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Hao M, Ling X, Sun Y, Wang X, Li W, Chang L, Zeng Z, Shi X, Niu M, Chen L, Liu T. Tracking endogenous proteins based on RNA editing-mediated genetic code expansion. Nat Chem Biol 2024; 20:721-731. [PMID: 38302606 DOI: 10.1038/s41589-023-01533-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/19/2023] [Indexed: 02/03/2024]
Abstract
Protein labeling approaches are important to study proteins in living cells, and genome editing tools make it possible to tag endogenous proteins to address the concerns associated with overexpression. Here we established RNA editing-mediated noncanonical amino acids (ncAAs) protein tagging (RENAPT) to site-specifically label endogenous proteins with ncAAs in living cells. RENAPT labels protein in a temporary and nonheritable manner and is not restricted by protospacer adjacent motif sequence. Using a fluorescent ncAA or ncAA with a bio-orthogonal reaction handle for subsequent dye labeling, we demonstrated that a variety of endogenous proteins can be imaged at their specific subcellular locations. In addition, two proteins can be tagged individually and simultaneously using two different ncAAs. Furthermore, endogenous ion channels and neuron-specific proteins can be real-time labeled in primary neurons. Thus, RENAPT presents a promising platform with broad applicability for tagging endogenous proteins in living cells to study their localization and functions.
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Affiliation(s)
- Min Hao
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Xinyu Ling
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Yi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Xue Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Wenzhe Li
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Liying Chang
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Zhiying Zeng
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Xiaomeng Shi
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Mengxiao Niu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Tao Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China.
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2
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Colón EM, Haddock LA, Lasalde C, Lin Q, Ramírez-Lugo JS, González CI. Characterization of the mIF4G Domains in the RNA Surveillance Protein Upf2p. Curr Issues Mol Biol 2023; 46:244-261. [PMID: 38248319 PMCID: PMC10814901 DOI: 10.3390/cimb46010017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/11/2023] [Accepted: 12/22/2023] [Indexed: 01/23/2024] Open
Abstract
Thirty percent of all mutations causing human disease generate mRNAs with premature termination codons (PTCs). Recognition and degradation of these PTC-containing mRNAs is carried out by the mechanism known as nonsense-mediated mRNA decay (NMD). Upf2 is a scaffold protein known to be a central component of the NMD surveillance pathway. It harbors three middle domains of eukaryotic initiation factor 4G (mIF4G-1, mIF4G-2, mIF4G-3) in its N-terminal region that are potentially important in regulating the surveillance pathway. In this study, we defined regions within the mIF4G-1 and mIF4G-2 that are required for proper function of Upf2p in NMD and translation termination in Saccharomyces cerevisiae. In addition, we narrowed down the activity of these regions to an aspartic acid (D59) in mIF4G-1 that is important for NMD activity and translation termination accuracy. Taken together, these studies suggest that inherently charged residues within mIF4G-1 of Upf2p play a role in the regulation of the NMD surveillance mechanism in S. cerevisiae.
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Affiliation(s)
- Edgardo M. Colón
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
- Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR 00926, USA
| | - Luis A. Haddock
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
- Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR 00926, USA
| | - Clarivel Lasalde
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
| | - Qishan Lin
- Department of Chemistry, University at Albany, Albany, NY 12222, USA;
- RNA Epitranscriptomics and Proteomics Resource, University at Albany, Albany, NY 12222, USA
| | - Juan S. Ramírez-Lugo
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
| | - Carlos I. González
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
- Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR 00926, USA
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3
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Staszewski J, Lazarewicz N, Konczak J, Migdal I, Maciaszczyk-Dziubinska E. UPF1-From mRNA Degradation to Human Disorders. Cells 2023; 12:cells12030419. [PMID: 36766761 PMCID: PMC9914065 DOI: 10.3390/cells12030419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/07/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
Up-frameshift protein 1 (UPF1) plays the role of a vital controller for transcripts, ready to react in the event of an incorrect translation mechanism. It is well known as one of the key elements involved in mRNA decay pathways and participates in transcript and protein quality control in several different aspects. Firstly, UPF1 specifically degrades premature termination codon (PTC)-containing products in a nonsense-mediated mRNA decay (NMD)-coupled manner. Additionally, UPF1 can potentially act as an E3 ligase and degrade target proteins independently from mRNA decay pathways. Thus, UPF1 protects cells against the accumulation of misfolded polypeptides. However, this multitasking protein may still hide many of its functions and abilities. In this article, we summarize important discoveries in the context of UPF1, its involvement in various cellular pathways, as well as its structural importance and mutational changes related to the emergence of various pathologies and disease states. Even though the state of knowledge about this protein has significantly increased over the years, there are still many intriguing aspects that remain unresolved.
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Affiliation(s)
- Jacek Staszewski
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
- Correspondence: (J.S.); (E.M.-D.)
| | - Natalia Lazarewicz
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
- Institute of Genetics and Development of Rennes, CNRS UMR 6290, University of Rennes 1, 35000 Rennes, France
| | - Julia Konczak
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
| | - Iwona Migdal
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
| | - Ewa Maciaszczyk-Dziubinska
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
- Correspondence: (J.S.); (E.M.-D.)
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4
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Alalam H, Zepeda-Martínez JA, Sunnerhagen P. Global SLAM-seq for accurate mRNA decay determination and identification of NMD targets. RNA (NEW YORK, N.Y.) 2022; 28:905-915. [PMID: 35296539 PMCID: PMC9074897 DOI: 10.1261/rna.079077.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Gene expression analysis requires accurate measurements of global RNA degradation rates, earlier problematic with methods disruptive to cell physiology. Recently, metabolic RNA labeling emerged as an efficient and minimally invasive technique applied in mammalian cells. Here, we have adapted SH-linked alkylation for the metabolic sequencing of RNA (SLAM-seq) for a global mRNA stability study in yeast using 4-thiouracil pulse-chase labeling. We assign high-confidence half-life estimates for 67.5% of expressed ORFs, and measure a median half-life of 9.4 min. For mRNAs where half-life estimates exist in the literature, their ranking order was in good agreement with previous data, indicating that SLAM-seq efficiently classifies stable and unstable transcripts. We then leveraged our yeast protocol to identify targets of the nonsense-mediated decay (NMD) pathway by measuring the change in RNA half-lives, instead of steady-state RNA level changes. With SLAM-seq, we assign 580 transcripts as putative NMD targets, based on their measured half-lives in wild-type and upf3Δ mutants. We find 225 novel targets, and observe a strong agreement with previous reports of NMD targets, 61.2% of our candidates being identified in previous studies. This indicates that SLAM-seq is a simpler and more economic method for global quantification of mRNA half-lives. Our adaptation for yeast yielded global quantitative measures of the NMD effect on transcript half-lives, high correlation with RNA half-lives measured previously with more technically challenging protocols, and identification of novel NMD regulated transcripts that escaped prior detection.
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Affiliation(s)
- Hanna Alalam
- Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, S-405 30 Göteborg, Sweden
| | | | - Per Sunnerhagen
- Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, S-405 30 Göteborg, Sweden
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5
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Molecular Determinants and Specificity of mRNA with Alternatively-Spliced UPF1 Isoforms, Influenced by an Insertion in the 'Regulatory Loop'. Int J Mol Sci 2021; 22:ijms222312744. [PMID: 34884553 PMCID: PMC8657986 DOI: 10.3390/ijms222312744] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 01/25/2023] Open
Abstract
The nonsense-mediated mRNA decay (NMD) pathway rapidly detects and degrades mRNA containing premature termination codons (PTCs). UP-frameshift 1 (UPF1), the master regulator of the NMD process, has two alternatively-spliced isoforms; one carries 353-GNEDLVIIWLR-363 insertion in the ‘regulatory loop (involved in mRNA binding)’. Such insertion can induce catalytic and/or ATPase activity, as determined experimentally; however, the kinetics and molecular level information are not fully understood. Herein, applying all-atom molecular dynamics, we probe the binding specificity of UPF1 with different GC- and AU-rich mRNA motifs and the influence of insertion to the viable control over UPF1 catalytic activity. Our results indicate two distinct conformations between 1B and RecA2 domains of UPF1: ‘open (isoform_2; without insertion)’ and ‘closed (isoform_1; with insertion)’. These structural movements correspond to an important stacking pattern in mRNA motifs, i.e., absence of stack formation in mRNA, with UPF1 isoform_2 results in the ‘open conformation’. Particularly, for UPF1 isoform_1, the increased distance between 1B and RecA2 domains has resulted in reducing the mRNA–UPF1 interactions. Lower fluctuating GC-rich mRNA motifs have better binding with UPF1, compared with AU-rich sequences. Except CCUGGGG, all other GC-rich motifs formed a 4-stack pattern with UPF1. High occupancy R363, D364, T627, and G862 residues were common binding GC-rich motifs, as were R363, N535, and T627 for the AU-rich motifs. The GC-rich motifs behave distinctly when bound to either of the isoforms; lower stability was observed with UPF1 isoform_2. The cancer-associated UPF1 variants (P533L/T and A839T) resulted in decreased protein–mRNA binding efficiency. Lack of mRNA stacking poses in the UPF1P533T system significantly decreased UPF1-mRNA binding efficiency and increased distance between 1B-RecA2. These novel findings can serve to further inform NMD-associated mechanistic and kinetic studies.
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6
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Palma M, Leroy C, Salomé-Desnoulez S, Werkmeister E, Kong R, Mongy M, Le Hir H, Lejeune F. A role for AKT1 in nonsense-mediated mRNA decay. Nucleic Acids Res 2021; 49:11022-11037. [PMID: 34634811 PMCID: PMC8565340 DOI: 10.1093/nar/gkab882] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 09/15/2021] [Accepted: 09/17/2021] [Indexed: 12/16/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a highly regulated quality control mechanism through which mRNAs harboring a premature termination codon are degraded. It is also a regulatory pathway for some genes. This mechanism is subject to various levels of regulation, including phosphorylation. To date only one kinase, SMG1, has been described to participate in NMD, by targeting the central NMD factor UPF1. Here, screening of a kinase inhibitor library revealed as putative NMD inhibitors several molecules targeting the protein kinase AKT1. We present evidence demonstrating that AKT1, a central player in the PI3K/AKT/mTOR signaling pathway, plays an essential role in NMD, being recruited by the UPF3X protein to phosphorylate UPF1. As AKT1 is often overactivated in cancer cells and as this should result in increased NMD efficiency, the possibility that this increase might affect cancer processes and be targeted in cancer therapy is discussed.
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Affiliation(s)
- Martine Palma
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.,Unité tumorigenèse et résistance aux traitements, Institut Pasteur de Lille, F-59000 Lille, France
| | - Catherine Leroy
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.,Unité tumorigenèse et résistance aux traitements, Institut Pasteur de Lille, F-59000 Lille, France
| | - Sophie Salomé-Desnoulez
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, F-59000 Lille, France
| | - Elisabeth Werkmeister
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, F-59000 Lille, France.,Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR9017 - CIIL - center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Rebekah Kong
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.,Unité tumorigenèse et résistance aux traitements, Institut Pasteur de Lille, F-59000 Lille, France
| | - Marc Mongy
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UMS 2014 - PLBS, F-59000 Lille, France
| | - Hervé Le Hir
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, 46 rue d'Ulm, 75005 Paris, France
| | - Fabrice Lejeune
- Univ. Lille, CNRS, Inserm, CHU Lille, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, F-59000 Lille, France.,Unité tumorigenèse et résistance aux traitements, Institut Pasteur de Lille, F-59000 Lille, France
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7
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Wang H, Li X, Tu Y, Zhang J. Catalytic Enantiodivergent Michael Addition by Subtle Adjustment of Achiral Amino Moiety of Dipeptide Phosphines. iScience 2020; 23:101138. [PMID: 32450512 PMCID: PMC7251764 DOI: 10.1016/j.isci.2020.101138] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/03/2020] [Accepted: 05/01/2020] [Indexed: 11/29/2022] Open
Abstract
Over the past decades, asymmetric catalysis has been intensely investigated as a powerful tool for the preparation of numerous chiral biologically active compounds. However, developing general and practical strategies for preparation of both enantiomers of a chiral molecule via asymmetric catalysis is still a challenge, particularly when the two enantiomers of a chiral catalyst are not easily prepared from natural chiral sources. Inspired by the biologic system, we report herein an unprecedented catalytic enantiodivergent Michael addition of pyridazinones to enones by subtle adjustment of achiral amino moiety of dipeptide phosphine catalysts. These two dipeptide phosphine catalysts, P5 and P8, could deliver both enantiomers of a series of N2-alkylpyridazinones in good yields (up to 99%) with high enantioselectivities (up to 99% ee) via the catalyst-controlled enantiodivergent addition of pyridazinones to enones.
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Affiliation(s)
- Huamin Wang
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai 200438, P. R. China; Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N. Zhongshan Road, Shanghai 200062, P. R. China
| | - Xiuzheng Li
- School of Pharmacy, Anhui Medical University, 81 N. Meishan Road, Hefei 230032, P. R.China
| | - Youshao Tu
- College of Chemistry and Life Science, Advanced Institute of Materials Science, Changchun University of Technology, 2055 N. Yan'an Avenue, Changchun 130012, P. R. China
| | - Junliang Zhang
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai 200438, P. R. China; Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N. Zhongshan Road, Shanghai 200062, P. R. China.
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8
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Beißel C, Grosse S, Krebber H. Dbp5/DDX19 between Translational Readthrough and Nonsense Mediated Decay. Int J Mol Sci 2020; 21:ijms21031085. [PMID: 32041247 PMCID: PMC7037193 DOI: 10.3390/ijms21031085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 01/21/2023] Open
Abstract
The DEAD-box protein Dbp5 (human DDX19) remodels RNA-protein complexes. Dbp5 functions in ribonucleoprotein export and translation termination. Termination occurs, when the ribosome has reached a stop codon through the Dbp5 mediated delivery of the eukaryotic termination factor eRF1. eRF1 contacts eRF3 upon dissociation of Dbp5, resulting in polypeptide chain release and subsequent ribosomal subunit splitting. Mutations in DBP5 lead to stop codon readthrough, because the eRF1 and eRF3 interaction is not controlled and occurs prematurely. This identifies Dbp5/DDX19 as a possible potent drug target for nonsense suppression therapy. Neurodegenerative diseases and cancer are caused in many cases by the loss of a gene product, because its mRNA contained a premature termination codon (PTC) and is thus eliminated through the nonsense mediated decay (NMD) pathway, which is described in the second half of this review. We discuss translation termination and NMD in the light of Dbp5/DDX19 and subsequently speculate on reducing Dbp5/DDX19 activity to allow readthrough of the PTC and production of a full-length protein to detract the RNA from NMD as a possible treatment for diseases.
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9
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Dehecq M, Decourty L, Namane A, Proux C, Kanaan J, Le Hir H, Jacquier A, Saveanu C. Nonsense-mediated mRNA decay involves two distinct Upf1-bound complexes. EMBO J 2018; 37:embj.201899278. [PMID: 30275269 DOI: 10.15252/embj.201899278] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 08/10/2018] [Accepted: 08/22/2018] [Indexed: 11/09/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a translation-dependent RNA degradation pathway involved in many cellular pathways and crucial for telomere maintenance and embryo development. Core NMD factors Upf1, Upf2 and Upf3 are conserved from yeast to mammals, but a universal NMD model is lacking. We used affinity purification coupled with mass spectrometry and an improved data analysis protocol to characterize the composition and dynamics of yeast NMD complexes in yeast (112 experiments). Unexpectedly, we identified two distinct complexes associated with Upf1: Upf1-23 (Upf1, Upf2, Upf3) and Upf1-decapping Upf1-decapping contained the mRNA decapping enzyme, together with Nmd4 and Ebs1, two proteins that globally affected NMD and were critical for RNA degradation mediated by the Upf1 C-terminal helicase region. The fact that Nmd4 association with RNA was partially dependent on Upf1-23 components and the similarity between Nmd4/Ebs1 and mammalian Smg5-7 proteins suggest that NMD operates through conserved, successive Upf1-23 and Upf1-decapping complexes. This model can be extended to accommodate steps that are missing in yeast, to serve for further mechanistic studies of NMD in eukaryotes.
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Affiliation(s)
- Marine Dehecq
- Génétique des Interactions Macromoléculaires, Genomes and Genetics Department, Institut Pasteur, Paris, France.,Université Pierre et Marie Curie, Paris, France
| | - Laurence Decourty
- Génétique des Interactions Macromoléculaires, Genomes and Genetics Department, Institut Pasteur, Paris, France
| | - Abdelkader Namane
- Génétique des Interactions Macromoléculaires, Genomes and Genetics Department, Institut Pasteur, Paris, France
| | - Caroline Proux
- Transcriptome and Epigenome, CITECH, Institut Pasteur, Paris, France
| | - Joanne Kanaan
- Expression des ARN Messagers Eucaryotes, Biology Department, CNRS UMR8197, Inserm U1024, Institut de Biologie de l'Ecole Normale Supérieure, Paris, France
| | - Hervé Le Hir
- Expression des ARN Messagers Eucaryotes, Biology Department, CNRS UMR8197, Inserm U1024, Institut de Biologie de l'Ecole Normale Supérieure, Paris, France
| | - Alain Jacquier
- Génétique des Interactions Macromoléculaires, Genomes and Genetics Department, Institut Pasteur, Paris, France
| | - Cosmin Saveanu
- Génétique des Interactions Macromoléculaires, Genomes and Genetics Department, Institut Pasteur, Paris, France
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10
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Abstract
Nonsense-mediated mRNA decay is a eukaryotic pathway that degrades transcripts with premature termination codons (PTCs). In most eukaryotes, thousands of transcripts are degraded by NMD, including many important regulators of developmental and stress response pathways. Transcripts can be targeted to NMD by the presence of an upstream ORF or by introduction of a PTC through alternative splicing. Many factors involved in the recognition of PTCs and the destruction of NMD targets have been characterized. While some are highly conserved, others have been repeatedly lost in eukaryotic lineages. Here, I detail the factors involved in NMD, our current understanding of their interactions and how they have evolved. I outline a classification system to describe NMD pathways based on the presence/absence of key NMD factors. These types of NMD pathways exist in multiple different lineages, indicating the plasticity of the NMD pathway through recurrent losses of NMD factors during eukaryotic evolution. By classifying the NMD pathways in this way, gaps in our understanding are revealed, even within well studied organisms. Finally, I discuss the likely driving force behind the origins of the NMD pathway before the appearance of the last eukaryotic common ancestor: transposable element expansion and the consequential origin of introns.
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Affiliation(s)
- James P B Lloyd
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia
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11
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Abstract
Nonsense-mediated mRNA decay is a eukaryotic pathway that degrades transcripts with premature termination codons (PTCs). In most eukaryotes, thousands of transcripts are degraded by NMD, including many important regulators of developmental and stress response pathways. Transcripts can be targeted to NMD by the presence of an upstream ORF or by introduction of a PTC through alternative splicing. Many factors involved in the recognition of PTCs and the destruction of NMD targets have been characterized. While some are highly conserved, others have been repeatedly lost in eukaryotic lineages. Here, I detail the factors involved in NMD, our current understanding of their interactions and how they have evolved. I outline a classification system to describe NMD pathways based on the presence/absence of key NMD factors. These types of NMD pathways exist in multiple different lineages, indicating the plasticity of the NMD pathway through recurrent losses of NMD factors during eukaryotic evolution. By classifying the NMD pathways in this way, gaps in our understanding are revealed, even within well studied organisms. Finally, I discuss the likely driving force behind the origins of the NMD pathway before the appearance of the last eukaryotic common ancestor: transposable element expansion and the consequential origin of introns.
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Affiliation(s)
- James P B Lloyd
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia
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12
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Beyond quality control: The role of nonsense-mediated mRNA decay (NMD) in regulating gene expression. Semin Cell Dev Biol 2018; 75:78-87. [DOI: 10.1016/j.semcdb.2017.08.053] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 11/23/2022]
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13
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Causier B, Li Z, De Smet R, Lloyd JPB, Van de Peer Y, Davies B. Conservation of Nonsense-Mediated mRNA Decay Complex Components Throughout Eukaryotic Evolution. Sci Rep 2017; 7:16692. [PMID: 29192227 PMCID: PMC5709506 DOI: 10.1038/s41598-017-16942-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 11/13/2017] [Indexed: 11/15/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is an essential eukaryotic process regulating transcript quality and abundance, and is involved in diverse processes including brain development and plant defenses. Although some of the NMD machinery is conserved between kingdoms, little is known about its evolution. Phosphorylation of the core NMD component UPF1 is critical for NMD and is regulated in mammals by the SURF complex (UPF1, SMG1 kinase, SMG8, SMG9 and eukaryotic release factors). However, since SMG1 is reportedly missing from the genomes of fungi and the plant Arabidopsis thaliana, it remains unclear how UPF1 is activated outside the metazoa. We used comparative genomics to determine the conservation of the NMD pathway across eukaryotic evolution. We show that SURF components are present in all major eukaryotic lineages, including fungi, suggesting that in addition to UPF1 and SMG1, SMG8 and SMG9 also existed in the last eukaryotic common ancestor, 1.8 billion years ago. However, despite the ancient origins of the SURF complex, we also found that SURF factors have been independently lost across the Eukarya, pointing to genetic buffering within the essential NMD pathway. We infer an ancient role for SURF in regulating UPF1, and the intriguing possibility of undiscovered NMD regulatory pathways.
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Affiliation(s)
- Barry Causier
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - Zhen Li
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052, Gent, Belgium.,VIB Center for Plant Systems Biology, Technologiepark 927, B-9052, Gent, Belgium
| | - Riet De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052, Gent, Belgium.,VIB Center for Plant Systems Biology, Technologiepark 927, B-9052, Gent, Belgium
| | - James P B Lloyd
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052, Gent, Belgium.,VIB Center for Plant Systems Biology, Technologiepark 927, B-9052, Gent, Belgium.,Department of Genetics, Genomics Research Institute, University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Brendan Davies
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
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14
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Hyperphosphorylation amplifies UPF1 activity to resolve stalls in nonsense-mediated mRNA decay. Nat Commun 2016; 7:12434. [PMID: 27511142 PMCID: PMC4987530 DOI: 10.1038/ncomms12434] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 07/04/2016] [Indexed: 12/13/2022] Open
Abstract
Many gene expression factors contain repetitive phosphorylation sites for single kinases, but the functional significance is poorly understood. Here we present evidence for hyperphosphorylation as a mechanism allowing UPF1, the central factor in nonsense-mediated decay (NMD), to increasingly attract downstream machinery with time of residence on target mRNAs. Indeed, slowing NMD by inhibiting late-acting factors triggers UPF1 hyperphosphorylation, which in turn enhances affinity for factors linking UPF1 to decay machinery. Mutational analyses reveal multiple phosphorylation sites contributing to different extents to UPF1 activity with no single site being essential. Moreover, the ability of UPF1 to undergo hyperphosphorylation becomes increasingly important for NMD when downstream factors are depleted. This hyperphosphorylation-dependent feedback mechanism may serve as a molecular clock ensuring timely degradation of target mRNAs while preventing degradation of non-targets, which, given the prevalence of repetitive phosphorylation among central gene regulatory factors, may represent an important general principle in gene expression. Gene expression is regulated by a range of mechanisms, including post-translational modifications such as phosphorylation. Here the authors present evidence for a feedback mechanism whereby hyperphosphorylation of UPF1 in response to delays in nonsense-mediated decay enhances recruitment of mRNA decay machinery.
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15
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Martínez-Montiel N, Morales-Lara L, Hernández-Pérez JM, Martínez-Contreras RD. In Silico Analysis of the Structural and Biochemical Features of the NMD Factor UPF1 in Ustilago maydis. PLoS One 2016; 11:e0148191. [PMID: 26863136 PMCID: PMC4749658 DOI: 10.1371/journal.pone.0148191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/14/2016] [Indexed: 11/23/2022] Open
Abstract
The molecular mechanisms regulating the accuracy of gene expression are still not fully understood. Among these mechanisms, Nonsense-mediated Decay (NMD) is a quality control process that detects post-transcriptionally abnormal transcripts and leads them to degradation. The UPF1 protein lays at the heart of NMD as shown by several structural and functional features reported for this factor mainly for Homo sapiens and Saccharomyces cerevisiae. This process is highly conserved in eukaryotes but functional diversity can be observed in various species. Ustilago maydis is a basidiomycete and the best-known smut, which has become a model to study molecular and cellular eukaryotic mechanisms. In this study, we performed in silico analysis to investigate the structural and biochemical properties of the putative UPF1 homolog in Ustilago maydis. The putative homolog for UPF1 was recognized in the annotated genome for the basidiomycete, exhibiting 66% identity with its human counterpart at the protein level. The known structural and functional domains characteristic of UPF1 homologs were also found. Based on the crystal structures available for UPF1, we constructed different three-dimensional models for umUPF1 in order to analyze the secondary and tertiary structural features of this factor. Using these models, we studied the spatial arrangement of umUPF1 and its capability to interact with UPF2. Moreover, we identified the critical amino acids that mediate the interaction of umUPF1 with UPF2, ATP, RNA and with UPF1 itself. Mutating these amino acids in silico showed an important effect over the native structure. Finally, we performed molecular dynamic simulations for UPF1 proteins from H. sapiens and U. maydis and the results obtained show a similar behavior and physicochemical properties for the protein in both organisms. Overall, our results indicate that the putative UPF1 identified in U. maydis shows a very similar sequence, structural organization, mechanical stability, physicochemical properties and spatial organization in comparison to the NMD factor depicted for Homo sapiens. These observations strongly support the notion that human and fungal UPF1 could perform equivalent biological activities.
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Affiliation(s)
- Nancy Martínez-Montiel
- Laboratorio de Ecología Molecular Microbiana, Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Laura Morales-Lara
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | | | - Rebeca D. Martínez-Contreras
- Laboratorio de Ecología Molecular Microbiana, Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, México
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16
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The RNA helicase DHX34 functions as a scaffold for SMG1-mediated UPF1 phosphorylation. Nat Commun 2016; 7:10585. [PMID: 26841701 PMCID: PMC4743010 DOI: 10.1038/ncomms10585] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 12/31/2015] [Indexed: 02/05/2023] Open
Abstract
Nonsense-mediated decay (NMD) is a messenger RNA quality-control pathway triggered by SMG1-mediated phosphorylation of the NMD factor UPF1. In recent times, the RNA helicase DHX34 was found to promote mRNP remodelling, leading to activation of NMD. Here we demonstrate the mechanism by which DHX34 functions in concert with SMG1. DHX34 comprises two distinct structural units, a core that binds UPF1 and a protruding carboxy-terminal domain (CTD) that binds the SMG1 kinase, as shown using truncated forms of DHX34 and electron microscopy of the SMG1–DHX34 complex. Truncation of the DHX34 CTD does not affect binding to UPF1; however, it compromises DHX34 binding to SMG1 to affect UPF1 phosphorylation and hence abrogate NMD. Altogether, these data suggest the existence of a complex comprising SMG1, UPF1 and DHX34, with DHX34 functioning as a scaffold for UPF1 and SMG1. This complex promotes UPF1 phosphorylation leading to functional NMD. UPF1 is a central Nonsense-mediated mRNA decay—(NMD), a mechanism to degrade mRNAs containing premature translation termination codons-factor—whose phosphorylation is key to triggering NMD. Here the authors show that the DHX34 helicase acts as a scaffold in promoting UPF1 phosphorylation by SMG1 to promotes NMD.
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17
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Fatscher T, Boehm V, Gehring NH. Mechanism, factors, and physiological role of nonsense-mediated mRNA decay. Cell Mol Life Sci 2015; 72:4523-44. [PMID: 26283621 PMCID: PMC11113733 DOI: 10.1007/s00018-015-2017-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 07/10/2015] [Accepted: 08/06/2015] [Indexed: 02/04/2023]
Abstract
Nonsense-mediated mRNA decay (NMD) is a translation-dependent, multistep process that degrades irregular or faulty messenger RNAs (mRNAs). NMD mainly targets mRNAs with a truncated open reading frame (ORF) due to premature termination codons (PTCs). In addition, NMD also regulates the expression of different types of endogenous mRNA substrates. A multitude of factors are involved in the tight regulation of the NMD mechanism. In this review, we focus on the molecular mechanism of mammalian NMD. Based on the published data, we discuss the involvement of translation termination in NMD initiation. Furthermore, we provide a detailed overview of the core NMD machinery, as well as several peripheral NMD factors, and discuss their function. Finally, we present an overview of diseases associated with NMD factor mutations and summarize the current state of treatment for genetic disorders caused by nonsense mutations.
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Affiliation(s)
- Tobias Fatscher
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Volker Boehm
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, Cologne, Germany.
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18
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He F, Jacobson A. Nonsense-Mediated mRNA Decay: Degradation of Defective Transcripts Is Only Part of the Story. Annu Rev Genet 2015; 49:339-66. [PMID: 26436458 DOI: 10.1146/annurev-genet-112414-054639] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is a eukaryotic surveillance mechanism that monitors cytoplasmic mRNA translation and targets mRNAs undergoing premature translation termination for rapid degradation. From yeasts to humans, activation of NMD requires the function of the three conserved Upf factors: Upf1, Upf2, and Upf3. Here, we summarize the progress in our understanding of the molecular mechanisms of NMD in several model systems and discuss recent experiments that address the roles of Upf1, the principal regulator of NMD, in the initial targeting and final degradation of NMD-susceptible mRNAs. We propose a unified model for NMD in which the Upf factors provide several functions during premature termination, including the stimulation of release factor activity and the dissociation and recycling of ribosomal subunits. In this model, the ultimate degradation of the mRNA is the last step in a complex premature termination process.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655; ,
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655; ,
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19
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Siwaszek A, Ukleja M, Dziembowski A. Proteins involved in the degradation of cytoplasmic mRNA in the major eukaryotic model systems. RNA Biol 2015; 11:1122-36. [PMID: 25483043 DOI: 10.4161/rna.34406] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The process of mRNA decay and surveillance is considered to be one of the main posttranscriptional gene expression regulation platforms in eukaryotes. The degradation of stable, protein-coding transcripts is normally initiated by removal of the poly(A) tail followed by 5'-cap hydrolysis and degradation of the remaining mRNA body by Xrn1. Alternatively, the exosome complex degrades mRNA in the 3'>5'direction. The newly discovered uridinylation-dependent pathway, which is present in many different organisms, also seems to play a role in bulk mRNA degradation. Simultaneously, to avoid the synthesis of incorrect proteins, special cellular machinery is responsible for the removal of faulty transcripts via nonsense-mediated, no-go, non-stop or non-functional 18S rRNA decay. This review is focused on the major eukaryotic cytoplasmic mRNA degradation pathways showing many similarities and pointing out main differences between the main model-species: yeast, Drosophila, plants and mammals.
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Affiliation(s)
- Aleksandra Siwaszek
- a Institute of Biochemistry and Biophysics ; Polish Academy of Sciences ; Warsaw , Poland
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20
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Li J, Silva-Sanchez C, Zhang T, Chen S, Li H. Phosphoproteomics technologies and applications in plant biology research. FRONTIERS IN PLANT SCIENCE 2015; 6:430. [PMID: 26136758 PMCID: PMC4468387 DOI: 10.3389/fpls.2015.00430] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/27/2015] [Indexed: 05/20/2023]
Abstract
Protein phosphorylation has long been recognized as an essential mechanism to regulate many important processes of plant life. However, studies on phosphorylation mediated signaling events in plants are challenged with low stoichiometry and dynamic nature of phosphorylated proteins. Significant advances in mass spectrometry based phosphoproteomics have taken place in recent decade, including phosphoprotein/phosphopeptide enrichment, detection and quantification, and phosphorylation site localization. This review describes a variety of separation and enrichment methods for phosphoproteins and phosphopeptides, the applications of technological innovations in plant phosphoproteomics, and highlights significant achievement of phosphoproteomics in the areas of plant signal transduction, growth and development.
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Affiliation(s)
- Jinna Li
- College of Life Sciences, Heilongjiang UniversityHarbin, China
| | - Cecilia Silva-Sanchez
- Proteomics and Mass Spectrometry, Interdisciplinary Center for Biotechnology Research, University of FloridaGainesville, FL, USA
| | - Tong Zhang
- Plant Molecular and Cellular Biology Program, Department of Biology, UF Genetics Institute, University of FloridaGainesville, FL, USA
| | - Sixue Chen
- College of Life Sciences, Heilongjiang UniversityHarbin, China
- Proteomics and Mass Spectrometry, Interdisciplinary Center for Biotechnology Research, University of FloridaGainesville, FL, USA
- Plant Molecular and Cellular Biology Program, Department of Biology, UF Genetics Institute, University of FloridaGainesville, FL, USA
| | - Haiying Li
- College of Life Sciences, Heilongjiang UniversityHarbin, China
- *Correspondence: Haiying Li, College of Life Sciences, Heilongjiang University, 74 Xuefu Rd, Harbin 150080, China
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21
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Shi M, Wang S, Yao Y, Li Y, Zhang H, Han F, Nie H, Su J, Wang Z, Yue L, Cao J, Li Y. Biological and clinical significance of epigenetic silencing of MARVELD1 gene in lung cancer. Sci Rep 2014; 4:7545. [PMID: 25520033 PMCID: PMC4269892 DOI: 10.1038/srep07545] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 12/01/2014] [Indexed: 01/20/2023] Open
Abstract
Epigenetic silence in cancer frequently altered signal-transduction pathways during the early stages of tumor development. Recent progress in the field of cancer epigenetics has led to new opportunities for diagnosis and treatment of cancer. We previously demonstrated that novel identified nuclear factor MARVELD1 was widely expressed in human tissues, but down-regulated by promoter methylation in multiple cancers. This study was carried out to determine the biological and clinical significance of MARVELD1 gene silencing in lung cancer. Here, we found the reduced MARVELD1 expression significantly correlated with diagnostic histopathology and malignant degree of lung cancers. DNA hypermethylation and histone deacetylation synergistically inactivated MARVELD1 gene in lung cancer cells. Moreover, MARVELD1 modulated the efficiency of nonsense-mediated mRNA decay (NMD) through interaction with NMD core factor SMG1. The decreased MARVELD1 level in lung cancer reduces NMD efficiency through diminishing the association between NMD complex component UPF1/SMG1 and premature termination codons containing mRNA (PTC-mRNA). The results suggested that MARVELD1 silencing is an appealing diagnostic biomarker for lung cancer and epigenetic silencing of MARVELD1 gene links with the regulatory mechanism of NMD pathway in lung cancer, which may be required for tumorigenesis.
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Affiliation(s)
- Ming Shi
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Shan Wang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Yuanfei Yao
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Yiqun Li
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Hao Zhang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Fang Han
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Huan Nie
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Jie Su
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Zeyu Wang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Lei Yue
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Jingyan Cao
- Department of Medical Oncology, Harbin Medical University Cancer Hospital, Harbin, China
| | - Yu Li
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
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22
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Celik A, Kervestin S, Jacobson A. NMD: At the crossroads between translation termination and ribosome recycling. Biochimie 2014; 114:2-9. [PMID: 25446649 DOI: 10.1016/j.biochi.2014.10.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 10/27/2014] [Indexed: 10/24/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is one of three regulatory mechanisms that monitor the cytoplasm for aberrant mRNAs. NMD is usually triggered by premature translation termination codons that arise from mutations, transcription errors, or inefficient splicing, but which also occur in transcripts with alternately spliced isoforms or upstream open reading frames, or in the context of long 3'-UTRs. This surveillance pathway requires detection of the nonsense codon by the eukaryotic release factors (eRF1 and eRF3) and the activities of the Upf proteins, but the exact mechanism by which a nonsense codon is recognized as premature, and the individual roles of the Upf proteins, are poorly understood. In this review, we highlight important differences between premature and normal termination. Based on our current understanding of normal termination and ribosome recycling, we propose a similar mechanism for premature termination events that includes a role for the Upf proteins. In this model, the Upf proteins not only target the mRNA and nascent peptide for degradation, but also assume the role of recycling factors and rescue a ribosome stalled at a premature nonsense codon. The ATPase and helicase activities of Upf1, with the help of Upf2 and Upf3, are thus thought to be the catalytic force in ribosome subunit dissociation and ribosome recycling at an otherwise poorly dissociable termination event. While this model is somewhat speculative, it provides a unified vision for current data and a direction for future research.
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Affiliation(s)
- Alper Celik
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01655-0122, USA
| | - Stephanie Kervestin
- CNRS FRE3630 Associated with Université Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01655-0122, USA.
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23
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Nicholson P, Josi C, Kurosawa H, Yamashita A, Mühlemann O. A novel phosphorylation-independent interaction between SMG6 and UPF1 is essential for human NMD. Nucleic Acids Res 2014; 42:9217-35. [PMID: 25053839 PMCID: PMC4132754 DOI: 10.1093/nar/gku645] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Eukaryotic mRNAs with premature translation-termination codons (PTCs) are recognized and eliminated by nonsense-mediated mRNA decay (NMD). NMD substrates can be degraded by different routes that all require phosphorylated UPF1 (P-UPF1) as a starting point. The endonuclease SMG6, which cleaves mRNA near the PTC, is one of the three known NMD factors thought to be recruited to nonsense mRNAs via an interaction with P-UPF1, leading to eventual mRNA degradation. By artificial tethering of SMG6 and mutants thereof to a reporter mRNA combined with knockdowns of various NMD factors, we demonstrate that besides its endonucleolytic activity, SMG6 also requires UPF1 and SMG1 to reduce reporter mRNA levels. Using in vivo and in vitro approaches, we further document that SMG6 and the unique stalk region of the UPF1 helicase domain, along with a contribution from the SQ domain, form a novel interaction and we also show that this region of the UPF1 helicase domain is critical for SMG6 function and NMD. Our results show that this interaction is required for NMD and for the capability of tethered SMG6 to degrade its bound RNA, suggesting that it contributes to the intricate regulation of UPF1 and SMG6 enzymatic activities.
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Affiliation(s)
- Pamela Nicholson
- Department of Chemistry and Biochemistry, University of Berne, Berne, CH-3012, Switzerland
| | - Christoph Josi
- Department of Chemistry and Biochemistry, University of Berne, Berne, CH-3012, Switzerland
| | - Hitomi Kurosawa
- Department of Microbiology, Yokohama City University, School of Medicine, 3-9, Fuku-ura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Akio Yamashita
- Department of Microbiology, Yokohama City University, School of Medicine, 3-9, Fuku-ura, Kanazawa-ku, Yokohama 236-0004, Japan
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Berne, Berne, CH-3012, Switzerland
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24
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Chakrabarti S, Bonneau F, Schüssler S, Eppinger E, Conti E. Phospho-dependent and phospho-independent interactions of the helicase UPF1 with the NMD factors SMG5-SMG7 and SMG6. Nucleic Acids Res 2014; 42:9447-60. [PMID: 25013172 PMCID: PMC4132714 DOI: 10.1093/nar/gku578] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a eukaryotic surveillance pathway that recognizes mRNAs with premature stop codons and targets them for rapid degradation. Evidence from previous studies has converged on UPF1 as the central NMD factor. In human cells, the SMG1 kinase phosphorylates UPF1 at the N-terminal and C-terminal tails, in turn allowing the recruitment of the NMD factors SMG5, SMG6 and SMG7. To understand the molecular mechanisms, we recapitulated these steps of NMD in vitro using purified components. We find that a short C-terminal segment of phosphorylated UPF1 containing the last two Ser-Gln motifs is recognized by the heterodimer of SMG5 and SMG7 14–3–3-like proteins. In contrast, the SMG6 14–3–3-like domain is a monomer. The crystal structure indicates that the phosphoserine binding site of the SMG6 14–3–3-like domain is similar to that of SMG5 and can mediate a weak phospho-dependent interaction with UPF1. The dominant SMG6–UPF1 interaction is mediated by a low-complexity region bordering the 14–3–3-like domain of SMG6 and by the helicase domain and C-terminal tail of UPF1. This interaction is phosphorylation independent. Our study demonstrates that SMG5–SMG7 and SMG6 exhibit different and non-overlapping modes of UPF1 recognition, thus pointing at distinguished roles in integrating the complex NMD interaction network.
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Affiliation(s)
- Sutapa Chakrabarti
- Max Planck Institute of Biochemistry, Structural Cell Biology Department, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Fabien Bonneau
- Max Planck Institute of Biochemistry, Structural Cell Biology Department, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Steffen Schüssler
- Max Planck Institute of Biochemistry, Structural Cell Biology Department, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Elfriede Eppinger
- Max Planck Institute of Biochemistry, Structural Cell Biology Department, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Elena Conti
- Max Planck Institute of Biochemistry, Structural Cell Biology Department, Am Klopferspitz 18, D-82152 Martinsried, Germany
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25
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Hoefig KP, Heissmeyer V. Degradation of oligouridylated histone mRNAs: see UUUUU and goodbye. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:577-89. [PMID: 24692427 DOI: 10.1002/wrna.1232] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 12/20/2022]
Abstract
During the cell cycle the expression of replication-dependent histones is tightly coupled to DNA synthesis. Histone messenger RNA (mRNA) levels strongly increase during early S-phase and rapidly decrease at the end of it. Here, we review the degradation of replication-dependent histone mRNAs, a paradigm of post-transcriptional gene regulation, in the context of processing, translation, and oligouridylation. Replication-dependent histone transcripts are characterized by the absence of introns and by the presence of a stem-loop structure at the 3' end of a very short 3' untranslated region (UTR). These features, together with a need for active translation, are a prerequisite for their rapid decay. The degradation is induced by 3' end additions of untemplated uridines, performed by terminal uridyl transferases. Such 3' oligouridylated transcripts are preferentially bound by the heteroheptameric LSM1-7 complex, which also interacts with the 3'→5' exonuclease ERI1 (also called 3'hExo). Presumably in cooperation with LSM1-7 and aided by the helicase UPF1, ERI1 degrades through the stem-loop of oligouridylated histone mRNAs in repeated rounds of partial degradation and reoligouridylation. Although histone mRNA decay is now known in some detail, important questions remain open: How is ceasing nuclear DNA replication relayed to the cytoplasmic histone mRNA degradation? Why is translation important for this process? Recent research on factors such as SLIP1, DBP5, eIF3, CTIF, CBP80/20, and ERI1 has provided new insights into the 3' end formation, the nuclear export, and the translation of histone mRNAs. We discuss how these results fit with the preparation of histone mRNAs for degradation, which starts as early as these transcripts are generated.
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Affiliation(s)
- Kai P Hoefig
- Institute of Molecular Immunology, Research Unit of Molecular Immune Regulation, Helmholtz Zentrum München, Munich, Germany
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