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Martín-Villanueva S, Galmozzi CV, Ruger-Herreros C, Kressler D, de la Cruz J. The Beak of Eukaryotic Ribosomes: Life, Work and Miracles. Biomolecules 2024; 14:882. [PMID: 39062596 PMCID: PMC11274626 DOI: 10.3390/biom14070882] [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: 06/19/2024] [Revised: 07/19/2024] [Accepted: 07/21/2024] [Indexed: 07/28/2024] Open
Abstract
Ribosomes are not totally globular machines. Instead, they comprise prominent structural protrusions and a myriad of tentacle-like projections, which are frequently made up of ribosomal RNA expansion segments and N- or C-terminal extensions of ribosomal proteins. This is more evident in higher eukaryotic ribosomes. One of the most characteristic protrusions, present in small ribosomal subunits in all three domains of life, is the so-called beak, which is relevant for the function and regulation of the ribosome's activities. During evolution, the beak has transitioned from an all ribosomal RNA structure (helix h33 in 16S rRNA) in bacteria, to an arrangement formed by three ribosomal proteins, eS10, eS12 and eS31, and a smaller h33 ribosomal RNA in eukaryotes. In this review, we describe the different structural and functional properties of the eukaryotic beak. We discuss the state-of-the-art concerning its composition and functional significance, including other processes apparently not related to translation, and the dynamics of its assembly in yeast and human cells. Moreover, we outline the current view about the relevance of the beak's components in human diseases, especially in ribosomopathies and cancer.
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Affiliation(s)
- Sara Martín-Villanueva
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Carla V. Galmozzi
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Carmen Ruger-Herreros
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Dieter Kressler
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland;
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
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Keidel A, Kögel A, Reichelt P, Kowalinski E, Schäfer IB, Conti E. Concerted structural rearrangements enable RNA channeling into the cytoplasmic Ski238-Ski7-exosome assembly. Mol Cell 2023; 83:4093-4105.e7. [PMID: 37879335 PMCID: PMC10659929 DOI: 10.1016/j.molcel.2023.09.037] [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: 06/06/2023] [Revised: 08/25/2023] [Accepted: 09/29/2023] [Indexed: 10/27/2023]
Abstract
The Ski2-Ski3-Ski8 (Ski238) helicase complex directs cytoplasmic mRNAs toward the nucleolytic exosome complex for degradation. In yeast, the interaction between Ski238 and exosome requires the adaptor protein Ski7. We determined different cryo-EM structures of the Ski238 complex depicting the transition from a rigid autoinhibited closed conformation to a flexible active open conformation in which the Ski2 helicase module has detached from the rest of Ski238. The open conformation favors the interaction of the Ski3 subunit with exosome-bound Ski7, leading to the recruitment of the exosome. In the Ski238-Ski7-exosome holocomplex, the Ski2 helicase module binds the exosome cap, enabling the RNA to traverse from the helicase through the internal exosome channel to the Rrp44 exoribonuclease. Our study pinpoints how conformational changes within the Ski238 complex regulate exosome recruitment for RNA degradation. We also reveal the remarkable conservation of helicase-exosome RNA channeling mechanisms throughout eukaryotic nuclear and cytoplasmic exosome complexes.
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Affiliation(s)
- Achim Keidel
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany
| | - Alexander Kögel
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany
| | - Peter Reichelt
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany
| | - Eva Kowalinski
- EMBL Grenoble, 71 Avenue des Martyrs, 38072 Grenoble, France
| | - Ingmar B Schäfer
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany.
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3
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Tomecki R, Drazkowska K, Kobylecki K, Tudek A. SKI complex: A multifaceted cytoplasmic RNA exosome cofactor in mRNA metabolism with links to disease, developmental processes, and antiviral responses. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1795. [PMID: 37384835 DOI: 10.1002/wrna.1795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/26/2023] [Accepted: 05/01/2023] [Indexed: 07/01/2023]
Abstract
RNA stability and quality control are integral parts of gene expression regulation. A key factor shaping eukaryotic transcriptomes, mainly via 3'-5' exoribonucleolytic trimming or degradation of diverse transcripts in nuclear and cytoplasmic compartments, is the RNA exosome. Precise exosome targeting to various RNA molecules requires strict collaboration with specialized auxiliary factors, which facilitate interactions with its substrates. The predominant class of cytoplasmic RNA targeted by the exosome are protein-coding transcripts, which are carefully scrutinized for errors during translation. Normal, functional mRNAs are turned over following protein synthesis by the exosome or by Xrn1 5'-3'-exonuclease, acting in concert with Dcp1/2 decapping complex. In turn, aberrant transcripts are eliminated by dedicated surveillance pathways, triggered whenever ribosome translocation is impaired. Cytoplasmic 3'-5' mRNA decay and surveillance are dependent on the tight cooperation between the exosome and its evolutionary conserved co-factor-the SKI (superkiller) complex (SKIc). Here, we summarize recent findings from structural, biochemical, and functional studies of SKIc roles in controlling cytoplasmic RNA metabolism, including links to various cellular processes. Mechanism of SKIc action is illuminated by presentation of its spatial structure and details of its interactions with exosome and ribosome. Furthermore, contribution of SKIc and exosome to various mRNA decay pathways, usually converging on recycling of ribosomal subunits, is delineated. A crucial physiological role of SKIc is emphasized by describing association between its dysfunction and devastating human disease-a trichohepatoenteric syndrome (THES). Eventually, we discuss SKIc functions in the regulation of antiviral defense systems, cell signaling and developmental transitions, emerging from interdisciplinary investigations. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Turnover and Surveillance > Regulation of RNA Stability RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Rafal Tomecki
- Laboratory of RNA Processing and Decay, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Karolina Drazkowska
- Laboratory of Epitranscriptomics, Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Kamil Kobylecki
- Laboratory of RNA Processing and Decay, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Tudek
- Laboratory of RNA Processing and Decay, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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4
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Lange H, Gagliardi D. Catalytic activities, molecular connections, and biological functions of plant RNA exosome complexes. THE PLANT CELL 2022; 34:967-988. [PMID: 34954803 PMCID: PMC8894942 DOI: 10.1093/plcell/koab310] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/16/2021] [Indexed: 05/08/2023]
Abstract
RNA exosome complexes provide the main 3'-5'-exoribonuclease activities in eukaryotic cells and contribute to the maturation and degradation of virtually all types of RNA. RNA exosomes consist of a conserved core complex that associates with exoribonucleases and with multimeric cofactors that recruit the enzyme to its RNA targets. Despite an overall high level of structural and functional conservation, the enzymatic activities and compositions of exosome complexes and their cofactor modules differ among eukaryotes. This review highlights unique features of plant exosome complexes, such as the phosphorolytic activity of the core complex, and discusses the exosome cofactors that operate in plants and are dedicated to the maturation of ribosomal RNA, the elimination of spurious, misprocessed, and superfluous transcripts, or the removal of mRNAs cleaved by the RNA-induced silencing complex and other mRNAs prone to undergo silencing.
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Affiliation(s)
- Heike Lange
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
- Author for correspondence:
| | - Dominique Gagliardi
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
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Machado de Amorim A, Chakrabarti S. Assembly of multicomponent machines in RNA metabolism: A common theme in mRNA decay pathways. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1684. [PMID: 34351053 DOI: 10.1002/wrna.1684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/05/2022]
Abstract
Multicomponent protein-RNA complexes comprising a ribonuclease and partner RNA helicase facilitate the turnover of mRNA in all domains of life. While these higher-order complexes provide an effective means of physically and functionally coupling the processes of RNA remodeling and decay, most ribonucleases and RNA helicases do not exhibit sequence specificity in RNA binding. This raises the question as to how these assemblies select substrates for processing and how the activities are orchestrated at the precise moment to ensure efficient decay. The answers to these apparent puzzles lie in the auxiliary components of the assemblies that might relay decay-triggering signals. Given their function within the assemblies, these components may be viewed as "sensors." The functions and mechanisms of action of the sensor components in various degradation complexes in bacteria and eukaryotes are highlighted here to discuss their roles in RNA decay processes. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition.
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Affiliation(s)
| | - Sutapa Chakrabarti
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
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6
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Cabrera-Quio LE, Schleiffer A, Mechtler K, Pauli A. Zebrafish Ski7 tunes RNA levels during the oocyte-to-embryo transition. PLoS Genet 2021; 17:e1009390. [PMID: 33600438 PMCID: PMC7924785 DOI: 10.1371/journal.pgen.1009390] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/02/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022] Open
Abstract
Post-transcriptional regulation of gene expression is crucial during the oocyte-to-embryo transition, a highly dynamic process characterized by the absence of nuclear transcription. Thus, changes to the RNA content are solely dependent on RNA degradation. Although several mechanisms that promote RNA decay during embryogenesis have been identified, it remains unclear which machineries contribute to remodeling the maternal transcriptome. Here, we focused on the degradation factor Ski7 in zebrafish. Homozygous ski7 mutant fish had higher proportions of both poor quality eggs and eggs that were unable to develop beyond the one-cell stage. Consistent with the idea that Ski7 participates in remodeling the maternal RNA content, transcriptome profiling identified hundreds of misregulated mRNAs in the absence of Ski7. Furthermore, upregulated genes were generally lowly expressed in wild type, suggesting that Ski7 maintains low transcript levels for this subset of genes. Finally, GO enrichment and proteomic analyses of misregulated factors implicated Ski7 in the regulation of redox processes. This was confirmed experimentally by an increased resistance of ski7 mutant embryos to reductive stress. Our results provide first insights into the physiological role of vertebrate Ski7 as a post-transcriptional regulator during the oocyte-to-embryo transition.
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Affiliation(s)
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Karl Mechtler
- Institute of Molecular Biotechnology, IMBA, Campus Vienna-Biocenter (VBC), Vienna, Austria
| | - Andrea Pauli
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
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7
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Weick EM, Lima CD. RNA helicases are hubs that orchestrate exosome-dependent 3'-5' decay. Curr Opin Struct Biol 2020; 67:86-94. [PMID: 33147539 DOI: 10.1016/j.sbi.2020.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/14/2020] [Accepted: 09/20/2020] [Indexed: 01/10/2023]
Abstract
The RNA exosome is a conserved complex of proteins that mediates 3'-5' RNA processing and decay. Its functions range from processing of non-coding RNAs such as ribosomal RNAs and decay of aberrant transcripts in the nucleus to cytoplasmic mRNA turnover and quality control. Ski2-like RNA helicases translocate substrates to exosome-associated ribonucleases and interact with the RNA exosome either directly or as part of multi-subunit helicase-containing complexes that identify and target RNA substrates for decay. Recent structures of these helicases with their RNA-binding partners or the RNA exosome have advanced our understanding of a system of modular and mutually exclusive contacts between the exosome and exosome-associated helicase complexes that shape the transcriptome by orchestrating exosome-dependent 3'-5' decay.
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Affiliation(s)
- Eva-Maria Weick
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Howard Hughes Medical Institute, 1275 York Avenue, New York, NY 10065, USA.
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8
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Zinoviev A, Hellen CUT, Pestova TV. In Vitro Characterization of the Activity of the Mammalian RNA Exosome on mRNAs in Ribosomal Translation Complexes. Methods Mol Biol 2020; 2062:327-354. [PMID: 31768984 DOI: 10.1007/978-1-4939-9822-7_16] [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] [Indexed: 10/18/2023]
Abstract
The RNA exosome is a multisubunit protein complex that exhibits a 3' to 5' exoribonuclease activity, endoribonuclease activity, and participates in a variety of RNA processing and degradation pathways in both the nucleus and the cytoplasm. Exosomes interact with various cofactors which target them to specific RNA substrates and processes. Investigation of the mechanisms by which mammalian RNA exosomes are targeted to specific RNA substrates requires the development of in vitro approaches for purification of exosomes and their co-factors, assembly of substrates and monitoring of the exosomal activity. Here, we describe protocols for in vitro reconstitution of ribosomal 80S elongation complexes on cap-labeled mRNAs and for assaying exosomal degradation of mRNAs in such complexes depending on the presence of GTPBP1, which has previously been implicated in directing the exosome to mRNA targets.
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Affiliation(s)
- Alexandra Zinoviev
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA.
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9
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Lange H, Ndecky SYA, Gomez-Diaz C, Pflieger D, Butel N, Zumsteg J, Kuhn L, Piermaria C, Chicher J, Christie M, Karaaslan ES, Lang PLM, Weigel D, Vaucheret H, Hammann P, Gagliardi D. RST1 and RIPR connect the cytosolic RNA exosome to the Ski complex in Arabidopsis. Nat Commun 2019; 10:3871. [PMID: 31455787 PMCID: PMC6711988 DOI: 10.1038/s41467-019-11807-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/05/2019] [Indexed: 02/01/2023] Open
Abstract
The RNA exosome is a key 3’−5’ exoribonuclease with an evolutionarily conserved structure and function. Its cytosolic functions require the co-factors SKI7 and the Ski complex. Here we demonstrate by co-purification experiments that the ARM-repeat protein RESURRECTION1 (RST1) and RST1 INTERACTING PROTEIN (RIPR) connect the cytosolic Arabidopsis RNA exosome to the Ski complex. rst1 and ripr mutants accumulate RNA quality control siRNAs (rqc-siRNAs) produced by the post-transcriptional gene silencing (PTGS) machinery when mRNA degradation is compromised. The small RNA populations observed in rst1 and ripr mutants are also detected in mutants lacking the RRP45B/CER7 core exosome subunit. Thus, molecular and genetic evidence supports a physical and functional link between RST1, RIPR and the RNA exosome. Our data reveal the existence of additional cytosolic exosome co-factors besides the known Ski subunits. RST1 is not restricted to plants, as homologues with a similar domain architecture but unknown function exist in animals, including humans. Cytosolic RNA degradation by the RNA exosome requires the Ski complex. Here the authors show that the proteins RST1 and RIPR assist the RNA exosome and the Ski complex in RNA degradation, thereby preventing the production of secondary siRNAs from endogenous mRNAs.
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Affiliation(s)
- Heike Lange
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France.
| | - Simon Y A Ndecky
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Carlos Gomez-Diaz
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - David Pflieger
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Nicolas Butel
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Julie Zumsteg
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Lauriane Kuhn
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Christina Piermaria
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Johana Chicher
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Michael Christie
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Ezgi S Karaaslan
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | | | - Detlef Weigel
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Hervé Vaucheret
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Philippe Hammann
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Dominique Gagliardi
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France.
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Kalisiak K, Kuliński TM, Tomecki R, Cysewski D, Pietras Z, Chlebowski A, Kowalska K, Dziembowski A. A short splicing isoform of HBS1L links the cytoplasmic exosome and SKI complexes in humans. Nucleic Acids Res 2018; 45:2068-2080. [PMID: 28204585 PMCID: PMC5389692 DOI: 10.1093/nar/gkw862] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/25/2016] [Accepted: 09/20/2016] [Indexed: 12/18/2022] Open
Abstract
The exosome complex is a major eukaryotic exoribonuclease that requires the SKI complex for its activity in the cytoplasm. In yeast, the Ski7 protein links both complexes, whereas a functional equivalent of the Ski7 has remained unknown in the human genome. Proteomic analysis revealed that a previously uncharacterized short splicing isoform of HBS1L (HBS1LV3) is the long-sought factor linking the exosome and SKI complexes in humans. In contrast, the canonical HBS1L variant, HBS1LV1, which acts as a ribosome dissociation factor, does not associate with the exosome and instead interacts with the mRNA surveillance factor PELOTA. Interestingly, both HBS1LV1 and HBS1LV3 interact with the SKI complex and HBS1LV1 seems to antagonize SKI/exosome supercomplex formation. HBS1LV3 contains a unique C-terminal region of unknown structure, with a conserved RxxxFxxxL motif responsible for exosome binding and may interact with the exosome core subunit RRP43 in a way that resembles the association between Rrp6 RNase and Rrp43 in yeast. HBS1LV3 or the SKI complex helicase (SKI2W) depletion similarly affected the transcriptome, deregulating multiple genes. Furthermore, half-lives of representative upregulated mRNAs were increased, supporting the involvement of HBS1LV3 and SKI2W in the same mRNA degradation pathway, essential for transcriptome homeostasis in the cytoplasm.
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Affiliation(s)
- Katarzyna Kalisiak
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Tomasz M. Kuliński
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Rafał Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Dominik Cysewski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Zbigniew Pietras
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
- International Institute of Molecular and Cell Biology in Warsaw, Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Aleksander Chlebowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Katarzyna Kowalska
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Andrzej Dziembowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
- To whom correspondence should be addressed. Tel: +48 22 5922033; Fax: +48 22 6584176;
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11
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Zinoviev A, Goyal A, Jindal S, LaCava J, Komar AA, Rodnina MV, Hellen CUT, Pestova TV. Functions of unconventional mammalian translational GTPases GTPBP1 and GTPBP2. Genes Dev 2018; 32:1226-1241. [PMID: 30108131 PMCID: PMC6120710 DOI: 10.1101/gad.314724.118] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/06/2018] [Indexed: 02/02/2023]
Abstract
In this study, Zinoviev et al. investigated how translational GTPases (GTPBPs) function in mRNA surveillance and ribosome-associated quality control. They demonstrate that GTPBP1 possesses eEF1A-like elongation activity, delivering cognate aa-tRNA to the ribosomal A site in a GTP-dependent manner, and that GTPBP2's binding to GTP was stimulated by Phe-tRNAPhe, lacked elongation activity, and did not stimulate exosomal degradation. Their results indicate that GTPBP1 and GTPBP2 have different functions. GTP-binding protein 1 (GTPBP1) and GTPBP2 comprise a divergent group of translational GTPases with obscure functions, which are most closely related to eEF1A, eRF3, and Hbs1. Although recent reports implicated GTPBPs in mRNA surveillance and ribosome-associated quality control, how they perform these functions remains unknown. Here, we demonstrate that GTPBP1 possesses eEF1A-like elongation activity, delivering cognate aminoacyl-transfer RNA (aa-tRNA) to the ribosomal A site in a GTP-dependent manner. It also stimulates exosomal degradation of mRNAs in elongation complexes. The kinetics of GTPBP1-mediated elongation argues against its functioning in elongation per se but supports involvement in mRNA surveillance. Thus, GTP hydrolysis by GTPBP1 is not followed by rapid peptide bond formation, suggesting that after hydrolysis, GTPBP1 retains aa-tRNA, delaying its accommodation in the A site. In physiological settings, this would cause ribosome stalling, enabling GTPBP1 to elicit quality control programs; e.g., by recruiting the exosome. GTPBP1 can also deliver deacylated tRNA to the A site, indicating that it might function via interaction with deacylated tRNA, which accumulates during stresses. Although GTPBP2's binding to GTP was stimulated by Phe-tRNAPhe, suggesting that its function might also involve interaction with aa-tRNA, GTPBP2 lacked elongation activity and did not stimulate exosomal degradation, indicating that GTPBP1 and GTPBP2 have different functions.
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Affiliation(s)
- Alexandra Zinoviev
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Akanksha Goyal
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Supriya Jindal
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, USA
| | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York 10065, USA
| | - Anton A Komar
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, USA
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Christopher U T Hellen
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Tatyana V Pestova
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA
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12
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Conservation of mRNA quality control factor Ski7 and its diversification through changes in alternative splicing and gene duplication. Proc Natl Acad Sci U S A 2018; 115:E6808-E6816. [PMID: 29967155 DOI: 10.1073/pnas.1801997115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eukaryotes maintain fidelity of gene expression by preferential degradation of aberrant mRNAs that arise by errors in RNA processing reactions. In Saccharomyces cerevisiae, Ski7 plays an important role in this mRNA quality control by mediating mRNA degradation by the RNA exosome. Ski7 was initially thought to be restricted to Saccharomyces cerevisiae and close relatives because the SKI7 gene and its paralog HBS1 arose by whole genome duplication (WGD) in a recent ancestor. We have recently shown that the preduplication gene was alternatively spliced and that Ski7 function predates WGD. Here, we use transcriptome analysis of diverse eukaryotes to show that diverse eukaryotes use alternative splicing of SKI7/HBS1 to encode two proteins. Although alternative splicing affects the same intrinsically disordered region of the protein, the pattern of splice site usage varies. This alternative splicing event arose in an early eukaryote that is a common ancestor of plants, animals, and fungi. Remarkably, through changes in alternative splicing and gene duplication, the Ski7 protein has diversified such that different species express one of four distinct Ski7-like proteins. We also show experimentally that the Saccharomyces cerevisiae SKI7 gene has undergone multiple changes that are incompatible with the Hbs1 function and may also have undergone additional changes to optimize mRNA quality control. The combination of transcriptome analysis in diverse eukaryotes and genetic analysis in yeast clarifies the mechanism by which a Ski7-like protein is expressed across eukaryotes and provides a unique view of changes in alternative splicing patterns of one gene over long evolutionary time.
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13
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Szádeczky-Kardoss I, Csorba T, Auber A, Schamberger A, Nyikó T, Taller J, Orbán TI, Burgyán J, Silhavy D. The nonstop decay and the RNA silencing systems operate cooperatively in plants. Nucleic Acids Res 2018; 46:4632-4648. [PMID: 29672715 PMCID: PMC5961432 DOI: 10.1093/nar/gky279] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 03/28/2018] [Accepted: 04/11/2018] [Indexed: 12/27/2022] Open
Abstract
Translation-dependent mRNA quality control systems protect the protein homeostasis of eukaryotic cells by eliminating aberrant transcripts and stimulating the decay of their protein products. Although these systems are intensively studied in animals, little is known about the translation-dependent quality control systems in plants. Here, we characterize the mechanism of nonstop decay (NSD) system in Nicotiana benthamiana model plant. We show that plant NSD efficiently degrades nonstop mRNAs, which can be generated by premature polyadenylation, and stop codon-less transcripts, which are produced by endonucleolytic cleavage. We demonstrate that in plants, like in animals, Pelota, Hbs1 and SKI2 proteins are required for NSD, supporting that NSD is an ancient and conserved eukaryotic quality control system. Relevantly, we found that NSD and RNA silencing systems cooperate in plants. Plant silencing predominantly represses target mRNAs through endonucleolytic cleavage in the coding region. Here we show that NSD is required for the elimination of 5' cleavage product of mi- or siRNA-guided silencing complex when the cleavage occurs in the coding region. We also show that NSD and nonsense-mediated decay (NMD) quality control systems operate independently in plants.
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Affiliation(s)
| | - Tibor Csorba
- Agricultural Biotechnology Institute, Szent-Györgyi 4, H-2100 Gödöllő, Hungary
| | - Andor Auber
- Agricultural Biotechnology Institute, Szent-Györgyi 4, H-2100 Gödöllő, Hungary
| | - Anita Schamberger
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary
| | - Tünde Nyikó
- Agricultural Biotechnology Institute, Szent-Györgyi 4, H-2100 Gödöllő, Hungary
| | - János Taller
- University Pannonia Georgikon, Festetics 7, 8360 Keszthely, Hungary
| | - Tamás I Orbán
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117 Budapest, Hungary
| | - József Burgyán
- Agricultural Biotechnology Institute, Szent-Györgyi 4, H-2100 Gödöllő, Hungary
| | - Dániel Silhavy
- Agricultural Biotechnology Institute, Szent-Györgyi 4, H-2100 Gödöllő, Hungary
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14
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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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15
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Abstract
Ribonucleic acid (RNA) homeostasis is dynamically modulated in response to changing physiological conditions. Tight regulation of RNA abundance through both transcription and degradation determines the amount, timing, and location of protein translation. This balance is of particular importance in neurons, which are among the most metabolically active and morphologically complex cells in the body. As a result, any disruptions in RNA degradation can have dramatic consequences for neuronal health. In this chapter, we will first discuss mechanisms of RNA stabilization and decay. We will then explore how the disruption of these pathways can lead to neurodegenerative disease.
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16
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Schmidt C, Kowalinski E, Shanmuganathan V, Defenouillère Q, Braunger K, Heuer A, Pech M, Namane A, Berninghausen O, Fromont-Racine M, Jacquier A, Conti E, Becker T, Beckmann R. The cryo-EM structure of a ribosome-Ski2-Ski3-Ski8 helicase complex. Science 2017; 354:1431-1433. [PMID: 27980209 DOI: 10.1126/science.aaf7520] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 09/26/2016] [Accepted: 11/21/2016] [Indexed: 01/06/2023]
Abstract
Ski2-Ski3-Ski8 (Ski) is a helicase complex functioning with the RNA-degrading exosome to mediate the 3'-5' messenger RNA (mRNA) decay in turnover and quality-control pathways. We report that the Ski complex directly associates with 80S ribosomes presenting a short mRNA 3' overhang. We determined the structure of an endogenous ribosome-Ski complex using cryo-electron microscopy (EM) with a local resolution of the Ski complex ranging from 4 angstroms (Å) in the core to about 10 Å for intrinsically flexible regions. Ribosome binding displaces the autoinhibitory domain of the Ski2 helicase, positioning it in an open conformation near the ribosomal mRNA entry tunnel. We observe that the mRNA 3' overhang is threaded directly from the small ribosomal subunit to the helicase channel of Ski2, primed for ongoing exosome-mediated 3'-5' degradation.
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Affiliation(s)
- Christian Schmidt
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany
| | - Eva Kowalinski
- Max Planck Institute of Biochemistry, Department of Structural Cell Biology, Am Klopferspitz 18, 82152 Martinsried, Munich, Germany
| | - Vivekanandan Shanmuganathan
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany
| | - Quentin Defenouillère
- Institut Pasteur, Génétique des Interactions Macromoléculaires, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3525, Rue du Docteur Roux 25-28, 75724 Paris, France.,Sorbonne Universités, UPMC Paris 6, Complexité du Vivant, 75252 Paris Cedex 05, France
| | - Katharina Braunger
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany
| | - André Heuer
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany
| | - Markus Pech
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany
| | - Abdelkader Namane
- Institut Pasteur, Génétique des Interactions Macromoléculaires, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3525, Rue du Docteur Roux 25-28, 75724 Paris, France
| | - Otto Berninghausen
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany
| | - Micheline Fromont-Racine
- Institut Pasteur, Génétique des Interactions Macromoléculaires, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3525, Rue du Docteur Roux 25-28, 75724 Paris, France
| | - Alain Jacquier
- Institut Pasteur, Génétique des Interactions Macromoléculaires, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3525, Rue du Docteur Roux 25-28, 75724 Paris, France
| | - Elena Conti
- Max Planck Institute of Biochemistry, Department of Structural Cell Biology, Am Klopferspitz 18, 82152 Martinsried, Munich, Germany.
| | - Thomas Becker
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany.
| | - Roland Beckmann
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany.
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17
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Zinder JC, Lima CD. Targeting RNA for processing or destruction by the eukaryotic RNA exosome and its cofactors. Genes Dev 2017; 31:88-100. [PMID: 28202538 PMCID: PMC5322736 DOI: 10.1101/gad.294769.116] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this review, Zinder and Lima highlight recent advances that have illuminated roles for the RNA exosome and its cofactors in specific biological pathways, alongside studies that attempted to dissect these activities through structural and biochemical characterization of nuclear and cytoplasmic RNA exosome complexes. The eukaryotic RNA exosome is an essential and conserved protein complex that can degrade or process RNA substrates in the 3′-to-5′ direction. Since its discovery nearly two decades ago, studies have focused on determining how the exosome, along with associated cofactors, achieves the demanding task of targeting particular RNAs for degradation and/or processing in both the nucleus and cytoplasm. In this review, we highlight recent advances that have illuminated roles for the RNA exosome and its cofactors in specific biological pathways, alongside studies that attempted to dissect these activities through structural and biochemical characterization of nuclear and cytoplasmic RNA exosome complexes.
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Affiliation(s)
- John C Zinder
- Tri-Institutional Training Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Structural Biology Program, Sloan Kettering Institute, New York, New York, 10065, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, New York, New York, 10065, USA.,Howard Hughes Medical Institute, New York, New York, 10065 USA
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18
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Jin Y, Richards NG, Waltho JP, Blackburn GM. Metal Fluorides as Analogues for Studies on Phosphoryl Transfer Enzymes. Angew Chem Int Ed Engl 2017; 56:4110-4128. [PMID: 27862756 DOI: 10.1002/anie.201606474] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Indexed: 12/27/2022]
Abstract
The 1994 structure of a transition-state analogue with AlF4- and GDP complexed to G1α, a small G protein, heralded a new field of research into the structure and mechanism of enzymes that manipulate the transfer of phosphoryl (PO3- ) groups. The number of enzyme structures in the PDB containing metal fluorides (MFx ) as ligands that imitate either a phosphoryl or a phosphate group was 357 at the end of 2016. They fall into three distinct geometrical classes: 1) Tetrahedral complexes based on BeF3- that mimic ground-state phosphates; 2) octahedral complexes, primarily based on AlF4- , which mimic "in-line" anionic transition states for phosphoryl transfer; and 3) trigonal bipyramidal complexes, represented by MgF3- and putative AlF30 moieties, which mimic the geometry of the transition state. The interpretation of these structures provides a deeper mechanistic understanding into the behavior and manipulation of phosphate monoesters in molecular biology. This Review provides a comprehensive overview of these structures, their uses, and their computational development.
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Affiliation(s)
- Yi Jin
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | | | | | - G Michael Blackburn
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, UK
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19
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Jin Y, Richards NG, Waltho JP, Blackburn GM. Metallfluoride als Analoga für Studien an Phosphoryltransferenzymen. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201606474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Yi Jin
- Department of Chemistry; University of York; York YO10 5DD Großbritannien
| | - Nigel G. Richards
- School of Chemistry; Cardiff University; Cardiff CF10 3AT Großbritannien
| | | | - G. Michael Blackburn
- Department of Molecular Biology and Biotechnology; University of Sheffield; Sheffield S10 2TN Großbritannien
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20
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Metal Fluorides: Tools for Structural and Computational Analysis of Phosphoryl Transfer Enzymes. Top Curr Chem (Cham) 2017; 375:36. [PMID: 28299727 PMCID: PMC5480424 DOI: 10.1007/s41061-017-0130-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/01/2017] [Indexed: 10/31/2022]
Abstract
The phosphoryl group, PO3-, is the dynamic structural unit in the biological chemistry of phosphorus. Its transfer from a donor to an acceptor atom, with oxygen much more prevalent than nitrogen, carbon, or sulfur, is at the core of a great majority of enzyme-catalyzed reactions involving phosphate esters, anhydrides, amidates, and phosphorothioates. The serendipitous discovery that the phosphoryl group could be labeled by "nuclear mutation," by substitution of PO3- by MgF3- or AlF4-, has underpinned the application of metal fluoride (MF x ) complexes to mimic transition states for enzymatic phosphoryl transfer reactions, with sufficient stability for experimental analysis. Protein crystallography in the solid state and 19F NMR in solution have enabled direct observation of ternary and quaternary protein complexes embracing MF x transition state models with precision. These studies have underpinned a radically new mechanistic approach to enzyme catalysis for a huge range of phosphoryl transfer processes, as varied as kinases, phosphatases, phosphomutases, and phosphohydrolases. The results, without exception, have endorsed trigonal bipyramidal geometry (tbp) for concerted, "in-line" stereochemistry of phosphoryl transfer. QM computations have established the validity of tbp MF x complexes as reliable models for true transition states, delivering similar bond lengths, coordination to essential metal ions, and virtually identical hydrogen bond networks. The emergence of protein control of reactant orbital overlap between bond-forming species within enzyme transition states is a new challenging theme for wider exploration.
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21
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Inada T. The Ribosome as a Platform for mRNA and Nascent Polypeptide Quality Control. Trends Biochem Sci 2017; 42:5-15. [DOI: 10.1016/j.tibs.2016.09.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 09/05/2016] [Accepted: 09/13/2016] [Indexed: 11/28/2022]
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22
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Horikawa W, Endo K, Wada M, Ito K. Mutations in the G-domain of Ski7 cause specific dysfunction in non-stop decay. Sci Rep 2016; 6:29295. [PMID: 27381255 PMCID: PMC4933942 DOI: 10.1038/srep29295] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 06/17/2016] [Indexed: 11/10/2022] Open
Abstract
Ski7 functions as a cofactor in both normal mRNA turnover and non-stop mRNA decay (NSD) mRNA surveillance in budding yeast. The N-terminal region of Ski7 (Ski7N) interacts with the ski-complex and the exosome. The C-terminal region of Ski7 (Ski7C) binds guanine nucleotides and shares overall sequence and structural homology with the proteins of the translational GTPase superfamily, especially the tRNA/tRNA-mimic carrier protein subfamilies such as EF1α, eRF3, and Hbs1. Previous reports showed that Ski7N polypeptide functions adequately in vivo, while Ski7C, if any, only slightly. Furthermore, Ski7C does not exhibit GTP-hydrolysing activities under normal conditions. Therefore, the physiological and functional significance of the conserved Ski7C is unclear. Here, we report strong genetic evidence suggesting differential roles for Ski7N and Ski7C in normal and specific mRNA turnover pathways by creating/isolating mutations in both Ski7N and Ski7C conserved motifs using indicator yeast strains. We concluded that Ski7C participates in mRNA surveillance as a regulatory module competitively with the Hbs1/Dom34 complex. Our results provide insights into the molecular regulatory mechanisms underlying mRNA surveillance.
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Affiliation(s)
- Wataru Horikawa
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan.,Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan
| | - Kei Endo
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan
| | - Miki Wada
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan.,Technical office, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Koichi Ito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan
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23
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Kowalinski E, Kögel A, Ebert J, Reichelt P, Stegmann E, Habermann B, Conti E. Structure of a Cytoplasmic 11-Subunit RNA Exosome Complex. Mol Cell 2016; 63:125-34. [PMID: 27345150 PMCID: PMC4942675 DOI: 10.1016/j.molcel.2016.05.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/26/2016] [Accepted: 05/18/2016] [Indexed: 10/28/2022]
Abstract
The RNA exosome complex associates with nuclear and cytoplasmic cofactors to mediate the decay, surveillance, or processing of a wide variety of transcripts. In the cytoplasm, the conserved core of the exosome (Exo10) functions together with the conserved Ski complex. The interaction of S. cerevisiae Exo10 and Ski is not direct but requires a bridging cofactor, Ski7. Here, we report the 2.65 Å resolution structure of S. cerevisiae Exo10 bound to the interacting domain of Ski7. Extensive hydrophobic interactions rationalize the high affinity and stability of this complex, pointing to Ski7 as a constitutive component of the cytosolic exosome. Despite the absence of sequence homology, cytoplasmic Ski7 and nuclear Rrp6 bind Exo10 using similar surfaces and recognition motifs. Knowledge of the interacting residues in the yeast complexes allowed us to identify a splice variant of human HBS1-Like as a Ski7-like exosome-binding protein, revealing the evolutionary conservation of this cytoplasmic cofactor.
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Affiliation(s)
- Eva Kowalinski
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Alexander Kögel
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Judith Ebert
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Peter Reichelt
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Elisabeth Stegmann
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Bianca Habermann
- Computational Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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24
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CryoEM structure of yeast cytoplasmic exosome complex. Cell Res 2016; 26:822-37. [PMID: 27174052 DOI: 10.1038/cr.2016.56] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/26/2016] [Accepted: 03/07/2016] [Indexed: 01/25/2023] Open
Abstract
The eukaryotic multi-subunit RNA exosome complex plays crucial roles in 3'-to-5' RNA processing and decay. Rrp6 and Ski7 are the major cofactors for the nuclear and cytoplasmic exosomes, respectively. In the cytoplasm, Ski7 helps the exosome to target mRNAs for degradation and turnover via a through-core pathway. However, the interaction between Ski7 and the exosome complex has remained unclear. The transaction of RNA substrates within the exosome is also elusive. In this work, we used single-particle cryo-electron microscopy to solve the structures of the Ski7-exosome complex in RNA-free and RNA-bound forms at resolutions of 4.2 Å and 5.8 Å, respectively. These structures reveal that the N-terminal domain of Ski7 adopts a structural arrangement and interacts with the exosome in a similar fashion to the C-terminal domain of nuclear Rrp6. Further structural analysis of exosomes with RNA substrates harboring 3' overhangs of different length suggests a switch mechanism of RNA-induced exosome activation in the through-core pathway of RNA processing.
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