1
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Yamagishi R, Kamachi F, Nakamura M, Yamazaki S, Kamiya T, Takasugi M, Cheng Y, Nonaka Y, Yukawa-Muto Y, Thuy LTT, Harada Y, Arai T, Loo TM, Yoshimoto S, Ando T, Nakajima M, Taguchi H, Ishikawa T, Akiba H, Miyake S, Kubo M, Iwakura Y, Fukuda S, Chen WY, Kawada N, Rudensky A, Nakae S, Hara E, Ohtani N. Gasdermin D-mediated release of IL-33 from senescent hepatic stellate cells promotes obesity-associated hepatocellular carcinoma. Sci Immunol 2022; 7:eabl7209. [PMID: 35749514 DOI: 10.1126/sciimmunol.abl7209] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Long-term senescent cells exhibit a secretome termed the senescence-associated secretory phenotype (SASP). Although the mechanisms of SASP factor induction have been intensively studied, the release mechanism and how SASP factors influence tumorigenesis in the biological context remain unclear. In this study, using a mouse model of obesity-induced hepatocellular carcinoma (HCC), we identified the release mechanism of SASP factors, which include interleukin-1β (IL-1β)- and IL-1β-dependent IL-33, from senescent hepatic stellate cells (HSCs) via gasdermin D (GSDMD) amino-terminal-mediated pore. We found that IL-33 was highly induced in senescent HSCs in an IL-1β-dependent manner in the tumor microenvironment. The release of both IL-33 and IL-1β was triggered by lipoteichoic acid (LTA), a cell wall component of gut microbiota that was transferred and accumulated in the liver tissue of high-fat diet-fed mice, and the release of these factors was mediated through cell membrane pores formed by the GSDMD amino terminus, which was cleaved by LTA-induced caspase-11. We demonstrated that IL-33 release from HSCs promoted HCC development via the activation of ST2-positive Treg cells in the liver tumor microenvironment. The accumulation of GSDMD amino terminus was also detected in HSCs from human NASH-associated HCC patients, suggesting that similar mechanism could be involved in a certain type of human HCC. These results uncover a release mechanism for SASP factors from sensitized senescent HSCs in the tumor microenvironment, thereby facilitating obesity-associated HCC progression. Furthermore, our findings highlight the therapeutic potential of inhibitors of GSDMD-mediated pore formation for HCC treatment.
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Affiliation(s)
- Ryota Yamagishi
- Department of Pathophysiology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University)
| | - Fumitaka Kamachi
- Department of Pathophysiology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University).,Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Masaru Nakamura
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Shota Yamazaki
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Tomonori Kamiya
- Department of Pathophysiology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University)
| | - Masaki Takasugi
- Department of Pathophysiology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University)
| | - Yi Cheng
- Department of Pathophysiology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University)
| | - Yoshiki Nonaka
- Department of Pathophysiology, Osaka City University, Graduate School of Medicine, Osaka, Japan
| | - Yoshimi Yukawa-Muto
- Department of Pathophysiology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University).,Department of Hepatology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University)
| | - Le Thi Thanh Thuy
- Department of Hepatology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University)
| | - Yohsuke Harada
- Laboratory of Pharmaceutical Immunology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Tatsuya Arai
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Tze Mun Loo
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan.,Cancer Institute, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan
| | - Shin Yoshimoto
- Cancer Institute, Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan
| | - Tatsuya Ando
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Masahiro Nakajima
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Hayao Taguchi
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Takamasa Ishikawa
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Hisaya Akiba
- Department of Immunology, Juntendo University School of Medicine, Tokyo, Japan
| | - Sachiko Miyake
- Department of Immunology, Juntendo University School of Medicine, Tokyo, Japan
| | - Masato Kubo
- Division of Molecular Pathology, Research Institute for Biomedical Science, Tokyo University of Science, Noda, Chiba, Japan.,Laboratory for Cytokine Regulation, Research Center for Integrative Medical Science (IMS), RIKEN Yokohama Institute, Yokohama, Kanagawa, Japan
| | - Yoichiro Iwakura
- Center for Animal Disease Models, Research Institute for Biomedical Sciences, Tokyo University of Science, Noda, Chiba, Japan
| | - Shinji Fukuda
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan.,Gut Environmental Design Group, Kanagawa Institute of Industrial Science and Technology, Kawasaki, Kanagawa, Japan.,Transborder Medical Research Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Wei-Yu Chen
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.,Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Norifumi Kawada
- Department of Hepatology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University)
| | - Alexander Rudensky
- Howard Hughes Medical Institute and Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Susumu Nakae
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Saitama, Japan
| | - Eiji Hara
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.,Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, Japan.,Center for Infectious Disease Education and Research (CiDER), Osaka University, Suita, Japan
| | - Naoko Ohtani
- Department of Pathophysiology, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan (formerly, Osaka City University).,Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan.,AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
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2
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Amine H, Ripin N, Sharma S, Stoecklin G, Allain FH, Séraphin B, Mauxion F. A conserved motif in human BTG1 and BTG2 proteins mediates interaction with the poly(A) binding protein PABPC1 to stimulate mRNA deadenylation. RNA Biol 2021; 18:2450-2465. [PMID: 34060423 PMCID: PMC8632095 DOI: 10.1080/15476286.2021.1925476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Antiproliferative BTG/Tob proteins interact directly with the CAF1 deadenylase subunit of the CCR4-NOT complex. This binding requires the presence of two conserved motifs, boxA and boxB, characteristic of the BTG/Tob APRO domain. Consistently, these proteins were shown to stimulate mRNA deadenylation and decay in several instances. Two members of the family, BTG1 and BTG2, were reported further to associate with the protein arginine methyltransferase PRMT1 through a motif, boxC, conserved only in this subset of proteins. We recently demonstrated that BTG1 and BTG2 also contact the first RRM domain of the cytoplasmic poly(A) binding protein PABPC1. To decipher the mode of interaction of BTG1 and BTG2 with partners, we performed nuclear magnetic resonance experiments as well as mutational and biochemical analyses. Our data demonstrate that, in the context of an APRO domain, the boxC motif is necessary and sufficient to allow interaction with PABPC1 but, unexpectedly, that it is not required for BTG2 association with PRMT1. We show further that the presence of a boxC motif in an APRO domain endows it with the ability to stimulate deadenylation in cellulo and in vitro. Overall, our results identify the molecular interface allowing BTG1 and BTG2 to activate deadenylation, a process recently shown to be necessary for maintaining T-cell quiescence.
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Affiliation(s)
- Hamza Amine
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Centre National de Recherche Scientifique (CNRS) UMR 7104, Illkirch, France.,Institut National de Santé et de Recherche Médicale (INSERM) U1258, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Nina Ripin
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zürich, Switzerland
| | - Sahil Sharma
- Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,German Cancer Research Center (DKFZ)-ZMBH Alliance, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Georg Stoecklin
- Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,German Cancer Research Center (DKFZ)-ZMBH Alliance, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Frédéric H Allain
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zürich, Switzerland.,Department of Biology, Institute of Biochemistry, ETH Zürich, Switzerland
| | - Bertrand Séraphin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Centre National de Recherche Scientifique (CNRS) UMR 7104, Illkirch, France.,Institut National de Santé et de Recherche Médicale (INSERM) U1258, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Fabienne Mauxion
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Centre National de Recherche Scientifique (CNRS) UMR 7104, Illkirch, France.,Institut National de Santé et de Recherche Médicale (INSERM) U1258, Illkirch, France.,Université de Strasbourg, Illkirch, France
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3
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Inagaki H, Hosoda N, Hoshino SI. DDX6 is a positive regulator of Ataxin-2/PAPD4 cytoplasmic polyadenylation machinery. Biochem Biophys Res Commun 2021; 553:9-16. [PMID: 33756349 DOI: 10.1016/j.bbrc.2021.03.066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/12/2021] [Indexed: 12/20/2022]
Abstract
The RNA-binding protein Ataxin-2 regulates translation and mRNA stability through cytoplasmic polyadenylation of the targets. Here we newly identified DDX6 as a positive regulator of the cytoplasmic polyadenylation. Analysis of Ataxin-2 interactome using LC-MS/MS revealed prominent interaction with the DEAD-box RNA helicase DDX6. DDX6 interacted with components of the Ataxin-2 polyadenylation machinery; Ataxin-2, PABPC1 and PAPD4. As in the case for Ataxin-2 downregulation, DDX6 downregulation led to an increase in Ataxin-2 target mRNAs with short poly(A) tails as well as a reduction in their protein expression. In contrast, Ataxin-2 target mRNAs with short poly(A) tails were decreased by the overexpression of Ataxin-2, which was compromised by the DDX6 downregulation. However, polyadenylation induced by Ataxin-2 tethering was not affected by the DDX6 downregulation. Taken together, these results suggest that DDX6 positively regulates Ataxin-2-induced cytoplasmic polyadenylation to maintain poly(A) tail length of the Ataxin-2 targets provably through accelerating binding of Ataxin-2 to the target mRNAs.
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Affiliation(s)
- Hiroto Inagaki
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Shin-Ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan.
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4
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Inagaki H, Hosoda N, Tsuiji H, Hoshino SI. Direct evidence that Ataxin-2 is a translational activator mediating cytoplasmic polyadenylation. J Biol Chem 2020; 295:15810-15825. [PMID: 32989052 DOI: 10.1074/jbc.ra120.013835] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 09/13/2020] [Indexed: 12/27/2022] Open
Abstract
The RNA-binding protein Ataxin-2 binds to and stabilizes a number of mRNA sequences, including that of the transactive response DNA-binding protein of 43 kDa (TDP-43). Ataxin-2 is additionally involved in several processes requiring translation, such as germline formation, long-term habituation, and circadian rhythm formation. However, it has yet to be unambiguously demonstrated that Ataxin-2 is actually involved in activating the translation of its target mRNAs. Here we provide direct evidence from a polysome profile analysis showing that Ataxin-2 enhances translation of target mRNAs. Our recently established method for transcriptional pulse-chase analysis under conditions of suppressing deadenylation revealed that Ataxin-2 promotes post-transcriptional polyadenylation of the target mRNAs. Furthermore, Ataxin-2 binds to a poly(A)-binding protein PABPC1 and a noncanonical poly(A) polymerase PAPD4 via its intrinsically disordered region (amino acids 906-1095) to recruit PAPD4 to the targets. Post-transcriptional polyadenylation by Ataxin-2 explains not only how it activates translation but also how it stabilizes target mRNAs, including TDP-43 mRNA. Ataxin-2 is known to be a potent modifier of TDP-43 proteinopathies and to play a causative role in the neurodegenerative disease spinocerebellar ataxia type 2, so these findings suggest that Ataxin-2-induced cytoplasmic polyadenylation and activation of translation might impact neurodegeneration (i.e. TDP-43 proteinopathies), and this process could be a therapeutic target for Ataxin-2-related neurodegenerative disorders.
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Affiliation(s)
- Hiroto Inagaki
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Hitomi Tsuiji
- Department of Biomedical Science, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Shin-Ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
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5
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ABCE1 Acts as a Positive Regulator of Exogenous RNA Decay. Viruses 2020; 12:v12020174. [PMID: 32033097 PMCID: PMC7077301 DOI: 10.3390/v12020174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/14/2020] [Accepted: 02/03/2020] [Indexed: 11/17/2022] Open
Abstract
The 2'-5'-oligoadenylate synthetase (OAS)/RNase L system protects hosts against pathogenic viruses through cleavage of the exogenous single-stranded RNA. In this system, an evolutionally conserved RNA quality control factor Dom34 (known as Pelota (Pelo) in higher eukaryotes) forms a surveillance complex with RNase L to recognize and eliminate the exogenous RNA in a manner dependent on translation. Here, we newly identified that ATP-binding cassette sub-family E member 1 (ABCE1), which is also known as RNase L inhibitor (RLI), is involved in the regulation of exogenous RNA decay. ABCE1 directly binds to form a complex with RNase L and accelerates RNase L dimer formation in the absence of 2'-5' oligoadenylates (2-5A). Depletion of ABCE1 represses 2-5A-induced RNase L activation and stabilizes exogenous RNA to a level comparable to that seen in RNase L depletion. The increased half-life of the RNA by the single depletion of either protein is not significantly affected by the double depletion of both proteins, suggesting that RNase L and ABCE1 act together to eliminate exogenous RNA. Our results indicate that ABCE1 functions as a positive regulator of exogenous RNA decay rather than an inhibitor of RNase L.
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6
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Nogimori T, Nishiura K, Kawashima S, Nagai T, Oishi Y, Hosoda N, Imataka H, Kitamura Y, Kitade Y, Hoshino SI. Dom34 mediates targeting of exogenous RNA in the antiviral OAS/RNase L pathway. Nucleic Acids Res 2019; 47:432-449. [PMID: 30395302 PMCID: PMC6326797 DOI: 10.1093/nar/gky1087] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/19/2018] [Indexed: 11/21/2022] Open
Abstract
The 2′-5′-oligoadenylate synthetase (OAS)/RNase L pathway is an innate immune system that protects hosts against pathogenic viruses and bacteria through cleavage of exogenous single-stranded RNA; however, this system's selective targeting mechanism remains unclear. Here, we identified an mRNA quality control factor Dom34 as a novel restriction factor for a positive-sense single-stranded RNA virus. Downregulation of Dom34 and RNase L increases viral replication, as well as half-life of the viral RNA. Dom34 directly binds RNase L to form a surveillance complex to recognize and eliminate the exogenous RNA in a manner dependent on translation. Interestingly, the feature detected by the surveillance complex is not the specific sequence of the viral RNA but the ‘exogenous nature’ of the RNA. We propose the following model for the selective targeting of exogenous RNA; OAS3 activated by the exogenous RNA releases 2′-5′-oligoadenylates (2–5A), which in turn converts latent RNase L to an active dimer. This accelerates formation of the Dom34-RNase L surveillance complex, and its selective localization to the ribosome on the exogenous RNA, thereby promoting degradation of the RNA. Our findings reveal that the selective targeting of exogenous RNA in antiviral defense occurs via a mechanism similar to that in the degradation of aberrant transcripts in RNA quality control.
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Affiliation(s)
- Takuto Nogimori
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Kyutatsu Nishiura
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Sho Kawashima
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Takahiro Nagai
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Yuka Oishi
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Hiroaki Imataka
- Department of Materials Science and Chemistry and Molecular Nanotechnology Research Center, Graduate School of Engineering, University of Hyogo, Himeji 671-2201, Japan
| | - Yoshiaki Kitamura
- Department of Biomolecular Science, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Yukio Kitade
- Department of Biomolecular Science, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Shin-Ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
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7
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Fukushima M, Hosoda N, Chifu K, Hoshino SI. TDP-43 accelerates deadenylation of target mRNAs by recruiting Caf1 deadenylase. FEBS Lett 2019; 593:277-287. [PMID: 30520513 DOI: 10.1002/1873-3468.13310] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/08/2018] [Accepted: 11/12/2018] [Indexed: 12/14/2022]
Abstract
TAR DNA-binding protein 43 (TDP-43) is an RNA-binding protein, whose loss-of-function mutation causes amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration. Recent studies demonstrated that TDP-43 binds to the 3' untranslated region (UTR) of target mRNAs to promote mRNA instability. Here, we show that TDP-43 recruits Caf1 deadenylase to mRNA targets and accelerates their deadenylation. Tethering TDP-43 to the mRNA 3'UTR recapitulates destabilization of the mRNA, and TDP-43 accelerates their deadenylation. This accelerated deadenylation is inhibited by a dominant negative mutant of Caf1. We find that TDP-43 physically interacts with Caf1. In addition, we provide evidence that TDP-43 regulates poly(A) tail length of endogenous Progranulin (GRN) mRNA. These results may shed light on the link between dysregulation of TDP-43-mediated mRNA deadenylation and pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Makoto Fukushima
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan
| | - Kotaro Chifu
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan
| | - Shin-Ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan
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8
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Sawazaki R, Imai S, Yokogawa M, Hosoda N, Hoshino SI, Mio M, Mio K, Shimada I, Osawa M. Characterization of the multimeric structure of poly(A)-binding protein on a poly(A) tail. Sci Rep 2018; 8:1455. [PMID: 29362417 PMCID: PMC5780489 DOI: 10.1038/s41598-018-19659-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 01/05/2018] [Indexed: 11/24/2022] Open
Abstract
Eukaryotic mature mRNAs possess a poly adenylate tail (poly(A)), to which multiple molecules of poly(A)-binding protein C1 (PABPC1) bind. PABPC1 regulates translation and mRNA metabolism by binding to regulatory proteins. To understand functional mechanism of the regulatory proteins, it is necessary to reveal how multiple molecules of PABPC1 exist on poly(A). Here, we characterize the structure of the multiple molecules of PABPC1 on poly(A), by using transmission electron microscopy (TEM), chemical cross-linking, and NMR spectroscopy. The TEM images and chemical cross-linking results indicate that multiple PABPC1 molecules form a wormlike structure in the PABPC1-poly(A) complex, in which the PABPC1 molecules are linearly arrayed. NMR and cross-linking analyses indicate that PABPC1 forms a multimer by binding to the neighbouring PABPC1 molecules via interactions between the RNA recognition motif (RRM) 2 in one molecule and the middle portion of the linker region of another molecule. A PABPC1 mutant lacking the interaction site in the linker, which possesses an impaired ability to form the multimer, reduced the in vitro translation activity, suggesting the importance of PABPC1 multimer formation in the translation process. We therefore propose a model of the PABPC1 multimer that provides clues to comprehensively understand the regulation mechanism of mRNA translation.
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Affiliation(s)
- Ryoichi Sawazaki
- Graduate School of Pharmaceutical Sciences, Keio University, Shibakoen, Minato-ku, Tokyo, 105-8512, Japan
| | - Shunsuke Imai
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Mariko Yokogawa
- Graduate School of Pharmaceutical Sciences, Keio University, Shibakoen, Minato-ku, Tokyo, 105-8512, Japan
| | - Nao Hosoda
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya, 467-8603, Japan
| | - Shin-Ichi Hoshino
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya, 467-8603, Japan
| | - Muneyo Mio
- Molecular Profiling Research Center for Drug Discovery and OPERANDO Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Koto-ku, Tokyo, 135-0064, Japan
| | - Kazuhiro Mio
- Molecular Profiling Research Center for Drug Discovery and OPERANDO Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Koto-ku, Tokyo, 135-0064, Japan
| | - Ichio Shimada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masanori Osawa
- Graduate School of Pharmaceutical Sciences, Keio University, Shibakoen, Minato-ku, Tokyo, 105-8512, Japan. .,Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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9
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Chen Y, Chen C, Zhang Z, Xiao H, Mao B, Huang H, Ding C, Lei L, Zhang H, Li J, Jiang M, Wang G. Expression of B-cell translocation gene 2 is associated with favorable prognosis in hepatocellular carcinoma patients and sensitizes irradiation-induced hepatocellular carcinoma cell apoptosis in vitro and in nude mice. Oncol Lett 2017; 13:2366-2372. [PMID: 28454405 DOI: 10.3892/ol.2017.5685] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 07/12/2016] [Indexed: 01/20/2023] Open
Abstract
B-cell translocation gene 2 (BTG2) proteins have been reported to be putative tumor suppressors in various cancer types. The present study first assessed BTG2 expression in 44 human liver cancer tissue specimens, then investigated BTG2 expression in the regulation of hepatocellular carcinoma (HCC) cell apoptosis with or without radiotherapy in vitro and in vivo. The results revealed that BTG2 protein expression was significantly reduced in HCC tissues, and associated with better survival for HCC patients (P=0.05). BTG2 overexpression also sensitized Huh7 cells to radiation-induced apoptosis in vitro and in a nude mouse model, although restoration of BTG2 expression per se did not affect the viability and apoptosis of HCC cells. Future studies would confirm the role of BTG2 in hepatoma, and further develop BTG2 as a therapeutic strategy for controlling HCC.
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Affiliation(s)
- Yuanyuan Chen
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Chuan Chen
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Zhimin Zhang
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - He Xiao
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Bijing Mao
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Huan Huang
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Chenchen Ding
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Lin Lei
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Hui Zhang
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Jian Li
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Mei Jiang
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
| | - Ge Wang
- Cancer Center, Institute of Surgical Research, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China
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10
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Yamagishi R, Tsusaka T, Mitsunaga H, Maehata T, Hoshino SI. The STAR protein QKI-7 recruits PAPD4 to regulate post-transcriptional polyadenylation of target mRNAs. Nucleic Acids Res 2016; 44:2475-90. [PMID: 26926106 PMCID: PMC4824116 DOI: 10.1093/nar/gkw118] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 02/16/2016] [Indexed: 12/20/2022] Open
Abstract
Emerging evidence has demonstrated that regulating the length of the poly(A) tail on an mRNA is an efficient means of controlling gene expression at the post-transcriptional level. In early development, transcription is silenced and gene expression is primarily regulated by cytoplasmic polyadenylation. In somatic cells, considerable progress has been made toward understanding the mechanisms of negative regulation by deadenylation. However, positive regulation through elongation of the poly(A) tail has not been widely studied due to the difficulty in distinguishing whether any observed increase in length is due to the synthesis of new mRNA, reduced deadenylation or cytoplasmic polyadenylation. Here, we overcame this barrier by developing a method for transcriptional pulse-chase analysis under conditions where deadenylases are suppressed. This strategy was used to show that a member of the Star family of RNA binding proteins, QKI, promotes polyadenylation when tethered to a reporter mRNA. Although multiple RNA binding proteins have been implicated in cytoplasmic polyadenylation during early development, previously only CPEB was known to function in this capacity in somatic cells. Importantly, we show that only the cytoplasmic isoform QKI-7 promotes poly(A) tail extension, and that it does so by recruiting the non-canonical poly(A) polymerase PAPD4 through its unique carboxyl-terminal region. We further show that QKI-7 specifically promotes polyadenylation and translation of three natural target mRNAs (hnRNPA1, p27kip1 and β-catenin) in a manner that is dependent on the QKI response element. An anti-mitogenic signal that induces cell cycle arrest at G1 phase elicits polyadenylation and translation of p27kip1 mRNA via QKI and PAPD4. Taken together, our findings provide significant new insight into a general mechanism for positive regulation of gene expression by post-transcriptional polyadenylation in somatic cells.
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Affiliation(s)
- Ryota Yamagishi
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Takeshi Tsusaka
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Hiroko Mitsunaga
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Takaharu Maehata
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Shin-ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
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11
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Yamagishi R, Hosoda N, Hoshino SI. Arsenite inhibits mRNA deadenylation through proteolytic degradation of Tob and Pan3. Biochem Biophys Res Commun 2014; 455:323-31. [PMID: 25446091 DOI: 10.1016/j.bbrc.2014.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 11/07/2014] [Indexed: 01/24/2023]
Abstract
The poly(A) tail of mRNAs plays pivotal roles in the posttranscriptional control of gene expression at both translation and mRNA stability. Recent findings demonstrate that the poly(A) tail is globally stabilized by some stresses. However, the mechanism underlying this phenomenon has not been elucidated. Here, we show that arsenite-induced oxidative stress inhibits deadenylation of mRNA primarily through downregulation of Tob and Pan3, both of which mediate the recruitment of deadenylases to mRNA. Arsenite selectively induces the proteolytic degradation of Tob and Pan3, and siRNA-mediated knockdown of Tob and Pan3 recapitulates stabilization of the mRNA poly(A) tail observed during arsenite stress. Although arsenite also inhibits translation by activating the eIF2α kinase HRI, arsenite-induced mRNA stabilization can be observed under HRI-depleted conditions. These results highlight the essential role of Tob and Pan3 in the stress-induced global stabilization of mRNA.
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Affiliation(s)
- Ryota Yamagishi
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Shin-ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.
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12
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Rufener SC, Mühlemann O. eIF4E-bound mRNPs are substrates for nonsense-mediated mRNA decay in mammalian cells. Nat Struct Mol Biol 2013; 20:710-7. [PMID: 23665581 DOI: 10.1038/nsmb.2576] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 04/04/2013] [Indexed: 12/27/2022]
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Saito S, Hosoda N, Hoshino SI. The Hbs1-Dom34 protein complex functions in non-stop mRNA decay in mammalian cells. J Biol Chem 2013; 288:17832-43. [PMID: 23667253 DOI: 10.1074/jbc.m112.448977] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In yeast, aberrant mRNAs lacking in-frame termination codons are recognized and degraded by the non-stop decay (NSD) pathway. The recognition of non-stop mRNAs involves a member of the eRF3 family of GTP-binding proteins, Ski7. Ski7 is thought to bind the ribosome stalled at the 3'-end of the mRNA poly(A) tail and recruit the exosome to degrade the aberrant message. However, Ski7 is not found in mammalian cells, and even the presence of the NSD mechanism itself has remained enigmatic. Here, we show that unstable non-stop mRNA is degraded in a translation-dependent manner in mammalian cells. The decay requires another eRF3 family member (Hbs1), its binding partner Dom34, and components of the exosome-Ski complex (Ski2/Mtr4 and Dis3). Hbs1-Dom34 binds to form a complex with the exosome-Ski complex. Also, the elimination of aberrant proteins produced from non-stop transcripts requires the RING finger protein listerin. These findings demonstrate that the NSD mechanism exists in mammalian cells and involves Hbs1, Dom34, and the exosome-Ski complex.
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Affiliation(s)
- Syuhei Saito
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
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14
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Doidge R, Mittal S, Aslam A, Winkler GS. The anti-proliferative activity of BTG/TOB proteins is mediated via the Caf1a (CNOT7) and Caf1b (CNOT8) deadenylase subunits of the Ccr4-not complex. PLoS One 2012; 7:e51331. [PMID: 23236473 PMCID: PMC3517456 DOI: 10.1371/journal.pone.0051331] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 11/06/2012] [Indexed: 11/19/2022] Open
Abstract
The human BTG/TOB protein family comprises six members (BTG1, BTG2/PC3/Tis21, BTG3/Ana, BTG4/PC3B, TOB1/Tob, and TOB2) that are characterised by a conserved BTG domain. This domain mediates interactions with the highly similar Caf1a (CNOT7) and Caf1b (CNOT8) catalytic subunits of the Ccr4-Not deadenylase complex. BTG/TOB proteins have anti-proliferative activity: knockdown of BTG/TOB can result in increased cell proliferation, whereas over-expression of BTG/TOB leads to inhibition of cell cycle progression. It was unclear whether the interaction between BTG/TOB proteins and the Caf1a/Caf1b deadenylases is necessary for the anti-proliferative activity of BTG/TOB. To address this question, we further characterised surface-exposed amino acid residues of BTG2 and TOB1 that mediate the interaction with the Caf1a and Caf1b deadenylase enzymes. We then analysed the role of BTG2 and TOB1 in the regulation of cell proliferation, translation and mRNA abundance using a mutant that is no longer able to interact with the Caf1a/Caf1b deadenylases. We conclude that the anti-proliferative activity of BTG/TOB proteins is mediated through interactions with the Caf1a and Caf1b deadenylase enzymes. Furthermore, we show that the activity of BTG/TOB proteins in the regulation of mRNA abundance and translation is dependent on Caf1a/Caf1b, and does not appear to require other Ccr4-Not components, including the Ccr4a (CNOT6)/Ccr4b (CNOT6L) deadenylases, or the non-catalytic subunits CNOT1 or CNOT3.
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Affiliation(s)
- Rachel Doidge
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Saloni Mittal
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Akhmed Aslam
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
| | - G. Sebastiaan Winkler
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, United Kingdom
- * E-mail:
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15
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Ogami K, Hosoda N, Funakoshi Y, Hoshino S. Antiproliferative protein Tob directly regulates c-myc proto-oncogene expression through cytoplasmic polyadenylation element-binding protein CPEB. Oncogene 2012. [PMID: 23178487 DOI: 10.1038/onc.2012.548] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The regulation of mRNA deadenylation constitutes a pivotal mechanism of the post-transcriptional control of gene expression. Here we show that the antiproliferative protein Tob, a component of the Caf1-Ccr4 deadenylase complex, is involved in regulating the expression of the proto-oncogene c-myc. The c-myc mRNA contains cis elements (CPEs) in its 3'-untranslated region (3'-UTR), which are recognized by the cytoplasmic polyadenylation element-binding protein (CPEB). CPEB recruits Caf1 deadenylase through interaction with Tob to form a ternary complex, CPEB-Tob-Caf1, and negatively regulates the expression of c-myc by accelerating the deadenylation and decay of its mRNA. In quiescent cells, c-myc mRNA is destabilized by the trans-acting complex (CPEB-Tob-Caf1), while in cells stimulated by the serum, both Tob and Caf1 are released from CPEB, and c-Myc expression is induced early after stimulation by the stabilization of its mRNA as an 'immediate-early gene'. Collectively, these results indicate that Tob is a key factor in the regulation of c-myc gene expression, which is essential for cell growth. Thus, Tob appears to function in the control of cell growth at least, in part, by regulating the expression of c-myc.
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Affiliation(s)
- K Ogami
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - N Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Y Funakoshi
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - S Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
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16
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Osawa M, Hosoda N, Nakanishi T, Uchida N, Kimura T, Imai S, Machiyama A, Katada T, Hoshino SI, Shimada I. Biological role of the two overlapping poly(A)-binding protein interacting motifs 2 (PAM2) of eukaryotic releasing factor eRF3 in mRNA decay. RNA (NEW YORK, N.Y.) 2012; 18:1957-67. [PMID: 23019593 PMCID: PMC3479387 DOI: 10.1261/rna.035311.112] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 07/31/2012] [Indexed: 05/18/2023]
Abstract
Eukaryotic releasing factor GSPT/eRF3 mediates translation termination-coupled mRNA decay via interaction with a cytosolic poly(A)-binding protein (PABPC1). A region of eRF3 containing two overlapping PAM2 (PABPC1-interacting motif 2) motifs is assumed to bind to the PABC domain of PABPC1, on the poly(A) tail of mRNA. PAM2 motifs are also found in the major deadenylases Caf1-Ccr4 and Pan2-Pan3, whose activities are enhanced upon PABPC1 binding to these motifs. Their deadenylase activities are regulated by eRF3, in which two overlapping PAM2 motifs competitively prevent interaction with PABPC1. However, it is unclear how these overlapping motifs recognize PABC and regulate deadenylase activity in a translation termination-coupled manner. We used a dominant-negative approach to demonstrate that the N-terminal PAM2 motif is critical for eRF3 binding to PABPC1 and that both motifs are required for function. Isothermal titration calorimetry (ITC) and NMR analyses revealed that the interaction is in equilibrium between the two PAM2-PABC complexes, where only one of the two overlapping PAM2 motifs is PABC-bound and the other is PABC-unbound and partially accessible to the other PABC. Based on these results, we proposed a biological role for the overlapping PAM2 motifs in the regulation of deadenylase accessibility to PABPC1 at the 3' end of poly(A).
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Affiliation(s)
- Masanori Osawa
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Nao Hosoda
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Tamiji Nakanishi
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Naoyuki Uchida
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Tomomi Kimura
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Shunsuke Imai
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Asako Machiyama
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Toshiaki Katada
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Shin-ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Ichio Shimada
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
- Biomedicinal Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST), Tokyo 135-0064, Japan
- Corresponding authorE-mail
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17
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Hoshino SI. Mechanism of the initiation of mRNA decay: role of eRF3 family G proteins. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:743-57. [PMID: 22965901 DOI: 10.1002/wrna.1133] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
mRNA decay is intimately linked to and regulated by translation in eukaryotes. However, it has remained unclear exactly how mRNA decay is linked to translation. Progress has been made in recent years in understanding the molecular mechanisms of the link between translation and mRNA decay. It has become clear that the eRF3 family of GTP-binding proteins acts as signal transducers that couple translation to mRNA decay and plays pivotal roles in the regulation of gene expression and mRNA quality control. During translation, the translation termination factor eRF3 in complex with eRF1 recognizes the termination codon which appears at the A site of the terminating ribosome. Depending on whether the termination codon is normal (bona fide) or aberrant (premature), deadenylation-dependent decay or nonsense-mediated mRNA decay (NMD) occurs. mRNA without termination codons and mRNA with the propensity to cause the ribosome to stall are recognized as aberrant by other members of the eRF3 family during translation, and these translational events cause nonstop mRNA decay (NSD) and no-go decay (NGD), respectively. In this review, we focus on how mRNA decay is triggered by translational events and summarize the initiation mechanism for the decay of both normal and aberrant mRNAs.
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Affiliation(s)
- Shin-ichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
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18
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Lin S, Zhu Q, Xu Y, Liu H, Zhang J, Xu J, Wang H, Sang Q, Xing Q, Fan J. The role of the TOB1 gene in growth suppression of hepatocellular carcinoma. Oncol Lett 2012; 4:981-987. [PMID: 23162636 DOI: 10.3892/ol.2012.864] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/25/2012] [Indexed: 12/24/2022] Open
Abstract
The TOB1 gene, mapped on 17q21, is a member of the BTG/Tob family. In breast cancer it has been identified as a candidate tumor suppressor gene. However, whether TOB1 is a bona fide tumor suppressor and downregulated in hepatocellular carcinoma (HCC) remains unclear. In addition, whether its expression is regulated through methylation requires investigation. In the present study, we therefore analyzed the expression of TOB1 in HCC and its methylation levels in human HCC and breast cancer. No significant difference in the expression levels of TOB1 was observed between tumor tissues and adjacent normal tissues in HCC. Quantitative methylation analysis by MassArray revealed no significant differences at single CpG sites or in the global promoter region, and all these CpG sites shared a similar methylation pattern in HCC and breast cancer. Moreover, 5-aza-2'-deoxycytidine treatment of three tumor cell lines did not cause elevation of TOB1 mRNA in HepG2 cell lines. Based on these data, we speculate that TOB1 may be a candidate non-tumor suppressor gene in HCC. Furthermore, the clinical outcome was not correlated with TOB1 expression or expression rate. In addition, TOB1 expression or expression rate was not correlated with the overall survival (OS) rates or cumulative recurrence rates. Taken together, we suggest that TOB1 does not act as a tumor suppressor in HCC.
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Affiliation(s)
- Sheyu Lin
- Institutes of Biomedical Sciences and Children's Hospital, Fudan University, Shanghai 200032; ; School of Life Sciences, Nantong University, Nantong 226019, P.R. China
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19
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Collart MA, Panasenko OO. The Ccr4--not complex. Gene 2011; 492:42-53. [PMID: 22027279 DOI: 10.1016/j.gene.2011.09.033] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/06/2011] [Accepted: 09/29/2011] [Indexed: 12/11/2022]
Abstract
The Ccr4-Not complex is a unique, essential and conserved multi-subunit complex that acts at the level of many different cellular functions to regulate gene expression. Two enzymatic activities, namely ubiquitination and deadenylation, are provided by different subunits of the complex. However, studies over the last decade have demonstrated a tantalizing multi-functionality of this complex that extends well beyond its identified enzymatic activities. Most of our initial knowledge about the Ccr4-Not complex stemmed from studies in yeast, but an increasing number of reports on this complex in other species are emerging. In this review we will discuss the structure and composition of the complex, and describe the different cellular functions with which the Ccr4-Not complex has been connected in different organisms. Finally, based upon our current state of knowledge, we will propose a model to explain how one complex can provide such multi-functionality. This model suggests that the Ccr4-Not complex might function as a "chaperone platform".
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Affiliation(s)
- Martine A Collart
- Dpt Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, 1211 Geneva 4, Switzerland.
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20
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Anti-proliferative protein Tob negatively regulates CPEB3 target by recruiting Caf1 deadenylase. EMBO J 2011; 30:1311-23. [PMID: 21336257 DOI: 10.1038/emboj.2011.37] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 01/24/2011] [Indexed: 01/17/2023] Open
Abstract
Tob is a member of the anti-proliferative protein family, which functions in transcription and mRNA decay. We have previously demonstrated that Tob is involved in the general mechanism of mRNA decay by mediating mRNA deadenylation through interaction with Caf1 and a general RNA-binding protein, PABPC1. Here, we focus on the role of Tob in the regulation of specific mRNA. We show that Tob binds directly to a sequence-specific RNA-binding protein, cytoplasmic polyadenylation element-binding protein 3 (CPEB3). CPEB3 negatively regulates the expression of a target by accelerating deadenylation and decay of its mRNA, which it achieves by tethering to the mRNA. The carboxyl-terminal RNA-binding domain of CPEB3 binds to the carboxyl-terminal unstructured region of Tob. Tob then binds Caf1 deadenylase and recruits it to CPEB3 to form a ternary complex. The CPEB3-accelerated deadenylation was abrogated by a dominant-negative mutant of either Caf1 or Tob. Together, these results indicate that Tob mediates the recruitment of Caf1 to the target of CPEB3 and elicits deadenylation and decay of the mRNA. Our results provide an explanation of how Tob regulates specific biological processes.
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21
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Yang R, Gaidamakov SA, Xie J, Lee J, Martino L, Kozlov G, Crawford AK, Russo AN, Conte MR, Gehring K, Maraia RJ. La-related protein 4 binds poly(A), interacts with the poly(A)-binding protein MLLE domain via a variant PAM2w motif, and can promote mRNA stability. Mol Cell Biol 2011; 31:542-56. [PMID: 21098120 PMCID: PMC3028612 DOI: 10.1128/mcb.01162-10] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 11/05/2010] [Accepted: 11/12/2010] [Indexed: 12/19/2022] Open
Abstract
The conserved RNA binding protein La recognizes UUU-3'OH on its small nuclear RNA ligands and stabilizes them against 3'-end-mediated decay. We report that newly described La-related protein 4 (LARP4) is a factor that can bind poly(A) RNA and interact with poly(A) binding protein (PABP). Yeast two-hybrid analysis and reciprocal immunoprecipitations (IPs) from HeLa cells revealed that LARP4 interacts with RACK1, a 40S ribosome- and mRNA-associated protein. LARP4 cosediments with 40S ribosome subunits and polyribosomes, and its knockdown decreases translation. Mutagenesis of the RNA binding or PABP interaction motifs decrease LARP4 association with polysomes. Several translation and mRNA metabolism-related proteins use a PAM2 sequence containing a critical invariant phenylalanine to make direct contact with the MLLE domain of PABP, and their competition for the MLLE is thought to regulate mRNA homeostasis. Unlike all ∼150 previously analyzed PAM2 sequences, LARP4 contains a variant PAM2 (PAM2w) with tryptophan in place of the phenylalanine. Binding and nuclear magnetic resonance (NMR) studies have shown that a peptide representing LARP4 PAM2w interacts with the MLLE of PABP within the affinity range measured for other PAM2 motif peptides. A cocrystal of PABC bound to LARP4 PAM2w shows tryptophan in the pocket in PABC-MLLE otherwise occupied by phenylalanine. We present evidence that LARP4 expression stimulates luciferase reporter activity by promoting mRNA stability, as shown by mRNA decay analysis of luciferase and cellular mRNAs. We propose that LARP4 activity is integrated with other PAM2 protein activities by PABP as part of mRNA homeostasis.
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Affiliation(s)
- Ruiqing Yang
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Sergei A. Gaidamakov
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Jingwei Xie
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Joowon Lee
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Luigi Martino
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Guennadi Kozlov
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Amanda K. Crawford
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Amy N. Russo
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Maria R. Conte
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Kalle Gehring
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
| | - Richard J. Maraia
- Intramural Research Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom, Department of Biochemistry, McGill University, Montreal, QC, Canada, Commissioned Corps, U.S. Public Health Service, Washington, DC
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