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Zhu Z, Li S, Yin X, Sun K, Song J, Ren W, Gao L, Zhi K. Review: Protein O-GlcNAcylation regulates DNA damage response: A novel target for cancer therapy. Int J Biol Macromol 2024; 264:130351. [PMID: 38403231 DOI: 10.1016/j.ijbiomac.2024.130351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 02/02/2024] [Accepted: 02/19/2024] [Indexed: 02/27/2024]
Abstract
The DNA damage response (DDR) safeguards the stable genetic information inheritance by orchestrating a complex protein network in response to DNA damage. However, this mechanism can often hamper the effectiveness of radiotherapy and DNA-damaging chemotherapy in destroying tumor cells, causing cancer resistance. Inhibiting DDR can significantly improve tumor cell sensitivity to radiotherapy and DNA-damaging chemotherapy. Thus, DDR can be a potential target for cancer treatment. Post-translational modifications (PTMs) of DDR-associated proteins profoundly affect their activity and function by covalently attaching new functional groups. O-GlcNAcylation (O-linked-N-acetylglucosaminylation) is an emerging PTM associated with adding and removing O-linked N-acetylglucosamine to serine and threonine residues of proteins. It acts as a dual sensor for nutrients and stress in the cell and is sensitive to DNA damage. However, the explanation behind the specific role of O-GlcNAcylation in the DDR remains remains to be elucidated. To illustrate the complex relationship between O-GlcNAcylation and DDR, this review systematically describes the role of O-GlcNAcylation in DNA repair, cell cycle, and chromatin. We also discuss the defects of current strategies for targeting O-GlcNAcylation-regulated DDR in cancer therapy and suggest potential directions to address them.
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Affiliation(s)
- Zhuang Zhu
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao 266555, China; School of Stomatology, Qingdao University, Qingdao 266003, China; Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, Qingdao 266555, China
| | - Shaoming Li
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao 266555, China; School of Stomatology, Qingdao University, Qingdao 266003, China; Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, Qingdao 266555, China
| | - Xiaopeng Yin
- Department of Oral and Maxillofacial Surgery, Central Laboratory of Jinan Stamotological Hospital, Jinan Key Laboratory of Oral Tissue Regeneration, Jinan 250001, Shandong Province, China
| | - Kai Sun
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao 266555, China; School of Stomatology, Qingdao University, Qingdao 266003, China; Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, Qingdao 266555, China
| | - Jianzhong Song
- Department of Oral and Maxilloafacial Surgery, People's Hospital of Rizhao, Rizhao, Shandong, China
| | - Wenhao Ren
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao 266555, China; Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, Qingdao 266555, China.
| | - Ling Gao
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao 266555, China; School of Stomatology, Qingdao University, Qingdao 266003, China; Key Lab of Oral Clinical Medicine, the Affiliated Hospital of Qingdao University, Qingdao 266003, China; Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, Qingdao 266555, China.
| | - Keqian Zhi
- Department of Oral and Maxillofacial Reconstruction, the Affiliated Hospital of Qingdao University, Qingdao 266555, China; School of Stomatology, Qingdao University, Qingdao 266003, China; Key Lab of Oral Clinical Medicine, the Affiliated Hospital of Qingdao University, Qingdao 266003, China; Department of Oral and Maxillofacial Surgery, the Affiliated Hospital of Qingdao University, Qingdao 266555, China.
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Writing and erasing O-GlcNAc from target proteins in cells. Biochem Soc Trans 2021; 49:2891-2901. [PMID: 34783346 DOI: 10.1042/bst20210865] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 12/15/2022]
Abstract
O-linked N-acetylglucosamine (O-GlcNAc) is a widespread reversible modification on nucleocytoplasmic proteins that plays an important role in many biochemical processes and is highly relevant to numerous human diseases. The O-GlcNAc modification has diverse functional impacts on individual proteins and glycosites, and methods for editing this modification on substrates are essential to decipher these functions. Herein, we review recent progress in developing methods for O-GlcNAc regulation, with a focus on methods for editing O-GlcNAc with protein- and site-selectivity in cells. The applications, advantages, and limitations of currently available strategies for writing and erasing O-GlcNAc and future directions are also discussed. These emerging approaches to manipulate O-GlcNAc on a target protein in cells will greatly accelerate the development of functional studies and enable therapeutic interventions in the O-GlcNAc field.
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OGA is associated with deglycosylation of NONO and the KU complex during DNA damage repair. Cell Death Dis 2021; 12:622. [PMID: 34135314 PMCID: PMC8209095 DOI: 10.1038/s41419-021-03910-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 06/04/2021] [Accepted: 06/08/2021] [Indexed: 02/01/2023]
Abstract
Accumulated evidence shows that OGT-mediated O-GlcNAcylation plays an important role in response to DNA damage repair. However, it is unclear if the “eraser” O-GlcNAcase (OGA) participates in this cellular process. Here, we examined the molecular mechanisms and biological functions of OGA in DNA damage repair, and found that OGA was recruited to the sites of DNA damage and mediated deglycosylation following DNA damage. The recruitment of OGA to DNA lesions is mediated by O-GlcNAcylation events. Moreover, we have dissected OGA using deletion mutants and found that C-terminal truncated OGA including the pseudo HAT domain was required for the recruitment of OGA to DNA lesions. Using unbiased protein affinity purification, we found that the pseudo HAT domain was associated with DNA repair factors including NONO and the Ku70/80 complex. Following DNA damage, both NONO and the Ku70/80 complex were O-GlcNAcylated by OGT. The pseudo HAT domain was required to recognize NONO and the Ku70/80 complex for their deglycosylation. Suppression of the deglycosylation prolonged the retention of NONO at DNA lesions and delayed NONO degradation on the chromatin, which impaired non-homologus end joining (NHEJ). Collectively, our study reveals that OGA-mediated deglycosylation plays a key role in DNA damage repair.
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Averbek S, Jakob B, Durante M, Averbeck NB. O-GlcNAcylation Affects the Pathway Choice of DNA Double-Strand Break Repair. Int J Mol Sci 2021; 22:ijms22115715. [PMID: 34071949 PMCID: PMC8198441 DOI: 10.3390/ijms22115715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 12/13/2022] Open
Abstract
Exposing cells to DNA damaging agents, such as ionizing radiation (IR) or cytotoxic chemicals, can cause DNA double-strand breaks (DSBs), which are crucial to repair to maintain genetic integrity. O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) is a post-translational modification (PTM), which has been reported to be involved in the DNA damage response (DDR) and chromatin remodeling. Here, we investigated the impact of O-GlcNAcylation on the DDR, DSB repair and chromatin status in more detail. We also applied charged particle irradiation to analyze differences of O-GlcNAcylation and its impact on DSB repair in respect of spatial dose deposition and radiation quality. Various techniques were used, such as the γH2AX foci assay, live cell microscopy and Fluorescence Lifetime Microscopy (FLIM) to detect DSB rejoining, protein accumulation and chromatin states after treating the cells with O-GlcNAc transferase (OGT) or O-GlcNAcase (OGA) inhibitors. We confirmed that O-GlcNAcylation of MDC1 is increased upon irradiation and identified additional repair factors related to Homologous Recombination (HR), CtIP and BRCA1, which were increasingly O-GlcNAcyated upon irradiation. This is consistent with our findings that the function of HR is affected by OGT inhibition. Besides, we found that OGT and OGA activity modulate chromatin compaction states, providing a potential additional level of DNA-repair regulation.
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Affiliation(s)
- Sera Averbek
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany; (S.A.); (B.J.); (M.D.)
- Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Burkhard Jakob
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany; (S.A.); (B.J.); (M.D.)
| | - Marco Durante
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany; (S.A.); (B.J.); (M.D.)
- Department of Physics, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Nicole B. Averbeck
- Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany; (S.A.); (B.J.); (M.D.)
- Correspondence:
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Ma J, Wu C, Hart GW. Analytical and Biochemical Perspectives of Protein O-GlcNAcylation. Chem Rev 2021; 121:1513-1581. [DOI: 10.1021/acs.chemrev.0c00884] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Junfeng Ma
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Georgetown University, Washington D.C. 20057, United States
| | - Ci Wu
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Georgetown University, Washington D.C. 20057, United States
| | - Gerald W. Hart
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, United States
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Lee SJ, Kwon OS. O-GlcNAc Transferase Inhibitor Synergistically Enhances Doxorubicin-Induced Apoptosis in HepG2 Cells. Cancers (Basel) 2020; 12:cancers12113154. [PMID: 33121131 PMCID: PMC7693581 DOI: 10.3390/cancers12113154] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 01/31/2023] Open
Abstract
Simple Summary We found that the combination treatment of doxorubicin (DOX) and O-GlcNAc transferase (OGT) inhibitor OSMI-1 has synergic therapeutic efficacy in the treatment of liver cancer. Our data show that DOX displayed cytotoxicity via the activation of p53 and the inflammatory NF-κB signaling pathway, while OSMI-1 evoked the ER stress response and inhibited NF-κB signaling. Therefore, DOX in combination with the OSMI-1 group showed a 20-fold reduction of tumor formation, whereas the DOX alone group reduced by 1.8-fold compared with control in a HepG2 cell xenograft model. Abstract The combination of chemotherapy with chemosensitizing agents is a common approach to enhance anticancer activity while reducing the dose-dependent adverse side effects of cancer treatment. Herein, we investigated doxorubicin (DOX) and O-GlcNAc transferase (OGT) inhibitor OSMI-1 combination treatment, which significantly enhanced apoptosis in hepatocellular carcinoma cells (HepG2) as a result of synergistic drug action in disparate stress signaling pathways. Treatment with a low dose of DOX or a suboptimal dose of OSMI-1 alone did not induce apoptotic cell death in HepG2 cells. However, the combination of DOX with OSMI-1 in HepG2 cells synergistically increased apoptotic cell death through the activation of both the p53 and mitochondrial Bcl2 pathways compared to DOX alone. We also demonstrated that the combination of DOX and OSMI-1 stimulated cell death, dramatically reducing cell proliferation and tumor growth in vivo using a HepG2 xenograft mouse model. These findings indicate that OSMI-1 acts as a potential chemosensitizer by enhancing DOX-induced cell death. This study provides insight into a possible mechanism of chemotherapy resistance, identifies potential novel drug targets, and suggests that OGT inhibition could be utilized in clinical applications to treat hepatocellular carcinoma as well as other cancer types.
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Lafont F, Fleury F, Benhelli-Mokrani H. DNA-PKcs Ser2056 auto-phosphorylation is affected by an O-GlcNAcylation/phosphorylation interplay. Biochim Biophys Acta Gen Subj 2020; 1864:129705. [PMID: 32805318 DOI: 10.1016/j.bbagen.2020.129705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/17/2020] [Accepted: 08/04/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND DNA dependent Protein Kinase (DNA-PK) is an heterotrimeric complex regulating the Non Homologous End Joining (NHEJ) double strand break (DSB) repair pathway. The activity of its catalytic subunit (DNA-PKcs) is regulated by multiple phosphorylations, like the Ser2056 one that impacts DSB end processing and telomeres integrity. O-GlcNAcylation is a post translational modification (PTM) closely related to phosphorylation and its implication in the modulation of DNA-PKcs activity during the DNA Damage Response (DDR) is unknown. METHODS Using IP techniques, and HeLa cell line, we evaluated the effect of pharmacological or siOGT mediated O-GlcNAc level modulation on DNA-PKcs O-GlcNAcylation. We used the RPA32 phosphorylation as a DNA-PKcs activity reporter substrate to evaluate the effect of O-GlcNAc modulators. RESULTS We show here that human DNA-PKcs is an O-GlcNAc modified protein and that this new PTM is responsive to the cell O-GlcNAcylation level modulation. Our findings reveal that DNA-PKcs hypo O-GlcNAcylation affects its kinase activity and that the bleomycin-induced Ser2056 phosphorylation, is modulated by DNA-PKcs O-GlcNAcylation. CONCLUSIONS DNA-PKcs Ser2056 phosphorylation is antagonistically linked to DNA-PKcs O-GlcNAcylation level modulation. GENERAL SIGNIFICANCE Given the essential role of DNA-PKcs Ser2056 phosphorylation in the DDR, this study brings data about the role of cell O-GlcNAc level on genome integrity maintenance.
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Affiliation(s)
- Florian Lafont
- Université de Nantes, CNRS, UFIP, UMR 6286, 44000 Nantes, France
| | - Fabrice Fleury
- Université de Nantes, CNRS, UFIP, UMR 6286, 44000 Nantes, France
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Chatham JC, Zhang J, Wende AR. Role of O-Linked N-Acetylglucosamine Protein Modification in Cellular (Patho)Physiology. Physiol Rev 2020; 101:427-493. [PMID: 32730113 DOI: 10.1152/physrev.00043.2019] [Citation(s) in RCA: 146] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the mid-1980s, the identification of serine and threonine residues on nuclear and cytoplasmic proteins modified by a N-acetylglucosamine moiety (O-GlcNAc) via an O-linkage overturned the widely held assumption that glycosylation only occurred in the endoplasmic reticulum, Golgi apparatus, and secretory pathways. In contrast to traditional glycosylation, the O-GlcNAc modification does not lead to complex, branched glycan structures and is rapidly cycled on and off proteins by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), respectively. Since its discovery, O-GlcNAcylation has been shown to contribute to numerous cellular functions, including signaling, protein localization and stability, transcription, chromatin remodeling, mitochondrial function, and cell survival. Dysregulation in O-GlcNAc cycling has been implicated in the progression of a wide range of diseases, such as diabetes, diabetic complications, cancer, cardiovascular, and neurodegenerative diseases. This review will outline our current understanding of the processes involved in regulating O-GlcNAc turnover, the role of O-GlcNAcylation in regulating cellular physiology, and how dysregulation in O-GlcNAc cycling contributes to pathophysiological processes.
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Affiliation(s)
- John C Chatham
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama; and Birmingham Veterans Affairs Medical Center, Birmingham, Alabama
| | - Jianhua Zhang
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama; and Birmingham Veterans Affairs Medical Center, Birmingham, Alabama
| | - Adam R Wende
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama; and Birmingham Veterans Affairs Medical Center, Birmingham, Alabama
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Miura Y, Hayakawa A, Kikuchi S, Tsumoto H, Umezawa K, Chiba Y, Soejima Y, Sawabe M, Fukui K, Akimoto Y, Endo T. Fumarate accumulation involved in renal diabetic fibrosis in Goto-Kakizaki rats. Arch Biochem Biophys 2019; 678:108167. [PMID: 31704098 DOI: 10.1016/j.abb.2019.108167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/31/2019] [Accepted: 11/02/2019] [Indexed: 01/01/2023]
Abstract
The Goto-Kakizaki (GK) rat is a spontaneous animal model of type 2 diabetes and early stage of diabetic nephropathy. However, the pathophysiological mechanisms contributing to the progression of diabetic nephropathy in GK rats remain unclear. Kidneys from 15-week old male diabetic GK/Jcl rats and age-matched Wistar rats, which have the same genetic background as GK rats, were used. Proteomic analyses of GK and Wistar kidneys were performed using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE). Differentially expressed proteins in GK rats were subjected to pathway analysis, and expression levels of hypoxia inducible factor 1α (HIF-1α) and transforming growth factor-β1 (TGF-β1), and fumarate accumulation in GK kidneys were examined. Azan staining and immunohistochemical staining of α-smooth muscle actin were performed in relation to fibrosis in GK kidneys. Proteomic analysis using 2D-DIGE, analysis of fumarate content, and expression analysis of HIF-1α, TGF-β1, and α-smooth muscle actin of GK rat's kidney, suggested the mechanism of fibrosis characterized as two stages in diabetic nephropathy of GK rats. Abnormalities of glucose metabolism such as elevated levels of 2-oxoglutarate dehydrogenase and reduction of fumarate hydratase caused the accumulation of fumarate followed by the upregulation of HIF-1α and TGF-β1 leading to fibrosis in diabetic nephropathy. Alterations in proteins involved in the tricarboxylic acid cycle are associated with fibrosis through fumarate accumulation in diabetic nephropathy of GK rats.
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Affiliation(s)
- Yuri Miura
- Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan.
| | - Atsuko Hayakawa
- Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan; Department of Bioscience and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama, 337-8570, Japan
| | - Shohei Kikuchi
- Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan; Department of Molecular Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Hiroki Tsumoto
- Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Keitaro Umezawa
- Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Yuko Chiba
- Department of Diabetes, Metabolism, and Endocrinology, Tokyo Metropolitan Geriatric Hospital, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Yurie Soejima
- Department of Molecular Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Motoji Sawabe
- Department of Molecular Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Koji Fukui
- Department of Bioscience and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama, 337-8570, Japan
| | - Yoshihiro Akimoto
- Department Anatomy, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo, 181-8611, Japan
| | - Tamao Endo
- Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
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Peixoto A, Relvas-Santos M, Azevedo R, Santos LL, Ferreira JA. Protein Glycosylation and Tumor Microenvironment Alterations Driving Cancer Hallmarks. Front Oncol 2019; 9:380. [PMID: 31157165 PMCID: PMC6530332 DOI: 10.3389/fonc.2019.00380] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/23/2019] [Indexed: 12/12/2022] Open
Abstract
Decades of research have disclosed a plethora of alterations in protein glycosylation that decisively impact in all stages of disease and ultimately contribute to more aggressive cell phenotypes. The biosynthesis of cancer-associated glycans and its reflection in the glycoproteome is driven by microenvironmental cues and these events act synergistically toward disease evolution. Such intricate crosstalk provides the molecular foundations for the activation of relevant oncogenic pathways and leads to functional alterations driving invasion and disease dissemination. However, it also provides an important source of relevant glyco(neo)epitopes holding tremendous potential for clinical intervention. Therefore, we highlight the transversal nature of glycans throughout the currently accepted cancer hallmarks, with emphasis on the crosstalk between glycans and the tumor microenvironment stromal components. Focus is also set on the pressing need to include glycans and glycoconjugates in comprehensive panomics models envisaging molecular-based precision medicine capable of improving patient care. We foresee that this may provide the necessary rationale for more comprehensive studies and molecular-based intervention.
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Affiliation(s)
- Andreia Peixoto
- Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology, Porto, Portugal.,Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal.,Tumour and Microenvironment Interactions Group, INEB-Institute for Biomedical Engineering, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Marta Relvas-Santos
- Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology, Porto, Portugal
| | - Rita Azevedo
- Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology, Porto, Portugal.,Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal
| | - Lúcio Lara Santos
- Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology, Porto, Portugal.,Department of Surgical Oncology, Portuguese Institute of Oncology, Porto, Portugal
| | - José Alexandre Ferreira
- Experimental Pathology and Therapeutics Group, Portuguese Institute of Oncology, Porto, Portugal.,Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Portugal.,Porto Comprehensive Cancer Center, Porto, Portugal
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Zachara NE. Critical observations that shaped our understanding of the function(s) of intracellular glycosylation (O-GlcNAc). FEBS Lett 2018; 592:3950-3975. [PMID: 30414174 DOI: 10.1002/1873-3468.13286] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022]
Abstract
Almost 100 years after the first descriptions of proteins conjugated to carbohydrates (mucins), several studies suggested that glycoproteins were not restricted to the serum, extracellular matrix, cell surface, or endomembrane system. In the 1980s, key data emerged demonstrating that intracellular proteins were modified by monosaccharides of O-linked β-N-acetylglucosamine (O-GlcNAc). Subsequently, this modification was identified on thousands of proteins that regulate cellular processes as diverse as protein aggregation, localization, post-translational modifications, activity, and interactions. In this Review, we will highlight critical discoveries that shaped our understanding of the molecular events underpinning the impact of O-GlcNAc on protein function, the role that O-GlcNAc plays in maintaining cellular homeostasis, and our understanding of the mechanisms that regulate O-GlcNAc-cycling.
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Affiliation(s)
- Natasha E Zachara
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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12
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Wang L, Chen S, Zhang Z, Zhang J, Mao S, Zheng J, Xuan Y, Liu M, Cai K, Zhang W, Guo Y, Zhai W, Yao X. Suppressed OGT expression inhibits cell proliferation while inducing cell apoptosis in bladder cancer. BMC Cancer 2018; 18:1141. [PMID: 30453909 PMCID: PMC6245611 DOI: 10.1186/s12885-018-5033-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 11/01/2018] [Indexed: 01/10/2023] Open
Abstract
Background This study aimed to explore hyper-O-linked N-acetylglucosaminylation (O-GlcNAcylation) with an elevation of the expression of O-linked-β-N-acetylglucosamine transferase (OGT) in human bladder cancer. Methods Immunohistochemical staining for OGT and O-GlcNAcylation was performed in 20 paired human bladder cancer and adjacent normal tissues, as well as in human bladder cancer tissue microarrays (N = 169). The expression level of OGT and O-GlcNAcylation in cell lines were detected using the Western blot analysis. The effects of O-GlcNAcylation on the cell proliferation of bladder cancer were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and clone formation assays. Cell apoptosis and cell cycle analysis were detected using flow cytometry. The autophagy of bladder cancer cells was investigated using the Western blot analysis, and GFP–LC3 plasmid was used to detect the autophagic flux. MTT assay was performed to detect the sensitivity of bladder cancer cells to cisplatin after OGT knockdown. Results The expression of OGT and the O-GlcNAcylation were upregulated in bladder cancer tissues and cell lines. O-GlcNAcylation and OGT were observed in nucleus and cytoplasm and found to be higher in muscle-invasive bladder cancer (MIBC) than in non-muscle-invasive bladder cancer (NMIBC). Reducing hyper-O-GlcNAcylation by OGT knockdown inhibited the proliferation of bladder cancer cells in vitro and xenograft tumor growth in vivo, triggered apoptosis, as well as led to cell cycle arrest. It also increased autophagy in bladder cancer cells. This study demonstrated increased autophagy pro-survival, but not pro-death. Reducing hyper-O-GlcNAcylation by OGT knockdown facilitated the chemosensitivity of bladder cancer cells to cis-platinum. Conclusions The data indicated that hyper-O-GlcNAcylation enhanced oncogenic phenotypes and was involved in DNA damage response in bladder cancer.
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Affiliation(s)
- Longsheng Wang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Shaojun Chen
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Ziwei Zhang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Junfeng Zhang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Shiyu Mao
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Jiayi Zheng
- Department of pathology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Yang Xuan
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Mengnan Liu
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Keke Cai
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Wentao Zhang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Yadong Guo
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Wei Zhai
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China
| | - Xudong Yao
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai, 200072, China.
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Chen PH, Chi JT, Boyce M. Functional crosstalk among oxidative stress and O-GlcNAc signaling pathways. Glycobiology 2018; 28:556-564. [PMID: 29548027 PMCID: PMC6054262 DOI: 10.1093/glycob/cwy027] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 02/14/2018] [Accepted: 03/13/2018] [Indexed: 12/12/2022] Open
Abstract
In metazoans, thousands of intracellular proteins are modified with O-linked β-N-acetylglucosamine (O-GlcNAc) in response to a wide range of stimuli and stresses. In particular, a complex and evolutionarily conserved interplay between O-GlcNAcylation and oxidative stress has emerged in recent years. Here, we review the current literature on the connections between O-GlcNAc and oxidative stress, with a particular emphasis on major signaling pathways, such as KEAP1/NRF2, FOXO, NFκB, p53 and cell metabolism. Taken together, this work sheds important light on the signaling functions of protein glycosylation and the mechanisms of stress responses alike and illuminates how the two are integrated in animal cell physiology.
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Affiliation(s)
- Po-Han Chen
- Department of Biochemistry
- Department of Molecular Genetics and Microbiology
- Center for Genomic and Computational Biology, Duke University School of Medicine, Durham, NC, USA
| | - Jen-Tsan Chi
- Department of Molecular Genetics and Microbiology
- Center for Genomic and Computational Biology, Duke University School of Medicine, Durham, NC, USA
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14
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O-GlcNAc elevation through activation of the hexosamine biosynthetic pathway enhances cancer cell chemoresistance. Cell Death Dis 2018; 9:485. [PMID: 29706631 PMCID: PMC5924752 DOI: 10.1038/s41419-018-0522-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/12/2018] [Accepted: 03/14/2018] [Indexed: 01/27/2023]
Abstract
Chemoresistance has become a major obstacle to the success of cancer therapy, but the mechanisms underlying chemoresistance are not yet fully understood. O-GlcNAcylation is a post-translational modification that is regulated by the hexosamine biosynthetic pathway (HBP) and has an important role in a wide range of cellular functions. Here we assessed the role of O-GlcNAcylation in chemoresistance and investigated the underlying cellular mechanisms. The results showed that the HBP has an important role in cancer cell chemoresistance by regulating O-GlcNAcylation. An increase in the levels of O-GlcNAcylation indicates an increased resistance of cancer cells to chemotherapy. Acute treatment with doxorubicin (DOX) or camptothecin (CPT) induced O-GlcNAcylation through HBP activation. In fact, the chemotherapy agents activated the AKT/X-box-binding protein 1 (XBP1) axis and then induced the HBP. Furthermore, the observed elevation of cellular O-GlcNAcylation led to activation of survival signalling pathways and chemoresistance in cancer cells. Finally, suppression of O-GlcNAcylation reduced the resistance of both established and primary cancer cells to chemotherapy. These results provide significant novel insights regarding the important role of the HBP and O-GlcNAcylation in regulating cancer chemoresistance. Thus, O-GlcNAc inhibition might offer a new strategy for improving the efficacy of chemotherapy.
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15
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Liu C, Li J. O-GlcNAc: A Sweetheart of the Cell Cycle and DNA Damage Response. Front Endocrinol (Lausanne) 2018; 9:415. [PMID: 30105004 PMCID: PMC6077185 DOI: 10.3389/fendo.2018.00415] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/02/2018] [Indexed: 01/22/2023] Open
Abstract
The addition and removal of O-linked N-acetylglucosamine (O-GlcNAc) to and from the Ser and Thr residues of proteins is an emerging post-translational modification. Unlike phosphorylation, which requires a legion of kinases and phosphatases, O-GlcNAc is catalyzed by the sole enzyme in mammals, O-GlcNAc transferase (OGT), and reversed by the sole enzyme, O-GlcNAcase (OGA). With the advent of new technologies, identification of O-GlcNAcylated proteins, followed by pinpointing the modified residues and understanding the underlying molecular function of the modification has become the very heart of the O-GlcNAc biology. O-GlcNAc plays a multifaceted role during the unperturbed cell cycle, including regulating DNA replication, mitosis, and cytokinesis. When the cell cycle is challenged by DNA damage stresses, O-GlcNAc also protects genome integrity via modifying an array of histones, kinases as well as scaffold proteins. Here we will focus on both cell cycle progression and the DNA damage response, summarize what we have learned about the role of O-GlcNAc in these processes and envision a sweeter research future.
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16
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Stress-induced O-GlcNAcylation: an adaptive process of injured cells. Biochem Soc Trans 2017; 45:237-249. [PMID: 28202678 DOI: 10.1042/bst20160153] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 11/30/2016] [Accepted: 12/14/2016] [Indexed: 02/07/2023]
Abstract
In the 30 years, since the discovery of nucleocytoplasmic glycosylation, O-GlcNAc has been implicated in regulating cellular processes as diverse as protein folding, localization, degradation, activity, post-translational modifications, and interactions. The cell co-ordinates these molecular events, on thousands of cellular proteins, in concert with environmental and physiological cues to fine-tune epigenetics, transcription, translation, signal transduction, cell cycle, and metabolism. The cellular stress response is no exception: diverse forms of injury result in dynamic changes to the O-GlcNAc subproteome that promote survival. In this review, we discuss the biosynthesis of O-GlcNAc, the mechanisms by which O-GlcNAc promotes cytoprotection, and the clinical significance of these data.
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17
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Martin B, Wang R, Cong WN, Daimon CM, Wu WW, Ni B, Becker KG, Lehrmann E, Wood WH, Zhang Y, Etienne H, van Gastel J, Azmi A, Janssens J, Maudsley S. Altered learning, memory, and social behavior in type 1 taste receptor subunit 3 knock-out mice are associated with neuronal dysfunction. J Biol Chem 2017; 292:11508-11530. [PMID: 28522608 DOI: 10.1074/jbc.m116.773820] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 05/03/2017] [Indexed: 12/19/2022] Open
Abstract
The type 1 taste receptor member 3 (T1R3) is a G protein-coupled receptor involved in sweet-taste perception. Besides the tongue, the T1R3 receptor is highly expressed in brain areas implicated in cognition, including the hippocampus and cortex. As cognitive decline is often preceded by significant metabolic or endocrinological dysfunctions regulated by the sweet-taste perception system, we hypothesized that a disruption of the sweet-taste perception in the brain could have a key role in the development of cognitive dysfunction. To assess the importance of the sweet-taste receptors in the brain, we conducted transcriptomic and proteomic analyses of cortical and hippocampal tissues isolated from T1R3 knock-out (T1R3KO) mice. The effect of an impaired sweet-taste perception system on cognition functions were examined by analyzing synaptic integrity and performing animal behavior on T1R3KO mice. Although T1R3KO mice did not present a metabolically disrupted phenotype, bioinformatic interpretation of the high-dimensionality data indicated a strong neurodegenerative signature associated with significant alterations in pathways involved in neuritogenesis, dendritic growth, and synaptogenesis. Furthermore, a significantly reduced dendritic spine density was observed in T1R3KO mice together with alterations in learning and memory functions as well as sociability deficits. Taken together our data suggest that the sweet-taste receptor system plays an important neurotrophic role in the extralingual central nervous tissue that underpins synaptic function, memory acquisition, and social behavior.
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Affiliation(s)
- Bronwen Martin
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Rui Wang
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Wei-Na Cong
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Caitlin M Daimon
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Wells W Wu
- From the Metabolism Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Bin Ni
- the Receptor Pharmacology Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Kevin G Becker
- the Gene Expression and Genomics Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Elin Lehrmann
- the Gene Expression and Genomics Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - William H Wood
- the Gene Expression and Genomics Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Yongqing Zhang
- the Gene Expression and Genomics Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Harmonie Etienne
- the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
| | - Jaana van Gastel
- the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
| | - Abdelkrim Azmi
- the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
| | - Jonathan Janssens
- the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
| | - Stuart Maudsley
- the Receptor Pharmacology Unit, NIA, National Institutes of Health, Baltimore, Maryland 21224, .,the Translational Neurobiology Group, VIB Department of Molecular Genetics, University of Antwerp, AN-2610 Antwerp, Belgium, and.,the Department of Biomedical Sciences, University of Antwerp, AN-2610 Antwerp, Belgium
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18
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O-GlcNAcylation and chromatin remodeling in mammals: an up-to-date overview. Biochem Soc Trans 2017; 45:323-338. [PMID: 28408473 DOI: 10.1042/bst20160388] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/30/2016] [Accepted: 01/05/2017] [Indexed: 02/07/2023]
Abstract
Post-translational modifications of histones and the dynamic DNA methylation cycle are finely regulated by a myriad of chromatin-binding factors and chromatin-modifying enzymes. Epigenetic modifications ensure local changes in the architecture of chromatin, thus controlling in fine the accessibility of the machinery of transcription, replication or DNA repair to the chromatin. Over the past decade, the nutrient-sensor enzyme O-GlcNAc transferase (OGT) has emerged as a modulator of chromatin remodeling. In mammals, OGT acts either directly through dynamic and reversible O-GlcNAcylation of histones and chromatin effectors, or in an indirect manner through its recruitment into chromatin-bound multiprotein complexes. In particular, there is an increasing amount of evidence of a cross-talk between OGT and the DNA dioxygenase ten-eleven translocation proteins that catalyze active DNA demethylation. Conversely, the stability of OGT itself can be controlled by the histone lysine-specific demethylase 2 (LSD2). Finally, a few studies have explored the role of O-GlcNAcase (OGA) in chromatin remodeling. In this review, we summarize the recent findings on the link between OGT, OGA and chromatin regulators in mammalian cellular models, and discuss their relevance in physiological and pathological conditions.
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19
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K.M. Ip C, Yin J, K.S. Ng P, Lin SY, B. Mills G. Genomic-Glycosylation Aberrations in Tumor Initiation, Progression and Management. AIMS MEDICAL SCIENCE 2016. [DOI: 10.3934/medsci.2016.4.386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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20
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Zhong J, Martinez M, Sengupta S, Lee A, Wu X, Chaerkady R, Chatterjee A, O'Meally RN, Cole RN, Pandey A, Zachara NE. Quantitative phosphoproteomics reveals crosstalk between phosphorylation and O-GlcNAc in the DNA damage response pathway. Proteomics 2015; 15:591-607. [PMID: 25263469 DOI: 10.1002/pmic.201400339] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/02/2014] [Accepted: 09/24/2014] [Indexed: 11/07/2022]
Abstract
The modification of intracellular proteins by monosaccharides of O-linked β-N-acetylglucosamine (O-GlcNAc) is an essential and dynamic PTM of metazoans. The addition and removal of O-GlcNAc is catalyzed by the O-GlcNAc transferase (OGT) and O-GlcNAcase, respectively. One mechanism by which O-GlcNAc is thought to mediate proteins is by regulating phosphorylation. To provide insight into the pathways regulated by O-GlcNAc, we have utilized SILAC-based quantitative proteomics to carry out comparisons of site-specific phosphorylation in OGT wild-type and Null cells. Quantitation of the phosphoproteome demonstrated that of 5529 phosphoserine, phosphothreonine, and phosphotyrosine sites, 232 phosphosites were upregulated and 133 downregulated in the absence of O-GlcNAc. Collectively, these data suggest that deletion of OGT has a profound effect on the phosphorylation of cell cycle and DNA damage response proteins. Key events were confirmed by biochemical analyses and demonstrate an increase in the activating autophosphorylation event on ATM (Ser1987) and on ATM's downstream targets p53, H2AX, and Chk2. Together, these data support widespread changes in the phosphoproteome upon removal of O-GlcNAc, suggesting that O-GlcNAc regulates processes such as the cell cycle, genomic stability, and lysosomal biogenesis. All MS data have been deposited in the ProteomeXchange with identifier PXD001153 (http://proteomecentral.proteomexchange.org/dataset/PXD001153).
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Affiliation(s)
- Jun Zhong
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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O-GlcNAcylation of eIF2α regulates the phospho-eIF2α-mediated ER stress response. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1860-9. [PMID: 25937070 DOI: 10.1016/j.bbamcr.2015.04.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/20/2015] [Accepted: 04/24/2015] [Indexed: 12/11/2022]
Abstract
O-GlcNAcylation is highly involved in cellular stress responses including the endoplasmic reticulum (ER) stress response. For example, glucosamine-induced flux through the hexosamine biosynthetic pathway can promote ER stress and ER stress inducers can change the total cellular level of O-GlcNAcylation. However, it is largely unknown which component(s) of the unfolded protein response (UPR) is directly regulated by O-GlcNAcylation. In this study, eukaryotic translation initiation factor 2α (eIF2α), a major branch of the UPR, was O-GlcNAcylated at Ser 219, Thr 239, and Thr 241. Upon ER stress, eIF2α is phosphorylated at Ser 51 by phosphorylated PKR-like ER kinase and this inhibits global translation initiation, except for that of specific mRNAs, including activating transcription factor 4, that induce stress-responsive genes such as C/EBP homologous protein (CHOP). Hyper-O-GlcNAcylation induced by O-GlcNAcase inhibitor (thiamet-G) treatment or O-GlcNAc transferase (OGT) overexpression hindered phosphorylation of eIF2α at Ser 51. The level of O-GlcNAcylation of eIF2α was changed by dithiothreitol treatment dependent on its phosphorylation at Ser 51. Point mutation of the O-GlcNAcylation sites of eIF2α increased its phosphorylation at Ser 51 and CHOP expression and resulted in increased apoptosis upon ER stress. These results suggest that O-GlcNAcylation of eIF2α affects its phosphorylation at Ser 51 and influences CHOP-mediated cell death. This O-GlcNAcylation of eIF2α was reproduced in thiamet-G-injected mouse liver. In conclusion, proper regulation of O-GlcNAcylation and phosphorylation of eIF2α is important to maintain cellular homeostasis upon ER stress.
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Ogawa M, Sawaguchi S, Kawai T, Nadano D, Matsuda T, Yagi H, Kato K, Furukawa K, Okajima T. Impaired O-linked N-acetylglucosaminylation in the endoplasmic reticulum by mutated epidermal growth factor (EGF) domain-specific O-linked N-acetylglucosamine transferase found in Adams-Oliver syndrome. J Biol Chem 2014; 290:2137-49. [PMID: 25488668 DOI: 10.1074/jbc.m114.598821] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Epidermal growth factor (EGF) domain-specific O-linked N-acetylglucosamine (EOGT) is an endoplasmic reticulum (ER)-resident O-linked N-acetylglucosamine (O-GlcNAc) transferase that acts on EGF domain-containing proteins such as Notch receptors. Recently, mutations in EOGT have been reported in patients with Adams-Oliver syndrome (AOS). Here, we have characterized enzymatic properties of mouse EOGT and EOGT mutants associated with AOS. Simultaneous expression of EOGT with Notch1 EGF repeats in human embryonic kidney 293T (HEK293T) cells led to immunoreactivity with the CTD110.6 antibody in the ER. Consistent with the GlcNAc modification in the ER, the enzymatic properties of EOGT are distinct from those of Golgi-resident GlcNAc transferases; the pH optimum of EOGT ranges from 7.0 to 7.5, and the Km value for UDP N-acetylglucosamine (UDP-GlcNAc) is 25 μm. Despite the relatively low Km value for UDP-GlcNAc, EOGT-catalyzed GlcNAcylation depends on the hexosamine pathway, as revealed by the increased O-GlcNAcylation of Notch1 EGF repeats upon supplementation with hexosamine, suggesting differential regulation of the luminal UDP-GlcNAc concentration in the ER and Golgi. As compared with wild-type EOGT, O-GlcNAcylation in the ER is nearly abolished in HEK293T cells exogenously expressing EOGT variants associated with AOS. Introduction of the W207S mutation resulted in degradation of the protein via the ubiquitin-proteasome pathway, although the stability and ER localization of EOGT(R377Q) were not affected. Importantly, the interaction between UDP-GlcNAc and EOGT(R377Q) was impaired without adversely affecting the acceptor substrate interaction. These results suggest that impaired glycosyltransferase activity in mutant EOGT proteins and the consequent defective O-GlcNAcylation in the ER constitute the molecular basis for AOS.
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Affiliation(s)
- Mitsutaka Ogawa
- From the Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, the Department of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829
| | - Shogo Sawaguchi
- From the Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065
| | - Takami Kawai
- From the Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065
| | - Daita Nadano
- the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601
| | - Tsukasa Matsuda
- the Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601
| | - Hirokazu Yagi
- the Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, and
| | - Koichi Kato
- the Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, and the Institute for Molecular Science and Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama Myodaiji, Okazaki 444-8787, Japan
| | - Koichi Furukawa
- From the Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065
| | - Tetsuya Okajima
- From the Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065,
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