1
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Tanaka T, Nakano T, Hozumi Y, Martelli AM, Goto K. Regulation of p53 and NF-κB transactivation activities by DGKζ in catalytic activity-dependent and -independent manners. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118953. [PMID: 33450306 DOI: 10.1016/j.bbamcr.2021.118953] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/15/2020] [Accepted: 01/02/2021] [Indexed: 01/03/2023]
Abstract
Diacylglycerol kinase (DGK) constitutes a family of enzymes that phosphorylate diacylglycerol to phosphatidic acid (PA). These lipids serve as second messengers, thereby activating distinct downstream cascades and different cellular responses. Therefore, DG-to-PA conversion activity induces a phase transition of signaling pathways. One member of the family, DGKζ, is involved closely with stress responses. Morphological data showing that DGKζ localizes predominantly to the nucleus and that it shuttles between the nucleus and the cytoplasm implicate DGKζ in the regulation of transcription factors during stress responses. Tumor suppressor p53 and NF-κB are major stress-responsive transcription factors. They exert opposing effects on cellular pathophysiology. Herein, we summarize DGKζ catalytic activity-dependent and -independent regulatory mechanisms of p53 and NF-κB transactivation activities, including p53 degradation and NF-κB nuclear translocation. We also discuss how each component of DGKζ-interacting protein complex modulates the specificity and selectivity of target gene expression.
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Affiliation(s)
- Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
| | - Tomoyuki Nakano
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Yasukazu Hozumi
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Alberto M Martelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, via Irnerio 48, 40126 Bologna, Italy
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
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2
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Beyond Lipid Signaling: Pleiotropic Effects of Diacylglycerol Kinases in Cellular Signaling. Int J Mol Sci 2020; 21:ijms21186861. [PMID: 32962151 PMCID: PMC7554708 DOI: 10.3390/ijms21186861] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/11/2020] [Accepted: 09/16/2020] [Indexed: 12/13/2022] Open
Abstract
The diacylglycerol kinase family, which can attenuate diacylglycerol signaling and activate phosphatidic acid signaling, regulates various signaling transductions in the mammalian cells. Studies on the regulation of diacylglycerol and phosphatidic acid levels by various enzymes, the identification and characterization of various diacylglycerol and phosphatidic acid-regulated proteins, and the overlap of different diacylglycerol and phosphatidic acid metabolic and signaling processes have revealed the complex and non-redundant roles of diacylglycerol kinases in regulating multiple biochemical and biological networks. In this review article, we summarized recent progress in the complex and non-redundant roles of diacylglycerol kinases, which is expected to aid in restoring dysregulated biochemical and biological networks in various pathological conditions at the bed side.
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3
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Xie D, Zhang S, Chen P, Deng W, Pan Y, Xie J, Wang J, Liao B, Sleasman JW, Zhong XP. Negative control of diacylglycerol kinase ζ-mediated inhibition of T cell receptor signaling by nuclear sequestration in mice. Eur J Immunol 2020; 50:1729-1745. [PMID: 32525220 DOI: 10.1002/eji.201948442] [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: 10/17/2019] [Revised: 04/17/2020] [Accepted: 06/09/2020] [Indexed: 12/16/2022]
Abstract
Diacylglycerol kinases (DGKs) play important roles in restraining diacylglycerol (DAG)-mediated signaling. Within the DGK family, the ζ isoform appears to be the most important isoform in T cells for controlling their development and function. DGKζ has been demonstrated to regulate T cell maturation, activation, anergy, effector/memory differentiation, defense against microbial infection, and antitumor immunity. Given its critical functions, DGKζ function should be tightly regulated to ensure proper signal transduction; however, mechanisms that control DGKζ function are still poorly understood. We report here that DGKζ dynamically translocates from the cytosol into the nuclei in T cells after TCR stimulation. In mice, DGKζ mutant defective in nuclear localization displayed enhanced ability to inhibit TCR-induced DAG-mediated signaling in primary T cells, maturation of conventional αβT and iNKT cells, and activation of peripheral T cells compared with WT DGKζ. Our study reveals for the first time nuclear sequestration of DGKζ as a negative control mechanism to spatially restrain it from terminating DAG mediated signaling in T cells. Our data suggest that manipulation of DGKζ nucleus-cytosol shuttling as a novel strategy to modulate DGKζ activity and immune responses for treatment of autoimmune diseases and cancer.
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Affiliation(s)
- Danli Xie
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Shimeng Zhang
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Pengcheng Chen
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Wenhai Deng
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Yun Pan
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Jinhai Xie
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Jinli Wang
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Bryce Liao
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - John W Sleasman
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina
| | - Xiao-Ping Zhong
- Division of Allergy and Immunology, Department of Pediatrics-Allergy and Immunology, Duke University Medical Center, Durham, North Carolina.,Department of Immunology, Duke University Medical Center, Durham, North Carolina.,Duke Cancer Institute, Duke University Medical Center, Durham, North Carolina
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4
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Akimoto R, Tanaka T, Nakano T, Hozumi Y, Kawamae K, Goto K. DGKζ depletion attenuates HIF-1α induction and SIRT1 expression, but enhances TAK1-mediated AMPKα phosphorylation under hypoxia. Cell Signal 2020; 71:109618. [PMID: 32224048 DOI: 10.1016/j.cellsig.2020.109618] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/21/2020] [Accepted: 03/25/2020] [Indexed: 12/31/2022]
Abstract
Cells cope with environmental changes through various mechanisms. Pathways involving HIF-1, SIRT1, and AMPK play major roles in energy homeostasis under stress conditions. Diacylglycerol kinase (DGK) constitutes an enzyme family that catalyzes conversion of diacylglycerol to phosphatidic acid. We reported earlier that energy depletion such as ischemia induces proteasomal degradation of DGKζ before cell death, suggesting involvement of DGKζ in energy homeostasis. This study examines how DGKζ depletion affects the regulation of HIF-1α, SIRT1, and AMPKα. Under hypoxia DGKζ depletion attenuates HIF-1α induction and SIRT1 expression, which might render cells vulnerable to energy stress. However, DGKζ depletion engenders enhanced AMPKα phosphorylation by upstream kinase TAK1 and an increase in intracellular ATP levels. Results suggest that DGKζ exerts a suppressive effect on TAK1 activity in the AMPK activation mechanism, and that DGKζ depletion might engender dysregulation of the AMPK-mediated energy sensor system.
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Affiliation(s)
- Ryo Akimoto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan; Department of Anesthesiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
| | - Tomoyuki Nakano
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Yasukazu Hozumi
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Kaneyuki Kawamae
- Department of Anesthesiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
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5
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Baudier J, Deloulme JC, Shaw GS. The Zn 2+ and Ca 2+ -binding S100B and S100A1 proteins: beyond the myths. Biol Rev Camb Philos Soc 2020; 95:738-758. [PMID: 32027773 DOI: 10.1111/brv.12585] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 01/06/2020] [Accepted: 01/20/2020] [Indexed: 12/17/2022]
Abstract
The S100 genes encode a conserved group of 21 vertebrate-specific EF-hand calcium-binding proteins. Since their discovery in 1965, S100 proteins have remained enigmatic in terms of their cellular functions. In this review, we summarize the calcium- and zinc-binding properties of the dimeric S100B and S100A1 proteins and highlight data that shed new light on the extracellular and intracellular regulation and functions of S100B. We point out that S100B and S100A1 homodimers are not functionally interchangeable and that in a S100A1/S100B heterodimer, S100A1 acts as a negative regulator for the ability of S100B to bind Zn2+ . The Ca2+ and Zn2+ -dependent interactions of S100B with a wide array of proteins form the basis of its activities and have led to the derivation of some initial rules for S100B recognition of protein targets. However, recent findings have strongly suggested that these rules need to be revisited. Here, we describe a new consensus S100B binding motif present in intracellular and extracellular vertebrate-specific proteins and propose a new model for stable interactions of S100B dimers with full-length target proteins. A chaperone-associated function for intracellular S100B in adaptive cellular stress responses is also discussed. This review may help guide future studies on the functions of S100 proteins in general.
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Affiliation(s)
- Jacques Baudier
- Institut de Biologie du Développement de Marseille-UMR CNRS 7288, Aix Marseille Université, 13288, Marseille Cedex 9, France
| | - Jean Christophe Deloulme
- Grenoble Institut des Neurosciences, INSERM U1216, Université Grenoble Alpes, 38000, Grenoble, France
| | - Gary S Shaw
- Department of Biochemistry, University of Western Ontario, London, Ontario, N6A5C1, Canada
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6
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Tanaka K, Tanaka T, Nakano T, Hozumi Y, Yanagida M, Araki Y, Iwazaki K, Takagi M, Goto K. Knockdown of DEAD-box RNA helicase DDX5 selectively attenuates serine 311 phosphorylation of NF-κB p65 subunit and expression level of anti-apoptotic factor Bcl-2. Cell Signal 2020; 65:109428. [DOI: 10.1016/j.cellsig.2019.109428] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/26/2019] [Accepted: 09/26/2019] [Indexed: 10/25/2022]
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7
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Tanaka T, Hozumi Y, Martelli AM, Iino M, Goto K. Nucleosome assembly proteins NAP1L1 and NAP1L4 modulate p53 acetylation to regulate cell fate. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118560. [DOI: 10.1016/j.bbamcr.2019.118560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/27/2019] [Accepted: 09/12/2019] [Indexed: 02/08/2023]
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8
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Massart J, Zierath JR. Role of Diacylglycerol Kinases in Glucose and Energy Homeostasis. Trends Endocrinol Metab 2019; 30:603-617. [PMID: 31331711 DOI: 10.1016/j.tem.2019.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 01/22/2023]
Abstract
Diacylglycerol kinases (DGKs) catalyze a reaction that converts diacylglycerol (DAG) to phosphatidic acid (PA). DAG and PA act as intermediates of de novo lipid synthesis, cellular membrane constituents, and signaling molecules. DGK isoforms regulate a variety of intracellular processes by terminating DAG signaling and activating PA-mediated pathways. The ten DGK isoforms are unique, not only structurally, but also in tissue-specific expression profiles, subcellular localization, regulatory mechanisms, and DAG preferences, suggesting isoform-specific functions. DAG accumulation has been associated with insulin resistance; however, this concept is challenged by opposing roles of DGK isoforms in the development of type 2 diabetes and obesity despite elevated DAG levels. This review focuses on the tissue- and isoform-specific role of DGK in glucose and energy homeostasis.
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Affiliation(s)
- Julie Massart
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark.
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9
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Nakano T, Ogasawara S, Tanaka T, Hozumi Y, Sano M, Sayama Y, Yamada S, Kaneko MK, Kato Y, Goto K. DzMab-1: Anti-Human Diacylglycerol Kinaseζ Monoclonal Antibody for Immunocytochemistry. Monoclon Antib Immunodiagn Immunother 2019; 38:179-182. [DOI: 10.1089/mab.2019.0024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Tomoyuki Nakano
- Department of Anatomy and Cell Biology, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Satoshi Ogasawara
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Yasukazu Hozumi
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita, Japan
| | - Masato Sano
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yusuke Sayama
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Shinji Yamada
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Mika K. Kaneko
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yukinari Kato
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Japan
- New Industry Creation Hatchery Center, Tohoku University, Sendai, Japan
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University Faculty of Medicine, Yamagata, Japan
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10
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Gu X, Wan G, Chen N, Li J, Chen B, Tang Y, Gu W, Jin C, Meng J, Zhang P, Liu L, Yang Z, Lu C. DGKζ Plays Crucial Roles in the Proliferation and Tumorigenicity of Human glioblastoma. Int J Biol Sci 2019; 15:1872-1881. [PMID: 31523189 PMCID: PMC6743304 DOI: 10.7150/ijbs.35193] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/23/2019] [Indexed: 12/27/2022] Open
Abstract
Glioblastoma is one of the most malignant brain cancers in adults, and it is a fatal disease because of its untimely pathogenetic location detection, infiltrative growth, and unfavorable prognosis. Unfortunately, multimodal treatment with maximal safe resection, chemotherapy and radiation has not increased the survival rate of patients with glioblastoma. Gene- and molecular-targeted therapy is considered to be a promising anticancer strategy for glioblastoma. The identification of novel potential targets in glioblastoma is of high importance. In this study, we found that both the mRNA and protein levels of diacylglycerol kinase ζ (DGKζ) were significantly higher in glioblastoma tissues than in precancerous lesions. The silencing of DGKζ by lentivirus-delivered shRNA reduced glioblastoma cell proliferation and induced G0/G1 phase arrest. Moreover, knockdown of DGKζ expression in U251 cells markedly reduced in vitro colony formation and in vivo tumorigenic capability. Further study showed that DGKζ inhibition resulted in decreases in cyclin D1, p-AKT and p-mTOR. Moreover, the rescue or overexpression of DGKζ in glioblastoma cells demonstrated the oncogenic function of DGKζ. In conclusion, these studies suggest that the suppression of DGKζ may inhibit the tumor growth of glioblastoma cells with high DGKζ expression. Thus, DGKζ might be a potential therapeutic target in malignant glioblastoma.
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Affiliation(s)
- Xuefeng Gu
- Collaborative Research Center, Shanghai University of Medicine & Health Sciences, Shanghai, PR China.,College of Fundamental Medicine, Shanghai University of Medicine & Health Sciences, Shanghai, PR China.,Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Guoqing Wan
- Collaborative Research Center, Shanghai University of Medicine & Health Sciences, Shanghai, PR China.,Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Nianhong Chen
- Collaborative Research Center, Shanghai University of Medicine & Health Sciences, Shanghai, PR China.,Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Jinhong Li
- Department of Neurosurgery, Jiangmen Central Hospital, Jiangmen, Guangdong, PR China
| | - Bing Chen
- Department of Neurosurgery, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, PR China
| | - Yeling Tang
- Collaborative Research Center, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Wangxian Gu
- Collaborative Research Center, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Cuiting Jin
- Collaborative Research Center, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Jihong Meng
- Collaborative Research Center, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Peng Zhang
- College of Clinical Medicine, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Li Liu
- College of Fundamental Medicine, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Zhifang Yang
- College of Fundamental Medicine, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
| | - Changlian Lu
- Collaborative Research Center, Shanghai University of Medicine & Health Sciences, Shanghai, PR China.,Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, PR China
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11
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Expression and localization of diacylglycerol kinase ζ in guinea pig cochlea and its functional implication under noise-exposure stress conditions. Histochem Cell Biol 2019; 151:461-474. [PMID: 30963236 DOI: 10.1007/s00418-019-01781-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2019] [Indexed: 12/31/2022]
Abstract
Cochlear hair cells are essential for the mechanotransduction of hearing. Sensorineural hearing loss can be irreversible because hair cells have a minimal ability to repair or regenerate themselves once damaged. In order to develop therapeutic interventions to prevent hair cell loss, it is necessary to understand the signaling pathway operating in cochlear hair cells and its alteration upon damage. Diacylglycerol kinase (DGK) regulates intracellular signal transduction through phosphorylation of lipidic second messenger diacylglycerol. We have previously reported characteristic expression and localization patterns of DGKs in various organs under pathophysiological conditions. Nevertheless, little is known about morphological and functional aspects of this enzyme family in the cochlea. First RT-PCR analysis reveals predominant mRNA expression of DGKα, DGKε and DGKζ. Immunohistochemical analysis shows that DGKζ localizes to the nuclei of inner hair cells (IHCs), outer hair cells (OHCs), supporting cells and spiral ganglion neurons in guinea pig cochlea under normal conditions. It is well known that loud noise exposure induces cochlear damage, thereby resulting in hair cell loss. In particular, OHCs are highly vulnerable to noise exposure than IHCs. We found that after 1 week of noise exposure DGKζ translocates from the nucleus to the cytoplasm in damage-sensitive OHCs and gradually disappears thereafter. In sharp contrast, DGKζ remains to the nucleus in damage-resistant IHCs. These results suggest that DGKζ cytoplasmic translocation is well correlated with cellular damage under noise-exposure stress conditions and is involved in delayed cell death in cochlear outer hair cells.
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12
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NAP1L1 regulates NF-κB signaling pathway acting on anti-apoptotic Mcl-1 gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1759-1768. [DOI: 10.1016/j.bbamcr.2017.06.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 06/28/2017] [Accepted: 06/30/2017] [Indexed: 01/20/2023]
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13
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Baldanzi G, Bettio V, Malacarne V, Graziani A. Diacylglycerol Kinases: Shaping Diacylglycerol and Phosphatidic Acid Gradients to Control Cell Polarity. Front Cell Dev Biol 2016; 4:140. [PMID: 27965956 PMCID: PMC5126041 DOI: 10.3389/fcell.2016.00140] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 11/14/2016] [Indexed: 12/24/2022] Open
Abstract
Diacylglycerol kinases (DGKs) terminate diacylglycerol (DAG) signaling and promote phosphatidic acid (PA) production. Isoform specific regulation of DGKs activity and localization allows DGKs to shape the DAG and PA gradients. The capacity of DGKs to constrain the areas of DAG signaling is exemplified by their role in defining the contact interface between T cells and antigen presenting cells: the immune synapse. Upon T cell receptor engagement, both DGK α and ζ metabolize DAG at the immune synapse thus constraining DAG signaling. Interestingly, their activity and localization are not fully redundant because DGKζ activity metabolizes the bulk of DAG in the cell, whereas DGKα limits the DAG signaling area localizing specifically at the periphery of the immune synapse. When DGKs terminate DAG signaling, the local PA production defines a new signaling domain, where PA recruits and activates a second wave of effector proteins. The best-characterized example is the role of DGKs in protrusion elongation and cell migration. Indeed, upon growth factor stimulation, several DGK isoforms, such as α, ζ, and γ, are recruited and activated at the plasma membrane. Here, local PA production controls cell migration by finely modulating cytoskeletal remodeling and integrin recycling. Interestingly, DGK-produced PA also controls the localization and activity of key players in cell polarity such as aPKC, Par3, and integrin β1. Thus, T cell polarization and directional migration may be just two instances of the general contribution of DGKs to the definition of cell polarity by local specification of membrane identity signaling.
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Affiliation(s)
- Gianluca Baldanzi
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Institute for Research and Cure of Autoimmune DiseasesNovara, Italy
| | - Valentina Bettio
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Institute for Research and Cure of Autoimmune DiseasesNovara, Italy
| | - Valeria Malacarne
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Division of Experimental Oncology, School of Medicine, University Vita e Salute San RaffaeleMilan, Italy
| | - Andrea Graziani
- Department of Translational Medicine, University of Piemonte OrientaleNovara, Italy; Division of Experimental Oncology, School of Medicine, University Vita e Salute San RaffaeleMilan, Italy
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14
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Liu T, Yu B, Kakino M, Fujimoto H, Ando Y, Hakuno F, Takahashi SI. A novel IRS-1-associated protein, DGKζ regulates GLUT4 translocation in 3T3-L1 adipocytes. Sci Rep 2016; 6:35438. [PMID: 27739494 PMCID: PMC5064357 DOI: 10.1038/srep35438] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/29/2016] [Indexed: 12/19/2022] Open
Abstract
Insulin receptor substrates (IRSs) are major targets of insulin receptor tyrosine kinases. Here we identified diacylglycerol kinase zeta (DGKζ) as an IRS-1-associated protein, and examined roles of DGKζ in glucose transporter 4 (GLUT4) translocation to the plasma membrane. When DGKζ was knocked-down in 3T3-L1 adipocytes, insulin-induced GLUT4 translocation was inhibited without affecting other mediators of insulin-dependent signaling. Similarly, knockdown of phosphatidylinositol 4-phosphate 5-kinase 1α (PIP5K1α), which had been reported to interact with DGKζ, also inhibited insulin-induced GLUT4 translocation. Moreover, DGKζ interacted with IRS-1 without insulin stimulation, but insulin stimulation decreased this interaction. Over-expression of sDGKζ (short-form DGKζ), which competed out DGKζ from IRS-1, enhanced GLUT4 translocation without insulin stimulation. Taking these results together with the data showing that cellular PIP5K activity was correlated with GLUT4 translocation ability, we concluded that IRS-1-associated DGKζ prevents GLUT4 translocation in the absence of insulin and that the DGKζ dissociated from IRS-1 by insulin stimulation enhances GLUT4 translocation through PIP5K1α activity.
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Affiliation(s)
- TingYu Liu
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - BuChin Yu
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Mamoru Kakino
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Hitoshi Fujimoto
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Yasutoshi Ando
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Fumihiko Hakuno
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Shin-Ichiro Takahashi
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
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15
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So V, Jalan D, Lemaire M, Topham MK, Hatch GM, Epand RM. Diacylglycerol kinase epsilon suppresses expression of p53 and glycerol kinase in mouse embryo fibroblasts. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1993-1999. [PMID: 27713003 DOI: 10.1016/j.bbalip.2016.09.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/22/2016] [Accepted: 09/30/2016] [Indexed: 01/24/2023]
Abstract
The incorporation of glycerol into lipid was measured using SV40 transformed mouse embryo fibroblasts (MEFs) from either wild-type (WT) mice or from mice in which the epsilon isoform of diacylglycerol kinase (DGKε) was knocked out (DGKε-/-). We present an explanation for our finding that DGKε-/- MEFs exhibited greater uptake of 3H-glycerol into the cell and a greater incorporation into lipids compared with their WT counterparts, with no change in the relative amounts of various lipids between the DGKε-/- and WT MEFs. Glycerol kinase is more highly expressed in the DGKε-/- cells than in their WT counterparts. In addition, the activity of glycerol kinase is greater in the DGKε-/- cells than in their WT counterparts. Other substrates that enter the cell independent of glycerol kinase, such as pyruvate or acetate, are incorporated into lipid to the same extent between DGKε-/- and WT cell lines. We also show that expression of p53, a transcription factor that increases the synthesis of glycerol kinase, is increased in DGKε-/- MEFs in comparison to WT cells. We conclude that the increased incorporation of glycerol into lipids in DGKε-/- cells is a consequence of up-regulation of glycerol kinase and not a result of an increase in the rate of lipid synthesis. Furthermore, increased expression of the pro-survival gene, p53, in cells knocked out for DGKε suggests that cells over-expressing DGKε would have a greater propensity to become tumorigenic.
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Affiliation(s)
- Vincent So
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Divyanshi Jalan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Mathieu Lemaire
- Nephrology Division & Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Institute of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Matthew K Topham
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, United States
| | - Grant M Hatch
- Department of Pharmacology and Therapeutics, Center for Research and Treatment of Atherosclerosis, DREAM Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
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16
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Hozumi Y, Nakano T, Tanaka T, Goto K. Localization of diacylglycerol kinase ζ in rat pancreatic islet cells under normal and streptozotocin-induced stress conditions . ACTA ACUST UNITED AC 2016. [DOI: 10.1679/aohc.76.23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yasukazu Hozumi
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine,
| | - Tomoyuki Nakano
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine,
| | - Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine,
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine,
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17
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Tanaka T, Tsuchiya R, Hozumi Y, Nakano T, Okada M, Goto K. Reciprocal regulation of p53 and NF-κB by diacylglycerol kinase ζ. Adv Biol Regul 2015; 60:15-21. [PMID: 26521214 DOI: 10.1016/j.jbior.2015.09.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 09/30/2015] [Accepted: 09/30/2015] [Indexed: 11/29/2022]
Abstract
Diacylglycerol kinase (DGK) participates in lipid mediated-signal transduction. It phosphorylates diacylglycerol (DG) to phosphatidic acid (PA), thereby regulating the balanced control of these second messenger actions. Previous reports have described that one DGK family, DGKζ, is closely involved in stress responses under various conditions. Cellular stress response, a physiological process enabling cells to cope with an altered environment, is finely tuned through various signaling cascades and their molecular crosstalk. The major components of stress response are p53 and NF-κB. p53 generally serves as a proapoptotic transcriptional factor, whereas NF-κB promotes resistance to programmed cell death under most circumstances. Recent studies have suggested that DGKζ facilitates p53 degradation in cytoplasm through ubiquitin proteasome system and that DGKζ deletion upregulates p53 protein levels under basal and DNA-damage conditions. Counter-intuitively, however, DGKζ deletion suppresses p53 transcriptional activity despite increased p53 levels. In contrast, DGKζ knockdown engenders enhancement of NF-κB pathway in response to cytokines such as TNF-α and IL-1β. In response to these cytokines, DGKζ downregulation accelerates phosphorylation of the p65 subunit and its nuclear translocation, thereby enhancing NF-κB transcriptional activity. Furthermore, DGKζ deficiency is shown to promote increased association of p65 subunit with the transcriptional cofactor CBP. It is particularly interesting that this association is observed even under basal conditions in the absence of stimulation. These findings suggest that DGKζ plays a role in sequestration of the limiting pool of CBP/p300 between the NF-κB p65 subunit and p53, and that DGKζ downregulation shifts CBP/p300 toward the NF-κB subunit to regulate reciprocally antagonistic phenotypes of these transcription factors.
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Affiliation(s)
- Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iida-Nishi 2-2-2, Yamagata 990-9585, Japan.
| | - Rieko Tsuchiya
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iida-Nishi 2-2-2, Yamagata 990-9585, Japan
| | - Yasukazu Hozumi
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iida-Nishi 2-2-2, Yamagata 990-9585, Japan
| | - Tomoyuki Nakano
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iida-Nishi 2-2-2, Yamagata 990-9585, Japan
| | - Masashi Okada
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iida-Nishi 2-2-2, Yamagata 990-9585, Japan
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Iida-Nishi 2-2-2, Yamagata 990-9585, Japan.
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18
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Loss of Diacylglycerol Kinase-Ζ Inhibits Cell Proliferation and Survival in Human Gliomas. Mol Neurobiol 2015; 53:5425-35. [DOI: 10.1007/s12035-015-9419-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 09/02/2015] [Indexed: 12/25/2022]
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19
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Abdullah A, Sane S, Freeling JL, Wang H, Zhang D, Rezvani K. Nucleocytoplasmic Translocation of UBXN2A Is Required for Apoptosis during DNA Damage Stresses in Colon Cancer Cells. J Cancer 2015; 6:1066-78. [PMID: 26516353 PMCID: PMC4615341 DOI: 10.7150/jca.12134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 08/02/2015] [Indexed: 12/12/2022] Open
Abstract
The subcellular localization, expression level, and activity of anti-cancer proteins alter in response to intrinsic and extrinsic cellular stresses to reverse tumor progression. The purpose of this study is to determine whether UBXN2A, an activator of the p53 tumor suppressor protein, has different subcellular compartmentalization in response to the stress of DNA damage. We measured trafficking of the UBXN2A protein in response to two different DNA damage stresses, UVB irradiation and the genotoxic agent Etoposide, in colon cancer cell lines. Using a cytosol-nuclear fractionation technique followed by western blot and immunofluorescence staining, we monitored and quantitated UBXN2A and p53 proteins as well as p53's downstream apoptotic pathway. We showed that the anti-cancer protein UBXN2A acts in the early phase of cell response to two different DNA damage stresses, being induced to translocate into the cytoplasm in a dose- and time-dependent manner. UVB-induced cytoplasmic UBXN2A binds to mortalin-2 (mot-2), a known oncoprotein in colon tumors. UVB-dependent upregulation of UBXN2A in the cytoplasm decreases p53 binding to mot-2 and activates apoptotic events in colon cancer cells. In contrast, the shRNA-mediated depletion of UBXN2A leads to significant reduction in apoptosis in colon cancer cells exposed to UVB and Etoposide. Leptomycin B (LMB), which was able to block UBXN2A nuclear export following Etoposide treatment, sustained p53-mot-2 interaction and had partially antagonistic effects with Etoposide on cell apoptosis. The present study shows that nucleocytoplasmic translocation of UBXN2A in response to stresses is necessary for its anti-cancer function in the cytoplasm. In addition, LMB-dependent suppression of UBXN2A's translocation to the cytoplasm upon stress allows the presence of an active mot-2 oncoprotein in the cytoplasm, resulting in p53 sequestration as well as activation of other mot-2-dependent growth promoting pathways.
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Affiliation(s)
- Ammara Abdullah
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
| | - Sanam Sane
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
| | - Jessica L Freeling
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
| | - Hongmin Wang
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
| | - Dong Zhang
- 2. Department of Biomedical Sciences, College of Osteopathic Medicine, New York Institute of Technology, Northern Blvd., P.O. Box 8000, Old Westbury, NY 11568-8000, USA
| | - Khosrow Rezvani
- 1. Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, 414 E. Clark Street, Lee Medical Building, Vermillion, SD 57069, USA
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20
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Hipkaeo W, Chomphoo S, Pakkarato S, Sakaew W, Sawatpanich T, Hozumi Y, Polsan Y, Hipkaeo D, Goto K, Kondo H. Selective localization of diacylglycerol kinase (DGK)ζ in the terminal tubule cells in the submandibular glands of early postnatal mice. Histochem Cell Biol 2015; 144:185-93. [PMID: 25952157 DOI: 10.1007/s00418-015-1328-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2015] [Indexed: 12/16/2022]
Abstract
The present immunohistochemical study was attempted to localize in the submandibular glands of mice at various postnatal stages a diacylglycerol kinase (DGK) isoform termed DGKζ which is characterized by a nuclear localization signal and a nuclear export signal. This attempt was based on following facts: the continuous postnatal differentiation of glandular cells in the rodent submandibular gland, the regulatory role of DGK in the activity of protein kinase C (PKC) through attenuation of diacylglycerol (DAG), and the possible involvement of PKC in various cellular activities including the saliva secretion as well as the cell differentiation. As a result, a selective localization of immunoreactivity for DGKζ was detected in terminal tubule (TT) cells which comprise a majority of the newborn acinar structure and differentiate into the intercalated duct cells and/or the acinar cells. The immunoreactivity was deposited in portions of the cytoplasm lateral and basal to the nucleus, but not in the nuclei themselves. Although the immunoreactive TT cells remained until later stages in female specimen than in male, they eventually disappeared in both sexes by young adult stages. The present finding suggests that the regulatory involvement of DGKζ in PKC functions via control of DAG is exerted in the differentiation of the TT cells. In addition, another possible involvement of DGKζ in the regulation of secretion of the TT cells as well as its functional significance of its nuclear localization in the submandibular ganglion cells was also discussed.
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Affiliation(s)
- Wiphawi Hipkaeo
- Nanomorphology-Based Apply Research Group and Electron Microscopy Unit, Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand,
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21
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Yang F, Petsalaki E, Rolland T, Hill DE, Vidal M, Roth FP. Protein domain-level landscape of cancer-type-specific somatic mutations. PLoS Comput Biol 2015; 11:e1004147. [PMID: 25794154 PMCID: PMC4368709 DOI: 10.1371/journal.pcbi.1004147] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 01/22/2015] [Indexed: 11/18/2022] Open
Abstract
Identifying driver mutations and their functional consequences is critical to our understanding of cancer. Towards this goal, and because domains are the functional units of a protein, we explored the protein domain-level landscape of cancer-type-specific somatic mutations. Specifically, we systematically examined tumor genomes from 21 cancer types to identify domains with high mutational density in specific tissues, the positions of mutational hotspots within these domains, and the functional and structural context where possible. While hotspots corresponding to specific gain-of-function mutations are expected for oncoproteins, we found that tumor suppressor proteins also exhibit strong biases toward being mutated in particular domains. Within domains, however, we observed the expected patterns of mutation, with recurrently mutated positions for oncogenes and evenly distributed mutations for tumor suppressors. For example, we identified both known and new endometrial cancer hotspots in the tyrosine kinase domain of the FGFR2 protein, one of which is also a hotspot in breast cancer, and found new two hotspots in the Immunoglobulin I-set domain in colon cancer. Thus, to prioritize cancer mutations for further functional studies aimed at more precise cancer treatments, we have systematically correlated mutations and cancer types at the protein domain level.
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Affiliation(s)
- Fan Yang
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
| | - Evangelia Petsalaki
- Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
| | - Thomas Rolland
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David E. Hill
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Marc Vidal
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Frederick P. Roth
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Canadian Institute for Advanced Research, Toronto, Ontario, Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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22
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Tsuchiya R, Tanaka T, Hozumi Y, Nakano T, Okada M, Topham MK, Iino M, Goto K. Downregulation of diacylglycerol kinase ζ enhances activation of cytokine-induced NF-κB signaling pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:361-9. [PMID: 25450975 DOI: 10.1016/j.bbamcr.2014.11.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 10/31/2014] [Accepted: 11/10/2014] [Indexed: 01/06/2023]
Abstract
The transcription factor NF-κB family serves as a key component of many pathophysiological events such as innate and adaptive immune response, inflammation, apoptosis, and oncogenesis. Various cell signals trigger activation of the regulatory mechanisms of NF-κB, resulting in its nuclear translocation and transcriptional initiation. The diacylglycerol kinase (DGK) family, a lipid second messenger-metabolizing enzyme in phosphoinositide signaling, is shown to regulate widely various cellular processes. Results of recent studies suggest that one family member, DGKζ, is closely involved in immune and inflammatory responses. Nevertheless, little is known about the regulatory mechanism of DGKζ on NF-κB pathway in cytokine-induced inflammatory signaling. This study shows that siRNA-mediated DGKζ knockdown in HeLa cells facilitates degradation of IκB, followed by nuclear translocation of NF-κB p65 subunit. In addition, DGKζ-deficient MEFs show upregulation of p65 subunit phosphorylation at Serine 468 and 536 and its interaction with CBP transcriptional coactivator upon TNF-α stimulation. These modifications of p65 subunit might engender enhanced NF-κB transcriptional reporter assay of DGKζ knockdown cells. These findings provide further insight into the regulatory mechanisms of cytokine-induced NF-κB activation.
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Affiliation(s)
- Rieko Tsuchiya
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan; Department of Dentistry, Oral and Maxillofacial Plastic and Reconstructive Surgery, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Yasukazu Hozumi
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Tomoyuki Nakano
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Masashi Okada
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Matthew K Topham
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Mitsuyoshi Iino
- Department of Dentistry, Oral and Maxillofacial Plastic and Reconstructive Surgery, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
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23
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Tanaka T, Iino M, Goto K. Knockdown of Sec8 enhances the binding affinity of c-Jun N-terminal kinase (JNK)-interacting protein 4 for mitogen-activated protein kinase kinase 4 (MKK4) and suppresses the phosphorylation of MKK4, p38, and JNK, thereby inhibiting apoptosis. FEBS J 2014; 281:5237-50. [PMID: 25244576 DOI: 10.1111/febs.13063] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 09/15/2014] [Accepted: 09/18/2014] [Indexed: 01/19/2023]
Abstract
The exocyst complex, also called the Sec6/8 complex, is important for targeting exocytic vesicles to specific docking sites on the plasma membrane in yeast and mammalian cells. In addition to these original findings, recent results of studies suggest that Sec8 is also involved in oncogenesis, although the functional implications of Sec8 in cancer cells are not well understood. c-Jun N-terminal kinase-interacting protein 4 (JIP4) is a scaffold protein that plays a crucial role in the regulation of mitogen-activated protein kinase (MAPK) signaling cascades. The present study examined how Sec8 is involved in JIP4-mediated MAPK signaling under apoptotic conditions. It was found that Sec8 binds to and regulates JIP4, and that knockdown of Sec8 enhances the binding of JIP4 to MAPK kinase 4, thereby decreasing the phosphorylation of MAPK kinase 4, JNK, and p38. These results raise the possibility that Sec8 serves as an important regulator of MAPK signaling cascades.
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Affiliation(s)
- Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Japan; Department of Dentistry, Oral and Maxillofacial Surgery, Plastic and Reconstructive Surgery, Yamagata University School of Medicine, Japan
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24
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Matsui H, Hozumi Y, Tanaka T, Okada M, Nakano T, Suzuki Y, Iseki K, Kakehata S, Topham MK, Goto K. Role of the N-terminal hydrophobic residues of DGKε in targeting the endoplasmic reticulum. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1842:1440-50. [PMID: 25048194 DOI: 10.1016/j.bbalip.2014.07.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/24/2014] [Accepted: 07/09/2014] [Indexed: 10/25/2022]
Abstract
The endoplasmic reticulum (ER), comprised of an interconnected membrane network, is a site of phospholipid and protein synthesis. The diacylglycerol kinase (DGK) enzyme family catalyzes phosphorylation of diacylglycerol to phosphatidic acid. Both of these lipids are known not only to serve as second messengers but also to represent intermediate precursors of lipids of various kinds. The DGK family is targeted to distinct subcellular sites in cDNA-transfected and native cells. Of DGKs, DGKε localizes primarily to the ER, suggesting that this isozyme plays a role in this organelle. Using experiments with various deletion and substitution mutants, this study examined the molecular mechanism of how DGKε is targeted to the ER. Results demonstrate that the N-terminal hydrophobic sequence 20-40 plays a necessary role in targeting of DGKε to the ER. This hydrophobic amino acid segment is predicted to adopt an α-helix structure, in which Leu22, L25, and L29 are present in mutual proximity, forming a hydrophobic patch. When these hydrophobic Leu residues were replaced with hydrophilic amino acid Gln, the mutant fragment designated DGKε (20-40/L22Q,L25Q,L29Q) exhibits diffuse distribution in the cytoplasm. Moreover, full-length DGKε containing these substitutions, DGKε (L22Q,L25Q,L29Q), is shown to distribute diffusely in the cytoplasm. These results indicate that the N-terminal hydrophobic residues play a key role in DGKε targeting to the ER membrane. Functionally, knockdown or deletion of DGKε affects the unfolding protein response pathways, thereby rendering the cells susceptible to apoptosis, to some degree, under ER stress conditions.
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Affiliation(s)
- Hirooki Matsui
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan; Department of Otolaryngology, Head and Neck Surgery, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Yasukazu Hozumi
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Toshiaki Tanaka
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Masashi Okada
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Tomoyuki Nakano
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Yusuke Suzuki
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan; Department of Otolaryngology, Head and Neck Surgery, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Ken Iseki
- Department of Emergency and Critical Care Medicine, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Seiji Kakehata
- Department of Otolaryngology, Head and Neck Surgery, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Matthew K Topham
- Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Kaoru Goto
- Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
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25
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Cellular expression and localization of DGKζ-interacting NAP1-like proteins in the brain and functional implications under hypoxic stress. Histochem Cell Biol 2014; 142:461-71. [DOI: 10.1007/s00418-014-1226-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2014] [Indexed: 11/27/2022]
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