1
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Vidya E, Jami-Alahmadi Y, Mayank AK, Rizwan J, Xu JMS, Cheng T, Leventis R, Sonenberg N, Wohlschlegel JA, Vera M, Duchaine TF. EDC-3 and EDC-4 regulate embryonic mRNA clearance and biomolecular condensate specialization. Cell Rep 2024; 43:114781. [PMID: 39331503 DOI: 10.1016/j.celrep.2024.114781] [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: 03/20/2024] [Revised: 08/09/2024] [Accepted: 09/05/2024] [Indexed: 09/29/2024] Open
Abstract
Animal development is dictated by the selective and timely decay of mRNAs in developmental transitions, but the impact of mRNA decapping scaffold proteins in development is unclear. This study unveils the roles and interactions of the DCAP-2 decapping scaffolds EDC-3 and EDC-4 in the embryonic development of C. elegans. EDC-3 facilitates the timely removal of specific embryonic mRNAs, including cgh-1, car-1, and ifet-1 by reducing their expression and preventing excessive accumulation of DCAP-2 condensates in somatic cells. We further uncover a role for EDC-3 in defining the boundaries between P bodies, germ granules, and stress granules. Finally, we show that EDC-4 counteracts EDC-3 and engenders the assembly of DCAP-2 with the GID (CTLH) complex, a ubiquitin ligase involved in maternal-to-zygotic transition (MZT). Our findings support a model where multiple RNA decay mechanisms temporally clear maternal and zygotic mRNAs throughout embryonic development.
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Affiliation(s)
- Elva Vidya
- Department of Biochemistry, McGill University, Montréal QC H3G 1Y6, Canada; Rosalind and Morris Goodman Cancer Institute, Montréal QC H3G 1Y6, Canada
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Adarsh K Mayank
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Javeria Rizwan
- Department of Biochemistry, McGill University, Montréal QC H3G 1Y6, Canada
| | - Jia Ming Stella Xu
- Department of Biochemistry, McGill University, Montréal QC H3G 1Y6, Canada
| | - Tianhao Cheng
- Department of Biochemistry, McGill University, Montréal QC H3G 1Y6, Canada; Rosalind and Morris Goodman Cancer Institute, Montréal QC H3G 1Y6, Canada
| | - Rania Leventis
- Department of Biochemistry, McGill University, Montréal QC H3G 1Y6, Canada; Rosalind and Morris Goodman Cancer Institute, Montréal QC H3G 1Y6, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montréal QC H3G 1Y6, Canada; Rosalind and Morris Goodman Cancer Institute, Montréal QC H3G 1Y6, Canada
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Maria Vera
- Department of Biochemistry, McGill University, Montréal QC H3G 1Y6, Canada
| | - Thomas F Duchaine
- Department of Biochemistry, McGill University, Montréal QC H3G 1Y6, Canada; Rosalind and Morris Goodman Cancer Institute, Montréal QC H3G 1Y6, Canada.
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2
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Brothers WR, Ali F, Kajjo S, Fabian MR. The EDC4-XRN1 interaction controls P-body dynamics to link mRNA decapping with decay. EMBO J 2023; 42:e113933. [PMID: 37621215 PMCID: PMC10620763 DOI: 10.15252/embj.2023113933] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 07/19/2023] [Accepted: 07/22/2023] [Indexed: 08/26/2023] Open
Abstract
Deadenylation-dependent mRNA decapping and decay is the major cytoplasmic mRNA turnover pathway in eukaryotes. Many mRNA decapping and decay factors are associated with each other via protein-protein interaction motifs. For example, the decapping enzyme DCP2 and the 5'-3' exonuclease XRN1 interact with the enhancer of mRNA-decapping protein 4 (EDC4), a large scaffold that has been reported to stimulate mRNA decapping. mRNA decapping and decay factors are also found in processing bodies (P-bodies), evolutionarily conserved ribonucleoprotein granules that are often enriched with mRNAs targeted for decay, yet paradoxically are not required for mRNA decay to occur. Here, we show that disrupting the EDC4-XRN1 interaction or altering their stoichiometry inhibits mRNA decapping, with microRNA-targeted mRNAs being stabilized in a translationally repressed state. Importantly, we demonstrate that this concomitantly leads to larger P-bodies that are responsible for preventing mRNA decapping. Finally, we demonstrate that P-bodies support cell viability and prevent stress granule formation when XRN1 is limiting. Taken together, these data demonstrate that the interaction between XRN1 and EDC4 regulates P-body dynamics to properly coordinate mRNA decapping with 5'-3' decay in human cells.
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Affiliation(s)
- William R Brothers
- Lady Davis Institute for Medical ResearchJewish General HospitalMontrealQCCanada
| | - Farah Ali
- Lady Davis Institute for Medical ResearchJewish General HospitalMontrealQCCanada
| | - Sam Kajjo
- Lady Davis Institute for Medical ResearchJewish General HospitalMontrealQCCanada
| | - Marc R Fabian
- Lady Davis Institute for Medical ResearchJewish General HospitalMontrealQCCanada
- Department of BiochemistryMcGill UniversityMontrealQCCanada
- Department of OncologyMcGill UniversityMontrealQCCanada
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3
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Abstract
The 5'-terminal cap is a fundamental determinant of eukaryotic gene expression which facilitates cap-dependent translation and protects mRNAs from exonucleolytic degradation. Enzyme-directed hydrolysis of the cap (decapping) decisively affects mRNA expression and turnover, and is a heavily regulated event. Following the identification of the decapping holoenzyme (Dcp1/2) over two decades ago, numerous studies revealed the complexity of decapping regulation across species and cell types. A conserved set of Dcp1/2-associated proteins, implicated in decapping activation and molecular scaffolding, were identified through genetic and molecular interaction studies, and yet their exact mechanisms of action are only emerging. In this review, we discuss the prevailing models on the roles and assembly of decapping co-factors, with considerations of conservation across species and comparison across physiological contexts. We next discuss the functional convergences of decapping machineries with other RNA-protein complexes in cytoplasmic P bodies and compare current views on their impact on mRNA stability and translation. Lastly, we review the current models of decapping activation and highlight important gaps in our current understanding.
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Affiliation(s)
- Elva Vidya
- Goodman Cancer Institute, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Thomas F. Duchaine
- Goodman Cancer Institute, McGill University, Montréal, QC, Canada
- Department of Biochemistry, McGill University, Montréal, QC, Canada
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4
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Shah A, Bhandari R. IP6K1 upregulates the formation of processing bodies by influencing protein-protein interactions on the mRNA cap. J Cell Sci 2021; 134:273758. [PMID: 34841428 DOI: 10.1242/jcs.259117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/11/2021] [Indexed: 11/20/2022] Open
Abstract
Inositol hexakisphosphate kinase 1 (IP6K1) is a small molecule kinase that catalyzes the conversion of the inositol phosphate IP6 to 5-IP7. We show that IP6K1 acts independently of its catalytic activity to upregulate the formation of processing bodies (P-bodies), which are cytoplasmic ribonucleoprotein granules that store translationally repressed mRNA. IP6K1 does not localise to P-bodies, but instead binds to ribosomes, where it interacts with the mRNA decapping complex - the scaffold protein EDC4, activator proteins DCP1A/B, decapping enzyme DCP2 and RNA helicase DDX6. Along with its partner 4E-T, DDX6 is known to nucleate protein-protein interactions on the 5' mRNA cap to facilitate P-body formation. IP6K1 binds the translation initiation complex eIF4F on the mRNA cap, augmenting the interaction of DDX6 with 4E-T (also known as EIF4ENIF1) and the cap-binding protein eIF4E. Cells with reduced IP6K1 show downregulated microRNA-mediated translational suppression and increased stability of DCP2-regulated transcripts. Our findings unveil IP6K1 as a novel facilitator of proteome remodelling on the mRNA cap, tipping the balance in favour of translational repression over initiation, thus leading to P-body assembly. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Akruti Shah
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal 576104, India
| | - Rashna Bhandari
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad 500039, India
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5
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Enwerem III, Elrod ND, Chang CT, Lin A, Ji P, Bohn JA, Levdansky Y, Wagner EJ, Valkov E, Goldstrohm AC. Human Pumilio proteins directly bind the CCR4-NOT deadenylase complex to regulate the transcriptome. RNA (NEW YORK, N.Y.) 2021; 27:445-464. [PMID: 33397688 PMCID: PMC7962487 DOI: 10.1261/rna.078436.120] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 12/28/2020] [Indexed: 05/13/2023]
Abstract
Pumilio paralogs, PUM1 and PUM2, are sequence-specific RNA-binding proteins that are essential for vertebrate development and neurological functions. PUM1&2 negatively regulate gene expression by accelerating degradation of specific mRNAs. Here, we determined the repression mechanism and impact of human PUM1&2 on the transcriptome. We identified subunits of the CCR4-NOT (CNOT) deadenylase complex required for stable interaction with PUM1&2 and to elicit CNOT-dependent repression. Isoform-level RNA sequencing revealed broad coregulation of target mRNAs through the PUM-CNOT repression mechanism. Functional dissection of the domains of PUM1&2 identified a conserved amino-terminal region that confers the predominant repressive activity via direct interaction with CNOT. In addition, we show that the mRNA decapping enzyme, DCP2, has an important role in repression by PUM1&2 amino-terminal regions. Our results support a molecular model of repression by human PUM1&2 via direct recruitment of CNOT deadenylation machinery in a decapping-dependent mRNA decay pathway.
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Affiliation(s)
- Isioma I I Enwerem
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Nathan D Elrod
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas 77550, USA
| | - Chung-Te Chang
- Department of Biochemistry, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Ai Lin
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas 77550, USA
| | - Ping Ji
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas 77550, USA
| | - Jennifer A Bohn
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Yevgen Levdansky
- Department of Biochemistry, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas 77550, USA
| | - Eugene Valkov
- Department of Biochemistry, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Aaron C Goldstrohm
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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6
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Borbolis F, Syntichaki P. Biological implications of decapping: beyond bulk mRNA decay. FEBS J 2021; 289:1457-1475. [PMID: 33660392 DOI: 10.1111/febs.15798] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/21/2021] [Accepted: 03/07/2021] [Indexed: 12/12/2022]
Abstract
It is well established that mRNA steady-state levels do not directly correlate with transcription rate. This is attributed to the multiple post-transcriptional mechanisms, which control both mRNA turnover and translation within eukaryotic cells. One such mechanism is the removal of the 5' end cap structure of RNAs (decapping). This 5' cap plays a fundamental role in cellular functions related to mRNA processing, transport, translation, quality control, and decay, while its chemical modifications influence the fate of cytoplasmic mRNAs. Decapping is a highly controlled process, performed by multiple decapping enzymes, and regulated by complex cellular networks. In this review, we provide an updated synopsis of 5' end modifications and functions, and give an overview of mRNA decapping enzymes, presenting their enzymatic properties. Focusing on DCP2 decapping enzyme, a major component on the 5'-3' mRNA decay pathway, we describe cis-elements and trans-acting factors that affect its activity, substrate specificity, and cellular localization. Finally, we discuss current knowledge on the biological functions of mRNA decapping and decay factors, highlighting the major questions that remain to be addressed.
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Affiliation(s)
- Fivos Borbolis
- Biomedical Research Foundation of the Academy of Athens, Center of Basic Research, Athens, Greece
| | - Popi Syntichaki
- Biomedical Research Foundation of the Academy of Athens, Center of Basic Research, Athens, Greece
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7
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Zarnack K, Balasubramanian S, Gantier MP, Kunetsky V, Kracht M, Schmitz ML, Sträßer K. Dynamic mRNP Remodeling in Response to Internal and External Stimuli. Biomolecules 2020; 10:biom10091310. [PMID: 32932892 PMCID: PMC7565591 DOI: 10.3390/biom10091310] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/02/2020] [Accepted: 09/08/2020] [Indexed: 02/06/2023] Open
Abstract
Signal transduction and the regulation of gene expression are fundamental processes in every cell. RNA-binding proteins (RBPs) play a key role in the post-transcriptional modulation of gene expression in response to both internal and external stimuli. However, how signaling pathways regulate the assembly of RBPs with mRNAs remains largely unknown. Here, we summarize observations showing that the formation and composition of messenger ribonucleoprotein particles (mRNPs) is dynamically remodeled in space and time by specific signaling cascades and the resulting post-translational modifications. The integration of signaling events with gene expression is key to the rapid adaptation of cells to environmental changes and stress. Only a combined approach analyzing the signal transduction pathways and the changes in post-transcriptional gene expression they cause will unravel the mechanisms coordinating these important cellular processes.
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Affiliation(s)
- Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, 60438 Frankfurt a.M., Germany;
| | | | - Michael P. Gantier
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia;
- Department of Molecular and Translational Science, Monash University, Clayton, VIC 3800, Australia
| | - Vladislav Kunetsky
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany;
| | - Michael Kracht
- Rudolf Buchheim Institute of Pharmacology, FB11, Justus Liebig University, 35392 Giessen, Germany;
| | - M. Lienhard Schmitz
- Institute of Biochemistry, FB11, Justus Liebig University, 35392 Giessen, Germany;
| | - Katja Sträßer
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany;
- Correspondence:
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8
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Brothers WR, Hebert S, Kleinman CL, Fabian MR. A non-canonical role for the EDC4 decapping factor in regulating MARF1-mediated mRNA decay. eLife 2020; 9:e54995. [PMID: 32510323 PMCID: PMC7279887 DOI: 10.7554/elife.54995] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/15/2020] [Indexed: 11/13/2022] Open
Abstract
EDC4 is a core component of processing (P)-bodies that binds the DCP2 decapping enzyme and stimulates mRNA decay. EDC4 also interacts with mammalian MARF1, a recently identified endoribonuclease that promotes oogenesis and contains a number of RNA binding domains, including two RRMs and multiple LOTUS domains. How EDC4 regulates MARF1 action and the identity of MARF1 target mRNAs is not known. Our transcriptome-wide analysis identifies bona fide MARF1 target mRNAs and indicates that MARF1 predominantly binds their 3' UTRs via its LOTUS domains to promote their decay. We also show that a MARF1 RRM plays an essential role in enhancing its endonuclease activity. Importantly, we establish that EDC4 impairs MARF1 activity by preventing its LOTUS domains from binding target mRNAs. Thus, EDC4 not only serves as an enhancer of mRNA turnover that binds DCP2, but also as a repressor that binds MARF1 to prevent the decay of MARF1 target mRNAs.
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Affiliation(s)
- William R Brothers
- Lady Davis Institute for Medical Research, Jewish General HospitalMontrealCanada
| | - Steven Hebert
- Lady Davis Institute for Medical Research, Jewish General HospitalMontrealCanada
| | - Claudia L Kleinman
- Lady Davis Institute for Medical Research, Jewish General HospitalMontrealCanada
- Department of Human Genetics, McGill UniversityMontrealCanada
| | - Marc R Fabian
- Lady Davis Institute for Medical Research, Jewish General HospitalMontrealCanada
- Department of Biochemistry, McGill UniversityMontrealCanada
- Department of Oncology, McGill UniversityMontrealCanada
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9
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Kim MH, Jeon J, Lee S, Lee JH, Gao L, Lee BH, Park JM, Kim YJ, Kwak JM. Proteasome subunit RPT2a promotes PTGS through repressing RNA quality control in Arabidopsis. NATURE PLANTS 2019; 5:1273-1282. [PMID: 31740770 DOI: 10.1038/s41477-019-0546-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/09/2019] [Indexed: 05/12/2023]
Abstract
RNA quality control (RQC) and post-transcriptional gene silencing (PTGS) target and degrade aberrant endogenous RNAs and foreign RNAs, contributing to homeostasis of cellular RNAs. In plants, RQC and PTGS compete for foreign and selected endogenous RNAs; however, little is known about the mechanism interconnecting the two pathways. Using a reporter system designed for monitoring PTGS, we revealed that the 26S proteasome subunit RPT2a enhances transgene PTGS by promoting the accumulation of transgene-derived short interfering RNAs without affecting their biogenesis. RPT2a physically associated with a subset of RQC components and downregulated the protein level. Overexpression of the RQC components interfered with transgene silencing, and impairment of the RQC machinery reinforced transgene PTGS attenuated by rpt2a. Overall, we demonstrate that the 26S proteasome subunit RPT2a promotes PTGS by repressing the RQC machinery to control foreign RNAs.
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Affiliation(s)
- Myung-Hee Kim
- Center for Plant Aging Research, Institute for Basic Science, Daegu, Republic of Korea
| | - Jieun Jeon
- Center for Plant Aging Research, Institute for Basic Science, Daegu, Republic of Korea
- Department of New Biology, DGIST, Daegu, Republic of Korea
| | - Seulbee Lee
- Center for Plant Aging Research, Institute for Basic Science, Daegu, Republic of Korea
| | - Jae Ho Lee
- Center for Plant Aging Research, Institute for Basic Science, Daegu, Republic of Korea
- Department of New Biology, DGIST, Daegu, Republic of Korea
| | - Lei Gao
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Byung-Hoon Lee
- Department of New Biology, DGIST, Daegu, Republic of Korea
| | - Jeong Mee Park
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Yun Ju Kim
- Center for Plant Aging Research, Institute for Basic Science, Daegu, Republic of Korea.
| | - June M Kwak
- Department of New Biology, DGIST, Daegu, Republic of Korea.
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10
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Inada T. The proteasome's balancing act. NATURE PLANTS 2019; 5:1203-1204. [PMID: 31740771 DOI: 10.1038/s41477-019-0551-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
- Toshifumi Inada
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
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11
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Díaz-Muñoz MD, Turner M. Uncovering the Role of RNA-Binding Proteins in Gene Expression in the Immune System. Front Immunol 2018; 9:1094. [PMID: 29875770 PMCID: PMC5974052 DOI: 10.3389/fimmu.2018.01094] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/02/2018] [Indexed: 12/29/2022] Open
Abstract
Fighting external pathogens requires an ever-changing immune system that relies on tight regulation of gene expression. Transcriptional control is the first step to build efficient responses while preventing immunodeficiencies and autoimmunity. Post-transcriptional regulation of RNA editing, location, stability, and translation are the other key steps for final gene expression, and they are all controlled by RNA-binding proteins (RBPs). Nowadays we have a deep understanding of how transcription factors control the immune system but recent evidences suggest that post-transcriptional regulation by RBPs is equally important for both development and activation of immune responses. Here, we review current knowledge about how post-transcriptional control by RBPs shapes our immune system and discuss the perspective of RBPs being the key players of a hidden immune cell epitranscriptome.
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Affiliation(s)
- Manuel D Díaz-Muñoz
- Centre de Physiopathologie Toulouse-Purpan, INSERM UMR1043/CNRS U5282, Toulouse, France
| | - Martin Turner
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, United Kingdom
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12
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Tenekeci U, Poppe M, Beuerlein K, Buro C, Müller H, Weiser H, Kettner-Buhrow D, Porada K, Newel D, Xu M, Chen ZJ, Busch J, Schmitz ML, Kracht M. K63-Ubiquitylation and TRAF6 Pathways Regulate Mammalian P-Body Formation and mRNA Decapping. Mol Cell 2017; 62:943-957. [PMID: 27315556 DOI: 10.1016/j.molcel.2016.05.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 01/22/2016] [Accepted: 05/13/2016] [Indexed: 01/09/2023]
Abstract
Signals and posttranslational modifications regulating the decapping step in mRNA degradation pathways are poorly defined. In this study we reveal the importance of K63-linked ubiquitylation for the assembly of decapping factors, P-body formation, and constitutive decay of instable mRNAs encoding mediators of inflammation by various experimental approaches. K63-branched ubiquitin chains also regulate IL-1-inducible phosphorylation of the P-body component DCP1a. The E3 ligase TRAF6 binds to DCP1a and indirectly regulates DCP1a phosphorylation, expression of decapping factors, and gene-specific mRNA decay. Mutation of six C-terminal lysines of DCP1a suppresses decapping activity and impairs the interaction with the mRNA decay factors DCP2, EDC4, and XRN1, but not EDC3, thus remodeling P-body architecture. The usage of ubiquitin chains for the proper assembly and function of the decay-competent mammalian decapping complex suggests an additional layer of control to allow a coordinated function of decapping activities and mRNA metabolism in higher eukaryotes.
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Affiliation(s)
- Ulas Tenekeci
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Michael Poppe
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Knut Beuerlein
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Christin Buro
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Helmut Müller
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Hendrik Weiser
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Daniela Kettner-Buhrow
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Katharina Porada
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Doris Newel
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Ming Xu
- Department of Molecular Biology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Zhijian J Chen
- Department of Molecular Biology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Julia Busch
- Institute of Biochemistry, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - M Lienhard Schmitz
- Institute of Biochemistry, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Michael Kracht
- Rudolf-Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany.
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13
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Wang CY, Wang YT, Hsiao WY, Wang SW. Involvement of fission yeast Pdc2 in RNA degradation and P-body function. RNA (NEW YORK, N.Y.) 2017; 23:493-503. [PMID: 28031482 PMCID: PMC5340913 DOI: 10.1261/rna.059766.116] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/21/2016] [Indexed: 05/03/2023]
Abstract
In this study we identified Pdc2, the fission yeast ortholog of human Pat1b protein, which forms a complex with Lsm1-7 and plays a role in coupling deadenylation and decapping. The involvement of Pdc2 in RNA degradation and P-body function was also determined. We found that Pdc2 interacts with Dcp2 and is required for decapping in vivo. Although not absolutely essential for P-body assembly, overexpression of Pdc2 enhanced P-body formation even in the absence of Pdc1, the fission yeast functional homolog of human Edc4 protein, indicating that Pdc2 also plays a role in P-body formation. Intriguingly, in the absence of Pdc2, Lsm1 was found to accumulate in the nucleus, suggesting that Pdc2 shuttling between nucleus and cytoplasm plays a role in decreasing the nuclear concentration of Lsm1 to increase Lsm1 in the cytoplasm. Furthermore, unlike other components of P-bodies, the deadenylase Ccr4 did not accumulate in P-bodies in cells growing under favorable conditions and was only recruited to P-bodies after deprivation of glucose in a Pdc2-Lsm1-dependent manner, indicating a function of Pdc2 in cellular response to environmental stress. In supporting this idea, pdc2 mutants are defective in recovery from glucose starvation with a much longer time to re-enter the cell cycle. In keeping with the notion that Pat1 is a nucleocytoplasmic protein, functioning also in the nucleus, we found that Pdc2 physically and genetically interacts with the nuclear 5'-3' exonuclease Dhp1. A function of Pdc2-Lsm1, in concert with Dhp1, regulating RNA by promoting its decapping/destruction in the nucleus was suggested.
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Affiliation(s)
- Chun-Yu Wang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County 350, Taiwan, Republic of China
| | - Yi-Ting Wang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County 350, Taiwan, Republic of China
| | - Wan-Yi Hsiao
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County 350, Taiwan, Republic of China
| | - Shao-Win Wang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County 350, Taiwan, Republic of China
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14
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Lardelli RM, Schaffer AE, Eggens VRC, Zaki MS, Grainger S, Sathe S, Van Nostrand EL, Schlachetzki Z, Rosti B, Akizu N, Scott E, Silhavy JL, Heckman LD, Rosti RO, Dikoglu E, Gregor A, Guemez-Gamboa A, Musaev D, Mande R, Widjaja A, Shaw TL, Markmiller S, Marin-Valencia I, Davies JH, de Meirleir L, Kayserili H, Altunoglu U, Freckmann ML, Warwick L, Chitayat D, Blaser S, Çağlayan AO, Bilguvar K, Per H, Fagerberg C, Christesen HT, Kibaek M, Aldinger KA, Manchester D, Matsumoto N, Muramatsu K, Saitsu H, Shiina M, Ogata K, Foulds N, Dobyns WB, Chi NC, Traver D, Spaccini L, Bova SM, Gabriel SB, Gunel M, Valente EM, Nassogne MC, Bennett EJ, Yeo GW, Baas F, Lykke-Andersen J, Gleeson JG. Biallelic mutations in the 3' exonuclease TOE1 cause pontocerebellar hypoplasia and uncover a role in snRNA processing. Nat Genet 2017; 49:457-464. [PMID: 28092684 PMCID: PMC5325768 DOI: 10.1038/ng.3762] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 12/07/2016] [Indexed: 02/08/2023]
Abstract
Deadenylases are best known for degrading the poly(A) tail during mRNA decay. The deadenylase family has expanded throughout evolution and, in mammals, consists of 12 Mg2+-dependent 3'-end RNases with substrate specificity that is mostly unknown. Pontocerebellar hypoplasia type 7 (PCH7) is a unique recessive syndrome characterized by neurodegeneration and ambiguous genitalia. We studied 12 human families with PCH7, uncovering biallelic, loss-of-function mutations in TOE1, which encodes an unconventional deadenylase. toe1-morphant zebrafish displayed midbrain and hindbrain degeneration, modeling PCH-like structural defects in vivo. Surprisingly, we found that TOE1 associated with small nuclear RNAs (snRNAs) incompletely processed spliceosomal. These pre-snRNAs contained 3' genome-encoded tails often followed by post-transcriptionally added adenosines. Human cells with reduced levels of TOE1 accumulated 3'-end-extended pre-snRNAs, and the immunoisolated TOE1 complex was sufficient for 3'-end maturation of snRNAs. Our findings identify the cause of a neurodegenerative syndrome linked to snRNA maturation and uncover a key factor involved in the processing of snRNA 3' ends.
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Affiliation(s)
- Rea M Lardelli
- University of California San Diego, La Jolla, California, USA
| | - Ashleigh E Schaffer
- University of California San Diego, La Jolla, California, USA.,Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA.,Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA
| | - Veerle R C Eggens
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, the Netherlands
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Stephanie Grainger
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Shashank Sathe
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA
| | - Eric L Van Nostrand
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA
| | - Zinayida Schlachetzki
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Basak Rosti
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Naiara Akizu
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Eric Scott
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Jennifer L Silhavy
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Laura Dean Heckman
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Rasim Ozgur Rosti
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Esra Dikoglu
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Anne Gregor
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Alicia Guemez-Gamboa
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Damir Musaev
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Rohit Mande
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Ari Widjaja
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Tim L Shaw
- University of California San Diego, La Jolla, California, USA
| | - Sebastian Markmiller
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA
| | - Isaac Marin-Valencia
- Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
| | - Justin H Davies
- Department of Paediatric Medicine, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Linda de Meirleir
- Pediatric Neurology and Metabolic Diseases, Universitair Ziekenhuis Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Hulya Kayserili
- Medical Genetics Department, Koc University School of Medicine, Istanbul, Turkey
| | - Umut Altunoglu
- Medical Genetics Department, Istanbul Medical Faculty, Istanbul University, Istanbul Turkey
| | - Mary Louise Freckmann
- Department of Clinical Genetics, The Canberra Hospital, Woden, Australian Capital Territory, Australia
| | - Linda Warwick
- Australian Capital Territory Genetic Service, The Canberra Hospital, Canberra City, Australian Capital Territory, Australia
| | - David Chitayat
- Department of Pediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Susan Blaser
- Division of Neuroradiology, Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ahmet Okay Çağlayan
- Department of Medical Genetics, School of Medicine, Istanbul Bilim University, Istanbul, Turkey.,Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology and Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kaya Bilguvar
- Department of Genetics, Yale Center for Genome Analysis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Huseyin Per
- Division of Pediatric Neurology, Department of Pediatrics, Erciyes University School of Medicine, Kayseri, Turkey
| | - Christina Fagerberg
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Henrik T Christesen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
| | - Maria Kibaek
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
| | - Kimberly A Aldinger
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - David Manchester
- Department of Pediatrics, Clinical Genetics and Metabolism, University of Colorado School of Medicine, Children's Hospital Colorado, Aurora, Colorado, USA
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University, Graduate School of Medicine, Yokohama, Japan
| | - Kazuhiro Muramatsu
- Department of Pediatrics, Gunma University School of Medicine, Showa-machi, Maebashi City, Japan
| | - Hirotomo Saitsu
- Department of Human Genetics, Yokohama City University, Graduate School of Medicine, Yokohama, Japan.,Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Masaaki Shiina
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kazuhiro Ogata
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Nicola Foulds
- Southampton University Hospitals Trust, Southampton, UK
| | - William B Dobyns
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Neil C Chi
- UCSD Cardiology, University of California San Diego, La Jolla, California, USA
| | - David Traver
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Luigina Spaccini
- Clinical Genetics Unit, Department of Women, Mother and Neonates, "Vittore Buzzi" Children's Hospital, Istituti Clinici di Perfezionamento, Milan, Italy
| | - Stefania Maria Bova
- Child Neurology Unit, Department of Pediatrics, "Vittore Buzzi" Children Hospital, Istituti Clinici di Perfezionamento, Milan, Italy
| | - Stacey B Gabriel
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
| | - Murat Gunel
- Yale Program on Neurogenetics, Departments of Neurosurgery, Neurobiology and Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Enza Maria Valente
- Section of Neurosciences, Department of Medicine and Surgery, University of Salerno, Salerno, Italy
| | - Marie-Cecile Nassogne
- Pediatric Neurology, Université Catholique de Louvain, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Eric J Bennett
- University of California San Diego, La Jolla, California, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California San Diego, La Jolla, California, USA.,Department of Physiology, National University of Singapore and Molecular Engineering Laboratory, A*STAR, Singapore
| | - Frank Baas
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, the Netherlands
| | | | - Joseph G Gleeson
- University of California San Diego, La Jolla, California, USA.,Laboratory of Pediatric Brain Disease and Howard Hughes Medical Institute, The Rockefeller University, New York, New York, USA
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15
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Boehm V, Gerbracht JV, Marx MC, Gehring NH. Interrogating the degradation pathways of unstable mRNAs with XRN1-resistant sequences. Nat Commun 2016; 7:13691. [PMID: 27917860 PMCID: PMC5150221 DOI: 10.1038/ncomms13691] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 10/25/2016] [Indexed: 12/22/2022] Open
Abstract
The turnover of messenger RNAs (mRNAs) is a key regulatory step of gene expression in eukaryotic cells. Due to the complexity of the mammalian degradation machinery, the contribution of decay factors to the directionality of mRNA decay is poorly understood. Here we characterize a molecular tool to interrogate mRNA turnover via the detection of XRN1-resistant decay fragments (xrFrag). Using nonsense-mediated mRNA decay (NMD) as a model pathway, we establish xrFrag analysis as a robust indicator of accelerated 5'-3' mRNA decay. In tethering assays, monitoring xrFrag accumulation allows to distinguish decapping and endocleavage activities from deadenylation. Moreover, xrFrag analysis of mRNA degradation induced by miRNAs, AU-rich elements (AREs) as well as the 3' UTRs of cytokine mRNAs reveals the contribution of 5'-3' decay and endonucleolytic cleavage. Our work uncovers formerly unrecognized modes of mRNA turnover and establishes xrFrag as a powerful tool for RNA decay analyses.
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Affiliation(s)
- Volker Boehm
- Institute for Genetics, Department of Biology, University of Cologne, Zuelpicher Straße 47a, 50674 Cologne, Germany
| | - Jennifer V Gerbracht
- Institute for Genetics, Department of Biology, University of Cologne, Zuelpicher Straße 47a, 50674 Cologne, Germany
| | - Marie-Charlotte Marx
- Institute for Genetics, Department of Biology, University of Cologne, Zuelpicher Straße 47a, 50674 Cologne, Germany
| | - Niels H Gehring
- Institute for Genetics, Department of Biology, University of Cologne, Zuelpicher Straße 47a, 50674 Cologne, Germany
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16
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The C-Terminal RGG Domain of Human Lsm4 Promotes Processing Body Formation Stimulated by Arginine Dimethylation. Mol Cell Biol 2016; 36:2226-35. [PMID: 27247266 DOI: 10.1128/mcb.01102-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/23/2016] [Indexed: 12/31/2022] Open
Abstract
Processing bodies (PBs) are conserved cytoplasmic aggregations of translationally repressed mRNAs assembled with mRNA decay factors. The aggregation of mRNA-protein (mRNP) complexes into PBs involves interactions between low-complexity regions of protein components of the mRNPs. In Saccharomyces cerevisiae, the carboxy (C)-terminal Q/N-rich domain of the Lsm4 subunit of the Lsm1-7 complex plays an important role in PB formation, but the C-terminal domain of Lsm4 in most eukaryotes is an RGG domain rather than Q/N rich. Here we show that the Lsm4 RGG domain promotes PB accumulation in human cells and that symmetric dimethylation of arginines within the RGG domain stimulates this process. A mutant Lsm4 protein lacking the RGG domain failed to rescue PB formation in cells depleted of endogenous Lsm4, although this mutant protein retained the ability to assemble with Lsm1-7, associate with decapping factors, and promote mRNA decay and translational repression. Mutation of the symmetrically dimethylated arginines within the RGG domain impaired the ability of Lsm4 to promote PB accumulation. Depletion of PRMT5, the primary protein arginine methyltransferase responsible for symmetric arginine dimethylation, including Lsm4, resulted in loss of PBs. We also uncovered the histone acetyltransferase 1 (HAT1)-RBBP7 lysine acetylase complex as an interaction partner of the Lsm4 RGG domain but found no evidence of a role for this complex in PB metabolism. Together, our findings suggest a stimulatory role for posttranslational modifications in PB accumulation and raise the possibility that mRNP dynamics are posttranslationally regulated.
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17
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Grudzien-Nogalska E, Kiledjian M. New insights into decapping enzymes and selective mRNA decay. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27425147 DOI: 10.1002/wrna.1379] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/23/2016] [Accepted: 06/27/2016] [Indexed: 01/04/2023]
Abstract
Removal of the 5' end cap is a critical determinant controlling mRNA stability and efficient gene expression. Removal of the cap is exquisitely controlled by multiple direct and indirect regulators that influence association with the cap and the catalytic step. A subset of these factors directly stimulate activity of the decapping enzyme, while others influence remodeling of factors bound to mRNA and indirectly stimulate decapping. Furthermore, the components of the general decapping machinery can also be recruited by mRNA-specific regulatory proteins to activate decapping. The Nudix hydrolase, Dcp2, identified as a first decapping enzyme, cleaves capped mRNA and initiates 5'-3' degradation. Extensive studies on Dcp2 led to broad understanding of its activity and the regulation of transcript specific decapping and decay. Interestingly, seven additional Nudix proteins possess intrinsic decapping activity in vitro and at least two, Nudt16 and Nudt3, are decapping enzymes that regulate mRNA stability in cells. Furthermore, a new class of decapping proteins within the DXO family preferentially function on incompletely capped mRNAs. Importantly, it is now evident that each of the characterized decapping enzymes predominantly modulates only a subset of mRNAs, suggesting the existence of multiple decapping enzymes functioning in distinct cellular pathways. WIREs RNA 2017, 8:e1379. doi: 10.1002/wrna.1379 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ewa Grudzien-Nogalska
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Megerditch Kiledjian
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
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18
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Lee KE, Heo JE, Kim JM, Hwang CS. N-Terminal Acetylation-Targeted N-End Rule Proteolytic System: The Ac/N-End Rule Pathway. Mol Cells 2016; 39:169-78. [PMID: 26883906 PMCID: PMC4794598 DOI: 10.14348/molcells.2016.2329] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/11/2016] [Accepted: 01/14/2016] [Indexed: 12/12/2022] Open
Abstract
Although Nα-terminal acetylation (Nt-acetylation) is a pervasive protein modification in eukaryotes, its general functions in a majority of proteins are poorly understood. In 2010, it was discovered that Nt-acetylation creates a specific protein degradation signal that is targeted by a new class of the N-end rule proteolytic system, called the Ac/N-end rule pathway. Here, we review recent advances in our understanding of the mechanism and biological functions of the Ac/N-end rule pathway, and its crosstalk with the Arg/N-end rule pathway (the classical N-end rule pathway).
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Affiliation(s)
- Kang-Eun Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Ji-Eun Heo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Jeong-Mok Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790–784,
Korea
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19
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Fu R, Olsen MT, Webb K, Bennett EJ, Lykke-Andersen J. Recruitment of the 4EHP-GYF2 cap-binding complex to tetraproline motifs of tristetraprolin promotes repression and degradation of mRNAs with AU-rich elements. RNA (NEW YORK, N.Y.) 2016; 22:373-382. [PMID: 26763119 PMCID: PMC4748815 DOI: 10.1261/rna.054833.115] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/30/2015] [Indexed: 06/05/2023]
Abstract
The zinc finger protein tristetraprolin (TTP) promotes translation repression and degradation of mRNAs containing AU-rich elements (AREs). Although much attention has been directed toward understanding the decay process and machinery involved, the translation repression role of TTP has remained poorly understood. Here we identify the cap-binding translation repression 4EHP-GYF2 complex as a cofactor of TTP. Immunoprecipitation and in vitro pull-down assays demonstrate that TTP associates with the 4EHP-GYF2 complex via direct interaction with GYF2, and mutational analyses show that this interaction occurs via conserved tetraproline motifs of TTP. Mutant TTP with diminished 4EHP-GYF2 binding is impaired in its ability to repress a luciferase reporter ARE-mRNA. 4EHP knockout mouse embryonic fibroblasts (MEFs) display increased induction and slower turnover of TTP-target mRNAs as compared to wild-type MEFs. Our work highlights the function of the conserved tetraproline motifs of TTP and identifies 4EHP-GYF2 as a cofactor in translational repression and mRNA decay by TTP.
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Affiliation(s)
- Rui Fu
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
| | - Myanna T Olsen
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
| | - Kristofor Webb
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
| | - Eric J Bennett
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
| | - Jens Lykke-Andersen
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
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20
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Post-Translational Modifications and RNA-Binding Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 907:297-317. [PMID: 27256391 DOI: 10.1007/978-3-319-29073-7_12] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RNA-binding proteins affect cellular metabolic programs through development and in response to cellular stimuli. Though much work has been done to elucidate the roles of a handful of RNA-binding proteins and their effect on RNA metabolism, the progress of studies to understand the effects of post-translational modifications of this class of proteins is far from complete. This chapter summarizes the work that has been done to identify the consequence of post-translational modifications to some RNA-binding proteins. The effects of these modifications have been shown to increase the panoply of functions that a given RNA-binding protein can assume. We will survey the experimental methods that are used to identify the presence of several protein modifications and methods that attempt to discern the consequence of these modifications.
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21
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Cytoplasmic mRNA turnover and ageing. Mech Ageing Dev 2015; 152:32-42. [PMID: 26432921 PMCID: PMC4710634 DOI: 10.1016/j.mad.2015.09.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 09/17/2015] [Accepted: 09/27/2015] [Indexed: 12/12/2022]
Abstract
We address the cytoplasmic mRNA decay processes that determine the mRNAs half-life. We briefly describe the major, evolutionary conserved, ageing pathways and mechanisms. We summarize critical findings that link mRNA turnover and ageing modulators.
Messenger RNA (mRNA) turnover that determines the lifetime of cytoplasmic mRNAs is a means to control gene expression under both normal and stress conditions, whereas its impact on ageing and age-related disorders has just become evident. Gene expression control is achieved at the level of the mRNA clearance as well as mRNA stability and accessibility to other molecules. All these processes are regulated by cis-acting motifs and trans-acting factors that determine the rates of translation and degradation of transcripts. Specific messenger RNA granules that harbor the mRNA decay machinery or various factors, involved in translational repression and transient storage of mRNAs, are also part of the mRNA fate regulation. Their assembly and function can be modulated to promote stress resistance to adverse conditions and over time affect the ageing process and the lifespan of the organism. Here, we provide insights into the complex relationships of ageing modulators and mRNA turnover mechanisms.
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22
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He F, Jacobson A. Control of mRNA decapping by positive and negative regulatory elements in the Dcp2 C-terminal domain. RNA (NEW YORK, N.Y.) 2015; 21:1633-47. [PMID: 26184073 PMCID: PMC4536323 DOI: 10.1261/rna.052449.115] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/08/2015] [Indexed: 05/23/2023]
Abstract
Decapping commits an mRNA to complete degradation and promotes general 5' to 3' decay, nonsense-mediated decay (NMD), and transcript-specific degradation. In Saccharomyces cerevisiae, a single decapping enzyme composed of a regulatory subunit (Dcp1) and a catalytic subunit (Dcp2) targets thousands of distinct substrate mRNAs. However, the mechanisms controlling this enzyme's in vivo activity and substrate specificity remain elusive. Here, using a genetic approach, we show that the large C-terminal domain of Dcp2 includes a set of conserved negative and positive regulatory elements. A single negative element inhibits enzymatic activity and controls the downstream functions of several positive elements. The positive elements recruit the specific decapping activators Edc3, Pat1, and Upf1 to form distinct decapping complexes and control the enzyme's substrate specificity and final activation. Our results reveal unforeseen regulatory mechanisms that control decapping enzyme activity and function in vivo, and define roles for several decapping activators in the regulation of mRNA decapping.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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