Li G, Meng F, Zhong X, Yu K, Zhang N, Zhang K, Huang H, Li W, Zhang J, Wang W, Ren Y, Liu Y.
DNA probe pulldown screening uncovers O-GlcNAcylation modulation of transcription factor DNA interactions.
Scientific reports2025
15(1)
40596516
Abstract: O-linked β-N-acetylglucosamine (O-GlcNAc), a critical post-translational modification predominantly found in the nucleus, plays a substantial role in regulating gene expression by modulating transcription factors (TFs) activity. However, quantitative analysis investigating the influence of O-GlcNAcylation on protein-DNA interactions at a proteome scale remains undone. Herein, a pulldown screening approach using a consensus TF response element (catTFRE) was employed to unravel the impact of fluctuating levels of O-GlcNAcylation on the DNA binding efficiency of endogenous TFs/co-factors. Utilizing quantitative proteomics, we identified a substantial enhancement in the binding capacity of 241 nuclear proteins (NPs) to DNA sequences due to elevated levels of O-GlcNAcylation, whereas a decrease in DNA binding was observed for 2 NPs concurrently. Intriguingly, the O-GlcNAcylation elevation significantly enhanced the binding of 146 TFs/co-factors to specific DNA sequences. We further established that the O-GlcNAcylation of several Forkhead family TFs, including FOXA1 and FOXC1, notably enhances their binding to specific DNA sequences in living cells. Our research presents an efficacious approach to assessing the impact of O-GlcNAcylation on the interactions between proteins and DNA. This significantly enhances our understanding of the role O-GlcNAcylation plays in the regulation of transcription.
Qiu S, Ma L, Yu K, Xu X, Zhang X, Yu W, Wang K, Tian X, Miao Y, Wang Y, Guo W, Xue X, Cui J, Yu X, Kang R, Zhou Q, Yu Y, Tang D, Wang J.
A pathological role of O-GlcNAcylation-driven TR11B production and function in lung adenocarcinoma.
Developmental cell2025
60(23)
40930100
Abstract: Cytokines link inflammation to tumorigenesis, but the role of post-translational modifications in regulating their function within the extra-tumoral environment remains poorly defined. Here, we identify tumor-derived tumor necrosis factor (TNF) receptor superfamily member 11B (TR11B) as a key driver of lung adenocarcinoma (LUAD) progression and therapeutic resistance. Mechanistically, O-GlcNAc transferase (OGT)-mediated O-GlcNAcylation at serine 151 stabilizes TR11B and facilitates its interaction with the membrane protein EPS15 homology domain-containing protein 1 (EHD1), promoting cyclin dependent kinase 2 (CDK2) phosphorylation and cell cycle progression. Clinically, elevated O-GlcNAcylated TR11B correlates with advanced LUAD. Genetic deletion of Ogt suppresses tumor development in LUAD mouse models. Importantly, celecoxib, an U.S. Food and Drug Administration (FDA)-approved drug, inhibits O-GlcNAcylation and exerts antitumor effects. These findings reveal a pathological role for cytokine O-GlcNAcylation in LUAD and identify this axis as a potential therapeutic target.
Srivastava PP, Dasari A, Kumar S, Gupta I, Jain D, Minocha S.
Epigenetic co-regulator HCF-1 promotes lung cancer via O-GlcNAcylation-dependent pathways.
Molecular therapy. Oncology2025
33(4)
41018975
Abstract: The rise in the incidences of lung cancer currently poses a global health challenge, making it crucial to understand the underlying molecular and cellular mechanisms. Host cell factor-1 (HCF-1), a conserved epigenetic transcriptional co-regulator, undergoes proteolytic maturation and glycosylation by O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT). Elevated O-GlcNAc and OGT levels have been observed in lung cancer, highlighting their potential significance in disease progression. In human lung cancer tissues, we observed a significant upregulation of HCF-1, which coincides with increased OGT, O-GlcNAc, and Nkx2.1 (a diagnostic marker for non-small cell lung cancer [NSCLSC]) levels. To further explore HCF-1's role mechanistically, we utilized the NSCLC cell lines, where HCF-1 depletion resulted in reduced proliferation, O-GlcNAcylation, Nkx2.1 expression, and O-GlcNAcylated proteins upon wheat germ agglutinin (WGA) pull-down, reinforcing its role in lung cancer progression. Additionally, Nkx2.1-mediated conditional knockout of HCF-1 impaired murine lung development and cell proliferation. Interestingly, OGT inhibition with OSMI-1 also reduced HCF-1, Nkx2.1 levels, and proliferation, suggesting a role for O-GlcNAcylation in HCF-1-mediated signaling cascades. Thus, our findings elucidate the critical role of HCF-1 and O-GlcNAcylation in lung cancer pathogenesis. These insights not only deepen our understanding of lung cancer pathogenesis but also identify potential molecular targets for studies aimed at intervention.
Vang S, Helton ES, Guo Y, Burpee B, Rose E, Easter M, Bollenbecker S, Hirsch MJ, Matthews EL, Jones LI, Howze PH 4th, Rajasekaran V, Denson R, Cochran P, Attah IK, Olson H, Clair G, Melkani G, Krick S, Barnes JW.
O-GlcNAc transferase regulates collagen deposition and fibrosis resolution in idiopathic pulmonary fibrosis.
Frontiers in immunology2024
15
38665916
Abstract: Idiopathic pulmonary fibrosis (IPF) is a chronic pulmonary disease that is characterized by an excessive accumulation of extracellular matrix (ECM) proteins (e.g. collagens) in the parenchyma, which ultimately leads to respiratory failure and death. While current therapies exist to slow the progression, no therapies are available to resolve fibrosis.
Hou C, Wu C, Wu Z, Cheng Y, Li W, Sun H, Ma J.
Systematic Evaluation of Affinity Enrichment Methods for O-GlcNAc Proteomics.
Journal of proteome research202439302247
Abstract: O-Linked β-N-acetylglucosamine (O-GlcNAc) modification (i.e., O-GlcNAcylation) on proteins plays critical roles in the regulation of diverse biological processes. However, protein O-GlcNAcylation analysis, especially at a large scale, has been a challenge. So far, a number of enrichment materials and methods have been developed for site-specific O-GlcNAc proteomics in different biological settings. Despite the presence of multiple methods, their performance for the O-GlcNAc proteomics is largely unclear. In this work, by using the lysates of PANC-1 cells (a pancreatic cancer cell line), we provided a head-to-head comparison of three affinity enrichment methods and materials (i.e., antibody, lectin AANL6, and an OGA mutant) for site-specific O-GlcNAc proteomics. The enriched peptides were analyzed by HCD product-dependent EThcD (i.e., HCD-pd-EThcD) mass spectrometry. The resulting data files were processed by three different data analysis packages (i.e., Sequest HT, Byonic, and FragPipe). Our data suggest that each method captures a subpopulation of the O-GlcNAc proteins. Besides the enrichment methods, we also observe complementarity between the different data analysis tools. Thus, combining different approaches holds promise for enhanced coverage of O-GlcNAc proteomics.
Xiong Y, Lu Z, Shao Y, Meng P, Wang G, Zhou X, Yao J, Bao H, Lu H.
Rapid and large-scale glycopeptide enrichment strategy based on chemical ligation.
National science review2024
11(11)
39534244
Abstract: Protein glycosylation, the most universal post-translational modification, is thought to play a crucial role in regulating multiple essential cellular processes. However, the low abundance of glycoproteins and the heterogeneity of glycans complicate their comprehensive analysis. Here, we develop a rapid and large-scale glycopeptide enrichment strategy via bioorthogonal ligation and trypsin cleavage. The enrichment process is performed in one tube to minimize sample loss and time costs. This method combines convenience and practicality, identifying over 900 O-GlcNAc sites from a 500 μg sample. Surprisingly, it allows simultaneous identification of N-glycosites, O-GlcNAc sites, O-GalNAc sites and N-glycans via a two-step enzymatic release strategy. Combined with quantitative analysis, it reveals the distinct O-GlcNAcylation patterns in different compartments during oxidative stress. In summary, our study offers a convenient and robust tool for glycoproteome and glycome profiling, facilitating in-depth analysis to elucidate the biological functions of glycosylation.
Wang G, Li Y, Wang T, Wang J, Yao J, Yan G, Zhang Y, Lu H.
Multi-comparative Thermal Proteome Profiling Uncovers New O-GlcNAc Proteins in a System-wide Method.
Analytical chemistry2023
95(2)
36580660
Abstract: Among diverse protein post-translational modifications, O-GlcNAcylation, a simple but essential monosaccharide modification, plays crucial roles in cellular processes and is closely related to various diseases. Despite its ubiquity in cells, properties of low stoichiometry and reversibility are hard nuts to crack in system-wide research of O-GlcNAc. Herein, we developed a novel method employing multi-comparative thermal proteome profiling for O-GlcNAc transferase (OGT) substrate discovery. Melting curves of proteins under different treatments were profiled and compared with high reproducibility and consistency. Consequently, proteins with significantly shifted stabilities caused by OGT and uridine-5'-diphosphate N-acetylglucosamine were screened out from which new O-GlcNAcylated proteins were uncovered.
Hung YW, Ouyang C, Ping X, Qi Y, Wang YC, Kung HJ, Ann DK.
Extracellular arginine availability modulates eIF2α O-GlcNAcylation and heme oxygenase 1 translation for cellular homeostasis.
Journal of biomedical science2023
30(1)
37217939
Abstract: Nutrient limitations often lead to metabolic stress during cancer initiation and progression. To combat this stress, the enzyme heme oxygenase 1 (HMOX1, commonly known as HO-1) is thought to play a key role as an antioxidant. However, there is a discrepancy between the level of HO-1 mRNA and its protein, particularly in cells under stress. O-linked β-N-acetylglucosamine (O-GlcNAc) modification of proteins (O-GlcNAcylation) is a recently discovered cellular signaling mechanism that rivals phosphorylation in many proteins, including eukaryote translation initiation factors (eIFs). The mechanism by which eIF2α O-GlcNAcylation regulates translation of HO-1 during extracellular arginine shortage (ArgS) remains unclear.
Wong YK, Wang J, Lim TK, Lin Q, Yap CT, Shen HM.
O-GlcNAcylation promotes fatty acid synthase activity under nutritional stress as a pro-survival mechanism in cancer cells.
Proteomics2022
22(9)
35083852
Abstract: Protein O-GlcNAcylation is a specific form of protein glycosylation that targets a wide range of proteins with important functions. O-GlcNAcylation is known to be deregulated in cancer and has been linked to multiple aspects of cancer pathology. Despite its ubiquity and importance, the current understanding of the role of O-GlcNAcylation in the stress response remains limited. In this study, we performed a quantitative chemical proteomics-based open study of the O-GlcNAcome in HeLa cells, and identified 163 differentially-glycosylated proteins under starvation, involving multiple metabolic pathways. Among them, fatty acid metabolism was found to be targeted and subsequent analysis confirmed that fatty acid synthase (FASN) is O-GlcNAcylated. O-GlcNAcylation led to enhanced de novo fatty acid synthesis (FAS) activity, and fatty acids contributed to the cytoprotective effects of O-GlcNAcylation under starvation. Moreover, dual inhibition of O-GlcNAcylation and FASN displayed a strong synergistic effect in vitro in inducing cell death in cancer cells. Together, the results from this study provide novel insights into the role of O-GlcNAcylation in the nutritional stress response and suggest the potential of combining inhibition of O-GlcNAcylation and FAS in cancer therapy.
Liu J, Hao Y, Wang C, Jin Y, Yang Y, Gu J, Chen X.
An Optimized Isotopic Photocleavable Tagging Strategy for Site-Specific and Quantitative Profiling of Protein O-GlcNAcylation in Colorectal Cancer Metastasis.
ACS chemical biology2022
17(3)
35254053
Abstract: O-linked-β-N-acetylglucosamine (O-GlcNAc) glycosylation is a ubiquitous protein post-translational modification of the emerging importance in metazoans. Of the thousands of O-GlcNAcylated proteins identified, many carry multiple modification sites with varied stoichiometry. To better match the scale of O-GlcNAc sites and their dynamic nature, we herein report an optimized strategy, termed isotopic photocleavable tagging for O-GlcNAc profiling (isoPTOP), which enables quantitative and site-specific profiling of O-GlcNAcylation with excellent specificity and sensitivity. In HeLa cells, ∼1500 O-GlcNAcylation sites were identified with the optimized procedures, which led to quantification of ∼1000 O-GlcNAcylation sites with isoPTOP. Furthermore, we apply isoPTOP to probe the O-GlcNAcylation dynamics in a pair of colorectal cancer (CRC) cell lines, SW480 and SW620 cells, which represent primary carcinoma and metastatic cells, representatively. The stoichiometric differences of 625 O-GlcNAcylation sites are quantified. Of these quantified sites, many occur on important regulators involved in tumor progression and metastasis. Our results provide a valuable database for understanding the functional role of O-GlcNAc in CRC. IsoPTOP should be applicable for investigating O-GlcNAcylation dynamics in various pathophysiological processes.
Chen Y, Tang F, Qin H, Yue X, Nie Y, Huang W, Ye M.
Endo-M Mediated Chemoenzymatic Approach Enables Reversible Glycopeptide Labeling for O-GlcNAcylation Analysis.
Angewandte Chemie (International ed. in English)2022
61(23)
35289036
Abstract: To selectively enrich O-linked β-N-acetylglucosamine (O-GlcNAc) peptides in their original form from complex samples, we report the first reversible chemoenzymatic labeling approach for proteomic analysis. In this strategy, the O-GlcNAc moieties are ligated with long N-glycans using an Endo-M mutant, which enables the enrichment of the labeled glycopeptides by hydrophilic interaction liquid chromatography (HILIC). The attached glycans on the enriched glycopeptides are removed by wild-type Endo-M/S to restore the O-GlcNAc moiety. Compared with classic chemoenzymatic labeling, this approach enables the tag-free identification, and eliminates the interference of bulky tags in glycopeptide detection. This approach presents a unique avenue for the proteome-wide analysis of protein O-GlcNAcylation to promote its mechanism research.
Fan Z, Li J, Liu T, Zhang Z, Qin W, Qian X.
A new tandem enrichment strategy for the simultaneous profiling of O-GlcNAcylation and phosphorylation in RNA-binding proteome.
The Analyst2021
146(4)
33465208
Abstract: RNA-protein interactions play important roles in almost every step of the lifetime of RNAs, such as RNA splicing, transporting, localization, translation and degradation. Post-translational modifications, such as O-GlcNAcylation and phosphorylation, and their "cross-talk" (OPCT) are essential to the activity and function regulation of RNA-binding proteins (RBPs). However, due to the extremely low abundance of O-GlcNAcylation and the lack of RBP-targeted enrichment strategies, large-scale simultaneous profiling of O-GlcNAcylation and phosphorylation on RBPs is still a challenging task. In the present study, we developed a tandem enrichment strategy combining metabolic labeling-based RNA tagging for selective purification of RBPs and HILIC-based enrichment for simultaneous O-GlcNAcylation and phosphorylation profiling. Benefiting from the sequence-independent RNA tagging by ethynyluridine (EU) labeling, 1115 RBPs binding to different types of RNAs were successfully enriched and identified by quantitative mass spectrometry (MS) analysis. Further HILIC enrichment on the tryptic-digested RBPs and MS analysis led to the first large-scale identification of O-GlcNAcylation and phosphorylation in the RNA-binding proteome, with 461 O-GlcNAc peptides corresponding to 300 RBPs and 671 phosphopeptides corresponding to 389 RBPs. Interestingly, ∼25% RBPs modified by two PTMs were found to be related to multiple metabolism pathways. This strategy has the advantage of high compatibility with MS and provides peptide-level evidence for the identification of O-GlcNAcylated RBPs. We expect it will support simultaneous mapping of O-GlcNAcylation and phosphorylation on RBPs and facilitate further elucidation of the crucial roles of OPCT in the function regulation of RBPs.
Xie X, Wu Q, Zhang K, Liu Y, Zhang N, Chen Q, Wang L, Li W, Zhang J, Liu Y.
O-GlcNAc modification regulates MTA1 transcriptional activity during breast cancer cell genotoxic adaptation.
Biochimica et biophysica acta. General subjects2021
1865(8)
34019948
Abstract: Chromatin modifier metastasis-associated protein 1 (MTA1), closely associated with tumor angiogenesis in breast cancer, plays an important role in gene expression and cancer cell behavior. Recently, an association between O-GlcNAc transferase (OGT) and MTA1 was identified by mass spectroscopy. However, the potential relationship between MTA1 and O-GlcNAc modification has not yet explored.
Ramirez DH, Yang B, D'Souza AK, Shen D, Woo CM.
Truncation of the TPR domain of OGT alters substrate and glycosite selection.
Analytical and bioanalytical chemistry2021
413(30)
34725712
Abstract: O-GlcNAc transferase (OGT) is an essential enzyme that installs O-linked N-acetylglucosamine (O-GlcNAc) to thousands of protein substrates. OGT and its isoforms select from these substrates through the tetratricopeptide repeat (TPR) domain, yet the impact of truncations to the TPR domain on substrate and glycosite selection is unresolved. Here, we report the effects of iterative truncations to the TPR domain of OGT on substrate and glycosite selection with the model protein GFP-JunB and the surrounding O-GlcNAc proteome in U2OS cells. Iterative truncation of the TPR domain of OGT maintains glycosyltransferase activity but alters subcellular localization of OGT in cells. The glycoproteome and glycosites modified by four OGT TPR isoforms were examined on the whole proteome and a single target protein, GFP-JunB. We found the greatest changes in O-GlcNAc on proteins associated with mRNA splicing processes and that the first four TPRs of the canonical nucleocytoplasmic OGT had the broadest substrate scope. Subsequent glycosite analysis revealed that alteration to the last four TPRs corresponded to the greatest shift in the resulting O-GlcNAc consensus sequence. This dataset provides a foundation to analyze how perturbations to the TPR domain and expression of OGT isoforms affect the glycosylation of substrates, which will be critical for future efforts in protein engineering of OGT, the biology of OGT isoforms, and diseases associated with the TPR domain of OGT.
Ramirez DH, Aonbangkhen C, Wu HY, Naftaly JA, Tang S, O'Meara TR, Woo CM.
Engineering a Proximity-Directed O-GlcNAc Transferase for Selective Protein O-GlcNAcylation in Cells.
ACS chemical biology2020
15(4)
32119511
Abstract: O-Linked β-N-acetylglucosamine (O-GlcNAc) is a monosaccharide that plays an essential role in cellular signaling throughout the nucleocytoplasmic proteome of eukaryotic cells. Strategies for selectively increasing O-GlcNAc levels on a target protein in cells would accelerate studies of this essential modification. Here, we report a generalizable strategy for introducing O-GlcNAc into selected target proteins in cells using a nanobody as a proximity-directing agent fused to O-GlcNAc transferase (OGT). Fusion of a nanobody that recognizes GFP (nGFP) or a nanobody that recognizes the four-amino acid sequence EPEA (nEPEA) to OGT yielded nanobody-OGT constructs that selectively delivered O-GlcNAc to a series of tagged target proteins (e.g., JunB, cJun, and Nup62). Truncation of the tetratricopeptide repeat domain as in OGT(4) increased selectivity for the target protein through the nanobody by reducing global elevation of O-GlcNAc levels in the cell. Quantitative chemical proteomics confirmed the increase in O-GlcNAc to the target protein by nanobody-OGT(4). Glycoproteomics revealed that nanobody-OGT(4) or full-length OGT produced a similar glycosite profile on the target protein JunB and Nup62. Finally, we demonstrate the ability to selectively target endogenous α-synuclein for O-GlcNAcylation in HEK293T cells. These first proximity-directed OGT constructs provide a flexible strategy for targeting additional proteins and a template for further engineering of OGT and the O-GlcNAc proteome in the future. The use of a nanobody to redirect OGT substrate selection for glycosylation of desired proteins in cells may further constitute a generalizable strategy for controlling a broader array of post-translational modifications in cells.
Zhu Y, Willems LI, Salas D, Cecioni S, Wu WB, Foster LJ, Vocadlo DJ.
Tandem Bioorthogonal Labeling Uncovers Endogenous Cotranslationally O-GlcNAc Modified Nascent Proteins.
Journal of the American Chemical Society2020
142(37)
32870666
Abstract: Hundreds of nuclear, cytoplasmic, and mitochondrial proteins within multicellular eukaryotes have hydroxyl groups of specific serine and threonine residues modified by the monosaccharide N-acetylglucosamine (GlcNAc). This modification, known as O-GlcNAc, has emerged as a central regulator of both cell physiology and human health. A key emerging function of O-GlcNAc appears to be to regulate cellular protein homeostasis. We previously showed, using overexpressed model proteins, that O-GlcNAc modification can occur cotranslationally and that this process prevents premature degradation of such nascent polypeptide chains. Here, we use tandem metabolic engineering strategies to label endogenously occurring nascent polypeptide chains within cells using O-propargyl-puromycin (OPP) and target the specific subset of nascent chains that are cotranslationally glycosylated with O-GlcNAc by metabolic saccharide engineering using tetra-O-acetyl-2-N-azidoacetyl-2-deoxy-d-galactopyranose (Ac4GalNAz). Using various combinations of sequential chemoselective ligation strategies, we go on to tag these analytes with a series of labels, allowing us to define conditions that enable their robust labeling. Two-step enrichment of these glycosylated nascent chains, combined with shotgun proteomics, allows us to identify a set of endogenous cotranslationally O-GlcNAc modified proteins. Using alternative targeted methods, we examine three of these identified proteins and further validate their cotranslational O-GlcNAcylation. These findings detail strategies to enable isolation and identification of extremely low abundance endogenous analytes present within complex protein mixtures. Moreover, this work opens the way to studies directed at understanding the roles of O-GlcNAc and other cotranslational protein modifications and should stimulate an improved understanding of the role of O-GlcNAc in cytoplasmic protein quality control and proteostasis.
Liu Y, Chen Q, Zhang N, Zhang K, Dou T, Cao Y, Liu Y, Li K, Hao X, Xie X, Li W, Ren Y, Zhang J.
Proteomic profiling and genome-wide mapping of O-GlcNAc chromatin-associated proteins reveal an O-GlcNAc-regulated genotoxic stress response.
Nature communications2020
11(1)
33214551
Abstract: O-GlcNAc modification plays critical roles in regulating the stress response program and cellular homeostasis. However, systematic and multi-omics studies on the O-GlcNAc regulated mechanism have been limited. Here, comprehensive data are obtained by a chemical reporter-based method to survey O-GlcNAc function in human breast cancer cells stimulated with the genotoxic agent adriamycin. We identify 875 genotoxic stress-induced O-GlcNAc chromatin-associated proteins (OCPs), including 88 O-GlcNAc chromatin-associated transcription factors and cofactors (OCTFs), subsequently map their genomic loci, and construct a comprehensive transcriptional reprogramming network. Notably, genotoxicity-induced O-GlcNAc enhances the genome-wide interactions of OCPs with chromatin. The dynamic binding switch of hundreds of OCPs from enhancers to promoters is identified as a crucial feature in the specific transcriptional activation of genes involved in the adaptation of cancer cells to genotoxic stress. The OCTF nuclear factor erythroid 2-related factor-1 (NRF1) is found to be a key response regulator in O-GlcNAc-modulated cellular homeostasis. These results provide a valuable clue suggesting that OCPs act as stress sensors by regulating the expression of various genes to protect cancer cells from genotoxic stress.
Phoomak C, Park D, Silsirivanit A, Sawanyawisuth K, Vaeteewoottacharn K, Detarya M, Wongkham C, Lebrilla CB, Wongkham S.
O-GlcNAc-induced nuclear translocation of hnRNP-K is associated with progression and metastasis of cholangiocarcinoma.
Molecular oncology2019
13(2)
30444036
Abstract: O-GlcNAcylation is a key post-translational modification that modifies the functions of proteins. Associations between O-GlcNAcylation, shorter survival of cholangiocarcinoma (CCA) patients, and increased migration/invasion of CCA cell lines have been reported. However, the specific O-GlcNAcylated proteins (OGPs) that participate in promotion of CCA progression are poorly understood. OGPs were isolated from human CCA cell lines, KKU-213 and KKU-214, using a click chemistry-based enzymatic labeling system, identified using LC-MS/MS, and searched against an OGP database. From the proteomic analysis, a total of 21 OGPs related to cancer progression were identified, of which 12 have not been previously reported. Among these, hnRNP-K, a multifaceted RNA- and DNA-binding protein known as a pre-mRNA-binding protein, was one of the most abundantly expressed, suggesting its involvement in CCA progression. O-GlcNAcylation of hnRNP-K was further verified by anti-OGP/anti-hnRNP-K immunoprecipitations and sWGA pull-down assays. The perpetuation of CCA by hnRNP-K was evaluated using siRNA, which revealed modulation of cyclin D1, XIAP, EMT markers, and MMP2 and MMP7 expression. In native CCA cells, hnRNP-K was primarily localized in the nucleus; however, when O-GlcNAcylation was suppressed, hnRNP-K was retained in the cytoplasm. These data signify an association between nuclear accumulation of hnRNP-K and the migratory capabilities of CCA cells. In human CCA tissues, expression of nuclear hnRNP-K was positively correlated with high O-GlcNAcylation levels, metastatic stage, and shorter survival of CCA patients. This study demonstrates the significance of O-GlcNAcylation on the nuclear translocation of hnRNP-K and its impact on the progression of CCA.
Berthier A, Vinod M, Porez G, Steenackers A, Alexandre J, Yamakawa N, Gheeraert C, Ploton M, Maréchal X, Dubois-Chevalier J, Hovasse A, Schaeffer-Reiss C, Cianférani S, Rolando C, Bray F, Duez H, Eeckhoute J, Lefebvre T, Staels B, Lefebvre P.
Combinatorial regulation of hepatic cytoplasmic signaling and nuclear transcriptional events by the OGT/REV-ERBα complex.
Proceedings of the National Academy of Sciences of the United States of America2018
115(47)
30397120
Abstract: The nuclear receptor REV-ERBα integrates the circadian clock with hepatic glucose and lipid metabolism by nucleating transcriptional comodulators at genomic regulatory regions. An interactomic approach identified O-GlcNAc transferase (OGT) as a REV-ERBα-interacting protein. By shielding cytoplasmic OGT from proteasomal degradation and favoring OGT activity in the nucleus, REV-ERBα cyclically increased O-GlcNAcylation of multiple cytoplasmic and nuclear proteins as a function of its rhythmically regulated expression, while REV-ERBα ligands mostly affected cytoplasmic OGT activity. We illustrate this finding by showing that REV-ERBα controls OGT-dependent activities of the cytoplasmic protein kinase AKT, an essential relay in insulin signaling, and of ten-of-eleven translocation (TET) enzymes in the nucleus. AKT phosphorylation was inversely correlated to REV-ERBα expression. REV-ERBα enhanced TET activity and DNA hydroxymethylated cytosine (5hmC) levels in the vicinity of REV-ERBα genomic binding sites. As an example, we show that the REV-ERBα/OGT complex modulates SREBP-1c gene expression throughout the fasting/feeding periods by first repressing AKT phosphorylation and by epigenomically priming the Srebf1 promoter for a further rapid response to insulin. Conclusion: REV-ERBα regulates cytoplasmic and nuclear OGT-controlled processes that integrate at the hepatic SREBF1 locus to control basal and insulin-induced expression of the temporally and nutritionally regulated lipogenic SREBP-1c transcript.
Lund PJ, Elias JE, Davis MM.
Global Analysis of O-GlcNAc Glycoproteins in Activated Human T Cells.
Journal of immunology (Baltimore, Md. : 1950)2016
197(8)
27655845
Abstract: T cell activation in response to Ag is largely regulated by protein posttranslational modifications. Although phosphorylation has been extensively characterized in T cells, much less is known about the glycosylation of serine/threonine residues by O-linked N-acetylglucosamine (O-GlcNAc). Given that O-GlcNAc appears to regulate cell signaling pathways and protein activity similarly to phosphorylation, we performed a comprehensive analysis of O-GlcNAc during T cell activation to address the functional importance of this modification and to identify the modified proteins. Activation of T cells through the TCR resulted in a global elevation of O-GlcNAc levels and in the absence of O-GlcNAc, IL-2 production and proliferation were compromised. T cell activation also led to changes in the relative expression of O-GlcNAc transferase (OGT) isoforms and accumulation of OGT at the immunological synapse of murine T cells. Using a glycoproteomics approach, we identified >200 O-GlcNAc proteins in human T cells. Many of the identified proteins had a functional relationship to RNA metabolism, and consistent with a connection between O-GlcNAc and RNA, inhibition of OGT impaired nascent RNA synthesis upon T cell activation. Overall, our studies provide a global analysis of O-GlcNAc dynamics during T cell activation and the first characterization, to our knowledge, of the O-GlcNAc glycoproteome in human T cells.
Zhao P, Viner R, Teo CF, Boons GJ, Horn D, Wells L.
Combining high-energy C-trap dissociation and electron transfer dissociation for protein O-GlcNAc modification site assignment.
Journal of proteome research2011
10(9)
21740066
Abstract: Mass spectrometry-based studies of proteins that are post-translationally modified by O-linked β-N-acetylglucosamine (O-GlcNAc) are challenged in effectively identifying the sites of modification while simultaneously sequencing the peptides. Here we tested the hypothesis that a combination of high-energy C-trap dissociation (HCD) and electron transfer dissociation (ETD) could specifically target the O-GlcNAc modified peptides and elucidate the amino acid sequence while preserving the attached GlcNAc residue for accurate site assignment. By taking advantage of the recently characterized O-GlcNAc-specific IgG monoclonal antibodies and the combination of HCD and ETD fragmentation techniques, O-GlcNAc modified proteins were enriched from HEK293T cells and subsequently characterized using the LTQ Orbitrap Velos ETD (Thermo Fisher Scientific) mass spectrometer. In our data set, 83 sites of O-GlcNAc modification are reported with high confidence confirming that the HCD/ETD combined approach is amenable to the detection and site assignment of O-GlcNAc modified peptides. Realizing HCD triggered ETD fragmentation on a linear ion trap/Orbitrap platform for more in-depth analysis and application of this technique to other post-translationally modified proteins are currently underway. Furthermore, this report illustrates that the O-GlcNAc transferase appears to demonstrate promiscuity with regards to the hydroxyl-containing amino acid modified in short stretches of primary sequence of the glycosylated polypeptides.
Fujiki R, Hashiba W, Sekine H, Yokoyama A, Chikanishi T, Ito S, Imai Y, Kim J, He HH, Igarashi K, Kanno J, Ohtake F, Kitagawa H, Roeder RG, Brown M, Kato S.
GlcNAcylation of histone H2B facilitates its monoubiquitination.
Nature2011
480(7378)
22121020
Abstract: Chromatin reorganization is governed by multiple post-translational modifications of chromosomal proteins and DNA. These histone modifications are reversible, dynamic events that can regulate DNA-driven cellular processes. However, the molecular mechanisms that coordinate histone modification patterns remain largely unknown. In metazoans, reversible protein modification by O-linked N-acetylglucosamine (GlcNAc) is catalysed by two enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). However, the significance of GlcNAcylation in chromatin reorganization remains elusive. Here we report that histone H2B is GlcNAcylated at residue S112 by OGT in vitro and in living cells. Histone GlcNAcylation fluctuated in response to extracellular glucose through the hexosamine biosynthesis pathway (HBP). H2B S112 GlcNAcylation promotes K120 monoubiquitination, in which the GlcNAc moiety can serve as an anchor for a histone H2B ubiquitin ligase. H2B S112 GlcNAc was localized to euchromatic areas on fly polytene chromosomes. In a genome-wide analysis, H2B S112 GlcNAcylation sites were observed widely distributed over chromosomes including transcribed gene loci, with some sites co-localizing with H2B K120 monoubiquitination. These findings suggest that H2B S112 GlcNAcylation is a histone modification that facilitates H2BK120 monoubiquitination, presumably for transcriptional activation.
Teo CF, Ingale S, Wolfert MA, Elsayed GA, Nöt LG, Chatham JC, Wells L, Boons GJ.
Glycopeptide-specific monoclonal antibodies suggest new roles for O-GlcNAc.
Nature chemical biology2010
6(5)
20305658
Abstract: Studies of post-translational modification by beta-N-acetyl-D-glucosamine (O-GlcNAc) are hampered by a lack of efficient tools such as O-GlcNAc-specific antibodies that can be used for detection, isolation and site localization. We have obtained a large panel of O-GlcNAc-specific IgG monoclonal antibodies having a broad spectrum of binding partners by combining three-component immunogen methodology with hybridoma technology. Immunoprecipitation followed by large-scale shotgun proteomics led to the identification of more than 200 mammalian O-GlcNAc-modified proteins, including a large number of new glycoproteins. A substantial number of the glycoproteins were enriched by only one of the antibodies. This observation, combined with the results of inhibition ELISAs, suggests that the antibodies, in addition to their O-GlcNAc dependence, also appear to have different but overlapping local peptide determinants. The monoclonal antibodies made it possible to delineate differentially modified proteins of liver in response to trauma-hemorrhage and resuscitation in a rat model.