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Lobel JH, Ingolia NT. Defining the mechanisms and properties of post-transcriptional regulatory disordered regions by high-throughput functional profiling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.01.578453. [PMID: 38370681 PMCID: PMC10871298 DOI: 10.1101/2024.02.01.578453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Disordered regions within RNA binding proteins are required to control mRNA decay and protein synthesis. To understand how these disordered regions modulate gene expression, we surveyed regulatory activity across the entire disordered proteome using a high-throughput functional assay. We identified hundreds of regulatory sequences within intrinsically disordered regions and demonstrate how these elements cooperate with core mRNA decay machinery to promote transcript turnover. Coupling high-throughput functional profiling with mutational scanning revealed diverse molecular features, ranging from defined motifs to overall sequence composition, underlying the regulatory effects of disordered peptides. Machine learning analysis implicated aromatic residues in particular contexts as critical determinants of repressor activity, consistent with their roles in forming protein-protein interactions with downstream effectors. Our results define the molecular principles and biochemical mechanisms that govern post-transcriptional gene regulation by disordered regions and exemplify the encoding of diverse yet specific functions in the absence of well-defined structure.
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Affiliation(s)
- Joseph H Lobel
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Nicholas T Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Lead contact
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2
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He F, Jacobson A. Eukaryotic mRNA decapping factors: molecular mechanisms and activity. FEBS J 2023; 290:5057-5085. [PMID: 36098474 PMCID: PMC10008757 DOI: 10.1111/febs.16626] [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: 06/30/2022] [Revised: 08/11/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022]
Abstract
Decapping is the enzymatic removal of 5' cap structures from mRNAs in eukaryotic cells. Cap structures normally enhance mRNA translation and stability, and their excision commits an mRNA to complete 5'-3' exoribonucleolytic digestion and generally ends the physical and functional cellular presence of the mRNA. Decapping plays a pivotal role in eukaryotic cytoplasmic mRNA turnover and is a critical and highly regulated event in multiple 5'-3' mRNA decay pathways, including general 5'-3' decay, nonsense-mediated mRNA decay (NMD), AU-rich element-mediated mRNA decay, microRNA-mediated gene silencing, and targeted transcript-specific mRNA decay. In the yeast Saccharomyces cerevisiae, mRNA decapping is carried out by a single Dcp1-Dcp2 decapping enzyme in concert with the accessory activities of specific regulators commonly known as decapping activators or enhancers. These regulatory proteins include the general decapping activators Edc1, 2, and 3, Dhh1, Scd6, Pat1, and the Lsm1-7 complex, as well as the NMD-specific factors, Upf1, 2, and 3. Here, we focus on in vivo mRNA decapping regulation in yeast. We summarize recently uncovered molecular mechanisms that control selective targeting of the yeast decapping enzyme and discuss new roles for specific decapping activators in controlling decapping enzyme targeting, assembly of target-specific decapping complexes, and the monitoring of mRNA translation. Further, we discuss the kinetic contribution of mRNA decapping for overall decay of different substrate mRNAs and highlight experimental evidence pointing to the functional coordination and physical coupling between events in mRNA deadenylation, decapping, and 5'-3' exoribonucleolytic decay.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, 368 Plantation Street, Worcester, MA 01655
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, 368 Plantation Street, Worcester, MA 01655
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3
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Krempl C, Lazzaretti D, Sprangers R. A structural biology view on the enzymes involved in eukaryotic mRNA turnover. Biol Chem 2023; 404:1101-1121. [PMID: 37709756 DOI: 10.1515/hsz-2023-0182] [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: 04/13/2023] [Accepted: 08/24/2023] [Indexed: 09/16/2023]
Abstract
The cellular environment contains numerous ribonucleases that are dedicated to process mRNA transcripts that have been targeted for degradation. Here, we review the three dimensional structures of the ribonuclease complexes (Pan2-Pan3, Ccr4-Not, Xrn1, exosome) and the mRNA decapping enzymes (Dcp2, DcpS) that are involved in mRNA turnover. Structures of major parts of these proteins have been experimentally determined. These enzymes and factors do not act in isolation, but are embedded in interaction networks which regulate enzyme activity and ensure that the appropriate substrates are recruited. The structural details of the higher order complexes that form can, in part, be accurately deduced from known structural data of sub-complexes. Interestingly, many of the ribonuclease and decapping enzymes have been observed in structurally different conformations. Together with experimental data, this highlights that structural changes are often important for enzyme function. We conclude that the known structural data of mRNA decay factors provide important functional insights, but that static structural data needs to be complemented with information regarding protein motions to complete the picture of how transcripts are turned over. In addition, we highlight multiple aspects that influence mRNA turnover rates, but that have not been structurally characterized so far.
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Affiliation(s)
- Christina Krempl
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Daniela Lazzaretti
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
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4
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Zhao Q, Pavanello L, Bartlam M, Winkler GS. Structure and function of molecular machines involved in deadenylation-dependent 5'-3' mRNA degradation. Front Genet 2023; 14:1233842. [PMID: 37876592 PMCID: PMC10590902 DOI: 10.3389/fgene.2023.1233842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/25/2023] [Indexed: 10/26/2023] Open
Abstract
In eukaryotic cells, the synthesis, processing, and degradation of mRNA are important processes required for the accurate execution of gene expression programmes. Fully processed cytoplasmic mRNA is characterised by the presence of a 5'cap structure and 3'poly(A) tail. These elements promote translation and prevent non-specific degradation. Degradation via the deadenylation-dependent 5'-3' degradation pathway can be induced by trans-acting factors binding the mRNA, such as RNA-binding proteins recognising sequence elements and the miRNA-induced repression complex. These factors recruit the core mRNA degradation machinery that carries out the following steps: i) shortening of the poly(A) tail by the Ccr4-Not and Pan2-Pan3 poly (A)-specific nucleases (deadenylases); ii) removal of the 5'cap structure by the Dcp1-Dcp2 decapping complex that is recruited by the Lsm1-7-Pat1 complex; and iii) degradation of the mRNA body by the 5'-3' exoribonuclease Xrn1. In this review, the biochemical function of the nucleases and accessory proteins involved in deadenylation-dependent mRNA degradation will be reviewed with a particular focus on structural aspects of the proteins and enzymes involved.
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Affiliation(s)
- Qi Zhao
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China
| | - Lorenzo Pavanello
- School of Pharmacy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Mark Bartlam
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China
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5
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McCombe CL, Catanzariti AM, Greenwood JR, Desai AM, Outram MA, Yu DS, Ericsson DJ, Brenner SE, Dodds PN, Kobe B, Jones DA, Williams SJ. A rust-fungus Nudix hydrolase effector decaps mRNA in vitro and interferes with plant immune pathways. THE NEW PHYTOLOGIST 2023; 239:222-239. [PMID: 36631975 DOI: 10.1111/nph.18727] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/02/2023] [Indexed: 06/02/2023]
Abstract
To infect plants, pathogenic fungi secrete small proteins called effectors. Here, we describe the catalytic activity and potential virulence function of the Nudix hydrolase effector AvrM14 from the flax rust fungus (Melampsora lini). We completed extensive in vitro assays to characterise the enzymatic activity of the AvrM14 effector. Additionally, we used in planta transient expression of wild-type and catalytically dead AvrM14 versions followed by biochemical assays, phenotypic analysis and RNA sequencing to unravel how the catalytic activity of AvrM14 impacts plant immunity. AvrM14 is an extremely selective enzyme capable of removing the protective 5' cap from mRNA transcripts in vitro. Homodimerisation of AvrM14 promoted biologically relevant mRNA cap cleavage in vitro and this activity was conserved in related effectors from other Melampsora spp. In planta expression of wild-type AvrM14, but not the catalytically dead version, suppressed immune-related reactive oxygen species production, altered the abundance of some circadian-rhythm-associated mRNA transcripts and reduced the hypersensitive cell-death response triggered by the flax disease resistance protein M1. To date, the decapping of host mRNA as a virulence strategy has not been described beyond viruses. Our results indicate that some fungal pathogens produce Nudix hydrolase effectors with in vitro mRNA-decapping activity capable of interfering with plant immunity.
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Affiliation(s)
- Carl L McCombe
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Ann-Maree Catanzariti
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Julian R Greenwood
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Anna M Desai
- Plant and Microbial Biology Department, University of California, Berkeley, CA, 94720, USA
| | - Megan A Outram
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Daniel S Yu
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Daniel J Ericsson
- Australian Synchrotron, Macromolecular Crystallography, Clayton, Vic., 3168, Australia
| | - Steven E Brenner
- Plant and Microbial Biology Department, University of California, Berkeley, CA, 94720, USA
| | - Peter N Dodds
- Black Mountain Science and Innovation Park, CSIRO Agriculture and Food, Canberra, ACT, 2601, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Qld, 4072, Australia
| | - David A Jones
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Simon J Williams
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
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6
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Krempl C, Wurm JP, Beck Erlach M, Kremer W, Sprangers R. Insights into the Structure of Invisible Conformations of Large Methyl Group Labeled Molecular Machines from High Pressure NMR. J Mol Biol 2023; 435:167922. [PMID: 37330282 DOI: 10.1016/j.jmb.2022.167922] [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: 10/19/2022] [Revised: 12/08/2022] [Accepted: 12/11/2022] [Indexed: 06/19/2023]
Abstract
Most proteins are highly flexible and can adopt conformations that deviate from the energetically most favorable ground state. Structural information on these lowly populated, alternative conformations is often lacking, despite the functional importance of these states. Here, we study the pathway by which the Dcp1:Dcp2 mRNA decapping complex exchanges between an autoinhibited closed and an open conformation. We make use of methyl Carr-Purcell-Meiboom-Gill (CPMG) NMR relaxation dispersion (RD) experiments that report on the population of the sparsely populated open conformation as well as on the exchange rate between the two conformations. To obtain volumetric information on the open conformation as well as on the transition state structure we made use of RD measurements at elevated pressures. We found that the open Dcp1:Dcp2 conformation has a lower molecular volume than the closed conformation and that the transition state is close in volume to the closed state. In the presence of ATP the volume change upon opening of the complex increases and the volume of the transition state lies in-between the volumes of the closed and open state. These findings show that ATP has an effect on the volume changes that are associated with the opening-closing pathway of the complex. Our results highlight the strength of pressure dependent NMR methods to obtain insights into structural features of protein conformations that are not directly observable. As our work makes use of methyl groups as NMR probes we conclude that the applied methodology is also applicable to high molecular weight complexes.
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Affiliation(s)
- Christina Krempl
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Jan Philip Wurm
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Markus Beck Erlach
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Werner Kremer
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany.
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7
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Krempl C, Sprangers R. Assessing the applicability of 19F labeled tryptophan residues to quantify protein dynamics. JOURNAL OF BIOMOLECULAR NMR 2023; 77:55-67. [PMID: 36639431 PMCID: PMC10149471 DOI: 10.1007/s10858-022-00411-2] [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: 08/20/2022] [Accepted: 12/20/2022] [Indexed: 05/03/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is uniquely suited to study the dynamics of biomolecules in solution. Most NMR studies exploit the spins of proton, carbon and nitrogen isotopes, as these atoms are highly abundant in proteins and nucleic acids. As an alternative and complementary approach, fluorine atoms can be introduced into biomolecules at specific sites of interest. These labels can then be used as sensitive probes for biomolecular structure, dynamics or interactions. Here, we address if the replacement of tryptophan with 5-fluorotryptophan residues has an effect on the overall dynamics of proteins and if the introduced fluorine probe is able to accurately report on global exchange processes. For the four different model proteins (KIX, Dcp1, Dcp2 and DcpS) that we examined, we established that 15N CPMG relaxation dispersion or EXSY profiles are not affected by the 5-fluorotryptophan, indicating that this replacement of a proton with a fluorine has no effect on the protein motions. However, we found that the motions that the 5-fluorotryptophan reports on can be significantly faster than the backbone motions. This implies that care needs to be taken when interpreting fluorine relaxation data in terms of global protein motions. In summary, our results underscore the great potential of fluorine NMR methods, but also highlight potential pitfalls that need to be considered.
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Affiliation(s)
- Christina Krempl
- Department of Biophysics I, Regensburg Center for Biochemistry, University of Regensburg, 93053, Regensburg, Germany
| | - Remco Sprangers
- Department of Biophysics I, Regensburg Center for Biochemistry, University of Regensburg, 93053, Regensburg, Germany.
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8
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Vijjamarri AK, Niu X, Vandermeulen MD, Onu C, Zhang F, Qiu H, Gupta N, Gaikwad S, Greenberg ML, Cullen PJ, Lin Z, Hinnebusch AG. Decapping factor Dcp2 controls mRNA abundance and translation to adjust metabolism and filamentation to nutrient availability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.05.522830. [PMID: 36711592 PMCID: PMC9881900 DOI: 10.1101/2023.01.05.522830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Degradation of most yeast mRNAs involves decapping by Dcp1/Dcp2. DEAD-box protein Dhh1 has been implicated as an activator of decapping, in coupling codon non-optimality to enhanced degradation, and as a translational repressor, but its functions in cells are incompletely understood. RNA-Seq analyses coupled with CAGE sequencing of all capped mRNAs revealed increased abundance of hundreds of mRNAs in dcp2 Δ cells that appears to result directly from impaired decapping rather than elevated transcription, which was confirmed by ChIP-Seq analysis of RNA Polymerase II occupancies genome-wide. Interestingly, only a subset of mRNAs requires Dhh1 for targeting by Dcp2, and also generally requires the other decapping activators Pat1, Lsm2, Edc3 or Scd6; whereas most of the remaining transcripts utilize NMD factors for Dcp2-mediated turnover. Neither inefficient translation initiation nor stalled elongation appears to be a major driver of Dhh1-enhanced mRNA degradation. Surprisingly, ribosome profiling revealed that dcp2 Δ confers widespread changes in relative TEs that generally favor well-translated mRNAs. Because ribosome biogenesis is reduced while capped mRNA abundance is increased by dcp2 Δ, we propose that an increased ratio of mRNA to ribosomes increases competition among mRNAs for limiting ribosomes to favor efficiently translated mRNAs in dcp2 Δ cells. Interestingly, genes involved in respiration or utilization of alternative carbon or nitrogen sources are derepressed, and both mitochondrial function and cell filamentation (a strategy for nutrient foraging) are elevated by dcp2 Δ, suggesting that mRNA decapping sculpts gene expression post-transcriptionally to fine-tune metabolic pathways and morphological transitions according to nutrient availability.
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Affiliation(s)
- Anil Kumar Vijjamarri
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Xiao Niu
- Department of Biology, Saint Louis University, St. Louis, MO
| | | | - Chisom Onu
- Department of Biological Sciences, Wayne State University, Detroit, MI
| | - Fan Zhang
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Hongfang Qiu
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Neha Gupta
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Swati Gaikwad
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | | | - Paul J Cullen
- Department of Biological Sciences, State University of Buffalo, Buffalo, NY
| | - Zhenguo Lin
- Department of Biology, Saint Louis University, St. Louis, MO
| | - Alan G Hinnebusch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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Maciej VD, Mateva N, Schwarz J, Dittmers T, Mallick M, Urlaub H, Chakrabarti S. Intrinsically disordered regions of tristetraprolin and DCP2 directly interact to mediate decay of ARE-mRNA. Nucleic Acids Res 2022; 50:10665-10679. [PMID: 36130271 PMCID: PMC9561381 DOI: 10.1093/nar/gkac797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 08/30/2022] [Accepted: 09/06/2022] [Indexed: 11/25/2022] Open
Abstract
The RNA-binding protein tristetraprolin (TTP) is a potent activator of mRNA decay, specifically for transcripts bearing AU-rich elements (AREs) in their 3′-untranslated regions. TTP functions as a mediator for mRNA decay by interacting with the decay machinery and recruiting it to the target ARE-mRNA. In this study, we report a weak, but direct interaction between TTP and the human decapping enzyme DCP2, which impacts the stability of ARE transcripts. The TTP–DCP2 interaction is unusual as it involves intrinsically disordered regions (IDRs) of both binding partners. We show that the IDR of DCP2 has a propensity for oligomerization and liquid–liquid phase separation in vitro. Binding of TTP to DCP2 leads to its partitioning into phase-separated droplets formed by DCP2, suggesting that molecular crowding might facilitate the weak interaction between the two proteins and enable assembly of a decapping-competent mRNA–protein complex on TTP-bound transcripts in cells. Our studies underline the role of weak interactions in the cellular interaction network and their contribution towards cellular functionality.
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Affiliation(s)
- Vincent D Maciej
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany
| | - Nevena Mateva
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany
| | - Juliane Schwarz
- Max Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry Group, Am Fassberg 11, D-37077 Goettingen, Germany.,University Medical Center Goettingen, Bioanalytics, Institute for Clinical Chemistry, Robert Koch Strasse 40, D-37075 Goettingen, Germany
| | - Theresa Dittmers
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany
| | - Megha Mallick
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany
| | - Henning Urlaub
- Max Planck Institute for Multidisciplinary Sciences, Bioanalytical Mass Spectrometry Group, Am Fassberg 11, D-37077 Goettingen, Germany.,University Medical Center Goettingen, Bioanalytics, Institute for Clinical Chemistry, Robert Koch Strasse 40, D-37075 Goettingen, Germany
| | - Sutapa Chakrabarti
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany
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10
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Observation of conformational changes that underlie the catalytic cycle of Xrn2. Nat Chem Biol 2022; 18:1152-1160. [PMID: 36008487 PMCID: PMC9512700 DOI: 10.1038/s41589-022-01111-6] [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: 03/02/2022] [Accepted: 07/07/2022] [Indexed: 12/19/2022]
Abstract
Nuclear magnetic resonance (NMR) methods that quantitatively probe motions on molecular and atomic levels have propelled the understanding of biomolecular processes for which static structures cannot provide a satisfactory description. In this work, we studied the structure and dynamics of the essential 100-kDa eukaryotic 5′→3′ exoribonuclease Xrn2. A combination of complementary fluorine and methyl-TROSY NMR spectroscopy reveals that the apo enzyme is highly dynamic around the catalytic center. These observed dynamics are in agreement with a transition of the enzyme from the ground state into a catalytically competent state. We show that the conformational equilibrium in Xrn2 shifts substantially toward the active state in the presence of substrate and magnesium. Finally, our data reveal that the dynamics in Xrn2 correlate with the RNA degradation rate, as a mutation that attenuates motions also affects catalytic activity. In that light, our results stress the importance of studies that go beyond static structural information. ![]()
Using methyl group and fluorine NMR spectroscopic methods, Overbeck et al revealed that the dynamics of the eukaryotic 5′→3′ exoribonuclease Xrn2 in the region around the active site are correlated with its catalytic activity.
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11
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Webb CT, Yang W, Riley BT, Hayes BK, Sivaraman KK, Malcolm TR, Harrop S, Atkinson SC, Kass I, Buckle AM, Drinkwater N, McGowan S. A metal ion-dependent conformational switch modulates activity of the Plasmodium M17 aminopeptidase. J Biol Chem 2022; 298:102119. [PMID: 35691342 PMCID: PMC9270245 DOI: 10.1016/j.jbc.2022.102119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 06/04/2022] [Accepted: 06/07/2022] [Indexed: 11/12/2022] Open
Abstract
The metal-dependent M17 aminopeptidases are conserved throughout all kingdoms of life. This large enzyme family is characterized by a conserved binuclear metal center and a distinctive homohexameric arrangement. Recently, we showed that hexamer formation in Plasmodium M17 aminopeptidases was controlled by the metal ion environment, although the functional necessity for hexamer formation is still unclear. To further understand the mechanistic role of the hexameric assembly, here we undertook an investigation of the structure and dynamics of the M17 aminopeptidase from Plasmodium falciparum, PfA-M17. We describe a novel structure of PfA-M17, which shows that the active sites of each trimer are linked by a dynamic loop, and loop movement is coupled with a drastic rearrangement of the binuclear metal center and substrate-binding pocket, rendering the protein inactive. Molecular dynamics simulations and biochemical analyses of PfA-M17 variants demonstrated that this rearrangement is inherent to PfA-M17, and that the transition between the active and inactive states is metal dependent and part of a dynamic regulatory mechanism. Key to the mechanism is a remodeling of the binuclear metal center, which occurs in response to a signal from the neighboring active site and serves to moderate the rate of proteolysis under different environmental conditions. In conclusion, this work identifies a precise mechanism by which oligomerization contributes to PfA-M17 function. Furthermore, it describes a novel role for metal cofactors in the regulation of enzymes, with implications for the wide range of metalloenzymes that operate via a two-metal ion catalytic center, including DNA processing enzymes and metalloproteases.
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Affiliation(s)
- Chaille T Webb
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton Melbourne, VIC 3800, Australia
| | - Wei Yang
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton Melbourne, VIC 3800, Australia; Current address Warshel Institute for Computational Biology, The Chinese University of Hong Kong, Shenzhen, 518172, China
| | - Blake T Riley
- Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton Melbourne, VIC 3800, Australia
| | - Brooke K Hayes
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton Melbourne, VIC 3800, Australia
| | - Komagal Kannan Sivaraman
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton Melbourne, VIC 3800, Australia
| | - Tess R Malcolm
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton Melbourne, VIC 3800, Australia
| | - Stephen Harrop
- Australian Synchrotron. 800 Blackburn Road, Clayton, VIC, 3168, Australia
| | - Sarah C Atkinson
- Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton Melbourne, VIC 3800, Australia
| | - Itamar Kass
- Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton Melbourne, VIC 3800, Australia; Victorian Life Sciences Computation Center, Monash University, Clayton 3800, Victoria, Australia; Current address InterX LTD, Ramat-Gan, Israel
| | - Ashley M Buckle
- Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton Melbourne, VIC 3800, Australia
| | - Nyssa Drinkwater
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton Melbourne, VIC 3800, Australia
| | - Sheena McGowan
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton Melbourne, VIC 3800, Australia.
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12
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He F, Wu C, Jacobson A. Dcp2 C-terminal cis-binding elements control selective targeting of the decapping enzyme by forming distinct decapping complexes. eLife 2022; 11:74410. [PMID: 35604319 PMCID: PMC9170289 DOI: 10.7554/elife.74410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 05/22/2022] [Indexed: 11/13/2022] Open
Abstract
A single Dcp1-Dcp2 decapping enzyme targets diverse classes of yeast mRNAs for decapping-dependent 5' to 3' decay, but the molecular mechanisms controlling mRNA selectivity by the enzyme remain elusive. Through extensive genetic analyses we reveal that Dcp2 C-terminal domain cis-regulatory elements control decapping enzyme target specificity by orchestrating formation of distinct decapping complexes. Two Upf1-binding motifs direct the decapping enzyme to NMD substrates, a single Edc3-binding motif targets both Edc3 and Dhh1 substrates, and Pat1-binding leucine-rich motifs target Edc3 and Dhh1 substrates under selective conditions. Although it functions as a unique targeting component of specific complexes, Edc3 is a common component of multiple complexes. Scd6 and Xrn1 also have specific binding sites on Dcp2, allowing them to be directly recruited to decapping complexes. Collectively, our results demonstrate that Upf1, Edc3, Scd6, and Pat1 function as regulatory subunits of the holo-decapping enzyme, controlling both its substrate specificity and enzymatic activation.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Chan Wu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, United States
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13
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One enzyme, many substrates: How the vaccinia virus enzyme D9 decaps host and viral mRNAs alike. Structure 2022; 30:653-654. [PMID: 35523121 DOI: 10.1016/j.str.2022.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The decapping enzyme D9 acts on host mRNA and viral double-stranded RNA to promote viral replication in host cells. In this issue of Structure, Peters et al. (2022) present crystal structures of m7GDP-bound D9 to highlight how a conventional fold is adapted to target a wide variety of RNA substrates.
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14
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Vidya E, Duchaine TF. Eukaryotic mRNA Decapping Activation. Front Genet 2022; 13:832547. [PMID: 35401681 PMCID: PMC8984151 DOI: 10.3389/fgene.2022.832547] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
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
- *Correspondence: Thomas F. Duchaine,
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15
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Naeli P, Winter T, Hackett AP, Alboushi L, Jafarnejad SM. The intricate balance between microRNA-induced mRNA decay and translational repression. FEBS J 2022; 290:2508-2524. [PMID: 35247033 DOI: 10.1111/febs.16422] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 02/08/2022] [Accepted: 03/03/2022] [Indexed: 12/23/2022]
Abstract
Post-transcriptional regulation of messenger RNAs (mRNAs) (i.e., mechanisms that control translation, stability and localization) is a critical focal point in spatiotemporal regulation of gene expression in response to changes in environmental conditions. The human genome encodes ~ 2000 microRNAs (miRNAs), each of which could control the expression of hundreds of protein-coding mRNAs by inducing translational repression and/or promoting mRNA decay. While mRNA degradation is a terminal event, translational repression is reversible and can be employed for rapid response to internal or external cues. Recent years have seen significant progress in our understanding of how miRNAs induce degradation or translational repression of the target mRNAs. Here, we review the recent findings that illustrate the cellular machinery that contributes to miRNA-induced silencing, with a focus on the factors that could influence translational repression vs. decay.
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Affiliation(s)
- Parisa Naeli
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
| | - Timothy Winter
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
| | - Angela P Hackett
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
| | - Lilas Alboushi
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
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16
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Peters JK, Tibble RW, Warminski M, Jemielity J, Gross JD. Structure of the poxvirus decapping enzyme D9 reveals its mechanism of cap recognition and catalysis. Structure 2022; 30:721-732.e4. [PMID: 35290794 PMCID: PMC9081138 DOI: 10.1016/j.str.2022.02.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 12/30/2021] [Accepted: 02/16/2022] [Indexed: 01/06/2023]
Abstract
Poxviruses encode decapping enzymes that remove the protective 5' cap from both host and viral mRNAs to commit transcripts for decay by the cellular exonuclease Xrn1. Decapping by these enzymes is critical for poxvirus pathogenicity by means of simultaneously suppressing host protein synthesis and limiting the accumulation of viral double-stranded RNA (dsRNA), a trigger for antiviral responses. Here we present a high-resolution structural view of the vaccinia virus decapping enzyme D9. This Nudix enzyme contains a domain organization different from other decapping enzymes in which a three-helix bundle is inserted into the catalytic Nudix domain. The 5' mRNA cap is positioned in a bipartite active site at the interface of the two domains. Specificity for the methylated guanosine cap is achieved by stacking between conserved aromatic residues in a manner similar to that observed in canonical cap-binding proteins VP39, eIF4E, and CBP20, and distinct from eukaryotic decapping enzyme Dcp2.
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17
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Heid CG, Bentham IP, Gheorghe R, Jambrina PG, Aoiz FJ, Brouard M. Inelastic collision dynamics of oriented NO molecules with Kr atoms. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1946607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Cornelia G. Heid
- Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Imogen P. Bentham
- Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Razvan Gheorghe
- Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Pablo G. Jambrina
- Departamento de Química Física, Universidad de Salamanca, Salamanca, Spain
| | - F. Javier Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, Madrid, Spain
| | - Mark Brouard
- Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, Oxford, UK
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18
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Wurm JP, Sung S, Kneuttinger AC, Hupfeld E, Sterner R, Wilmanns M, Sprangers R. Molecular basis for the allosteric activation mechanism of the heterodimeric imidazole glycerol phosphate synthase complex. Nat Commun 2021; 12:2748. [PMID: 33980881 PMCID: PMC8115485 DOI: 10.1038/s41467-021-22968-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 04/07/2021] [Indexed: 01/14/2023] Open
Abstract
Imidazole glycerol phosphate synthase (HisFH) is a heterodimeric bienzyme complex operating at a central branch point of metabolism. HisFH is responsible for the HisH-catalyzed hydrolysis of glutamine to glutamate and ammonia, which is then used for a cyclase reaction by HisF. The HisFH complex is allosterically regulated but the underlying mechanism is not well understood. Here, we elucidate the molecular basis of the long range, allosteric activation of HisFH. We establish that the catalytically active HisFH conformation is only formed when the substrates of both HisH and HisF are bound. We show that in this conformation an oxyanion hole in the HisH active site is established, which rationalizes the observed 4500-fold allosteric activation compared to the inactive conformation. In solution, the inactive and active conformations are in a dynamic equilibrium and the HisFH turnover rates correlate with the population of the active conformation, which is in accordance with the ensemble model of allostery. The allosteric regulation of the bienzyme complex imidazole glycerol phosphate synthase (HisFH) remains to be elucidated. Here, the authors provide structural insights into the dynamic allosteric mechanism by which ligand binding to the cyclase and glutaminase active sites of HisFH regulate enzyme activation.
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Affiliation(s)
- Jan Philip Wurm
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Sihyun Sung
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Andrea Christa Kneuttinger
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Enrico Hupfeld
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Reinhard Sterner
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Matthias Wilmanns
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany. .,University Hamburg Clinical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany.
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19
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Biomolecular condensates amplify mRNA decapping by biasing enzyme conformation. Nat Chem Biol 2021; 17:615-623. [PMID: 33767388 PMCID: PMC8476181 DOI: 10.1038/s41589-021-00774-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 02/16/2021] [Indexed: 02/07/2023]
Abstract
Cells organize biochemical processes into biological condensates. P-bodies are cytoplasmic condensates that are enriched in enzymes important for mRNA degradation and have been identified as sites of both storage and decay. How these opposing outcomes can be achieved in condensates remains unresolved. mRNA decapping immediately precedes degradation, and the Dcp1/Dcp2 decapping complex is enriched in P-bodies. Here, we show that Dcp1/Dcp2 activity is modulated in condensates and depends on the interactions promoting phase separation. We find that Dcp1/Dcp2 phase separation stabilizes an inactive conformation in Dcp2 to inhibit decapping. The activator Edc3 causes a conformational change in Dcp2 and rewires the protein-protein interactions to stimulate decapping in condensates. Disruption of the inactive conformation dysregulates decapping in condensates. Our results indicate that the regulation of enzymatic activity in condensates relies on a coupling across length scales ranging from microns to ångstroms. We propose that this regulatory mechanism may control the functional state of P-bodies and related phase-separated compartments.
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20
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Sprangers R. High-pressure NMR measurements provide insights into the different structural states that proteins can adopt. Biophys J 2021; 120:749-751. [PMID: 33561391 DOI: 10.1016/j.bpj.2021.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 10/22/2022] Open
Affiliation(s)
- Remco Sprangers
- Department of Biophysics I, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany.
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21
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Luo Y, Schofield JA, Na Z, Hann T, Simon MD, Slavoff SA. Discovery of cellular substrates of human RNA-decapping enzyme DCP2 using a stapled bicyclic peptide inhibitor. Cell Chem Biol 2020; 28:463-474.e7. [PMID: 33357462 DOI: 10.1016/j.chembiol.2020.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/29/2020] [Accepted: 12/04/2020] [Indexed: 01/23/2023]
Abstract
DCP2 is an RNA-decapping enzyme that controls the stability of human RNAs that encode factors functioning in transcription and the immune response. While >1,800 human DCP2 substrates have been identified, compensatory expression changes secondary to genetic ablation of DCP2 have complicated a complete mapping of its regulome. Cell-permeable, selective chemical inhibitors of DCP2 could provide a powerful tool to study DCP2 specificity. Here, we report phage display selection of CP21, a bicyclic peptide ligand to DCP2. CP21 has high affinity and selectivity for DCP2 and inhibits DCP2 decapping activity toward selected RNA substrates in human cells. CP21 increases formation of P-bodies, liquid condensates enriched in intermediates of RNA decay, in a manner that resembles the deletion or mutation of DCP2. We used CP21 to identify 76 previously unreported DCP2 substrates. This work demonstrates that DCP2 inhibition can complement genetic approaches to study RNA decay.
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Affiliation(s)
- Yang Luo
- Department of Chemistry, Yale University, New Haven, CT 06520, USA; Chemical Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Jeremy A Schofield
- Chemical Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06529, USA
| | - Zhenkun Na
- Department of Chemistry, Yale University, New Haven, CT 06520, USA; Chemical Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Tanja Hann
- Yale Combined Program in the Biological and Biomedical Sciences, Yale University, New Haven, CT 06520, USA
| | - Matthew D Simon
- Chemical Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06529, USA
| | - Sarah A Slavoff
- Department of Chemistry, Yale University, New Haven, CT 06520, USA; Chemical Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06529, USA.
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22
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Charenton C, Gaudon-Plesse C, Back R, Ulryck N, Cosson L, Séraphin B, Graille M. Pby1 is a direct partner of the Dcp2 decapping enzyme. Nucleic Acids Res 2020; 48:6353-6366. [PMID: 32396195 PMCID: PMC7293026 DOI: 10.1093/nar/gkaa337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/17/2020] [Accepted: 04/23/2020] [Indexed: 12/27/2022] Open
Abstract
Most eukaryotic mRNAs harbor a characteristic 5′ m7GpppN cap that promotes pre-mRNA splicing, mRNA nucleocytoplasmic transport and translation while also protecting mRNAs from exonucleolytic attacks. mRNA caps are eliminated by Dcp2 during mRNA decay, allowing 5′-3′ exonucleases to degrade mRNA bodies. However, the Dcp2 decapping enzyme is poorly active on its own and requires binding to stable or transient protein partners to sever the cap of target mRNAs. Here, we analyse the role of one of these partners, the yeast Pby1 factor, which is known to co-localize into P-bodies together with decapping factors. We report that Pby1 uses its C-terminal domain to directly bind to the decapping enzyme. We solved the structure of this Pby1 domain alone and bound to the Dcp1–Dcp2–Edc3 decapping complex. Structure-based mutant analyses reveal that Pby1 binding to the decapping enzyme is required for its recruitment into P-bodies. Moreover, Pby1 binding to the decapping enzyme stimulates growth in conditions in which decapping activation is compromised. Our results point towards a direct connection of Pby1 with decapping and P-body formation, both stemming from its interaction with the Dcp1–Dcp2 holoenzyme.
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Affiliation(s)
- Clément Charenton
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris, 91128 Palaiseau, France
| | - Claudine Gaudon-Plesse
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Centre National de Recherche Scientifique (CNRS) UMR 7104, Illkirch, France.,Institut National de Santé et de Recherche Médicale (INSERM) U1258, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Régis Back
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris, 91128 Palaiseau, France
| | - Nathalie Ulryck
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris, 91128 Palaiseau, France
| | - Loreline Cosson
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris, 91128 Palaiseau, France
| | - Bertrand Séraphin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,Centre National de Recherche Scientifique (CNRS) UMR 7104, Illkirch, France.,Institut National de Santé et de Recherche Médicale (INSERM) U1258, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Marc Graille
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, IP Paris, 91128 Palaiseau, France
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23
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Molecular basis of the selective processing of short mRNA substrates by the DcpS mRNA decapping enzyme. Proc Natl Acad Sci U S A 2020; 117:19237-19244. [PMID: 32723815 PMCID: PMC7431086 DOI: 10.1073/pnas.2009362117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In eukoryotes, 3′ to 5′ mRNA degradation is a major pathway to reduce mRNA levels and, thus, an important means to regulate gene expression. Herein, messenger RNA (mRNA) is hydrolyzed from the 3′ end by the exosome complex, producing short capped RNA fragments, which are decapped by DcpS. Our data show that DcpS is only active on mRNA that have undergone prior processing by the exosome. This DcpS selection mechanism is conserved from yeast to humans and is caused by the inability of the enzyme to undergo structural changes that are required for the formation of a catalytically active state around long mRNA transcripts. Our work thus reveals the mechanistic basis that ensures an efficient interplay between DcpS and the exosome. The 5′ messenger RNA (mRNA) cap structure enhances translation and protects the transcript against exonucleolytic degradation. During mRNA turnover, this cap is removed from the mRNA. This decapping step is catalyzed by the Scavenger Decapping Enzyme (DcpS), in case the mRNA has been exonucleolyticly shortened from the 3′ end by the exosome complex. Here, we show that DcpS only processes mRNA fragments that are shorter than three nucleotides in length. Based on a combination of methyl transverse relaxation optimized (TROSY) NMR spectroscopy and X-ray crystallography, we established that the DcpS substrate length-sensing mechanism is based on steric clashes between the enzyme and the third nucleotide of a capped mRNA. For longer mRNA substrates, these clashes prevent conformational changes in DcpS that are required for the formation of a catalytically competent active site. Point mutations that enlarge the space for the third nucleotide in the mRNA body enhance the activity of DcpS on longer mRNA species. We find that this mechanism to ensure that the enzyme is not active on translating long mRNAs is conserved from yeast to humans. Finally, we show that the products that the exosome releases after 3′ to 5′ degradation of the mRNA body are indeed short enough to be decapped by DcpS. Our data thus directly confirms the notion that mRNA products of the exosome are direct substrates for DcpS. In summary, we demonstrate a direct relationship between conformational changes and enzyme activity that is exploited to achieve substrate selectivity.
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24
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Schütz S, Sprangers R. Methyl TROSY spectroscopy: A versatile NMR approach to study challenging biological systems. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 116:56-84. [PMID: 32130959 DOI: 10.1016/j.pnmrs.2019.09.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/09/2019] [Accepted: 09/25/2019] [Indexed: 05/21/2023]
Abstract
A major goal in structural biology is to unravel how molecular machines function in detail. To that end, solution-state NMR spectroscopy is ideally suited as it is able to study biological assemblies in a near natural environment. Based on methyl TROSY methods, it is now possible to record high-quality data on complexes that are far over 100 kDa in molecular weight. In this review, we discuss the theoretical background of methyl TROSY spectroscopy, the information that can be extracted from methyl TROSY spectra and approaches that can be used to assign methyl resonances in large complexes. In addition, we touch upon insights that have been obtained for a number of challenging biological systems, including the 20S proteasome, the RNA exosome, molecular chaperones and G-protein-coupled receptors. We anticipate that methyl TROSY methods will be increasingly important in modern structural biology approaches, where information regarding static structures is complemented with insights into conformational changes and dynamic intermolecular interactions.
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Affiliation(s)
- Stefan Schütz
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Remco Sprangers
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany.
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25
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Wurm JP, Sprangers R. Dcp2: an mRNA decapping enzyme that adopts many different shapes and forms. Curr Opin Struct Biol 2019; 59:115-123. [PMID: 31473440 PMCID: PMC6900585 DOI: 10.1016/j.sbi.2019.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/22/2019] [Accepted: 07/30/2019] [Indexed: 02/01/2023]
Abstract
Structure of the active state of the Dcp2 decapping enzyme. Insights into the structural states that are sampled in solution. Details regarding the intermolecular network that Dcp2 is embedded in.
Eukaryotic mRNAs contain a 5’ cap structure that protects the transcript against rapid exonucleolytic degradation. The regulation of cellular mRNA levels therefore depends on a precise control of the mRNA decapping pathways. The major mRNA decapping enzyme in eukaryotic cells is Dcp2. It is regulated by interactions with several activators, including Dcp1, Edc1, and Edc3, as well as by an autoinhibition mechanism. The structural and mechanistical characterization of Dcp2 complexes has long been impeded by the high flexibility and dynamic nature of the enzyme. Here we review recent insights into the catalytically active conformation of the mRNA decapping complex, the mode of action of decapping activators and the large interactions network that Dcp2 is embedded in.
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Affiliation(s)
- Jan Philip Wurm
- Department of Biophysics I, University of Regensburg, 93053, Regensburg, Germany.
| | - Remco Sprangers
- Department of Biophysics I, University of Regensburg, 93053, Regensburg, Germany.
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26
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Paquette DR, Tibble RW, Daifuku TS, Gross JD. Control of mRNA decapping by autoinhibition. Nucleic Acids Res 2019; 46:6318-6329. [PMID: 29618050 PMCID: PMC6158755 DOI: 10.1093/nar/gky233] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 03/19/2018] [Indexed: 12/11/2022] Open
Abstract
5′ mediated cytoplasmic RNA decay is a conserved cellular process in eukaryotes. While the functions of the structured core domains in this pathway are well-studied, the role of abundant intrinsically disordered regions (IDRs) is lacking. Here we reconstitute the Dcp1:Dcp2 complex containing a portion of the disordered C-terminus and show its activity is autoinhibited by linear interaction motifs. Enhancers of decapping (Edc) 1 and 3 cooperate to activate decapping by different mechanisms: Edc3 alleviates autoinhibition by binding IDRs and destabilizing an inactive form of the enzyme, whereas Edc1 stabilizes the transition state for catalysis. Both activators are required to fully stimulate an autoinhibited Dcp1:Dcp2 as Edc1 alone cannot overcome the decrease in activity attributed to the C-terminal extension. Our data provide a mechanistic framework for combinatorial control of decapping by protein cofactors, a principle that is likely conserved in multiple 5′ mRNA decay pathways.
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Affiliation(s)
- David R Paquette
- Integrative Program in Quantitative Biology, Graduate Group in Biophysics, University of California, San Francisco, CA 94158, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Ryan W Tibble
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA.,Program in Chemistry and Chemical Biology, University of California, San Francisco, CA 94158, USA
| | - Tristan S Daifuku
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - John D Gross
- Integrative Program in Quantitative Biology, Graduate Group in Biophysics, University of California, San Francisco, CA 94158, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA.,Program in Chemistry and Chemical Biology, University of California, San Francisco, CA 94158, USA
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27
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Leitner A, Dorn G, Allain FHT. Combining Mass Spectrometry (MS) and Nuclear Magnetic Resonance (NMR) Spectroscopy for Integrative Structural Biology of Protein-RNA Complexes. Cold Spring Harb Perspect Biol 2019; 11:a032359. [PMID: 31262947 PMCID: PMC6601463 DOI: 10.1101/cshperspect.a032359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Deciphering complex RNA-protein interactions on a (near-)atomic level is a hurdle that hinders advancing our understanding of fundamental processes in RNA metabolism and RNA-based gene regulation. To overcome challenges associated with individual structure determination methods, structural information derived from complementary biophysical methods can be combined in integrative structural biology approaches. Here, we review recent advances in such hybrid structural approaches with a focus on combining mass spectrometric analysis of cross-linked protein-RNA complexes and nuclear magnetic resonance (NMR) spectroscopy.
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Affiliation(s)
- Alexander Leitner
- Institute of Molecular Systems Biology, Department of Biology, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zürich, Switzerland
| | - Georg Dorn
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Frédéric H-T Allain
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
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28
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He F, Celik A, Wu C, Jacobson A. General decapping activators target different subsets of inefficiently translated mRNAs. eLife 2018; 7:34409. [PMID: 30520724 PMCID: PMC6300357 DOI: 10.7554/elife.34409] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 12/04/2018] [Indexed: 12/18/2022] Open
Abstract
The Dcp1-Dcp2 decapping enzyme and the decapping activators Pat1, Dhh1, and Lsm1 regulate mRNA decapping, but their mechanistic integration is unknown. We analyzed the gene expression consequences of deleting PAT1, LSM1, or DHH1, or the DCP2 C-terminal domain, and found that: i) the Dcp2 C-terminal domain is an effector of both negative and positive regulation; ii) rather than being global activators of decapping, Pat1, Lsm1, and Dhh1 directly target specific subsets of yeast mRNAs and loss of the functions of each of these factors has substantial indirect consequences for genome-wide mRNA expression; and iii) transcripts targeted by Pat1, Lsm1, and Dhh1 exhibit only partial overlap, are generally translated inefficiently, and, as expected, are targeted to decapping-dependent decay. Our results define the roles of Pat1, Lsm1, and Dhh1 in decapping of general mRNAs and suggest that these factors may monitor mRNA translation and target unique features of individual mRNAs.
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Affiliation(s)
- Feng He
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Massachusetts, United States
| | - Alper Celik
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Massachusetts, United States
| | - Chan Wu
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Massachusetts, United States
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Massachusetts, United States
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29
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Mugridge JS, Coller J, Gross JD. Structural and molecular mechanisms for the control of eukaryotic 5'-3' mRNA decay. Nat Struct Mol Biol 2018; 25:1077-1085. [PMID: 30518847 DOI: 10.1038/s41594-018-0164-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/31/2018] [Indexed: 12/15/2022]
Abstract
5'-3' RNA decay pathways are critical for quality control and regulation of gene expression. Structural and biochemical studies have provided insights into the key nucleases that carry out deadenylation, decapping, and exonucleolysis during 5'-3' decay, but detailed understanding of how these activities are coordinated is only beginning to emerge. Here we review recent mechanistic insights into the control of 5'-3' RNA decay, including coupling between translation and decay, coordination between the complexes and activities that process 5' and 3' RNA termini, conformational control of enzymatic activity, liquid phase separation, and RNA modifications.
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Affiliation(s)
- Jeffrey S Mugridge
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Jeff Coller
- The Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH, USA
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA.
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30
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Charenton C, Graille M. mRNA decapping: finding the right structures. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2018.0164. [PMID: 30397101 DOI: 10.1098/rstb.2018.0164] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2018] [Indexed: 12/14/2022] Open
Abstract
In eukaryotes, the elimination of the m7GpppN mRNA cap, a process known as decapping, is a critical, largely irreversible and highly regulated step of mRNA decay that withdraws the targeted mRNAs from the pool of translatable templates. The decapping reaction is catalysed by a multi-protein complex formed by the Dcp2 catalytic subunit and its Dcp1 cofactor, a holoenzyme that is poorly active on its own and needs several accessory proteins (Lsm1-7 complex, Pat1, Edc1-2, Edc3 and/or EDC4) to be fully efficient. Here, we discuss the several crystal structures of Dcp2 domains bound to various partners (proteins or small molecules) determined in the last couple of years that have considerably improved our current understanding of how Dcp2, assisted by its various activators, is recruited to its mRNA targets and adopts its active conformation upon substrate recognition. We also describe how, over the years, elegant integrative structural biology approaches combined to biochemistry and genetics led to the identification of the correct structure of the active Dcp1-Dcp2 holoenzyme among the many available conformations trapped by X-ray crystallography.This article is part of the theme issue '5' and 3' modifications controlling RNA degradation'.
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Affiliation(s)
- Clément Charenton
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, F-91128 Palaiseau cedex, France
| | - Marc Graille
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, F-91128 Palaiseau cedex, France
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31
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Buller AR, van Roye P, Cahn JK, Scheele RA, Herger M, Arnold FH. Directed Evolution Mimics Allosteric Activation by Stepwise Tuning of the Conformational Ensemble. J Am Chem Soc 2018; 140:7256-7266. [PMID: 29712420 PMCID: PMC5999571 DOI: 10.1021/jacs.8b03490] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Allosteric enzymes contain a wealth of catalytic diversity that remains distinctly underutilized for biocatalysis. Tryptophan synthase is a model allosteric system and a valuable enzyme for the synthesis of noncanonical amino acids (ncAA). Previously, we evolved the β-subunit from Pyrococcus furiosus, PfTrpB, for ncAA synthase activity in the absence of its native partner protein PfTrpA. However, the precise mechanism by which mutation activated TrpB to afford a stand-alone catalyst remained enigmatic. Here, we show that directed evolution caused a gradual change in the rate-limiting step of the catalytic cycle. Concomitantly, the steady-state distribution of the intermediates shifts to favor covalently bound Trp adducts, which have increased thermodynamic stability. The biochemical properties of these evolved, stand-alone TrpBs converge on those induced in the native system by allosteric activation. High-resolution crystal structures of the wild-type enzyme, an intermediate in the lineage, and the final variant, encompassing five distinct chemical states, show that activating mutations have only minor structural effects on their immediate environment. Instead, mutation stabilizes the large-scale motion of a subdomain to favor an otherwise transiently populated closed conformational state. This increase in stability enabled the first structural description of Trp covalently bound in a catalytically active TrpB, confirming key features of catalysis. These data combine to show that sophisticated models of allostery are not a prerequisite to recapitulating its complex effects via directed evolution, opening the way to engineering stand-alone versions of diverse allosteric enzymes.
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Affiliation(s)
- Andrew R. Buller
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Paul van Roye
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Jackson K.B. Cahn
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Vladimir-Prelog-Weg 4, Zurich 8093, Switzerland
| | - Remkes A. Scheele
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Michael Herger
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Frances H. Arnold
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
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32
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Schulte M, Petrović D, Neudecker P, Hartmann R, Pietruszka J, Willbold S, Willbold D, Panwalkar V. Conformational Sampling of the Intrinsically Disordered C-Terminal Tail of DERA Is Important for Enzyme Catalysis. ACS Catal 2018; 8:3971-3984. [PMID: 30101036 PMCID: PMC6080863 DOI: 10.1021/acscatal.7b04408] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/24/2018] [Indexed: 12/13/2022]
Abstract
2-Deoxyribose-5-phosphate aldolase (DERA) catalyzes the reversible conversion of acetaldehyde and glyceraldehyde-3-phosphate into deoxyribose-5-phosphate. DERA is used as a biocatalyst for the synthesis of drugs such as statins and is a promising pharmaceutical target due to its involvement in nucleotide catabolism. Despite previous biochemical studies suggesting the catalytic importance of the C-terminal tyrosine residue found in several bacterial DERAs, the structural and functional basis of its participation in catalysis remains elusive because the electron density for the last eight to nine residues (i.e., the C-terminal tail) is absent in all available crystal structures. Using a combination of NMR spectroscopy and molecular dynamics simulations, we conclusively show that the rarely studied C-terminal tail of E. coli DERA (ecDERA) is intrinsically disordered and exists in equilibrium between open and catalytically relevant closed states, where the C-terminal tyrosine (Y259) enters the active site. Nuclear Overhauser effect distance restraints, obtained due to the presence of a substantial closed state population, were used to derive the solution-state structure of the ecDERA closed state. Real-time NMR hydrogen/deuterium exchange experiments reveal that Y259 is required for efficiency of the proton abstraction step of the catalytic reaction. Phosphate titration experiments show that, in addition to the phosphate-binding residues located near the active site, as observed in the available crystal structures, ecDERA contains previously unknown auxiliary phosphate-binding residues on the C-terminal tail which could facilitate in orienting Y259 in an optimal position for catalysis. Thus, we present significant insights into the structural and mechanistic importance of the ecDERA C-terminal tail and illustrate the role of conformational sampling in enzyme catalysis.
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Affiliation(s)
- Marianne Schulte
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- Institute of Complex Systems 6 (ICS-6): Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Dušan Petrović
- Institute of Complex Systems 6 (ICS-6): Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Philipp Neudecker
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- Institute of Complex Systems 6 (ICS-6): Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rudolf Hartmann
- Institute of Complex Systems 6 (ICS-6): Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Jörg Pietruszka
- Institute of Bioorganic Chemistry, Heinrich-Heine-Universität im Forschungszentrum Jülich, 52425 Jülich, Germany
- Institute of Bio- and Geosciences 1 (IBG-1): Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Sabine Willbold
- Central Institute of Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Dieter Willbold
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- Institute of Complex Systems 6 (ICS-6): Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Vineet Panwalkar
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
- Institute of Complex Systems 6 (ICS-6): Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany
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33
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Heck AM, Wilusz J. The Interplay between the RNA Decay and Translation Machinery in Eukaryotes. Cold Spring Harb Perspect Biol 2018; 10:a032839. [PMID: 29311343 PMCID: PMC5932591 DOI: 10.1101/cshperspect.a032839] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
RNA decay plays a major role in regulating gene expression and is tightly networked with other aspects of gene expression to effectively coordinate post-transcriptional regulation. The goal of this work is to provide an overview of the major factors and pathways of general messenger RNA (mRNA) decay in eukaryotic cells, and then discuss the effective interplay of this cytoplasmic process with the protein synthesis machinery. Given the transcript-specific and fluid nature of mRNA stability in response to changing cellular conditions, understanding the fundamental networking between RNA decay and translation will provide a foundation for a complete mechanistic understanding of this important aspect of cell biology.
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Affiliation(s)
- Adam M Heck
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80525
- Program in Cell & Molecular Biology, Colorado State University, Fort Collins, Colorado 80525
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80525
- Program in Cell & Molecular Biology, Colorado State University, Fort Collins, Colorado 80525
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34
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Mugridge JS, Tibble RW, Ziemniak M, Jemielity J, Gross JD. Structure of the activated Edc1-Dcp1-Dcp2-Edc3 mRNA decapping complex with substrate analog poised for catalysis. Nat Commun 2018; 9:1152. [PMID: 29559651 PMCID: PMC5861098 DOI: 10.1038/s41467-018-03536-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 02/22/2018] [Indexed: 11/17/2022] Open
Abstract
The conserved decapping enzyme Dcp2 recognizes and removes the 5′ eukaryotic cap from mRNA transcripts in a critical step of many cellular RNA decay pathways. Dcp2 is a dynamic enzyme that functions in concert with the essential activator Dcp1 and a diverse set of coactivators to selectively and efficiently decap target mRNAs in the cell. Here we present a 2.84 Å crystal structure of K. lactis Dcp1–Dcp2 in complex with coactivators Edc1 and Edc3, and with substrate analog bound to the Dcp2 active site. Our structure shows how Dcp2 recognizes cap substrate in the catalytically active conformation of the enzyme, and how coactivator Edc1 forms a three-way interface that bridges the domains of Dcp2 to consolidate the active conformation. Kinetic data reveal Dcp2 has selectivity for the first transcribed nucleotide during the catalytic step. The heterotetrameric Edc1–Dcp1–Dcp2–Edc3 structure shows how coactivators Edc1 and Edc3 can act simultaneously to activate decapping catalysis. The decapping enzyme Dcp2 removes the 5′ eukaryotic cap from mRNA transcripts and acts in concert with its essential activator Dcp1 and various coactivators. Here the authors present the structure of the fully-activated mRNA decapping complex, which reveals how Dcp2 recognizes the cap substrate and coactivators Edc1 and Edc3 activate catalysis.
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Affiliation(s)
- Jeffrey S Mugridge
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Ryan W Tibble
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, 94158, USA.,Program in Chemistry and Chemical Biology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Marcin Ziemniak
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089, Warsaw, Poland.,Centre of New Technologies, University of Warsaw, 02-097, Warsaw, Poland.,Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, 02-089, Warsaw, Poland
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, 02-097, Warsaw, Poland
| | - John D Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, 94158, USA. .,Program in Chemistry and Chemical Biology, University of California, San Francisco, San Francisco, CA, 94158, USA.
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35
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Valkov E, Jonas S, Weichenrieder O. Mille viae in eukaryotic mRNA decapping. Curr Opin Struct Biol 2017; 47:40-51. [PMID: 28591671 DOI: 10.1016/j.sbi.2017.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Accepted: 05/22/2017] [Indexed: 12/20/2022]
Abstract
Cellular mRNA levels are regulated via rates of transcription and decay. Since the removal of the mRNA 5'-cap by the decapping enzyme DCP2 is generally an irreversible step towards decay, it requires regulation. Control of DCP2 activity is likely effected by two interdependent means: by conformational control of the DCP2-DCP1 complex, and by assembly control of the decapping network, an array of mutually interacting effector proteins. Here, we compare three recent and conformationally distinct crystal structures of the DCP2-DCP1 decapping complex in the presence of substrate analogs and decapping enhancers and we discuss alternative substrate recognition modes for the catalytic domain of DCP2. Together with structure-based insight into decapping network assembly, we propose that DCP2-mediated decapping follows more than one path.
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Affiliation(s)
- Eugene Valkov
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Stefanie Jonas
- Institute of Biochemistry, ETH Zürich, Otto-Stern Weg 3, 8093 Zürich, Switzerland.
| | - Oliver Weichenrieder
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany.
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