1
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Mars JC, Culjkovic-Kraljacic B, Borden KL. eIF4E orchestrates mRNA processing, RNA export and translation to modify specific protein production. Nucleus 2024; 15:2360196. [PMID: 38880976 PMCID: PMC11185188 DOI: 10.1080/19491034.2024.2360196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 05/22/2024] [Indexed: 06/18/2024] Open
Abstract
The eukaryotic translation initiation factor eIF4E acts as a multifunctional factor that simultaneously influences mRNA processing, export, and translation in many organisms. Its multifactorial effects are derived from its capacity to bind to the methyl-7-guanosine cap on the 5'end of mRNAs and thus can act as a cap chaperone for transcripts in the nucleus and cytoplasm. In this review, we describe the multifactorial roles of eIF4E in major mRNA-processing events including capping, splicing, cleavage and polyadenylation, nuclear export and translation. We discuss the evidence that eIF4E acts at two levels to generate widescale changes to processing, export and ultimately the protein produced. First, eIF4E alters the production of components of the mRNA processing machinery, supporting a widescale reprogramming of multiple mRNA processing events. In this way, eIF4E can modulate mRNA processing without physically interacting with target transcripts. Second, eIF4E also physically interacts with both capped mRNAs and components of the RNA processing or translation machineries. Further, specific mRNAs are sensitive to eIF4E only in particular mRNA processing events. This selectivity is governed by the presence of cis-acting elements within mRNAs known as USER codes that recruit relevant co-factors engaging the appropriate machinery. In all, we describe the molecular bases for eIF4E's multifactorial function and relevant regulatory pathways, discuss the basis for selectivity, present a compendium of ~80 eIF4E-interacting factors which play roles in these activities and provide an overview of the relevance of its functions to its oncogenic potential. Finally, we summarize early-stage clinical studies targeting eIF4E in cancer.
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Affiliation(s)
- Jean-Clément Mars
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC, Canada
| | - Biljana Culjkovic-Kraljacic
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC, Canada
| | - Katherine L.B. Borden
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC, Canada
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2
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Shin MK, Chang J, Park J, Lee HJ, Woo JS, Kim YK. Nonsense-mediated mRNA decay of mRNAs encoding a signal peptide occurs primarily after mRNA targeting to the endoplasmic reticulum. Mol Cells 2024; 47:100049. [PMID: 38513766 PMCID: PMC11016901 DOI: 10.1016/j.mocell.2024.100049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/16/2024] [Accepted: 03/17/2024] [Indexed: 03/23/2024] Open
Abstract
Translation of messenger ribonucleic acids (mRNAs) encoding integral membrane proteins or secreted proteins occurs on the surface of the endoplasmic reticulum (ER). When a nascent signal peptide is synthesized from the mRNAs, the ribosome-nascent chain complex (RNC) is recognized by the signal recognition particle (SRP) and then transported to the surface of the ER. The appropriate targeting of the RNC-SRP complex to the ER is monitored by a quality control pathway, a nuclear cap-binding complex (CBC)-ensured translational repression of RNC-SRP (CENTRE). In this study, using ribosome profiling of CBC-associated and eukaryotic translation initiation factor 4E-associated mRNAs, we reveal that, at the transcriptomic level, CENTRE is in charge of the translational repression of the CBC-RNC-SRP until the complex is specifically transported to the ER. We also find that CENTRE inhibits the nonsense-mediated mRNA decay (NMD) of mRNAs within the CBC-RNC-SRP. The NMD occurs only after the CBC-RNC-SRP is targeted to the ER and after eukaryotic translation initiation factor 4E replaces CBC. Our data indicate dual surveillance for properly targeting mRNAs encoding integral membrane or secretory proteins to the ER. CENTRE blocks gene expression at the translation level before the CBC-RNC-SRP delivery to the ER, and NMD monitors mRNA quality after its delivery to the ER.
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Affiliation(s)
- Min-Kyung Shin
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Jeeyoon Chang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Joori Park
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Hyuk-Joon Lee
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Jae-Sung Woo
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Yoon Ki Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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3
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Blake LA, De La Cruz A, Wu B. Imaging spatiotemporal translation regulation in vivo. Semin Cell Dev Biol 2024; 154:155-164. [PMID: 36963991 PMCID: PMC10514244 DOI: 10.1016/j.semcdb.2023.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023]
Abstract
Translation is regulated spatiotemporally to direct protein synthesis when and where it is needed. RNA localization and local translation have been observed in various subcellular compartments, allowing cells to rapidly and finely adjust their proteome post-transcriptionally. Local translation on membrane-bound organelles is important to efficiently synthesize proteins targeted to the organelles. Protein-RNA phase condensates restrict RNA spatially in membraneless organelles and play essential roles in translation regulation and RNA metabolism. In addition, the temporal translation kinetics not only determine the amount of protein produced, but also serve as an important checkpoint for the quality of ribosomes, mRNAs, and nascent proteins. Translation imaging provides a unique capability to study these fundamental processes in the native environment. Recent breakthroughs in imaging enabled real-time visualization of translation of single mRNAs, making it possible to determine the spatial distribution and key biochemical parameters of in vivo translation dynamics. Here we reviewed the recent advances in translation imaging methods and their applications to study spatiotemporal translation regulation in vivo.
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Affiliation(s)
- Lauren A Blake
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ana De La Cruz
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bin Wu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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4
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Kurosaki T, Rambout X, Maquat LE. FMRP-mediated spatial regulation of physiologic NMD targets in neuronal cells. Genome Biol 2024; 25:31. [PMID: 38263082 PMCID: PMC10804635 DOI: 10.1186/s13059-023-03146-x] [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: 05/16/2023] [Accepted: 12/14/2023] [Indexed: 01/25/2024] Open
Abstract
In non-polarized cells, nonsense-mediated mRNA decay (NMD) generally begins during the translation of newly synthesized mRNAs after the mRNAs are exported to the cytoplasm. Binding of the FMRP translational repressor to UPF1 on NMD targets mainly inhibits NMD. However, in polarized cells like neurons, FMRP additionally localizes mRNAs to cellular projections. Here, we review the literature and evaluate available transcriptomic data to conclude that, in neurons, the translation of physiologic NMD targets bound by FMRP is partially inhibited until the mRNAs localize to projections. There, FMRP displacement in response to signaling induces a burst in protein synthesis followed by rapid mRNA decay.
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA
| | - Xavier Rambout
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA.
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA.
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5
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Carrard J, Lejeune F. Nonsense-mediated mRNA decay, a simplified view of a complex mechanism. BMB Rep 2023; 56:625-632. [PMID: 38052423 PMCID: PMC10761751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/31/2023] [Accepted: 11/17/2023] [Indexed: 12/07/2023] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is both a quality control mechanism and a gene regulation pathway. It has been studied for more than 30 years, with an accumulation of many mechanistic details that have often led to debate and hence to different models of NMD activation, particularly in higher eukaryotes. Two models seem to be opposed, since the first requires intervention of the exon junction complex (EJC) to recruit NMD factors downstream of the premature termination codon (PTC), whereas the second involves an EJC-independent mechanism in which NMD factors concentrate in the 3'UTR to initiate NMD in the presence of a PTC. In this review we describe both models, giving recent molecular details and providing experimental arguments supporting one or the other model. In the end it is certainly possible to imagine that these two mechanisms co-exist, rather than viewing them as mutually exclusive. [BMB Reports 2023; 56(12): 625-632].
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Affiliation(s)
- Julie Carrard
- Univ. Lille, CNRS, Inserm, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, Lille F-59000, France
| | - Fabrice Lejeune
- Univ. Lille, CNRS, Inserm, UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, Lille F-59000, France
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6
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Meydan S, Guydosh NR. Is there a localized role for translational quality control? RNA (NEW YORK, N.Y.) 2023; 29:1623-1643. [PMID: 37582617 PMCID: PMC10578494 DOI: 10.1261/rna.079683.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
It is known that mRNAs and the machinery that translates them are not uniformly distributed throughout the cytoplasm. As a result, the expression of some genes is localized to particular parts of the cell and this makes it possible to carry out important activities, such as growth and signaling, in three-dimensional space. However, the functions of localized gene expression are not fully understood, and the underlying mechanisms that enable localized expression have not been determined in many cases. One consideration that could help in addressing these challenges is the role of quality control (QC) mechanisms that monitor translating ribosomes. On a global level, QC pathways are critical for detecting aberrant translation events, such as a ribosome that stalls while translating, and responding by activating stress pathways and resolving problematic ribosomes and mRNAs at the molecular level. However, it is unclear how these pathways, even when uniformly active throughout the cell, affect local translation. Importantly, some QC pathways have themselves been reported to be enriched in the proximity of particular organelles, but the extent of such localized activity remains largely unknown. Here, we describe the major QC pathways and review studies that have begun to explore their roles in localized translation. Given the limited data in this area, we also pose broad questions about the possibilities and limitations for how QC pathways could facilitate localized gene expression in the cell with the goal of offering ideas for future experimentation.
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Affiliation(s)
- Sezen Meydan
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nicholas R Guydosh
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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7
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Karousis ED, Mühlemann O. The broader sense of nonsense. Trends Biochem Sci 2022; 47:921-935. [PMID: 35780009 DOI: 10.1016/j.tibs.2022.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/30/2022] [Accepted: 06/08/2022] [Indexed: 12/21/2022]
Abstract
The term 'nonsense-mediated mRNA decay' (NMD) was initially coined to describe the translation-dependent degradation of mRNAs harboring premature termination codons (PTCs), but it is meanwhile known that NMD also targets many canonical mRNAs with numerous biological implications. The molecular mechanisms determining on which RNAs NMD ensues are only partially understood. Considering the broad range of NMD-sensitive RNAs and the variable degrees of their degradation, we highlight here the hallmarks of mammalian NMD and point out open questions. We review the links between NMD and disease by summarizing the role of NMD in cancer, neurodegeneration, and viral infections. Finally, we describe strategies to modulate NMD activity and specificity as potential therapeutic approaches for various diseases.
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Affiliation(s)
- Evangelos D Karousis
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.
| | - Oliver Mühlemann
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.
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8
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Marques AR, Santos JX, Martiniano H, Vilela J, Rasga C, Romão L, Vicente AM. Gene Variants Involved in Nonsense-Mediated mRNA Decay Suggest a Role in Autism Spectrum Disorder. Biomedicines 2022; 10:biomedicines10030665. [PMID: 35327467 PMCID: PMC8945030 DOI: 10.3390/biomedicines10030665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 02/07/2023] Open
Abstract
Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental condition with unclear etiology. Many genes have been associated with ASD risk, but the underlying mechanisms are still poorly understood. An important post-transcriptional regulatory mechanism that plays an essential role during neurodevelopment, the Nonsense-Mediated mRNA Decay (NMD) pathway, may contribute to ASD risk. In this study, we gathered a list of 46 NMD factors and regulators and investigated the role of genetic variants in these genes in ASD. By conducting a comprehensive search for Single Nucleotide Variants (SNVs) in NMD genes using Whole Exome Sequencing data from 1828 ASD patients, we identified 270 SNVs predicted to be damaging in 28.7% of the population. We also analyzed Copy Number Variants (CNVs) from two cohorts of ASD patients (N = 3570) and discovered 38 CNVs in 1% of cases. Importantly, we discovered 136 genetic variants (125 SNVs and 11 CNVs) in 258 ASD patients that were located within protein domains required for NMD. These gene variants are classified as damaging using in silico prediction tools, and therefore may interfere with proper NMD function in ASD. The discovery of NMD genes as candidates for ASD in large patient genomic datasets provides evidence supporting the involvement of the NMD pathway in ASD pathophysiology.
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Affiliation(s)
- Ana Rita Marques
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - João Xavier Santos
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - Hugo Martiniano
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - Joana Vilela
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - Célia Rasga
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
| | - Luísa Romão
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
- Departamento de Genética Humana, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal
| | - Astrid Moura Vicente
- Departamento de Promoção da Saúde e Doenças Não Transmissíveis, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal; (A.R.M.); (J.X.S.); (H.M.); (J.V.); (C.R.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal;
- Correspondence:
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9
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Gilbert A, Saveanu C. Unusual SMG suspects recruit degradation enzymes in nonsense-mediated mRNA decay. Bioessays 2022; 44:e2100296. [PMID: 35266563 DOI: 10.1002/bies.202100296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/27/2022] [Accepted: 03/02/2022] [Indexed: 11/09/2022]
Abstract
Degradation of eukaryotic RNAs that contain premature termination codons (PTC) during nonsense-mediated mRNA decay (NMD) is initiated by RNA decapping or endonucleolytic cleavage driven by conserved factors. Models for NMD mechanisms, including recognition of PTCs or the timing and role of protein phosphorylation for RNA degradation are challenged by new results. For example, the depletion of the SMG5/7 heterodimer, thought to activate RNA degradation by decapping, leads to a phenotype showing a defect of endonucleolytic activity of NMD complexes. This phenotype is not correlated to a decreased binding of the endonuclease SMG6 with the core NMD factor UPF1, suggesting that it is the result of an imbalance between active (e.g., in polysomes) and inactive (e.g., in RNA-protein condensates) states of NMD complexes. Such imbalance between multiple complexes is not restricted to NMD and should be taken into account when establishing causal links between gene function perturbation and observed phenotypes.
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Affiliation(s)
- Agathe Gilbert
- Institut Pasteur, Sorbonne Université, CNRS UMR-3525, Paris, F-75015, France
| | - Cosmin Saveanu
- Institut Pasteur, Sorbonne Université, CNRS UMR-3525, Paris, F-75015, France
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10
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Udy DB, Bradley RK. Nonsense-mediated mRNA decay uses complementary mechanisms to suppress mRNA and protein accumulation. Life Sci Alliance 2022; 5:e202101217. [PMID: 34880103 PMCID: PMC8711849 DOI: 10.26508/lsa.202101217] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/13/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is an essential, highly conserved quality control pathway that detects and degrades mRNAs containing premature termination codons. Although the essentiality of NMD is frequently ascribed to its prevention of truncated protein accumulation, the extent to which NMD actually suppresses proteins encoded by NMD-sensitive transcripts is less well-understood than NMD-mediated suppression of mRNA. Here, we describe a reporter system that permits accurate quantification of both mRNA and protein levels via stable integration of paired reporters encoding NMD-sensitive and NMD-insensitive transcripts into the AAVS1 safe harbor loci in human cells. We use this system to demonstrate that NMD suppresses proteins encoded by NMD-sensitive transcripts by up to eightfold more than the mRNA itself. Our data indicate that NMD limits the accumulation of proteins encoded by NMD substrates by mechanisms beyond mRNA degradation, such that even when NMD-sensitive mRNAs escape destruction, their encoded proteins are still effectively suppressed.
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Affiliation(s)
- Dylan B Udy
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA, USA
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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11
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Mars JC, Ghram M, Culjkovic-Kraljacic B, Borden KLB. The Cap-Binding Complex CBC and the Eukaryotic Translation Factor eIF4E: Co-Conspirators in Cap-Dependent RNA Maturation and Translation. Cancers (Basel) 2021; 13:6185. [PMID: 34944805 PMCID: PMC8699206 DOI: 10.3390/cancers13246185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 12/26/2022] Open
Abstract
The translation of RNA into protein is a dynamic process which is heavily regulated during normal cell physiology and can be dysregulated in human malignancies. Its dysregulation can impact selected groups of RNAs, modifying protein levels independently of transcription. Integral to their suitability for translation, RNAs undergo a series of maturation steps including the addition of the m7G cap on the 5' end of RNAs, splicing, as well as cleavage and polyadenylation (CPA). Importantly, each of these steps can be coopted to modify the transcript signal. Factors that bind the m7G cap escort these RNAs through different steps of maturation and thus govern the physical nature of the final transcript product presented to the translation machinery. Here, we describe these steps and how the major m7G cap-binding factors in mammalian cells, the cap binding complex (CBC) and the eukaryotic translation initiation factor eIF4E, are positioned to chaperone transcripts through RNA maturation, nuclear export, and translation in a transcript-specific manner. To conceptualize a framework for the flow and integration of this genetic information, we discuss RNA maturation models and how these integrate with translation. Finally, we discuss how these processes can be coopted by cancer cells and means to target these in malignancy.
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Affiliation(s)
- Jean-Clement Mars
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Mehdi Ghram
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Biljana Culjkovic-Kraljacic
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Katherine L B Borden
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
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12
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UPF1: From mRNA Surveillance to Protein Quality Control. Biomedicines 2021; 9:biomedicines9080995. [PMID: 34440199 PMCID: PMC8392595 DOI: 10.3390/biomedicines9080995] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/03/2021] [Accepted: 08/05/2021] [Indexed: 12/20/2022] Open
Abstract
Selective recognition and removal of faulty transcripts and misfolded polypeptides are crucial for cell viability. In eukaryotic cells, nonsense-mediated mRNA decay (NMD) constitutes an mRNA surveillance pathway for sensing and degrading aberrant transcripts harboring premature termination codons (PTCs). NMD functions also as a post-transcriptional gene regulatory mechanism by downregulating naturally occurring mRNAs. As NMD is activated only after a ribosome reaches a PTC, PTC-containing mRNAs inevitably produce truncated and potentially misfolded polypeptides as byproducts. To cope with the emergence of misfolded polypeptides, eukaryotic cells have evolved sophisticated mechanisms such as chaperone-mediated protein refolding, rapid degradation of misfolded polypeptides through the ubiquitin–proteasome system, and sequestration of misfolded polypeptides to the aggresome for autophagy-mediated degradation. In this review, we discuss how UPF1, a key NMD factor, contributes to the selective removal of faulty transcripts via NMD at the molecular level. We then highlight recent advances on UPF1-mediated communication between mRNA surveillance and protein quality control.
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13
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Park Y, Park J, Hwang HJ, Kim L, Jeong K, Song HK, Rufener SC, Mühlemann O, Kim YK. Translation mediated by the nuclear cap-binding complex is confined to the perinuclear region via a CTIF-DDX19B interaction. Nucleic Acids Res 2021; 49:8261-8276. [PMID: 34232997 PMCID: PMC8373075 DOI: 10.1093/nar/gkab579] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 06/08/2021] [Accepted: 06/23/2021] [Indexed: 12/29/2022] Open
Abstract
Newly synthesized mRNA is translated during its export through the nuclear pore complex, when its 5′-cap structure is still bound by the nuclear cap-binding complex (CBC), a heterodimer of cap-binding protein (CBP) 80 and CBP20. Despite its critical role in mRNA surveillance, the mechanism by which CBC-dependent translation (CT) is regulated remains unknown. Here, we demonstrate that the CT initiation factor (CTIF) is tethered in a translationally incompetent manner to the perinuclear region by the DEAD-box helicase 19B (DDX19B). DDX19B hands over CTIF to CBP80, which is associated with the 5′-cap of a newly exported mRNA. The resulting CBP80–CTIF complex then initiates CT in the perinuclear region. We also show that impeding the interaction between CTIF and DDX19B leads to uncontrolled CT throughout the cytosol, consequently dysregulating nonsense-mediated mRNA decay. Altogether, our data provide molecular evidence supporting the importance of tight control of local translation in the perinuclear region.
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Affiliation(s)
- Yeonkyoung Park
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul 02841, Republic of Korea.,Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Joori Park
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul 02841, Republic of Korea.,Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Hyun Jung Hwang
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul 02841, Republic of Korea.,Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Leehyeon Kim
- Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Kwon Jeong
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul 02841, Republic of Korea.,Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Hyun Kyu Song
- Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Simone C Rufener
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Yoon Ki Kim
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul 02841, Republic of Korea.,Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
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14
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Zhu X, Zhang H, Mendell JT. Ribosome Recycling by ABCE1 Links Lysosomal Function and Iron Homeostasis to 3' UTR-Directed Regulation and Nonsense-Mediated Decay. Cell Rep 2021; 32:107895. [PMID: 32668236 PMCID: PMC7433747 DOI: 10.1016/j.celrep.2020.107895] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 06/09/2020] [Accepted: 06/22/2020] [Indexed: 12/26/2022] Open
Abstract
Nonsense-mediated decay (NMD) is a pathway that degrades mRNAs containing premature termination codons. Here we describe a genome-wide screen for NMD factors that uncovers an unexpected mechanism that broadly governs 3' untranslated region (UTR)-directed regulation. The screen reveals that NMD requires lysosomal acidification, which allows transferrin-mediated iron uptake, which, in turn, is necessary for iron-sulfur (Fe-S) cluster biogenesis. This pathway maintains the activity of the Fe-S cluster-containing ribosome recycling factor ABCE1, whose impaired function results in movement of ribosomes into 3' UTRs, where they displace exon junction complexes, abrogating NMD. Importantly, these effects extend beyond NMD substrates, with ABCE1 activity required to maintain the accessibility of 3' UTRs to diverse regulators, including microRNAs and RNA binding proteins. Because of the sensitivity of the Fe-S cluster of ABCE1 to iron availability and reactive oxygen species, these findings reveal an unanticipated vulnerability of 3' UTR-directed regulation to lysosomal dysfunction, iron deficiency, and oxidative stress.
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Affiliation(s)
- Xiaoqiang Zhu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - He Zhang
- Quantitative Biomedical Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Joshua T Mendell
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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15
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Maudlin IE, Kelly S, Schwede A, Carrington M. VSG mRNA levels are regulated by the production of functional VSG protein. Mol Biochem Parasitol 2021; 241:111348. [PMID: 33352254 PMCID: PMC7871013 DOI: 10.1016/j.molbiopara.2020.111348] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 02/06/2023]
Abstract
The bloodstream form of Trypanosoma brucei persists in mammalian hosts through a population survival strategy depending on antigenic variation of a cell surface coat composed of the variant surface glycoprotein (VSG). The integrity of the VSG coat is essential and blocking its synthesis results in a cell division cycle arrest just prior to cytokinesis. This observation indicates that VSG levels are monitored and that the cell has mechanisms to respond to a disruption of synthesis. Here, the regulation of VSG mRNA levels has been investigated by first measuring VSG mRNA copy number, and second using ectopic expression of VSG transgenes containing premature termination codons. The findings are that (i) VSG mRNA copy number varies with the identity of the VSG and (ii) a pathway detects synthesis of non-functional VSG protein and results in an increase in VSG mRNA levels.
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Affiliation(s)
- Isabella E Maudlin
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom
| | - Steve Kelly
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, United Kingdom
| | - Angela Schwede
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom.
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom.
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16
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May JP, Simon AE. Targeting of viral RNAs by Upf1-mediated RNA decay pathways. Curr Opin Virol 2020; 47:1-8. [PMID: 33341474 DOI: 10.1016/j.coviro.2020.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/10/2020] [Accepted: 11/12/2020] [Indexed: 12/25/2022]
Abstract
Viral RNAs are susceptible to co-translational RNA decay pathways mediated by the RNA helicase Upstream frameshift 1 (Upf1). Upf1 is a key component in nonsense-mediated decay (NMD), Staufen1-mediated mRNA decay (SMD), and structure-mediated RNA decay (SRD) pathways, among others. Diverse families of viruses have features that predispose them to Upf1 targeting, but have evolved means to escape decay through the action of cis-acting or trans-acting viral factors. Studies aimed at understanding how viruses are subjected to and circumvent NMD have increased our understanding of NMD target selection of host mRNAs. This review focuses on the knowledge gained from studying NMD in viral systems as well as related Upf1-dependent pathways and how these pathways restrict virus replication.
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Affiliation(s)
- Jared P May
- Department of Cell and Molecular Biology and Biochemistry, School of Biological and Chemical Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
| | - Anne E Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland - College Park, College Park, MD, USA.
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17
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Dou Y, Kalmykova S, Pashkova M, Oghbaie M, Jiang H, Molloy KR, Chait BT, Rout MP, Fenyö D, Jensen TH, Altukhov I, LaCava J. Affinity proteomic dissection of the human nuclear cap-binding complex interactome. Nucleic Acids Res 2020; 48:10456-10469. [PMID: 32960270 PMCID: PMC7544204 DOI: 10.1093/nar/gkaa743] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/22/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022] Open
Abstract
A 5′,7-methylguanosine cap is a quintessential feature of RNA polymerase II-transcribed RNAs, and a textbook aspect of co-transcriptional RNA processing. The cap is bound by the cap-binding complex (CBC), canonically consisting of nuclear cap-binding proteins 1 and 2 (NCBP1/2). Interest in the CBC has recently renewed due to its participation in RNA-fate decisions via interactions with RNA productive factors as well as with adapters of the degradative RNA exosome. A novel cap-binding protein, NCBP3, was recently proposed to form an alternative CBC together with NCBP1, and to interact with the canonical CBC along with the protein SRRT. The theme of post-transcriptional RNA fate, and how it relates to co-transcriptional ribonucleoprotein assembly, is abundant with complicated, ambiguous, and likely incomplete models. In an effort to clarify the compositions of NCBP1-, 2- and 3-related macromolecular assemblies, we have applied an affinity capture-based interactome screen where the experimental design and data processing have been modified to quantitatively identify interactome differences between targets under a range of experimental conditions. This study generated a comprehensive view of NCBP-protein interactions in the ribonucleoprotein context and demonstrates the potential of our approach to benefit the interpretation of complex biological pathways.
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Affiliation(s)
- Yuhui Dou
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | - Maria Pashkova
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Mehrnoosh Oghbaie
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, USA.,European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Hua Jiang
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, USA
| | - Kelly R Molloy
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, USA
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, USA
| | - David Fenyö
- Department of Biochemistry and Molecular Pharmacology, Institute for Systems Genetics, NYU Langone Health, New York, USA
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Ilya Altukhov
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, USA.,European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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18
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Abstract
Viruses have evolved in tandem with the organisms that they infect. Afflictions of the plant and animal kingdoms with viral infections have forced the host organism to evolve new or exploit existing systems to develop the countermeasures needed to offset viral insults. As one example, nonsense-mediated mRNA decay, a cellular quality-control mechanism ensuring the translational fidelity of mRNA transcripts, has been used to restrict virus replication in both plants and animals. In response, viruses have developed a slew of means to disrupt or become insensitive to NMD, providing researchers with potential new reagents that can be used to more fully understand the NMD mechanism.
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Affiliation(s)
- Maximilian Wei-Lin Popp
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Hana Cho
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
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19
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Gerbracht JV, Boehm V, Britto-Borges T, Kallabis S, Wiederstein JL, Ciriello S, Aschemeier DU, Krüger M, Frese CK, Altmüller J, Dieterich C, Gehring NH. CASC3 promotes transcriptome-wide activation of nonsense-mediated decay by the exon junction complex. Nucleic Acids Res 2020; 48:8626-8644. [PMID: 32621609 PMCID: PMC7470949 DOI: 10.1093/nar/gkaa564] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/20/2020] [Accepted: 07/01/2020] [Indexed: 01/08/2023] Open
Abstract
The exon junction complex (EJC) is an essential constituent and regulator of spliced messenger ribonucleoprotein particles (mRNPs) in metazoans. As a core component of the EJC, CASC3 was described to be pivotal for EJC-dependent nuclear and cytoplasmic processes. However, recent evidence suggests that CASC3 functions differently from other EJC core proteins. Here, we have established human CASC3 knockout cell lines to elucidate the cellular role of CASC3. In the knockout cells, overall EJC composition and EJC-dependent splicing are unchanged. A transcriptome-wide analysis reveals that hundreds of mRNA isoforms targeted by nonsense-mediated decay (NMD) are upregulated. Mechanistically, recruiting CASC3 to reporter mRNAs by direct tethering or via binding to the EJC stimulates mRNA decay and endonucleolytic cleavage at the termination codon. Building on existing EJC-NMD models, we propose that CASC3 equips the EJC with the persisting ability to communicate with the NMD machinery in the cytoplasm. Collectively, our results characterize CASC3 as a peripheral EJC protein that tailors the transcriptome by promoting the degradation of EJC-dependent NMD substrates.
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Affiliation(s)
| | - Volker Boehm
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - Thiago Britto-Borges
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, University of Heidelberg, 69120 Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Sebastian Kallabis
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janica L Wiederstein
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Simona Ciriello
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | | | - Marcus Krüger
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Christian K Frese
- CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, University of Heidelberg, 69120 Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Niels H Gehring
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
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20
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Schieweck R, Ninkovic J, Kiebler MA. RNA-binding proteins balance brain function in health and disease. Physiol Rev 2020; 101:1309-1370. [PMID: 33000986 DOI: 10.1152/physrev.00047.2019] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Posttranscriptional gene expression including splicing, RNA transport, translation, and RNA decay provides an important regulatory layer in many if not all molecular pathways. Research in the last decades has positioned RNA-binding proteins (RBPs) right in the center of posttranscriptional gene regulation. Here, we propose interdependent networks of RBPs to regulate complex pathways within the central nervous system (CNS). These are involved in multiple aspects of neuronal development and functioning, including higher cognition. Therefore, it is not sufficient to unravel the individual contribution of a single RBP and its consequences but rather to study and understand the tight interplay between different RBPs. In this review, we summarize recent findings in the field of RBP biology and discuss the complex interplay between different RBPs. Second, we emphasize the underlying dynamics within an RBP network and how this might regulate key processes such as neurogenesis, synaptic transmission, and synaptic plasticity. Importantly, we envision that dysfunction of specific RBPs could lead to perturbation within the RBP network. This would have direct and indirect (compensatory) effects in mRNA binding and translational control leading to global changes in cellular expression programs in general and in synaptic plasticity in particular. Therefore, we focus on RBP dysfunction and how this might cause neuropsychiatric and neurodegenerative disorders. Based on recent findings, we propose that alterations in the entire regulatory RBP network might account for phenotypic dysfunctions observed in complex diseases including neurodegeneration, epilepsy, and autism spectrum disorders.
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Affiliation(s)
- Rico Schieweck
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Jovica Ninkovic
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Michael A Kiebler
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
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21
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The Branched Nature of the Nonsense-Mediated mRNA Decay Pathway. Trends Genet 2020; 37:143-159. [PMID: 33008628 DOI: 10.1016/j.tig.2020.08.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/11/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is a conserved translation-coupled quality control mechanism in all eukaryotes that regulates the expression of a significant fraction of both the aberrant and normal transcriptomes. In vertebrates, NMD has become an essential process owing to expansion of the diversity of NMD-regulated transcripts, particularly during various developmental processes. Surprisingly, however, some core NMD factors that are essential for NMD in simpler organisms appear to be dispensable for vertebrate NMD. At the same time, numerous NMD enhancers and suppressors have been identified in multicellular organisms including vertebrates. Collectively, the available data suggest that vertebrate NMD is a complex, branched pathway wherein individual branches regulate specific mRNA subsets to fulfill distinct physiological functions.
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22
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Kurilla A, Szőke A, Auber A, Káldi K, Silhavy D. Expression of the translation termination factor eRF1 is autoregulated by translational readthrough and 3'UTR intron-mediated NMD in Neurospora crassa. FEBS Lett 2020; 594:3504-3517. [PMID: 32869294 DOI: 10.1002/1873-3468.13918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/30/2020] [Accepted: 08/17/2020] [Indexed: 01/24/2023]
Abstract
Eukaryotic release factor 1 (eRF1) is a translation termination factor that binds to the ribosome at stop codons. The expression of eRF1 is strictly controlled, since its concentration defines termination efficiency and frequency of translational readthrough. Here, we show that eRF1 expression in Neurospora crassa is controlled by an autoregulatory circuit that depends on the specific 3'UTR structure of erf1 mRNA. The stop codon context of erf1 promotes readthrough that protects the mRNA from its 3'UTR-induced nonsense-mediated mRNA decay (NMD). High eRF1 concentration leads to inefficient readthrough, thereby allowing NMD-mediated erf1 degradation. We propose that eRF1 expression is controlled by similar autoregulatory circuits in many fungi and seed plants and discuss the evolution of autoregulatory systems of different translation termination factors.
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Affiliation(s)
- Anita Kurilla
- Department of Genetics, NARIC, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Anita Szőke
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Andor Auber
- Department of Genetics, NARIC, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Krisztina Káldi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Dániel Silhavy
- Department of Genetics, NARIC, Agricultural Biotechnology Institute, Gödöllő, Hungary.,Biological Research Centre, Institute of Plant Biology, Szeged, Hungary
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23
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Adachi H, Yu YT. Pseudouridine-mediated stop codon readthrough in S. cerevisiae is sequence context-independent. RNA (NEW YORK, N.Y.) 2020; 26:1247-1256. [PMID: 32434780 PMCID: PMC7430670 DOI: 10.1261/rna.076042.120] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/19/2020] [Indexed: 05/26/2023]
Abstract
We have previously shown that when the uridine of a stop codon (UAA, UAG, or UGA) is pseudouridylated, the ribosome reads through the modified stop codon. However, it is not clear as to whether or not the pseudouridine (Ψ)-mediated readthrough is dependent on the sequence context of mRNA. Here, we use several different approaches and the yeast system to address this question. We show that when a stop codon (premature termination codon, PTC) is introduced into the coding region of a reporter mRNA at several different positions (with different sequence contexts) and pseudouridylated, we detect similar levels of readthrough. Using mutational and selection/screen analyses, we also show that the upstream sequence (relative to PTC) as well as the nucleotides surrounding the PTC (upstream and downstream) play a minimal role (if at all) in Ψ-mediated ribosome readthrough. Interestingly, we detect no suppression of NMD (nonsense-mediated mRNA decay) by targeted PTC pseudouridylation in the yeast system. Our results indicate that Ψ-mediated nonsense suppression occurs at the translational level, and that the suppression is sequence context-independent, unlike some previously characterized rare stop codon readthrough events.
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Affiliation(s)
- Hironori Adachi
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, New York 14642, USA
| | - Yi-Tao Yu
- Department of Biochemistry and Biophysics, Center for RNA Biology, University of Rochester Medical Center, Rochester, New York 14642, USA
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24
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Karousis ED, Gurzeler LA, Annibaldis G, Dreos R, Mühlemann O. Human NMD ensues independently of stable ribosome stalling. Nat Commun 2020; 11:4134. [PMID: 32807779 PMCID: PMC7431590 DOI: 10.1038/s41467-020-17974-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 07/20/2020] [Indexed: 12/18/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a translation-dependent RNA degradation pathway that is important for the elimination of faulty, and the regulation of normal, mRNAs. The molecular details of the early steps in NMD are not fully understood but previous work suggests that NMD activation occurs as a consequence of ribosome stalling at the termination codon (TC). To test this hypothesis, we established an in vitro translation-coupled toeprinting assay based on lysates from human cells that allows monitoring of ribosome occupancy at the TC of reporter mRNAs. In contrast to the prevailing NMD model, our in vitro system reveals similar ribosomal occupancy at the stop codons of NMD-sensitive and NMD-insensitive reporter mRNAs. Moreover, ribosome profiling reveals a similar density of ribosomes at the TC of endogenous NMD-sensitive and NMD-insensitive mRNAs in vivo. Together, these data show that NMD activation is not accompanied by stable stalling of ribosomes at TCs. Nonsense-mediated mRNA decay (NMD) was thought to ensue when ribosomes fail to terminate translation properly. However, the authors observe similar ribosome occupancy at stop codons of NMD sensitive and insensitive mRNAs, showing that human NMD is not activated by stable ribosome stalling as previously suggested.
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Affiliation(s)
- Evangelos D Karousis
- Department of Chemistry and Biochemistry, University of Bern, CH-3012, Bern, Switzerland
| | - Lukas-Adrian Gurzeler
- Department of Chemistry and Biochemistry, University of Bern, CH-3012, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, CH-3012, Bern, Switzerland
| | - Giuditta Annibaldis
- Department of Chemistry and Biochemistry, University of Bern, CH-3012, Bern, Switzerland
| | - René Dreos
- Center for Integrative Genomics, Université de Lausanne, CH-1015, Lausanne, Switzerland
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, CH-3012, Bern, Switzerland.
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25
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Dave P, Chao JA. Insights into mRNA degradation from single-molecule imaging in living cells. Curr Opin Struct Biol 2020; 65:89-95. [PMID: 32659634 DOI: 10.1016/j.sbi.2020.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/15/2020] [Accepted: 06/02/2020] [Indexed: 10/23/2022]
Abstract
Single-molecule fluorescence microscopy techniques have enabled the lifecycle of individual RNA transcripts to be quantitatively measured in living cells. The application of these approaches to monitor mRNA degradation, however, has presented a challenge to unequivocally detect these events due to the inherent loss-of-signal resulting from decay of a transcript. Here, we highlight the recent technological developments that have enabled the spatial and temporal dynamics of mRNA degradation of individual transcripts to be visualized within living cells.
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Affiliation(s)
- Pratik Dave
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Jeffrey A Chao
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.
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26
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Lavysh D, Neu-Yilik G. UPF1-Mediated RNA Decay-Danse Macabre in a Cloud. Biomolecules 2020; 10:E999. [PMID: 32635561 PMCID: PMC7407380 DOI: 10.3390/biom10070999] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/18/2020] [Accepted: 06/29/2020] [Indexed: 12/21/2022] Open
Abstract
Nonsense-mediated RNA decay (NMD) is the prototype example of a whole family of RNA decay pathways that unfold around a common central effector protein called UPF1. While NMD in yeast appears to be a linear pathway, NMD in higher eukaryotes is a multifaceted phenomenon with high variability with respect to substrate RNAs, degradation efficiency, effector proteins and decay-triggering RNA features. Despite increasing knowledge of the mechanistic details, it seems ever more difficult to define NMD and to clearly distinguish it from a growing list of other UPF1-mediated RNA decay pathways (UMDs). With a focus on mammalian, we here critically examine the prevailing NMD models and the gaps and inconsistencies in these models. By exploring the minimal requirements for NMD and other UMDs, we try to elucidate whether they are separate and definable pathways, or rather variations of the same phenomenon. Finally, we suggest that the operating principle of the UPF1-mediated decay family could be considered similar to that of a computing cloud providing a flexible infrastructure with rapid elasticity and dynamic access according to specific user needs.
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Affiliation(s)
- Daria Lavysh
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany;
- Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany
- Department Clinical Pediatric Oncology, Hopp Kindertumorzentrum am NCT Heidelberg, 69120 Heidelberg, Germany
| | - Gabriele Neu-Yilik
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany;
- Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany
- Department Clinical Pediatric Oncology, Hopp Kindertumorzentrum am NCT Heidelberg, 69120 Heidelberg, Germany
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27
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Nonsense-mediated mRNA decay factor UPF1 promotes aggresome formation. Nat Commun 2020; 11:3106. [PMID: 32561765 PMCID: PMC7305299 DOI: 10.1038/s41467-020-16939-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 05/30/2020] [Indexed: 12/13/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) typifies an mRNA surveillance pathway. Because NMD necessitates a translation event to recognize a premature termination codon on mRNAs, truncated misfolded polypeptides (NMD-polypeptides) could potentially be generated from NMD substrates as byproducts. Here, we show that when the ubiquitin–proteasome system is overwhelmed, various misfolded polypeptides including NMD-polypeptides accumulate in the aggresome: a perinuclear nonmembranous compartment eventually cleared by autophagy. Hyperphosphorylation of the key NMD factor UPF1 is required for selective targeting of the misfolded polypeptide aggregates toward the aggresome via the CTIF–eEF1A1–DCTN1 complex: the aggresome-targeting cellular machinery. Visualization at a single-particle level reveals that UPF1 increases the frequency and fidelity of movement of CTIF aggregates toward the aggresome. Furthermore, the apoptosis induced by proteotoxic stresses is suppressed by UPF1 hyperphosphorylation. Altogether, our data provide evidence that UPF1 functions in the regulation of a protein surveillance as well as an mRNA quality control. Nonsense-mediated mRNA decay (NMD) is a translation-coupled process that eliminates mRNAs containing premature translation-termination codons. Here the authors identify a role for the NMD factor UPF1 in protein quality control, whereby truncated misfolded polypeptides are cleared through autophagy.
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Borden KLB, Volpon L. The diversity, plasticity, and adaptability of cap-dependent translation initiation and the associated machinery. RNA Biol 2020; 17:1239-1251. [PMID: 32496897 PMCID: PMC7549709 DOI: 10.1080/15476286.2020.1766179] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Translation initiation is a critical facet of gene expression with important impacts that underlie cellular responses to stresses and environmental cues. Its dysregulation in many diseases position this process as an important area for the development of new therapeutics. The gateway translation factor eIF4E is typically considered responsible for ‘global’ or ‘canonical’ m7G cap-dependent translation. However, eIF4E impacts translation of specific transcripts rather than the entire translatome. There are many alternative cap-dependent translation mechanisms that also contribute to the translation capacity of the cell. We review the diversity of these, juxtaposing more recently identified mechanisms with eIF4E-dependent modalities. We also explore the multiplicity of functions played by translation factors, both within and outside protein synthesis, and discuss how these differentially contribute to their ultimate physiological impacts. For comparison, we discuss some modalities for cap-independent translation. In all, this review highlights the diverse mechanisms that engage and control translation in eukaryotes.
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Affiliation(s)
- Katherine L B Borden
- Institute of Research in Immunology and Cancer (IRIC), Department of Pathology and Cell Biology, Université de Montréal , Montreal, Québec, Canada
| | - Laurent Volpon
- Institute of Research in Immunology and Cancer (IRIC), Department of Pathology and Cell Biology, Université de Montréal , Montreal, Québec, Canada
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29
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PABPN1, a Target of p63, Modulates Keratinocyte Differentiation through Regulation of p63α mRNA Translation. J Invest Dermatol 2020; 140:2166-2177.e6. [PMID: 32243883 DOI: 10.1016/j.jid.2020.03.942] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/04/2020] [Accepted: 03/09/2020] [Indexed: 01/25/2023]
Abstract
p63 is expressed from two promoters and produces two N-terminal isoforms, TAp63 and ΔNp63. Alternative splicing creates three C-terminal isoforms p63α, p63β, and p63δ, whereas alternative polyadenylation (APA) in coding sequence creates two more C-terminal isoforms p63γ and p63ε. Although several transcription factors have been identified to differentially regulate the N-terminal p63 isoforms, it is unclear how the C-terminal p63 isoforms are regulated. Thus, we determined whether PABPN1, a key regulator of APA, may differentially regulate the C-terminal p63 isoforms. We found that PABPN1 deficiency increases p63γ mRNA through APA in coding sequence. We also found that PABPN1 is necessary for p63α translation by modulating the binding of translation initiation factors eIF4E and eIF4G to p63α mRNA. Moreover, we found that the p53 family, especially p63α, regulates PABPN1 transcription, suggesting that the mutual regulation between p63 and PABPN1 forms a feedback loop. Furthermore, we found that PABPN1 deficiency inhibits keratinocyte cell growth, which can be rescued by ectopic ΔNp63α. Finally, we found that PABPN1 controls the terminal differentiation of HaCaT keratinocytes by modulating ΔNp63α expression. Taken together, our findings suggest that PABPN1 is a key regulator of the C-terminal p63 isoforms through APA in coding sequence and mRNA translation and that the p63-PABPN1 loop modulates p63 activity and the APA landscape.
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30
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Kurosaki T, Popp MW, Maquat LE. Quality and quantity control of gene expression by nonsense-mediated mRNA decay. Nat Rev Mol Cell Biol 2020; 20:406-420. [PMID: 30992545 DOI: 10.1038/s41580-019-0126-2] [Citation(s) in RCA: 428] [Impact Index Per Article: 107.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonsense-mediated mRNA decay (NMD) is one of the best characterized and most evolutionarily conserved cellular quality control mechanisms. Although NMD was first found to target one-third of mutated, disease-causing mRNAs, it is now known to also target ~10% of unmutated mammalian mRNAs to facilitate appropriate cellular responses - adaptation, differentiation or death - to environmental changes. Mutations in NMD genes in humans are associated with intellectual disability and cancer. In this Review, we discuss how NMD serves multiple purposes in human cells by degrading both mutated mRNAs to protect the integrity of the transcriptome and normal mRNAs to control the quantities of unmutated transcripts.
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.,Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Maximilian W Popp
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.,Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA. .,Center for RNA Biology, University of Rochester, Rochester, NY, USA.
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31
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Mechanisms and Regulation of Nonsense-Mediated mRNA Decay and Nonsense-Associated Altered Splicing in Lymphocytes. Int J Mol Sci 2020; 21:ijms21041335. [PMID: 32079193 PMCID: PMC7072976 DOI: 10.3390/ijms21041335] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 12/11/2022] Open
Abstract
The presence of premature termination codons (PTCs) in transcripts is dangerous for the cell as they encode potentially deleterious truncated proteins that can act with dominant-negative or gain-of-function effects. To avoid the synthesis of these shortened polypeptides, several RNA surveillance systems can be activated to decrease the level of PTC-containing mRNAs. Nonsense-mediated mRNA decay (NMD) ensures an accelerated degradation of mRNAs harboring PTCs by using several key NMD factors such as up-frameshift (UPF) proteins. Another pathway called nonsense-associated altered splicing (NAS) upregulates transcripts that have skipped disturbing PTCs by alternative splicing. Thus, these RNA quality control processes eliminate abnormal PTC-containing mRNAs from the cells by using positive and negative responses. In this review, we describe the general mechanisms of NMD and NAS and their respective involvement in the decay of aberrant immunoglobulin and TCR transcripts in lymphocytes.
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32
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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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33
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Sulkowska A, Auber A, Sikorski PJ, Silhavy DN, Auth M, Sitkiewicz E, Jean V, Merret RM, Bousquet-Antonelli CC, Kufel J. RNA Helicases from the DEA(D/H)-Box Family Contribute to Plant NMD Efficiency. PLANT & CELL PHYSIOLOGY 2020; 61:144-157. [PMID: 31560399 DOI: 10.1093/pcp/pcz186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 09/16/2019] [Indexed: 06/10/2023]
Abstract
Nonsense-mediated mRNA decay (NMD) is a conserved eukaryotic RNA surveillance mechanism that degrades aberrant mRNAs comprising a premature translation termination codon. The adenosine triphosphate (ATP)-dependent RNA helicase up-frameshift 1 (UPF1) is a major NMD factor in all studied organisms; however, the complexity of this mechanism has not been fully characterized in plants. To identify plant NMD factors, we analyzed UPF1-interacting proteins using tandem affinity purification coupled to mass spectrometry. Canonical members of the NMD pathway were found along with numerous NMD candidate factors, including conserved DEA(D/H)-box RNA helicase homologs of human DDX3, DDX5 and DDX6, translation initiation factors, ribosomal proteins and transport factors. Our functional studies revealed that depletion of DDX3 helicases enhances the accumulation of NMD target reporter mRNAs but does not result in increased protein levels. In contrast, silencing of DDX6 group leads to decreased accumulation of the NMD substrate. The inhibitory effect of DDX6-like helicases on NMD was confirmed by transient overexpression of RH12 helicase. These results indicate that DDX3 and DDX6 helicases in plants have a direct and opposing contribution to NMD and act as functional NMD factors.
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Affiliation(s)
- Aleksandra Sulkowska
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Andor Auber
- Agricultural Biotechnology Institute, Szent-Gy�rgyi 4, H-2100 G�d�llő, Hungary
| | - Pawel J Sikorski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Dï Niel Silhavy
- Agricultural Biotechnology Institute, Szent-Gy�rgyi 4, H-2100 G�d�llő, Hungary
| | - Mariann Auth
- Agricultural Biotechnology Institute, Szent-Gy�rgyi 4, H-2100 G�d�llő, Hungary
| | - Ewa Sitkiewicz
- Proteomics Laboratory, Biophysics Department, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warszawa, Poland
| | - Viviane Jean
- UMR5096 LGDP, Universit� de Perpignan Via Domitia, UMR5096 LGDP58, Avenue Paul Alduy, 66860 Perpignan Cedex, France
- CNRS, UMR5096 LGDP, Perpignan Cedex, France
| | - Rï My Merret
- UMR5096 LGDP, Universit� de Perpignan Via Domitia, UMR5096 LGDP58, Avenue Paul Alduy, 66860 Perpignan Cedex, France
- CNRS, UMR5096 LGDP, Perpignan Cedex, France
| | - Cï Cile Bousquet-Antonelli
- UMR5096 LGDP, Universit� de Perpignan Via Domitia, UMR5096 LGDP58, Avenue Paul Alduy, 66860 Perpignan Cedex, France
- CNRS, UMR5096 LGDP, Perpignan Cedex, France
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
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34
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Mino T, Iwai N, Endo M, Inoue K, Akaki K, Hia F, Uehata T, Emura T, Hidaka K, Suzuki Y, Standley DM, Okada-Hatakeyama M, Ohno S, Sugiyama H, Yamashita A, Takeuchi O. Translation-dependent unwinding of stem-loops by UPF1 licenses Regnase-1 to degrade inflammatory mRNAs. Nucleic Acids Res 2019; 47:8838-8859. [PMID: 31329944 PMCID: PMC7145602 DOI: 10.1093/nar/gkz628] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/05/2019] [Accepted: 07/12/2019] [Indexed: 01/14/2023] Open
Abstract
Regnase-1-mediated mRNA decay (RMD), in which inflammatory mRNAs harboring specific stem–loop structures are degraded, is a critical part of proper immune homeostasis. Prior to initial translation, Regnase-1 associates with target stem–loops but does not carry out endoribonucleolytic cleavage. Single molecule imaging revealed that UPF1 is required to first unwind the stem–loops, thus licensing Regnase-1 to proceed with RNA degradation. Following translation, Regnase-1 physically associates with UPF1 using two distinct points of interaction: The Regnase-1 RNase domain binds to SMG1-phosphorylated residue T28 in UPF1; in addition, an intrinsically disordered segment in Regnase-1 binds to the UPF1 RecA domain, enhancing the helicase activity of UPF1. The SMG1-UPF1–Regnase-1 axis targets pioneer rounds of translation and is critical for rapid resolution of inflammation through restriction of the number of proteins translated by a given mRNA. Furthermore, small-molecule inhibition of SMG1 prevents RNA unwinding in dendritic cells, allowing post-transcriptional control of innate immune responses.
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Affiliation(s)
- Takashi Mino
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Noriki Iwai
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Masayuki Endo
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.,Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kentaro Inoue
- Department of Computer Science and Systems Engineering, Faculty of Engineering, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Kotaro Akaki
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Fabian Hia
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Takuya Uehata
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Tomoko Emura
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kumi Hidaka
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yutaka Suzuki
- Laboratory of Functional Genomics, Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
| | - Daron M Standley
- Department of Genome Informatics, Genome Information Research Center, Research Institute for Microbial Diseases (RIMD), Osaka University, Osaka 565-0871, Japan
| | - Mariko Okada-Hatakeyama
- Laboratory for Integrated Cellular Systems, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan.,Laboratory of Cell Systems, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Shigeo Ohno
- Department of Molecular Biology, Yokohama City University School of Medicine, Kanagawa 236-0004, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.,Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Akio Yamashita
- Department of Molecular Biology, Yokohama City University School of Medicine, Kanagawa 236-0004, Japan
| | - Osamu Takeuchi
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
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35
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Hoek TA, Khuperkar D, Lindeboom RGH, Sonneveld S, Verhagen BMP, Boersma S, Vermeulen M, Tanenbaum ME. Single-Molecule Imaging Uncovers Rules Governing Nonsense-Mediated mRNA Decay. Mol Cell 2019; 75:324-339.e11. [PMID: 31155380 PMCID: PMC6675935 DOI: 10.1016/j.molcel.2019.05.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 03/15/2019] [Accepted: 05/07/2019] [Indexed: 01/09/2023]
Abstract
Nonsense-mediated decay (NMD) is a surveillance system that degrades mRNAs containing a premature termination codon (PTC) and plays important roles in protein homeostasis and disease. The efficiency of NMD is variable, impacting the clinical outcome of genetic mutations. However, limited resolution of bulk analyses has hampered the study of NMD efficiency. Here, we develop an assay to visualize NMD of individual mRNA molecules in real time. We find that NMD occurs with equal probability during each round of translation of an mRNA molecule. However, this probability is variable and depends on the exon sequence downstream of the PTC, the PTC-to-intron distance, and the number of introns both upstream and downstream of the PTC. Additionally, a subpopulation of mRNAs can escape NMD, further contributing to variation in NMD efficiency. Our study uncovers real-time dynamics of NMD, reveals key mechanisms that influence NMD efficiency, and provides a powerful method to study NMD.
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Affiliation(s)
- Tim A Hoek
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Deepak Khuperkar
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Rik G H Lindeboom
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, Nijmegen 6500 HB, the Netherlands
| | - Stijn Sonneveld
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Bram M P Verhagen
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Sanne Boersma
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University Nijmegen, Nijmegen 6500 HB, the Netherlands
| | - Marvin E Tanenbaum
- Oncode Institute, Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, the Netherlands.
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36
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Chaudhary S, Jabre I, Reddy ASN, Staiger D, Syed NH. Perspective on Alternative Splicing and Proteome Complexity in Plants. TRENDS IN PLANT SCIENCE 2019; 24:496-506. [PMID: 30852095 DOI: 10.1016/j.tplants.2019.02.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/28/2019] [Accepted: 02/08/2019] [Indexed: 05/02/2023]
Abstract
Alternative splicing (AS) generates multiple transcripts from the same gene, however, AS contribution to proteome complexity remains elusive in plants. AS is prevalent under stress conditions in plants, but it is counterintuitive why plants would invest in protein synthesis under declining energy supply. We propose that plants employ AS not only to potentially increasing proteomic complexity, but also to buffer against the stress-responsive transcriptome to reduce the metabolic cost of translating all AS transcripts. To maximise efficiency under stress, plants may make fewer proteins with disordered domains via AS to diversify substrate specificity and maintain sufficient regulatory capacity. Furthermore, we suggest that chromatin state-dependent AS engenders short/long-term stress memory to mediate reproducible transcriptional response in the future.
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Affiliation(s)
- Saurabh Chaudhary
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK; These authors contributed equally to this work
| | - Ibtissam Jabre
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK; These authors contributed equally to this work
| | - Anireddy S N Reddy
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1878, USA
| | - Dorothee Staiger
- RNA Biology and Molecular Physiology, Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Naeem H Syed
- School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK.
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37
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Fluorescence Imaging Methods to Investigate Translation in Single Cells. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032722. [PMID: 30082468 DOI: 10.1101/cshperspect.a032722] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Translation is the fundamental biological process that converts the genetic information in messenger RNAs (mRNAs) into functional proteins. Translation regulation allows cells to control when, where, and how many proteins are synthesized. Much of what we know about translation comes from ensemble approaches that measure the average of many cells. The cellular and molecular heterogeneity in the regulation of translation remains largely elusive. Fluorescence microscopy allows interrogation of biological problems with single-molecule, single-cell sensitivity. In recent years, improved design of reagents and microscopy tools has led to improved spatial and temporal resolution of translation imaging. It is now possible to track global translation in specific subcellular compartments and follow the translation dynamics of single transcripts. Highlighted here is the recent progress in translation imaging with emphasis on in vivo translation dynamics. These tools will be invaluable to the study of translation regulation.
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38
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Kim YK, Maquat LE. UPFront and center in RNA decay: UPF1 in nonsense-mediated mRNA decay and beyond. RNA (NEW YORK, N.Y.) 2019; 25:407-422. [PMID: 30655309 PMCID: PMC6426291 DOI: 10.1261/rna.070136.118] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nonsense-mediated mRNA decay (NMD), which is arguably the best-characterized translation-dependent regulatory pathway in mammals, selectively degrades mRNAs as a means of post-transcriptional gene control. Control can be for the purpose of ensuring the quality of gene expression. Alternatively, control can facilitate the adaptation of cells to changes in their environment. The key to NMD, no matter what its purpose, is the ATP-dependent RNA helicase upstream frameshift 1 (UPF1), without which NMD fails to occur. However, UPF1 does much more than regulate NMD. As examples, UPF1 is engaged in functionally diverse mRNA decay pathways mediated by a variety of RNA-binding proteins that include staufen, stem-loop-binding protein, glucocorticoid receptor, and regnase 1. Moreover, UPF1 promotes tudor-staphylococcal/micrococcal-like nuclease-mediated microRNA decay. In this review, we first focus on how the NMD machinery recognizes an NMD target and triggers mRNA degradation. Next, we compare and contrast the mechanisms by which UPF1 functions in the decay of other mRNAs and also in microRNA decay. UPF1, as a protein polymath, engenders cells with the ability to shape their transcriptome in response to diverse biological and physiological needs.
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Affiliation(s)
- Yoon Ki Kim
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul 02841, Republic of Korea
- Division of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
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39
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Karousis ED, Mühlemann O. Nonsense-Mediated mRNA Decay Begins Where Translation Ends. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032862. [PMID: 29891560 DOI: 10.1101/cshperspect.a032862] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is arguably the best-studied eukaryotic messenger RNA (mRNA) surveillance pathway, yet fundamental questions concerning the molecular mechanism of target RNA selection remain unsolved. Besides degrading defective mRNAs harboring premature termination codons (PTCs), NMD also targets many mRNAs encoding functional full-length proteins. Thus, NMD impacts on a cell's transcriptome and is implicated in a range of biological processes that affect a broad spectrum of cellular homeostasis. Here, we focus on the steps involved in the recognition of NMD targets and the activation of NMD. We summarize the accumulating evidence that tightly links NMD to translation termination and we further discuss the recruitment and activation of the mRNA degradation machinery and the regulation of this complex series of events. Finally, we review emerging ideas concerning the mechanistic details of NMD activation and the potential role of NMD as a general surveyor of translation efficacy.
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Affiliation(s)
- Evangelos D Karousis
- Department of Chemistry and Biochemistry, University of Bern, CH-3012 Bern, Switzerland
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, CH-3012 Bern, Switzerland
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40
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Jaffrey SR, Wilkinson MF. Nonsense-mediated RNA decay in the brain: emerging modulator of neural development and disease. Nat Rev Neurosci 2018; 19:715-728. [PMID: 30410025 PMCID: PMC6396682 DOI: 10.1038/s41583-018-0079-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Steady-state RNA levels are controlled by the balance between RNA synthesis and RNA turnover. A selective RNA turnover mechanism that has received recent attention in neurons is nonsense-mediated RNA decay (NMD). NMD has been shown to influence neural development, neural stem cell differentiation decisions, axon guidance and synaptic plasticity. In humans, NMD factor gene mutations cause some forms of intellectual disability and are associated with neurodevelopmental disorders, including schizophrenia and autism spectrum disorder. Impairments in NMD are linked to neurodegenerative disorders, including amyotrophic lateral sclerosis. We discuss these findings, their clinical implications and challenges for the future.
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Affiliation(s)
- Samie R Jaffrey
- Department of Pharmacology, Weill Medical College, Cornell University, New York, NY, USA.
| | - Miles F Wilkinson
- Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, La Jolla, CA, USA.
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41
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Abstract
In mammals, cap-dependent translation of mRNAs is initiated by two distinct mechanisms: cap-binding complex (CBC; a heterodimer of CBP80 and 20)-dependent translation (CT) and eIF4E-dependent translation (ET). Both translation initiation mechanisms share common features in driving cap-dependent translation; nevertheless, they can be distinguished from each other based on their molecular features and biological roles. CT is largely associated with mRNA surveillance such as nonsense-mediated mRNA decay (NMD), whereas ET is predominantly involved in the bulk of protein synthesis. However, several recent studies have demonstrated that CT and ET have similar roles in protein synthesis and mRNA surveillance. In a subset of mRNAs, CT preferentially drives the cap-dependent translation, as ET does, and ET is responsible for mRNA surveillance, as CT does. In this review, we summarize and compare the molecular features of CT and ET with a focus on the emerging roles of CT in translation.
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Affiliation(s)
- Incheol Ryu
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul 02841,
Korea
- School of Life Sciences, Korea University, Seoul 02841,
Korea
| | - Yoon Ki Kim
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul 02841,
Korea
- School of Life Sciences, Korea University, Seoul 02841,
Korea
- Corresponding author. Tel: +82-2-3290-3410; Fax: +82-2-923-9923; E-mail:
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42
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Lejeune F. Nonsense-mediated mRNA decay at the crossroads of many cellular pathways. BMB Rep 2018; 50:175-185. [PMID: 28115040 PMCID: PMC5437961 DOI: 10.5483/bmbrep.2017.50.4.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Indexed: 12/22/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a surveillance mechanism ensuring the fast decay of mRNAs harboring a premature termination codon (PTC). As a quality control mechanism, NMD distinguishes PTCs from normal termination codons in order to degrade PTC-carrying mRNAs only. For this, NMD is connected to various other cell processes which regulate or activate it under specific cell conditions or in response to mutations, mis-regulations, stresses, or particular cell programs. These cell processes and their connections with NMD are the focus of this review, which aims both to illustrate the complexity of the NMD mechanism and its regulation and to highlight the cellular consequences of NMD inhibition.
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Affiliation(s)
- Fabrice Lejeune
- University Lille, UMR8161 - M3T - Mechanisms of Tumorigenesis and Target Therapies; CNRS, UMR 8161, 3Institut Pasteur de Lille, F-59000 Lille, France
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43
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Martinez-Nunez RT, Wallace A, Coyne D, Jansson L, Rush M, Ennajdaoui H, Katzman S, Bailey J, Deinhardt K, Sanchez-Elsner T, Sanford JR. Modulation of nonsense mediated decay by rapamycin. Nucleic Acids Res 2017; 45:3448-3459. [PMID: 27899591 PMCID: PMC5389481 DOI: 10.1093/nar/gkw1109] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 10/28/2016] [Indexed: 01/24/2023] Open
Abstract
Rapamycin is a naturally occurring macrolide whose target is at the core of nutrient and stress regulation in a wide range of species. Despite well-established roles as an inhibitor of cap-dependent mRNA translation, relatively little is known about its effects on other modes of RNA processing. Here, we characterize the landscape of rapamycin-induced post-transcriptional gene regulation. Transcriptome analysis of rapamycin-treated cells reveals genome-wide changes in alternative mRNA splicing and pronounced changes in NMD-sensitive isoforms. We demonstrate that despite well-documented attenuation of cap-dependent mRNA translation, rapamycin can augment NMD of certain transcripts. Rapamycin-treatment significantly reduces the levels of both endogenous and exogenous Premature Termination Codon (PTC)-containing mRNA isoforms and its effects are dose-, UPF1- and 4EBP-dependent. The PTC-containing SRSF6 transcript exhibits a shorter half-life upon rapamycin-treatment as compared to the non-PTC isoform. Rapamycin-treatment also causes depletion of PTC-containing mRNA isoforms from polyribosomes, underscoring the functional relationship between translation and NMD. Enhanced NMD activity also correlates with an enrichment of the nuclear Cap Binding Complex (CBC) in rapamycin-treated cells. Our data demonstrate that rapamycin modulates global RNA homeostasis by NMD.
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Affiliation(s)
- Rocio T Martinez-Nunez
- University of California Santa Cruz, Department of Molecular, Cellular and Developmental Biology, Santa Cruz, CA 95064, USA.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Andrew Wallace
- University of California Santa Cruz, Department of Molecular, Cellular and Developmental Biology, Santa Cruz, CA 95064, USA
| | - Doyle Coyne
- University of California Santa Cruz, Department of Molecular, Cellular and Developmental Biology, Santa Cruz, CA 95064, USA
| | - Linnea Jansson
- University of California Santa Cruz, Department of Molecular, Cellular and Developmental Biology, Santa Cruz, CA 95064, USA
| | - Miles Rush
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Hanane Ennajdaoui
- University of California Santa Cruz, Department of Molecular, Cellular and Developmental Biology, Santa Cruz, CA 95064, USA
| | - Sol Katzman
- Center for Biomolecular Science and Engineering, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95060, USA
| | - Joanne Bailey
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Katrin Deinhardt
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Tilman Sanchez-Elsner
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Jeremy R Sanford
- University of California Santa Cruz, Department of Molecular, Cellular and Developmental Biology, Santa Cruz, CA 95064, USA
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44
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Celik A, He F, Jacobson A. NMD monitors translational fidelity 24/7. Curr Genet 2017; 63:1007-1010. [PMID: 28536849 PMCID: PMC5668330 DOI: 10.1007/s00294-017-0709-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 05/17/2017] [Accepted: 05/18/2017] [Indexed: 11/30/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is generally thought to be a eukaryotic mRNA surveillance pathway tasked with the elimination of transcripts harboring an in-frame premature termination codon (PTC). As presently conceived, NMD acting in this manner minimizes the likelihood that potentially toxic polypeptide fragments would accumulate in the cytoplasm. This notion is to be contrasted to the results of systematic RNA-Seq and microarray analyses of NMD substrates in multiple model systems, two different experimental approaches which have shown that many mRNAs identified as NMD substrates fail to contain a PTC. Our recent results provide insight into, as well as a possible solution for, this conundrum. By high-resolution profiling of mRNAs that accumulate in yeast when the principal NMD regulatory genes (UPF1, UPF2, and UPF3) are deleted, we identified approximately 900 NMD substrates, the majority of which are normal-looking mRNAs that lack PTCs. Analyses of ribosomal profiling data revealed that the latter mRNAs tended to manifest elevated rates of out-of-frame translation, a phenomenon that would lead to premature translation termination in alternative reading frames. These results, and related observations of heterogeneity in mRNA isoforms, suggest that NMD should be reconsidered as a probabilistic mRNA quality control pathway that is continually active throughout an mRNA’s life cycle.
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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, USA
| | - Feng He
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01655, USA
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01655, USA.
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45
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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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46
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Brogna S, McLeod T, Petric M. The Meaning of NMD: Translate or Perish. Trends Genet 2016; 32:395-407. [PMID: 27185236 DOI: 10.1016/j.tig.2016.04.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/02/2016] [Accepted: 04/25/2016] [Indexed: 02/08/2023]
Abstract
Premature translation termination leads to a reduced mRNA level in all types of organisms. In eukaryotes, the phenomenon is known as nonsense-mediated mRNA decay (NMD). This is commonly regarded as the output of a specific surveillance and destruction mechanism that is activated by the presence of a premature translation termination codon (PTC) in an atypical sequence context. Despite two decades of research, it is still unclear how NMD discriminates between PTCs and normal stop codons. We suggest that cells do not possess any such mechanism and instead propose a new model in which this mRNA depletion is a consequence of the appearance of long tracts of mRNA that are unprotected by scanning ribosomes.
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Affiliation(s)
- Saverio Brogna
- University of Birmingham, School of Biosciences, Edgbaston, Birmingham, B15 2TT, UK.
| | - Tina McLeod
- University of Birmingham, School of Biosciences, Edgbaston, Birmingham, B15 2TT, UK
| | - Marija Petric
- University of Birmingham, School of Biosciences, Edgbaston, Birmingham, B15 2TT, UK
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47
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Karousis ED, Nasif S, Mühlemann O. Nonsense-mediated mRNA decay: novel mechanistic insights and biological impact. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:661-82. [PMID: 27173476 PMCID: PMC6680220 DOI: 10.1002/wrna.1357] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/31/2016] [Accepted: 04/04/2016] [Indexed: 12/19/2022]
Abstract
Nonsense‐mediated mRNA decay (NMD) was originally coined to define a quality control mechanism that targets mRNAs with truncated open reading frames due to the presence of a premature termination codon. Meanwhile, it became clear that NMD has a much broader impact on gene expression and additional biological functions beyond quality control are continuously being discovered. We review here the current views regarding the molecular mechanisms of NMD, according to which NMD ensues on mRNAs that fail to terminate translation properly, and point out the gaps in our understanding. We further summarize the recent literature on an ever‐rising spectrum of biological processes in which NMD appears to be involved, including homeostatic control of gene expression, development and differentiation, as well as viral defense. WIREs RNA 2016, 7:661–682. doi: 10.1002/wrna.1357 This article is categorized under:
RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Turnover and Surveillance > Regulation of RNA Stability
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Affiliation(s)
| | - Sofia Nasif
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
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48
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Schweingruber C, Soffientini P, Ruepp MD, Bachi A, Mühlemann O. Identification of Interactions in the NMD Complex Using Proximity-Dependent Biotinylation (BioID). PLoS One 2016; 11:e0150239. [PMID: 26934103 PMCID: PMC4774922 DOI: 10.1371/journal.pone.0150239] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/02/2016] [Indexed: 01/09/2023] Open
Abstract
Proximity-dependent trans-biotinylation by the Escherichia coli biotin ligase BirA mutant R118G (BirA*) allows stringent streptavidin affinity purification of proximal proteins. This so-called BioID method provides an alternative to the widely used co-immunoprecipitation (co-IP) to identify protein-protein interactions. Here, we used BioID, on its own and combined with co-IP, to identify proteins involved in nonsense-mediated mRNA decay (NMD), a post-transcriptional mRNA turnover pathway that targets mRNAs that fail to terminate translation properly. In particular, we expressed BirA* fused to the well characterized NMD factors UPF1, UPF2 and SMG5 and detected by liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS) the streptavidin-purified biotinylated proteins. While the identified already known interactors confirmed the usefulness of BioID, we also found new potentially important interactors that have escaped previous detection by co-IP, presumably because they associate only weakly and/or very transiently with the NMD machinery. Our results suggest that SMG5 only transiently contacts the UPF1-UPF2-UPF3 complex and that it provides a physical link to the decapping complex. In addition, BioID revealed among others CRKL and EIF4A2 as putative novel transient interactors with NMD factors, but whether or not they have a function in NMD remains to be elucidated.
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Affiliation(s)
- Christoph Schweingruber
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | | | - Marc-David Ruepp
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Angela Bachi
- IFOM-FIRC Institute of Molecular Oncology, Milan, Italy
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
- * E-mail:
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49
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Abstract
Nonsense-mediated mRNA decay (NMD) is an mRNA quality-control mechanism that typifies all eukaryotes examined to date. NMD surveys newly synthesized mRNAs and degrades those that harbor a premature termination codon (PTC), thereby preventing the production of truncated proteins that could result in disease in humans. This is evident from dominantly inherited diseases that are due to PTC-containing mRNAs that escape NMD. Although many cellular NMD targets derive from mistakes made during, for example, pre-mRNA splicing and, possibly, transcription initiation, NMD also targets ∼10% of normal physiological mRNAs so as to promote an appropriate cellular response to changing environmental milieus, including those that induce apoptosis, maturation or differentiation. Over the past ∼35 years, a central goal in the NMD field has been to understand how cells discriminate mRNAs that are targeted by NMD from those that are not. In this Cell Science at a Glance and the accompanying poster, we review progress made towards this goal, focusing on human studies and the role of the key NMD factor up-frameshift protein 1 (UPF1).
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
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50
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Park J, Ahn S, Jayabalan AK, Ohn T, Koh HC, Hwang J. Insulin Signaling Augments eIF4E-Dependent Nonsense-Mediated mRNA Decay in Mammalian Cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1859:896-905. [PMID: 26708722 DOI: 10.1016/j.bbagrm.2015.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 12/14/2015] [Accepted: 12/17/2015] [Indexed: 12/13/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) modulates the level of mRNA harboring a premature termination codon (PTC) in a translation-dependent manner. Inhibition of translation is known to impair NMD; however, few studies have investigated the correlation between enhanced translation and increased NMD. Here, we demonstrate that insulin signaling events increase translation, leading to an increase in NMD of eIF4E-bound transcripts. We provide evidence that (i) insulin-mediated enhancement of translation augments NMD and rapamycin abrogates this enhancement; (ii) an increase in AKT phosphorylation due to inhibition of PTEN facilitates NMD; (iii) insulin stimulation increases the binding of up-frameshift factor 1 (UPF1), most likely to eIF4E-bound PTC-containing transcripts; and (iv) insulin stimulation induces the colocalization of UPF1 and eIF4E in processing bodies. These results illustrate how extracellular signaling promotes the removal of eIF4E-bound NMD targets.
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Affiliation(s)
- Jungyun Park
- Graduate School for Biomedical Science & Engineering, FTC1202-8, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Seyoung Ahn
- Graduate School for Biomedical Science & Engineering, FTC1202-8, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Aravinth K Jayabalan
- Department of Cellular and Molecular Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Takbum Ohn
- Department of Cellular and Molecular Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea
| | - Hyun Chul Koh
- Department of Pharmacology, College of Medicine, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
| | - Jungwook Hwang
- Graduate School for Biomedical Science & Engineering, FTC1202-8, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea; Department of Medical Genetics, College of Medicine, FTC1202-8, Hanyang University, 222 Wangimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
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