kDa pI value 4.63, but migrates as 130-kDa band...
O-Linked N-acetylglucosamine (O-GlcNAc) glycosylation is a dynamic modification of eukaryotic nuclear and cytosolic proteins analogous to protein phosphorylation. We have cloned characterized novel gene for an O-GlcNAc transferase (OGT) that shares no sequence homology or structural similarities with other glycosyltransferases. The OGT highly conserved (up 80% identity) in all eukaryotes examined. Unlike previously described glycosyltransferases, localized the cytosol nucleus. contains...
Microtubule-associated protein tau is abnormally hyperphosphorylated and aggregated into neurofibrillary tangles in brains of individuals with Alzheimer's disease (AD) other tauopathies. Tau pathology critical to pathogenesis correlates the severity dementia. However, mechanisms leading abnormal hyperphosphorylation are unknown. Here, we demonstrate that human brain was modified by O-GlcNAcylation, a type O-glycosylation which monosaccharide β- N -acetylglucosamine (GlcNAc) attaches...
Cellular response to environmental, physiological, or chemical stress is key survival following injury disease. Here we describe a unique signaling mechanism by which cells detect and respond in order survive. A wide variety of stimuli rapidly increase nucleocytoplasmic protein modification O-linked β-N-acetylglucosamine (O-GlcNAc), an essential post-translational Ser Thr residues metazoans. Blocking this modification, reducing it, renders more sensitive results decreased cell survival;...
Glycosylation of nuclear and cytoplasmic proteins by 0-linked N-acetylglucosamine (0-GlcNAc) monosaccharides is an abundant, ubiquitous, transient posttranslational modification.To characterize enzymes involved in removal these sugars, a neutral N-acetyl-p-D-glucosaminidase (0-GlcNAcase) with strong selectivity for 0-GlcNAc-synthetic glycopeptides has been purified over 22,000-fold from rat spleen homogenate.The 0-GlcNAcase two major polypeptides apparent M, = 54,000 (cy subunit) 51,000 ( p...
Previously our laboratory reported the discovery of a novel protein-saccharide linkage in which single Nacetylglucosamine (GlcNAc) residues are attached 0-linkages to protein (Torres, C. R., and Hart, G. W.
Increased flux of glucose through the hexosamine biosynthetic pathway (HSP) is believed to mediate hyperglycemia-induced insulin resistance in diabetes. The end product HSP, UDPβ- N -acetylglucosamine (GlcNAc), a donor sugar nucleotide for complex glycosylation secretory and O-linked GlcNAc (O-GlcNAc) addition nucleocytoplasmic proteins. Cycling O-GlcNAc posttranslational modification was blocked by pharmacological inhibition O-GlcNAcase, enzyme that catalyzes removal from proteins, with O...
c-Myc is a helix-loop-helix leucine zipper phosphoprotein that heterodimerizes with Max and regulates gene transcription in cell proliferation, differentiation, programmed death. Previously, we demonstrated modified by O-linked N-acetylglucosamine (O-GlcNAc) within or nearby the N-terminal transcriptional activation domain (Chou, T.-Y., Dang, C. V., Hart, G. W.(1995) Proc. Natl. Acad. Sci. U.S.A. 92, 4417-4421). In this paper, identified O-GlcNAc attachment site(s) on c-Myc. purified from...
A novel form of protein-saccharide linkage consisting single N-acetylglucosamine (GlcNAc) residues attached in O-linkages directly to the polypeptide backbone has been described (Holt, G. D., and W. Hart, 1986, J. Biol. Chem., 261:8049-8057). This modification was found on proteins distributed throughout cell, although bearing O-linked GlcNAc moieties were particularly abundant cytosolic nuclear envelope fractions rat liver. In accompanying article (Snow, C. M., A. Senior, L. Gerace, 1987,...
Using a combination of conventional and affinity chromatographic techniques, we have purified uridine diphospho-N-acetylglucosamine:polypeptide beta-N-acetylglucosaminyltransferase (O-GlcNAc transferase) over 30,000-fold from rat liver cytosol. The transferase is soluble very large, migrating with an apparent molecular weight 340,000 on sieve chromatography. Analysis the enzyme sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals two protein species at 110 (alpha subunit) 78...
Identifying sites of post-translational modifications on proteins is a major challenge in proteomics. O-Linked beta-N-acetylglucosamine (O-GlcNAc) dynamic nucleocytoplasmic modification more analogous to phosphorylation than classical complex O-glycosylation. We describe mass spectrometry-based method for the identification modified by O-GlcNAc that relies mild beta-elimination followed Michael addition with dithiothreitol (BEMAD). Using synthetic peptides, we also show biotin pentylamine...
The Ogt gene encodes a glycosyltransferase that links N-acetylglucosamine to serine and threonine residues (O-GlcNAc) on nuclear cytosolic proteins. Efforts study mammalian model of deficiency have been hindered by the requirement for this X-linked in embryonic stem cell viability, necessitating use conditional mutagenesis vivo. We extended these observations segregating mutation distinct somatic types, including neurons, thymocytes, fibroblasts, latter an approach developed inducible...