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Luanpitpong S, Poohadsuan J, Klaihmon P, Kang X, Tangkiettrakul K, Issaragrisil S. Metabolic sensor O-GlcNAcylation regulates megakaryopoiesis and thrombopoiesis through c-Myc stabilization and integrin perturbation. Stem cells (Dayton, Ohio) 2021 39(6) 33544938
Abstract:
Metabolic state of hematopoietic stem cells (HSCs) is an important regulator of self-renewal and lineage-specific differentiation. Posttranslational modification of proteins via O-GlcNAcylation is an ideal metabolic sensor, but how it contributes to megakaryopoiesis and thrombopoiesis remains unknown. Here, we reveal for the first time that cellular O-GlcNAcylation levels decline along the course of megakaryocyte (MK) differentiation from human-derived hematopoietic stem and progenitor cells (HSPCs). Inhibition of O-GlcNAc transferase (OGT) that catalyzes O-GlcNAcylation prolongedly decreases O-GlcNAcylation and induces the acquisition of CD34+ CD41a+ MK-like progenitors and its progeny CD34- CD41a+ /CD42b+ megakaryoblasts (MBs)/MKs from HSPCs, consequently resulting in increased CD41a+ and CD42b+ platelets. Using correlation and co-immunoprecipitation analyses, we further identify c-Myc as a direct downstream target of O-GlcNAcylation in MBs/MKs and provide compelling evidence on the regulation of platelets by novel O-GlcNAc/c-Myc axis. Our data indicate that O-GlcNAcylation posttranslationally regulates c-Myc stability by interfering with its ubiquitin-mediated proteasomal degradation. Depletion of c-Myc upon inhibition of OGT promotes platelet formation in part through the perturbation of cell adhesion molecules, that is, integrin-α4 and integrin-β7, as advised by gene ontology and enrichment analysis for RNA sequencing and validated herein. Together, our findings provide a novel basic knowledge on the regulatory role of O-GlcNAcylation in megakaryopoiesis and thrombopoiesis that could be important in understanding hematologic disorders whose etiology are related to impaired platelet production and may have clinical applications toward an ex vivo platelet production for transfusion.
O-GlcNAc proteins:
MYC
Species: Homo sapiens
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Luanpitpong S, Rodboon N, Samart P, Vinayanuwattikun C, Klamkhlai S, Chanvorachote P, Rojanasakul Y, Issaragrisil S. A novel TRPM7/O-GlcNAc axis mediates tumour cell motility and metastasis by stabilising c-Myc and caveolin-1 in lung carcinoma. British journal of cancer 2020 123(8) 32684624
Abstract:
Calcium is an essential signal transduction element that has been associated with aggressive behaviours in several cancers. Cell motility is a prerequisite for metastasis, the major cause of lung cancer death, yet its association with calcium signalling and underlying regulatory axis remains an unexplored area.
O-GlcNAc proteins:
MYC, CAV1
Species: Homo sapiens
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Lei L, Xie J, Yu J, Li Y, Liu Y. Parallel study on protein O-GlcNAcylation in prostate cancer cell with a sensitive microarray biochip. Analytical biochemistry 2018 558 30086259
Abstract:
Although a variety of approaches have been developed to analyze protein O-GlcNAcylation, efficient investigations on O-GlcNAcylation of proteins of interest in high-throughput manner are still in high demand to further explore its functionality. In this work, we first develop a powerful microarray platform for a sensitive, specific and high-throughput analysis of protein O-GlcNAcylation. The developed array biochip is then utilized to parallelly analyze the O-GlcNAcylation of three oncogenic transcription factors C-Myc, NF-κB and p53 in normal prostate epithelial cell (RWPE-1) and prostate cancer cell line (PC-3). The levels of O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) are also monitored by the microarray platform. The experimental results show that the overall O-GlcNAcylation and OGT expression level are obviously elevated in PC-3 as compared to RWPE-1. The protein expression-normalized O-GlcNAcylation of C-Myc and NF-κB in PC-3 is significantly higher than that in RWPE-1, while opposite result is observed from p53. In addition, the biological behaviors including proliferation and migration of PC-3 cells are also studied when OGA inhibitor Thiamet G is applied to elevate the total O-GlcNAcylation level.
O-GlcNAc proteins:
MYC, P53, TF65
Species: Homo sapiens
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Taparra K, Wang H, Malek R, Lafargue A, Barbhuiya MA, Wang X, Simons BW, Ballew M, Nugent K, Groves J, Williams RD, Shiraishi T, Verdone J, Yildirir G, Henry R, Zhang B, Wong J, Wang KK, Nelkin BD, Pienta KJ, Felsher D, Zachara NE, Tran PT. O-GlcNAcylation is required for mutant KRAS-induced lung tumorigenesis. The Journal of clinical investigation 2018 128(11) 30130254
Abstract:
Mutant KRAS drives glycolytic flux in lung cancer, potentially impacting aberrant protein glycosylation. Recent evidence suggests aberrant KRAS drives flux of glucose into the hexosamine biosynthetic pathway (HBP). HBP is required for various glycosylation processes, such as protein N- or O-glycosylation and glycolipid synthesis. However, its function during tumorigenesis is poorly understood. One contributor and proposed target of KRAS-driven cancers is a developmentally conserved epithelial plasticity program called epithelial-mesenchymal transition (EMT). Here we showed in novel autochthonous mouse models that EMT accelerated KrasG12D lung tumorigenesis by upregulating expression of key enzymes of the HBP pathway. We demonstrated that HBP was required for suppressing KrasG12D-induced senescence, and targeting HBP significantly delayed KrasG12D lung tumorigenesis. To explore the mechanism, we investigated protein glycosylation downstream of HBP and found elevated levels of O-linked β-N-acetylglucosamine (O-GlcNAcylation) posttranslational modification on intracellular proteins. O-GlcNAcylation suppressed KrasG12D oncogene-induced senescence (OIS) and accelerated lung tumorigenesis. Conversely, loss of O-GlcNAcylation delayed lung tumorigenesis. O-GlcNAcylation of proteins SNAI1 and c-MYC correlated with the EMT-HBP axis and accelerated lung tumorigenesis. Our results demonstrated that O-GlcNAcylation was sufficient and required to accelerate KrasG12D lung tumorigenesis in vivo, which was reinforced by epithelial plasticity programs.
O-GlcNAc proteins:
MYC
Species: Homo sapiens
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Luanpitpong S, Angsutararux P, Samart P, Chanthra N, Chanvorachote P, Issaragrisil S. Hyper-O-GlcNAcylation induces cisplatin resistance via regulation of p53 and c-Myc in human lung carcinoma. Scientific reports 2017 7(1) 28878262
Abstract:
Aberrant metabolism in hexosamine biosynthetic pathway (HBP) has been observed in several cancers, affecting cellular signaling and tumor progression. However, the role of O-GlcNAcylation, a post-translational modification through HBP flux, in apoptosis remains unclear. Here, we found that hyper-O-GlcNAcylation in lung carcinoma cells by O-GlcNAcase inhibition renders the cells to apoptosis resistance to cisplatin (CDDP). Profiling of various key regulatory proteins revealed an implication of either p53 or c-Myc in the apoptosis regulation by O-GlcNAcylation, independent of p53 status. Using co-immunoprecipitation and correlation analyses, we found that O-GlcNAcylation of p53 under certain cellular contexts, i.e. high p53 activation, promotes its ubiquitin-mediated proteasomal degradation, resulting in a gain of oncogenic and anti-apoptotic functions. By contrast, O-GlcNAcylation of c-Myc inhibits its ubiquitination and subsequent proteasomal degradation. Gene manipulation studies revealed that O-GlcNAcylation of p53/c-Myc is in part a regulator of CDDP-induced apoptosis. Accordingly, we classified CDDP resistance by hyper-O-GlcNAcylation in lung carcinoma cells as either p53 or c-Myc dependence based on their molecular targets. Together, our findings provide novel mechanisms for the regulation of lung cancer cell apoptosis that could be important in understanding clinical drug resistance and suggest O-GlcNAcylation as a potential target for cancer therapy.
O-GlcNAc proteins:
MYC, P53
Species: Homo sapiens
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Zeng Q, Zhao RX, Chen J, Li Y, Li XD, Liu XL, Zhang WM, Quan CS, Wang YS, Zhai YX, Wang JW, Youssef M, Cui R, Liang J, Genovese N, Chow LT, Li YL, Xu ZX. O-linked GlcNAcylation elevated by HPV E6 mediates viral oncogenesis. Proceedings of the National Academy of Sciences of the United States of America 2016 113(33) 27482104
Abstract:
High-risk human papillomaviruses (HPVs) are causative agents of anogenital cancers and a fraction of head and neck cancers. The mechanisms involved in the progression of HPV neoplasias to cancers remain largely unknown. Here, we report that O-linked GlcNAcylation (O-GlcNAc) and O-GlcNAc transferase (OGT) were markedly increased in HPV-caused cervical neoplasms relative to normal cervix, whereas O-GlcNAcase (OGA) levels were not altered. Transduction of HPV16 oncogene E6 or E6/E7 into mouse embryonic fibroblasts (MEFs) up-regulated OGT mRNA and protein, elevated the level of O-GlcNAc, and promoted cell proliferation while reducing cellular senescence. Conversely, in HPV-18-transformed HeLa cervical carcinoma cells, inhibition of O-GlcNAc with a low concentration of a chemical inhibitor impaired the transformed phenotypes in vitro. We showed that E6 elevated c-MYC via increased protein stability attributable to O-GlcNAcylation on Thr58. Reduction of HPV-mediated cell viability by a high concentration of O-GlcNAc inhibitor was partially rescued by elevated c-MYC. Finally, knockdown of OGT or O-GlcNAc inhibition in HeLa cells or in TC-1 cells, a mouse cell line transformed by HPV16 E6/E7 and activated K-RAS, reduced c-MYC and suppressed tumorigenesis and metastasis. Thus, we have uncovered a mechanism for HPV oncoprotein-mediated transformation. These findings may eventually aid in the development of effective therapeutics for HPV-associated malignancies by targeting aberrant O-GlcNAc.
O-GlcNAc proteins:
MYC, MYC
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Burén S, Gomes AL, Teijeiro A, Fawal MA, Yilmaz M, Tummala KS, Perez M, Rodriguez-Justo M, Campos-Olivas R, Megías D, Djouder N. Regulation of OGT by URI in Response to Glucose Confers c-MYC-Dependent Survival Mechanisms. Cancer cell 2016 30(2) 27505673
Abstract:
Cancer cells can adapt and survive under low nutrient conditions, but underlying mechanisms remain poorly explored. We demonstrate here that glucose maintains a functional complex between the co-chaperone URI, PP1γ, and OGT, the enzyme catalyzing O-GlcNAcylation. Glucose deprivation induces the activation of PKA, which phosphorylates URI at Ser-371, resulting in PP1γ release and URI-mediated OGT inhibition. Low OGT activity reduces O-GlcNAcylation and promotes c-MYC degradation to maintain cell survival. In the presence of glucose, PP1γ-bound URI increases OGT and c-MYC levels. Accordingly, mice expressing non-phosphorylatable URI (S371A) in hepatocytes exhibit high OGT activity and c-MYC stabilization, accelerating liver tumorigenesis in agreement with c-MYC oncogenic functions. Our work uncovers that URI-regulated OGT confers c-MYC-dependent survival functions in response to glucose fluctuations.
O-GlcNAc proteins:
RMP, MYC
Species: Homo sapiens
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Shi Y, Tomic J, Wen F, Shaha S, Bahlo A, Harrison R, Dennis JW, Williams R, Gross BJ, Walker S, Zuccolo J, Deans JP, Hart GW, Spaner DE. Aberrant O-GlcNAcylation characterizes chronic lymphocytic leukemia. Leukemia 2010 24(9) 20668475
Abstract:
O-linked N-Acetylglucosamine (O-GlcNAc) post-translational modifications originate from the activity of the hexosamine pathway, and are known to affect intracellular signaling processes. As aberrant responses to microenvironmental signals are a feature of chronic lymphocytic leukemia (CLL), O-GlcNAcylated protein levels were measured in primary CLL cells. In contrast to normal circulating and tonsillar B cells, CLL cells expressed high levels of O-GlcNAcylated proteins, including p53, c-myc and Akt. O-GlcNAcylation in CLL cells increased following activation with cytokines and through toll-like receptors (TLRs), or after loading with hexosamine pathway substrates. However, high baseline O-GlcNAc levels were associated with impaired signaling responses to TLR agonists, chemotherapeutic agents, B cell receptor crosslinking and mitogens. Indolent and aggressive clinical behavior of CLL cells were found to correlate with higher and lower O-GlcNAc levels, respectively. These findings suggest that intracellular O-GlcNAcylation is associated with the pathogenesis of CLL, which could potentially have therapeutic implications.
O-GlcNAc proteins:
OGT1, MYC, P53, AKT1
Species: Homo sapiens
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Nandi A, Sprung R, Barma DK, Zhao Y, Kim SC, Falck JR, Zhao Y. Global identification of O-GlcNAc-modified proteins. Analytical chemistry 2006 78(2) 16408927
Abstract:
The O-linked N-acetylglucosamine (O-GlcNAc) modification of serine/threonine residues is an abundant posttranslational modification present in cytosolic and nuclear proteins. The functions and subproteome of O-GlcNAc modification remain largely undefined. Here we report the application of the tagging-via-substrate (TAS) approach for global identification of O-GlcNAc-modified proteins. The TAS method utilizes an O-GlcNAc azide analogue for metabolic labeling of O-GlcNAc-modified proteins, which can be chemoselectively conjugated for detection and enrichment of the proteins for proteomics studies. Our study led to the identification of 199 putative O-GlcNAc-modified proteins from HeLa cells, among which 23 were confirmed using reciprocal immunoprecipitation. Functional classification shows that proteins with diverse functions are modified by O-GlcNAc, implying that O-GlcNAc might be involved in the regulation of multiple cellular pathways.
Species: Homo sapiens
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Chou TY, Hart GW, Dang CV. c-Myc is glycosylated at threonine 58, a known phosphorylation site and a mutational hot spot in lymphomas. The Journal of biological chemistry 1995 270(32) 7642555
Abstract:
c-Myc is a helix-loop leucine zipper phosphoprotein that heterodimerizes with Max and regulates gene transcription in cell proliferation, cell differentiation, and programmed cell death. Previously, we demonstrated that c-Myc is modified by O-linked N-acetylglucosamine (O-GlcNAc) within or nearby the N-terminal transcriptional activation domain (Chou, T.-Y., Dang, C.V., and Hart, G.W. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 4417-4421). In this paper, we identified the O-GlcNAc attachment site(s) on c-Myc. c-Myc purified from sf9 insect cells was trypsinized, and its GlcNAc moieties were enzymically labeled with [3H]galactose. The [3H]galactose-labeled glycopeptides were isolated by reverse phase high performance liquid chromatography and then subjected to gas-phase sequencing, manual Edman degradation, and laser desorption/ionization mass spectrometry. These analyses show that threonine 58, an in vivo phosphorylation site in the transactivation domain, is the major O-GlcNAc glycosylation site of c-Myc. Mutation of threonine 58, frequently found in retroviral v-Myc proteins and in human Burkitt and AIDS-related lymphomas, is associated with enhanced transforming activity and tumorigenicity. The reciprocal glycosylation and phosphorylation at this biologically significant amino acid residue may play an important role in the regulation of the functions of c-Myc.
O-GlcNAc proteins:
MYC
Species: Homo sapiens
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Chou TY, Dang CV, Hart GW. Glycosylation of the c-Myc transactivation domain. Proceedings of the National Academy of Sciences of the United States of America 1995 92(10) 7753821
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.
O-GlcNAc proteins:
MYC
Species: Homo sapiens
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