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Kofman C, Willi JA, Karim AS, Jewett MC. Ribosome Pool Engineering Increases Protein Biosynthesis Yields. ACS CENTRAL SCIENCE 2024; 10:871-881. [PMID: 38680563 PMCID: PMC11046459 DOI: 10.1021/acscentsci.3c01413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 05/01/2024]
Abstract
The biosynthetic capability of the bacterial ribosome motivates efforts to understand and harness sequence-optimized versions for synthetic biology. However, functional differences between natively occurring ribosomal RNA (rRNA) operon sequences remain poorly characterized. Here, we use an in vitro ribosome synthesis and translation platform to measure protein production capabilities of ribosomes derived from all unique combinations of 16S and 23S rRNAs from seven distinct Escherichia coli rRNA operon sequences. We observe that polymorphisms that distinguish native E. coli rRNA operons lead to significant functional changes in the resulting ribosomes, ranging from negligible or low gene expression to matching the protein production activity of the standard rRNA operon B sequence. We go on to generate strains expressing single rRNA operons and show that not only do some purified in vivo expressed homogeneous ribosome pools outperform the wild-type, heterogeneous ribosome pool but also that a crude cell lysate made from the strain expressing only operon A ribosomes shows significant yield increases for a panel of medically and industrially relevant proteins. We anticipate that ribosome pool engineering can be applied as a tool to increase yields across many protein biomanufacturing systems, as well as improve basic understanding of ribosome heterogeneity and evolution.
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Affiliation(s)
- Camila Kofman
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Jessica A. Willi
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Ashty S. Karim
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Michael C. Jewett
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Department
of Bioengineering, Stanford University, Stanford California 94305, United States
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2
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Matsuura-Suzuki E, Shimazu T, Takahashi M, Kotoshiba K, Suzuki T, Kashiwagi K, Sohtome Y, Akakabe M, Sodeoka M, Dohmae N, Ito T, Shinkai Y, Iwasaki S. METTL18-mediated histidine methylation of RPL3 modulates translation elongation for proteostasis maintenance. eLife 2022; 11:e72780. [PMID: 35674491 PMCID: PMC9177149 DOI: 10.7554/elife.72780] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 05/26/2022] [Indexed: 12/24/2022] Open
Abstract
Protein methylation occurs predominantly on lysine and arginine residues, but histidine also serves as a methylation substrate. However, a limited number of enzymes responsible for this modification have been reported. Moreover, the biological role of histidine methylation has remained poorly understood to date. Here, we report that human METTL18 is a histidine methyltransferase for the ribosomal protein RPL3 and that the modification specifically slows ribosome traversal on Tyr codons, allowing the proper folding of synthesized proteins. By performing an in vitro methylation assay with a methyl donor analog and quantitative mass spectrometry, we found that His245 of RPL3 is methylated at the τ-N position by METTL18. Structural comparison of the modified and unmodified ribosomes showed stoichiometric modification and suggested a role in translation reactions. Indeed, genome-wide ribosome profiling and an in vitro translation assay revealed that translation elongation at Tyr codons was suppressed by RPL3 methylation. Because the slower elongation provides enough time for nascent protein folding, RPL3 methylation protects cells from the cellular aggregation of Tyr-rich proteins. Our results reveal histidine methylation as an example of a ribosome modification that ensures proteome integrity in cells.
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Affiliation(s)
- Eriko Matsuura-Suzuki
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering ResearchSaitamaJapan
| | - Tadahiro Shimazu
- Cellular Memory Laboratory, RIKEN Cluster for Pioneering ResearchSaitamaJapan
| | - Mari Takahashi
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics ResearchYokohamaJapan
| | - Kaoru Kotoshiba
- Cellular Memory Laboratory, RIKEN Cluster for Pioneering ResearchSaitamaJapan
| | - Takehiro Suzuki
- Biomolecular Characterization Unit, Technology Platform Division, RIKEN Center for Sustainable Resource ScienceSaitamaJapan
| | - Kazuhiro Kashiwagi
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics ResearchYokohamaJapan
| | - Yoshihiro Sohtome
- RIKEN Center for Sustainable Resource ScienceSaitamaJapan
- Synthetic Organic Chemistry Lab, RIKEN Cluster for Pioneering ResearchSaitamaJapan
| | - Mai Akakabe
- Synthetic Organic Chemistry Lab, RIKEN Cluster for Pioneering ResearchSaitamaJapan
| | - Mikiko Sodeoka
- RIKEN Center for Sustainable Resource ScienceSaitamaJapan
- Synthetic Organic Chemistry Lab, RIKEN Cluster for Pioneering ResearchSaitamaJapan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, Technology Platform Division, RIKEN Center for Sustainable Resource ScienceSaitamaJapan
| | - Takuhiro Ito
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics ResearchYokohamaJapan
| | - Yoichi Shinkai
- Cellular Memory Laboratory, RIKEN Cluster for Pioneering ResearchSaitamaJapan
| | - Shintaro Iwasaki
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering ResearchSaitamaJapan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of TokyoChibaJapan
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3
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Timsit Y, Grégoire SP. Towards the Idea of Molecular Brains. Int J Mol Sci 2021; 22:ijms222111868. [PMID: 34769300 PMCID: PMC8584932 DOI: 10.3390/ijms222111868] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/28/2021] [Indexed: 02/06/2023] Open
Abstract
How can single cells without nervous systems perform complex behaviours such as habituation, associative learning and decision making, which are considered the hallmark of animals with a brain? Are there molecular systems that underlie cognitive properties equivalent to those of the brain? This review follows the development of the idea of molecular brains from Darwin’s “root brain hypothesis”, through bacterial chemotaxis, to the recent discovery of neuron-like r-protein networks in the ribosome. By combining a structural biology view with a Bayesian brain approach, this review explores the evolutionary labyrinth of information processing systems across scales. Ribosomal protein networks open a window into what were probably the earliest signalling systems to emerge before the radiation of the three kingdoms. While ribosomal networks are characterised by long-lasting interactions between their protein nodes, cell signalling networks are essentially based on transient interactions. As a corollary, while signals propagated in persistent networks may be ephemeral, networks whose interactions are transient constrain signals diffusing into the cytoplasm to be durable in time, such as post-translational modifications of proteins or second messenger synthesis. The duration and nature of the signals, in turn, implies different mechanisms for the integration of multiple signals and decision making. Evolution then reinvented networks with persistent interactions with the development of nervous systems in metazoans. Ribosomal protein networks and simple nervous systems display architectural and functional analogies whose comparison could suggest scale invariance in information processing. At the molecular level, the significant complexification of eukaryotic ribosomal protein networks is associated with a burst in the acquisition of new conserved aromatic amino acids. Knowing that aromatic residues play a critical role in allosteric receptors and channels, this observation suggests a general role of π systems and their interactions with charged amino acids in multiple signal integration and information processing. We think that these findings may provide the molecular basis for designing future computers with organic processors.
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Affiliation(s)
- Youri Timsit
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara GOSEE, 3 rue Michel-Ange, 75016 Paris, France
- Correspondence:
| | - Sergeant-Perthuis Grégoire
- Institut de Mathématiques de Jussieu—Paris Rive Gauche (IMJ-PRG), UMR 7586, CNRS-Université Paris Diderot, 75013 Paris, France;
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4
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Martinez-Seidel F, Beine-Golovchuk O, Hsieh YC, Eshraky KE, Gorka M, Cheong BE, Jimenez-Posada EV, Walther D, Skirycz A, Roessner U, Kopka J, Pereira Firmino AA. Spatially Enriched Paralog Rearrangements Argue Functionally Diverse Ribosomes Arise during Cold Acclimation in Arabidopsis. Int J Mol Sci 2021; 22:6160. [PMID: 34200446 PMCID: PMC8201131 DOI: 10.3390/ijms22116160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/23/2021] [Accepted: 06/01/2021] [Indexed: 12/15/2022] Open
Abstract
Ribosome biogenesis is essential for plants to successfully acclimate to low temperature. Without dedicated steps supervising the 60S large subunits (LSUs) maturation in the cytosol, e.g., Rei-like (REIL) factors, plants fail to accumulate dry weight and fail to grow at suboptimal low temperatures. Around REIL, the final 60S cytosolic maturation steps include proofreading and assembly of functional ribosomal centers such as the polypeptide exit tunnel and the P-Stalk, respectively. In consequence, these ribosomal substructures and their assembly, especially during low temperatures, might be changed and provoke the need for dedicated quality controls. To test this, we blocked ribosome maturation during cold acclimation using two independent reil double mutant genotypes and tested changes in their ribosomal proteomes. Additionally, we normalized our mutant datasets using as a blank the cold responsiveness of a wild-type Arabidopsis genotype. This allowed us to neglect any reil-specific effects that may happen due to the presence or absence of the factor during LSU cytosolic maturation, thus allowing us to test for cold-induced changes that happen in the early nucleolar biogenesis. As a result, we report that cold acclimation triggers a reprogramming in the structural ribosomal proteome. The reprogramming alters the abundance of specific RP families and/or paralogs in non-translational LSU and translational polysome fractions, a phenomenon known as substoichiometry. Next, we tested whether the cold-substoichiometry was spatially confined to specific regions of the complex. In terms of RP proteoforms, we report that remodeling of ribosomes after a cold stimulus is significantly constrained to the polypeptide exit tunnel (PET), i.e., REIL factor binding and functional site. In terms of RP transcripts, cold acclimation induces changes in RP families or paralogs that are significantly constrained to the P-Stalk and the ribosomal head. The three modulated substructures represent possible targets of mechanisms that may constrain translation by controlled ribosome heterogeneity. We propose that non-random ribosome heterogeneity controlled by specialized biogenesis mechanisms may contribute to a preferential or ultimately even rigorous selection of transcripts needed for rapid proteome shifts and successful acclimation.
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Affiliation(s)
- Federico Martinez-Seidel
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia;
| | - Olga Beine-Golovchuk
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
- Heidelberg University, Biochemie-Zentrum, Nuclear Pore Complex and Ribosome Assembly, 69120 Heidelberg, Germany
| | - Yin-Chen Hsieh
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
- Institute for Arctic and Marine Biology, UiT Arctic University of Norway, 9037 Tromsø, Norway
| | - Kheloud El Eshraky
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
| | - Michal Gorka
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
| | - Bo-Eng Cheong
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia;
- Biotechnology Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Malaysia
| | - Erika V. Jimenez-Posada
- Grupo de Biotecnología-Productos Naturales, Universidad Tecnológica de Pereira, Pereira 660003, Colombia;
- Emerging Infectious Diseases and Tropical Medicine Research Group—Sci-Help, Pereira 660009, Colombia
| | - Dirk Walther
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
| | - Aleksandra Skirycz
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
| | - Ute Roessner
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia;
| | - Joachim Kopka
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
| | - Alexandre Augusto Pereira Firmino
- Willmitzer Department, Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany; (O.B.-G.); (Y.-C.H.); (K.E.E.); (M.G.); (B.-E.C.); (D.W.); (A.S.); (J.K.); (A.A.P.F.)
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5
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Małecki JM, Odonohue MF, Kim Y, Jakobsson ME, Gessa L, Pinto R, Wu J, Davydova E, Moen A, Olsen JV, Thiede B, Gleizes PE, Leidel SA, Falnes PØ. Human METTL18 is a histidine-specific methyltransferase that targets RPL3 and affects ribosome biogenesis and function. Nucleic Acids Res 2021; 49:3185-3203. [PMID: 33693809 PMCID: PMC8034639 DOI: 10.1093/nar/gkab088] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 01/21/2021] [Accepted: 02/02/2021] [Indexed: 01/11/2023] Open
Abstract
Protein methylation occurs primarily on lysine and arginine, but also on some other residues, such as histidine. METTL18 is the last uncharacterized member of a group of human methyltransferases (MTases) that mainly exert lysine methylation, and here we set out to elucidate its function. We found METTL18 to be a nuclear protein that contains a functional nuclear localization signal and accumulates in nucleoli. Recombinant METTL18 methylated a single protein in nuclear extracts and in isolated ribosomes from METTL18 knockout (KO) cells, identified as 60S ribosomal protein L3 (RPL3). We also performed an RPL3 interactomics screen and identified METTL18 as the most significantly enriched MTase. We found that His-245 in RPL3 carries a 3-methylhistidine (3MH; τ-methylhistidine) modification, which was absent in METTL18 KO cells. In addition, both recombinant and endogenous METTL18 were found to be automethylated at His-154, thus further corroborating METTL18 as a histidine-specific MTase. Finally, METTL18 KO cells displayed altered pre-rRNA processing, decreased polysome formation and codon-specific changes in mRNA translation, indicating that METTL18-mediated methylation of RPL3 is important for optimal ribosome biogenesis and function. In conclusion, we have here established METTL18 as the second human histidine-specific protein MTase, and demonstrated its functional relevance.
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Affiliation(s)
- Jędrzej M Małecki
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Marie-Francoise Odonohue
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre for Integrative Biology (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Yeji Kim
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Magnus E Jakobsson
- Proteomics Program, Faculty of Health and Medical Sciences, Novo Nordisk Foundation, Center for Protein Research (NNF-CPR), University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Luca Gessa
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Rita Pinto
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Jie Wu
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Erna Davydova
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Anders Moen
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Jesper V Olsen
- Proteomics Program, Faculty of Health and Medical Sciences, Novo Nordisk Foundation, Center for Protein Research (NNF-CPR), University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Bernd Thiede
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
| | - Pierre-Emmanuel Gleizes
- Molecular, Cellular and Developmental Biology Unit (MCD), Centre for Integrative Biology (CBI), University of Toulouse, CNRS, UPS, 31062 Toulouse, France
| | - Sebastian A Leidel
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Pål Ø Falnes
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, 0316 Oslo, Norway
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6
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Abstract
To perform an accurate protein synthesis, ribosomes accomplish complex tasks involving the long-range communication between its functional centres such as the peptidyl transfer centre, the tRNA bindings sites and the peptide exit tunnel. How information is transmitted between these sites remains one of the major challenges in current ribosome research. Many experimental studies have revealed that some r-proteins play essential roles in remote communication and the possible involvement of r-protein networks in these processes have been recently proposed. Our phylogenetic, structural and mathematical study reveals that of the three kingdom's r-protein networks converged towards non-random graphs where r-proteins collectively coevolved to optimize interconnection between functional centres. The massive acquisition of conserved aromatic residues at the interfaces and along the extensions of the newly connected eukaryotic r-proteins also highlights that a strong selective pressure acts on their sequences probably for the formation of new allosteric pathways in the network.
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7
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Calvet LE, Matviienko S, Ducluzaux P. Network theory of the bacterial ribosome. PLoS One 2020; 15:e0239700. [PMID: 33017414 PMCID: PMC7535068 DOI: 10.1371/journal.pone.0239700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 09/08/2020] [Indexed: 02/07/2023] Open
Abstract
In the past two decades, research into the biochemical, biophysical and structural properties of the ribosome have revealed many different steps of protein translation. Nevertheless, a complete understanding of how they lead to a rapid and accurate protein synthesis still remains a challenge. Here we consider a coarse network analysis in the bacterial ribosome formed by the connectivity between ribosomal (r) proteins and RNAs at different stages in the elongation cycle. The ribosomal networks are found to be dis-assortative and small world, implying that the structure allows for an efficient exchange of information between distant locations. An analysis of centrality shows that the second and fifth domains of 23S rRNA are the most important elements in all of the networks. Ribosomal protein hubs connect to much fewer nodes but are shown to provide important connectivity within the network (high closeness centrality). A modularity analysis reveals some of the different functional communities, indicating some known and some new possible communication pathways Our mathematical results confirm important communication pathways that have been discussed in previous research, thus verifying the use of this technique for representing the ribosome, and also reveal new insights into the collective function of ribosomal elements.
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Affiliation(s)
- Laurie E. Calvet
- CNRS, Centre de Nanosciences et Nanotechnologies, Université Paris-Saclay, Palaiseau, France
- * E-mail:
| | - Serhii Matviienko
- CNRS, Centre de Nanosciences et Nanotechnologies, Université Paris-Saclay, Palaiseau, France
| | - Pierre Ducluzaux
- CNRS, Centre de Nanosciences et Nanotechnologies, Université Paris-Saclay, Palaiseau, France
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8
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Timsit Y, Bennequin D. Nervous-Like Circuits in the Ribosome Facts, Hypotheses and Perspectives. Int J Mol Sci 2019; 20:ijms20122911. [PMID: 31207893 PMCID: PMC6627100 DOI: 10.3390/ijms20122911] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/08/2019] [Accepted: 06/10/2019] [Indexed: 12/16/2022] Open
Abstract
In the past few decades, studies on translation have converged towards the metaphor of a “ribosome nanomachine”; they also revealed intriguing ribosome properties challenging this view. Many studies have shown that to perform an accurate protein synthesis in a fluctuating cellular environment, ribosomes sense, transfer information and even make decisions. This complex “behaviour” that goes far beyond the skills of a simple mechanical machine has suggested that the ribosomal protein networks could play a role equivalent to nervous circuits at a molecular scale to enable information transfer and processing during translation. We analyse here the significance of this analogy and establish a preliminary link between two fields: ribosome structure-function studies and the analysis of information processing systems. This cross-disciplinary analysis opens new perspectives about the mechanisms of information transfer and processing in ribosomes and may provide new conceptual frameworks for the understanding of the behaviours of unicellular organisms.
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Affiliation(s)
- Youri Timsit
- Mediterranean Institute of Oceanography UM 110, Aix-Marseille Université, CNRS, IRD, Campus de Luminy, 13288 Marseille, France.
| | - Daniel Bennequin
- Institut de Mathématiques de Jussieu - Paris Rive Gauche (IMJ-PRG) Université Paris Diderot, bâtiment Sophie-Germain, 8, place Aurélie Nemours, 75013 Paris, France.
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9
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Kürkçüoğlu Ö. Exploring allosteric communication in multiple states of the bacterial ribosome using residue network analysis. Turk J Biol 2018; 42:392-404. [PMID: 30930623 PMCID: PMC6438126 DOI: 10.3906/biy-1802-77] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Antibiotic resistance is one of the most important problems of our era and hence the discovery of new effective therapeutics is urgent. At this point, studying the allosteric communication pathways in the bacterial ribosome and revealing allosteric sites/residues is critical for designing new inhibitors or repurposing readily approved drugs for this enormous machine. To shed light onto molecular details of the allosteric mechanisms, here we construct residue networks of the bacterial ribosomal complex at four different states of translation by using an effective description of the intermolecular interactions. Centrality analysis of these networks highlights the functional roles of structural components and critical residues on the ribosomal complex. High betweenness scores reveal pathways of residues connecting numerous sites on the structure. Interestingly, these pathways assemble highly conserved residues, drug binding sites, and known allosterically linked regions on the same structure. This study proposes a new residue-level model to test how distant sites on the molecular machine may be linked through hub residues that are critically located on the contact topology to inherently form communication pathways. Findings also indicate intersubunit bridges B1b, B3, B5, B7, and B8 as critical targets to design novel antibiotics.
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Affiliation(s)
- Özge Kürkçüoğlu
- Department of Chemical Engineering, Faculty of Chemical-Metallurgical Engineering, İstanbul Technical University , İstanbul , Turkey
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10
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Clarke SG. The ribosome: A hot spot for the identification of new types of protein methyltransferases. J Biol Chem 2018; 293:10438-10446. [PMID: 29743234 DOI: 10.1074/jbc.aw118.003235] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cellular physiology depends on the alteration of protein structures by covalent modification reactions. Using a combination of bioinformatic, genetic, biochemical, and mass spectrometric approaches, it has been possible to probe ribosomal proteins from the yeast Saccharomyces cerevisiae for post-translationally methylated amino acid residues and for the enzymes that catalyze these modifications. These efforts have resulted in the identification and characterization of the first protein histidine methyltransferase, the first N-terminal protein methyltransferase, two unusual types of protein arginine methyltransferases, and a new type of cysteine methylation. Two of these enzymes may modify their substrates during ribosomal assembly because the final methylated histidine and arginine residues are buried deep within the ribosome with contacts only with RNA. Two of these modifications occur broadly in eukaryotes, including humans, whereas the others demonstrate a more limited phylogenetic range. Analysis of strains where the methyltransferase genes are deleted has given insight into the physiological roles of these modifications. These reactions described here add diversity to the modifications that generate the typical methylated lysine and arginine residues previously described in histones and other proteins.
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Affiliation(s)
- Steven G Clarke
- From the Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, Los Angeles, California 90095
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11
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Identification of potential allosteric communication pathways between functional sites of the bacterial ribosome by graph and elastic network models. Biochim Biophys Acta Gen Subj 2017; 1861:3131-3141. [PMID: 28917952 DOI: 10.1016/j.bbagen.2017.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND Accumulated evidence indicates that bacterial ribosome employs allostery throughout its structure for protein synthesis. The nature of the allosteric communication between remote functional sites remains unclear, but the contact topology and dynamics of residues may play role in transmission of a perturbation to distant sites. METHODS/RESULTS We employ two computationally efficient approaches - graph and elastic network modeling to gain insights about the allosteric communication in ribosome. Using graph representation of the structure, we perform k-shortest pathways analysis between peptidyl transferase center-ribosomal tunnel, decoding center-peptidyl transferase center - previously reported functional sites having allosteric communication. Detailed analysis on intact structures points to common and alternative shortest pathways preferred by different states of translation. All shortest pathways capture drug target sites and allosterically important regions. Elastic network model further reveals that residues along all pathways have the ability of quickly establishing pair-wise communication and to help the propagation of a perturbation in long-ranges during functional motions of the complex. CONCLUSIONS Contact topology and inherent dynamics of ribosome configure potential communication pathways between functional sites in different translation states. Inter-subunit bridges B2a, B3 and P-tRNA come forward for their high potential in assisting allostery during translation. Especially B3 emerges as a potential druggable site. GENERAL SIGNIFICANCE This study indicates that the ribosome topology forms a basis for allosteric communication, which can be disrupted by novel drugs to kill drug-resistant bacteria. Our computationally efficient approach not only overlaps with experimental evidence on allosteric regulation in ribosome but also proposes new druggable sites.
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12
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Gulay SP, Bista S, Varshney A, Kirmizialtin S, Sanbonmatsu KY, Dinman JD. Tracking fluctuation hotspots on the yeast ribosome through the elongation cycle. Nucleic Acids Res 2017; 45:4958-4971. [PMID: 28334755 PMCID: PMC5416885 DOI: 10.1093/nar/gkx112] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/06/2017] [Indexed: 11/15/2022] Open
Abstract
Chemical modification was used to quantitatively determine the flexibility of nearly the entire rRNA component of the yeast ribosome through 8 discrete stages of translational elongation, revealing novel observations at the gross and fine-scales. These include (i) the bulk transfer of energy through the intersubunit bridges from the large to the small subunit after peptidyltransfer, (ii) differences in the interaction of the sarcin ricin loop with the two elongation factors and (iii) networked information exchange pathways that may functionally facilitate intra- and intersubunit coordination, including the 5.8S rRNA. These analyses reveal hot spots of fluctuations that set the stage for large-scale conformational changes essential for translocation and enable the first molecular dynamics simulation of an 80S complex. Comprehensive datasets of rRNA base flexibilities provide a unique resource to the structural biology community that can be computationally mined to complement ongoing research toward the goal of understanding the dynamic ribosome.
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Affiliation(s)
- Suna P Gulay
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Sujal Bista
- Department of Computer Science, University of Maryland, College Park, MD 20742, USA
| | - Amitabh Varshney
- Department of Computer Science, University of Maryland, College Park, MD 20742, USA
| | - Serdal Kirmizialtin
- Chemistry Program, New York University Abu Dhabi, Abu Dhabi, UAE.,The New Mexico Consortium, Los Alamos, NM 87544, USA
| | - Karissa Y Sanbonmatsu
- The New Mexico Consortium, Los Alamos, NM 87544, USA.,Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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13
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Wawiórka L, Molestak E, Szajwaj M, Michalec-Wawiórka B, Boguszewska A, Borkiewicz L, Liudkovska V, Kufel J, Tchórzewski M. Functional analysis of the uL11 protein impact on translational machinery. Cell Cycle 2017; 15:1060-72. [PMID: 26939941 DOI: 10.1080/15384101.2016.1154245] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The ribosomal GTPase associated center constitutes the ribosomal area, which is the landing platform for translational GTPases and stimulates their hydrolytic activity. The ribosomal stalk represents a landmark structure in this center, and in eukaryotes is composed of uL11, uL10 and P1/P2 proteins. The modus operandi of the uL11 protein has not been exhaustively studied in vivo neither in prokaryotic nor in eukaryotic cells. Using a yeast model, we have brought functional insight into the translational apparatus deprived of uL11, filling the gap between structural and biochemical studies. We show that the uL11 is an important element in various aspects of 'ribosomal life'. uL11 is involved in 'birth' (biogenesis and initiation), by taking part in Tif6 release and contributing to ribosomal subunit-joining at the initiation step of translation. uL11 is particularly engaged in the 'active life' of the ribosome, in elongation, being responsible for the interplay with eEF1A and fidelity of translation and contributing to a lesser extent to eEF2-dependent translocation. Our results define the uL11 protein as a critical GAC element universally involved in trGTPase 'productive state' stabilization, being primarily a part of the ribosomal element allosterically contributing to the fidelity of the decoding event.
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Affiliation(s)
- Leszek Wawiórka
- a Department of Molecular Biology , Maria Curie-Skłodowska University , Lublin , Poland
| | - Eliza Molestak
- a Department of Molecular Biology , Maria Curie-Skłodowska University , Lublin , Poland
| | - Monika Szajwaj
- a Department of Molecular Biology , Maria Curie-Skłodowska University , Lublin , Poland
| | | | | | - Lidia Borkiewicz
- a Department of Molecular Biology , Maria Curie-Skłodowska University , Lublin , Poland
| | - Vladyslava Liudkovska
- b Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw , Warsaw , Poland
| | - Joanna Kufel
- b Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw , Warsaw , Poland
| | - Marek Tchórzewski
- a Department of Molecular Biology , Maria Curie-Skłodowska University , Lublin , Poland
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14
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Fernández-Pevida A, Martín-Villanueva S, Murat G, Lacombe T, Kressler D, de la Cruz J. The eukaryote-specific N-terminal extension of ribosomal protein S31 contributes to the assembly and function of 40S ribosomal subunits. Nucleic Acids Res 2016; 44:7777-91. [PMID: 27422873 PMCID: PMC5027506 DOI: 10.1093/nar/gkw641] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/07/2016] [Indexed: 11/12/2022] Open
Abstract
The archaea-/eukaryote-specific 40S-ribosomal-subunit protein S31 is expressed as an ubiquitin fusion protein in eukaryotes and consists of a conserved body and a eukaryote-specific N-terminal extension. In yeast, S31 is a practically essential protein, which is required for cytoplasmic 20S pre-rRNA maturation. Here, we have studied the role of the N-terminal extension of the yeast S31 protein. We show that deletion of this extension partially impairs cell growth and 40S subunit biogenesis and confers hypersensitivity to aminoglycoside antibiotics. Moreover, the extension harbours a nuclear localization signal that promotes active nuclear import of S31, which associates with pre-ribosomal particles in the nucleus. In the absence of the extension, truncated S31 inefficiently assembles into pre-40S particles and two subpopulations of mature small subunits, one lacking and another one containing truncated S31, can be identified. Plasmid-driven overexpression of truncated S31 partially suppresses the growth and ribosome biogenesis defects but, conversely, slightly enhances the hypersensitivity to aminoglycosides. Altogether, these results indicate that the N-terminal extension facilitates the assembly of S31 into pre-40S particles and contributes to the optimal translational activity of mature 40S subunits but has only a minor role in cytoplasmic cleavage of 20S pre-rRNA at site D.
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Affiliation(s)
- Antonio Fernández-Pevida
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avda. Manuel Siurot, s/n; E-41013 Seville, Spain Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Sara Martín-Villanueva
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avda. Manuel Siurot, s/n; E-41013 Seville, Spain Departamento de Genética, Universidad de Sevilla, Seville, Spain
| | - Guillaume Murat
- Unit of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - Thierry Lacombe
- Department of Microbiology and Molecular Medicine, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Dieter Kressler
- Unit of Biochemistry, Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avda. Manuel Siurot, s/n; E-41013 Seville, Spain Departamento de Genética, Universidad de Sevilla, Seville, Spain
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15
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Penzo M, Carnicelli D, Montanaro L, Brigotti M. A reconstituted cell-free assay for the evaluation of the intrinsic activity of purified human ribosomes. Nat Protoc 2016; 11:1309-25. [PMID: 27336708 DOI: 10.1038/nprot.2016.072] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We describe a cell-free translation system for evaluating the activity of ribosomes stringently purified from human cells. This system is based on in vitro reconstitution of the cellular translation machinery, in which a ribosome-free rabbit reticulocyte lysate (RRL) is reassembled with human ribosomes and in vitro-transcribed reporter mRNAs. The protocol describes the preparation of the RRL-derived fractions, purification of ribosomes devoid of detectable nonribosomal-associated factors, and assembly of the reactions to evaluate ribosomal translational efficiency and fidelity using appropriate reporter transcripts. The whole procedure can be completed in ∼2.5 d (plus 2 weeks for RRL preparation and cell expansion time). This protocol can be applied to study intrinsic functional properties (cis-acting element-mediated translation initiation or translational fidelity) of ribosome populations from different sources (including nonhuman origin). It is therefore useful for the characterization of ribosomal function in ribosomopathies and cancer, and it will be applicable in the emerging fields of ribosome diversity and specialized ribosomes.
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Affiliation(s)
- Marianna Penzo
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Domenica Carnicelli
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Lorenzo Montanaro
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Maurizio Brigotti
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy
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16
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Taoka M, Nobe Y, Yamaki Y, Yamauchi Y, Ishikawa H, Takahashi N, Nakayama H, Isobe T. The complete chemical structure of Saccharomyces cerevisiae rRNA: partial pseudouridylation of U2345 in 25S rRNA by snoRNA snR9. Nucleic Acids Res 2016; 44:8951-8961. [PMID: 27325748 PMCID: PMC5062969 DOI: 10.1093/nar/gkw564] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/10/2016] [Indexed: 12/19/2022] Open
Abstract
We present the complete chemical structures of the rRNAs from the eukaryotic model organism, Saccharomyces cerevisiae. The final structures, as determined with mass spectrometry-based methodology that includes a stable isotope-labelled, non-modified reference RNA, contain 112 sites with 12 different post-transcriptional modifications, including a previously unidentified pseudouridine at position 2345 in 25S rRNA. Quantitative mass spectrometry-based stoichiometric analysis of the different modifications at each site indicated that 94 sites were almost fully modified, whereas the remaining 18 sites were modified to a lesser extent. Superimposed three-dimensional modification maps for S. cerevisiae and Schizosaccharomyces pombe rRNAs confirmed that most of the modified nucleotides are located in functionally important interior regions of the ribosomes. We identified snR9 as the snoRNA responsible for pseudouridylation of U2345 and showed that this pseudouridylation occurs co-transcriptionally and competitively with 2′-O-methylation of U2345. This study ends the uncertainty concerning whether all modified nucleotides in S. cerevisiae rRNAs have been identified and provides a resource for future structural, functional and biogenesis studies of the eukaryotic ribosome.
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Affiliation(s)
- Masato Taoka
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Yuko Nobe
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Yuka Yamaki
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Yoshio Yamauchi
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Hideaki Ishikawa
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan Department of Biotechnology, United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu-shi, Tokyo 183-8509, Japan
| | - Nobuhiro Takahashi
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan Department of Biotechnology, United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu-shi, Tokyo 183-8509, Japan
| | - Hiroshi Nakayama
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Toshiaki Isobe
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan
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17
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Neuron-Like Networks Between Ribosomal Proteins Within the Ribosome. Sci Rep 2016; 6:26485. [PMID: 27225526 PMCID: PMC4881015 DOI: 10.1038/srep26485] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 05/03/2016] [Indexed: 01/16/2023] Open
Abstract
From brain to the World Wide Web, information-processing networks share common scale invariant properties. Here, we reveal the existence of neural-like networks at a molecular scale within the ribosome. We show that with their extensions, ribosomal proteins form complex assortative interaction networks through which they communicate through tiny interfaces. The analysis of the crystal structures of 50S eubacterial particles reveals that most of these interfaces involve key phylogenetically conserved residues. The systematic observation of interactions between basic and aromatic amino acids at the interfaces and along the extension provides new structural insights that may contribute to decipher the molecular mechanisms of signal transmission within or between the ribosomal proteins. Similar to neurons interacting through “molecular synapses”, ribosomal proteins form a network that suggest an analogy with a simple molecular brain in which the “sensory-proteins” innervate the functional ribosomal sites, while the “inter-proteins” interconnect them into circuits suitable to process the information flow that circulates during protein synthesis. It is likely that these circuits have evolved to coordinate both the complex macromolecular motions and the binding of the multiple factors during translation. This opens new perspectives on nanoscale information transfer and processing.
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18
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Al-Hadid Q, Roy K, Chanfreau G, Clarke SG. Methylation of yeast ribosomal protein Rpl3 promotes translational elongation fidelity. RNA (NEW YORK, N.Y.) 2016; 22:489-98. [PMID: 26826131 PMCID: PMC4793205 DOI: 10.1261/rna.054569.115] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 12/14/2015] [Indexed: 05/05/2023]
Abstract
Rpl3, a highly conserved ribosomal protein, is methylated at histidine 243 by the Hpm1 methyltransferase in Saccharomyces cerevisiae. Histidine 243 lies close to the peptidyl transferase center in a functionally important region of Rpl3 designated as the basic thumb that coordinates the decoding, peptidyl transfer, and translocation steps of translation elongation. Hpm1 was recently implicated in ribosome biogenesis and translation. However, the biological role of methylation of its Rpl3 substrate has not been identified. Here we interrogate the role of Rpl3 methylation at H243 by investigating the functional impact of mutating this histidine residue to alanine (rpl3-H243A). Akin to Hpm1-deficient cells, rpl3-H243A cells accumulate 35S and 23S pre-rRNA precursors to a similar extent, confirming an important role for histidine methylation in pre-rRNA processing. In contrast, Hpm1-deficient cells but not rpl3-H243A mutants show perturbed levels of ribosomal subunits. We show that Hpm1 has multiple substrates in different subcellular fractions, suggesting that methylation of proteins other than Rpl3 may be important for controlling ribosomal subunit levels. Finally, translational fidelity assays demonstrate that like Hpm1-deficient cells, rpl3-H243A mutants have defects in translation elongation resulting in decreased translational accuracy. These data suggest that Rpl3 methylation at H243 is playing a significant role in translation elongation, likely via the basic thumb, but has little impact on ribosomal subunit levels. Hpm1 is therefore a multifunctional methyltransferase with independent roles in ribosome biogenesis and translation.
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Affiliation(s)
- Qais Al-Hadid
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Kevin Roy
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Guillaume Chanfreau
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Steven G Clarke
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095, USA
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19
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Bowen AM, Musalgaonkar S, Moomau CA, Gulay SP, Mirvis M, Dinman JD. Ribosomal protein uS19 mutants reveal its role in coordinating ribosome structure and function. ACTA ACUST UNITED AC 2015; 3:e1117703. [PMID: 26824029 PMCID: PMC4721500 DOI: 10.1080/21690731.2015.1117703] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/15/2015] [Accepted: 11/03/2015] [Indexed: 01/16/2023]
Abstract
Prior studies identified allosteric information pathways connecting functional centers in the large ribosomal subunit to the decoding center in the small subunit through the B1a and B1b/c intersubunit bridges in yeast. In prokaryotes a single SSU protein, uS13, partners with H38 (the A-site finger) and uL5 to form the B1a and B1b/c bridges respectively. In eukaryotes, the SSU component was split into 2 separate proteins during the course of evolution. One, also known as uS13, participates in B1b/c bridge with uL5 in eukaryotes. The other, called uS19 is the SSU partner in the B1a bridge with H38. Here, polyalanine mutants of uS19 involved in the uS19/uS13 and the uS19/H38 interfaces were used to elucidate the important amino acid residues involved in these intersubunit communication pathways. Two key clusters of amino acids were identified: one located at the junction between uS19 and uS13, and a second that appears to interact with the distal tip of H38. Biochemical analyses reveal that these mutations shift the ribosomal rotational equilibrium toward the unrotated state, increasing ribosomal affinity for tRNAs in the P-site and for ternary complex in the A-site, and inhibit binding of the translocase, eEF2. These defects in turn affect specific aspects of translational fidelity. These findings suggest that uS19 plays a critical role as a conduit of information exchange between the large and small ribosomal subunits directly through the B1a, and indirectly through the B1b/c bridges.
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Affiliation(s)
- Alicia M Bowen
- Department of Chemistry and Biochemistry; University of Maryland ; College Park, MD USA
| | - Sharmishtha Musalgaonkar
- Department of Cell Biology and Molecular Genetics; University of Maryland ; College Park, MD USA
| | - Christine A Moomau
- Department of Cell Biology and Molecular Genetics; University of Maryland ; College Park, MD USA
| | - Suna P Gulay
- Department of Cell Biology and Molecular Genetics; University of Maryland ; College Park, MD USA
| | - Mary Mirvis
- Department of Cell Biology and Molecular Genetics; University of Maryland ; College Park, MD USA
| | - Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics; University of Maryland ; College Park, MD USA
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20
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Musalgaonkar S, Moomau CA, Dinman JD. Ribosomes in the balance: structural equilibrium ensures translational fidelity and proper gene expression. Nucleic Acids Res 2014; 42:13384-92. [PMID: 25389262 PMCID: PMC4245932 DOI: 10.1093/nar/gku1020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
At equilibrium, empty ribosomes freely transit between the rotated and un-rotated states. In the cell, the binding of two translation elongation factors to the same general region of the ribosome stabilizes one state over the other. These stabilized states are resolved by expenditure of energy in the form of GTP hydrolysis. A prior study employing mutants of a late assembling peripheral ribosomal protein suggested that ribosome rotational status determines its affinity for elongation factors, and hence translational fidelity and gene expression. Here, mutants of the early assembling integral ribosomal protein uL2 are used to test the generality of this hypothesis. rRNA structure probing analyses reveal that mutations in the uL2 B7b bridge region shift the equilibrium toward the rotated state, propagating rRNA structural changes to all of the functional centers of ribosome. Structural disequilibrium unbalances ribosome biochemically: rotated ribosomes favor binding of the eEF2 translocase and disfavor that of the elongation ternary complex. This manifests as specific translational fidelity defects, impacting the expression of genes involved in telomere maintenance. A model is presented describing how cyclic intersubunit rotation ensures the unidirectionality of translational elongation, and how perturbation of rotational equilibrium affects specific aspects of translational fidelity and cellular gene expression.
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Affiliation(s)
- Sharmishtha Musalgaonkar
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Christine A Moomau
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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21
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Histidine methylation of yeast ribosomal protein Rpl3p is required for proper 60S subunit assembly. Mol Cell Biol 2014; 34:2903-16. [PMID: 24865971 DOI: 10.1128/mcb.01634-13] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Histidine protein methylation is an unusual posttranslational modification. In the yeast Saccharomyces cerevisiae, the large ribosomal subunit protein Rpl3p is methylated at histidine 243, a residue that contacts the 25S rRNA near the P site. Rpl3p methylation is dependent upon the presence of Hpm1p, a candidate seven-beta-strand methyltransferase. In this study, we elucidated the biological activities of Hpm1p in vitro and in vivo. Amino acid analyses reveal that Hpm1p is responsible for all of the detectable protein histidine methylation in yeast. The modification is found on a polypeptide corresponding to the size of Rpl3p in ribosomes and in a nucleus-containing organelle fraction but was not detected in proteins of the ribosome-free cytosol fraction. In vitro assays demonstrate that Hpm1p has methyltransferase activity on ribosome-associated but not free Rpl3p, suggesting that its activity depends on interactions with ribosomal components. hpm1 null cells are defective in early rRNA processing, resulting in a deficiency of 60S subunits and translation initiation defects that are exacerbated in minimal medium. Cells lacking Hpm1p are resistant to cycloheximide and verrucarin A and have decreased translational fidelity. We propose that Hpm1p plays a role in the orchestration of the early assembly of the large ribosomal subunit and in faithful protein production.
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22
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Bypass of the pre-60S ribosomal quality control as a pathway to oncogenesis. Proc Natl Acad Sci U S A 2014; 111:5640-5. [PMID: 24706786 DOI: 10.1073/pnas.1400247111] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ribosomopathies are a class of diseases caused by mutations that affect the biosynthesis and/or functionality of the ribosome. Although they initially present as hypoproliferative disorders, such as anemia, patients have elevated risk of hyperproliferative disease (cancer) by midlife. Here, this paradox is explored using the rpL10-R98S (uL16-R98S) mutant yeast model of the most commonly identified ribosomal mutation in acute lymphoblastic T-cell leukemia. This mutation causes a late-stage 60S subunit maturation failure that targets mutant ribosomes for degradation. The resulting deficit in ribosomes causes the hypoproliferative phenotype. This 60S subunit shortage, in turn, exerts pressure on cells to select for suppressors of the ribosome biogenesis defect, allowing them to reestablish normal levels of ribosome production and cell proliferation. However, suppression at this step releases structurally and functionally defective ribosomes into the translationally active pool, and the translational fidelity defects of these mutants culminate in destabilization of selected mRNAs and shortened telomeres. We suggest that in exchange for resolving their short-term ribosome deficits through compensatory trans-acting suppressors, cells are penalized in the long term by changes in gene expression that ultimately undermine cellular homeostasis.
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23
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García-Gómez JJ, Fernández-Pevida A, Lebaron S, Rosado IV, Tollervey D, Kressler D, de la Cruz J. Final pre-40S maturation depends on the functional integrity of the 60S subunit ribosomal protein L3. PLoS Genet 2014; 10:e1004205. [PMID: 24603549 PMCID: PMC3945201 DOI: 10.1371/journal.pgen.1004205] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 01/13/2014] [Indexed: 01/21/2023] Open
Abstract
Ribosomal protein L3 is an evolutionarily conserved protein that participates in the assembly of early pre-60S particles. We report that the rpl3[W255C] allele, which affects the affinity and function of translation elongation factors, impairs cytoplasmic maturation of 20S pre-rRNA. This was not seen for other mutations in or depletion of L3 or other 60S ribosomal proteins. Surprisingly, pre-40S particles containing 20S pre-rRNA form translation-competent 80S ribosomes, and translation inhibition partially suppresses 20S pre-rRNA accumulation. The GTP-dependent translation initiation factor Fun12 (yeast eIF5B) shows similar in vivo binding to ribosomal particles from wild-type and rpl3[W255C] cells. However, the GTPase activity of eIF5B failed to stimulate processing of 20S pre-rRNA when assayed with ribosomal particles purified from rpl3[W255C] cells. We conclude that L3 plays an important role in the function of eIF5B in stimulating 3′ end processing of 18S rRNA in the context of 80S ribosomes that have not yet engaged in translation. These findings indicate that the correct conformation of the GTPase activation region is assessed in a quality control step during maturation of cytoplasmic pre-ribosomal particles. Recent progress has provided us with detailed knowledge of the structure and function of eukaryotic ribosomes. However, our understanding of the intricate processes of pre-ribosome assembly and the transition to translation-competent ribosomal subunits remains incomplete. The early and intermediate steps of ribosome assembly occur successively in the nucleolus and nucleoplasm. The pre-ribosomal subunits are then exported to the cytoplasm where final maturation steps, notably including D site cleavage of the 20S pre-rRNA to mature 18S rRNA, confer subunit joining and translation competence. Recent evidence indicates that pre-40S subunits are subject to a quality control step involving the GTP-dependent translation initiation factor eIF5B/Fun12, in the context of 80S-like ribosomes. Here, we demonstrate the involvement of 60S subunits in promoting 20S pre-rRNA cleavage. In particular, we show that a specific point mutation in the 60S subunit ribosomal protein L3 (rpl3[W255C]) leads to the accumulation of pre-40S particles that contain the 20S pre-rRNA but are translation-competent. Notably, this mutation prevents the stimulation of the GTPase activity of eIF5B/Fun12, which is also required for site D cleavage. We conclude that L3 plays an important role in regulating the function of eIF5B/Fun12 during 3′ end processing of 18S rRNA at site D, in the context of 80S ribosomes that have not yet engaged in translation.
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MESH Headings
- Alleles
- Cytoplasm/genetics
- Cytoplasm/metabolism
- Eukaryotic Initiation Factors/genetics
- Mutation
- Proteasome Endopeptidase Complex/genetics
- Proteasome Endopeptidase Complex/metabolism
- Protein Binding
- RNA Precursors/genetics
- RNA, Ribosomal, 18S/genetics
- Ribosomal Protein L3
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosome Subunits, Large, Eukaryotic/genetics
- Ribosome Subunits, Large, Eukaryotic/metabolism
- Ribosome Subunits, Small, Eukaryotic/genetics
- Ribosome Subunits, Small, Eukaryotic/metabolism
- Saccharomyces cerevisiae/genetics
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Affiliation(s)
- Juan J. García-Gómez
- Departamento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Antonio Fernández-Pevida
- Departamento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Simon Lebaron
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Iván V. Rosado
- Departamento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - David Tollervey
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Dieter Kressler
- Unit of Biochemistry, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Jesús de la Cruz
- Departamento de Genética, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
- * E-mail:
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24
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Advani VM, Belew AT, Dinman JD. Yeast telomere maintenance is globally controlled by programmed ribosomal frameshifting and the nonsense-mediated mRNA decay pathway. ACTA ACUST UNITED AC 2014; 1:e24418. [PMID: 24563826 PMCID: PMC3908577 DOI: 10.4161/trla.24418] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 03/21/2013] [Accepted: 03/22/2013] [Indexed: 11/26/2022]
Abstract
We have previously shown that ~10% of all eukaryotic mRNAs contain potential programmed -1 ribosomal frameshifting (-1 PRF) signals and that some function as mRNA destabilizing elements through the Nonsense-Mediated mRNA Decay (NMD) pathway by directing translating ribosomes to premature termination codons. Here, the connection between -1 PRF, NMD and telomere end maintenance are explored. Functional -1 PRF signals were identified in the mRNAs encoding two components of yeast telomerase, EST1 and EST2, and in mRNAs encoding proteins involved in recruiting telomerase to chromosome ends, STN1 and CDC13. All of these elements responded to mutants and drugs previously known to stimulate or inhibit -1 PRF, further supporting the hypothesis that they promote -1 PRF through the canonical mechanism. All affected the steady-state abundance of a reporter mRNA and the wide range of -1 PRF efficiencies promoted by these elements enabled the determination of an inverse logarithmic relationship between -1 PRF efficiency and mRNA accumulation. Steady-state abundances of the endogenous EST1, EST2, STN1 and CDC13 mRNAs were similarly inversely proportional to changes in -1 PRF efficiency promoted by mutants and drugs, supporting the hypothesis that expression of these genes is post-transcriptionally controlled by -1 PRF under native conditions. Overexpression of EST2 by ablation of -1 PRF signals or inhibition of NMD promoted formation of shorter telomeres and accumulation of large budded cells at the G2/M boundary. A model is presented describing how limitation and maintenance of correct stoichiometries of telomerase components by -1 PRF is used to maintain yeast telomere length.
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Affiliation(s)
- Vivek M Advani
- Department of Cell Biology and Molecular Genetics; University of Maryland; College Park MD, USA
| | - Ashton T Belew
- Department of Cell Biology and Molecular Genetics; University of Maryland; College Park MD, USA
| | - Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics; University of Maryland; College Park MD, USA
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25
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Sulima SO, Gülay SP, Anjos M, Patchett S, Meskauskas A, Johnson AW, Dinman JD. Eukaryotic rpL10 drives ribosomal rotation. Nucleic Acids Res 2013; 42:2049-63. [PMID: 24214990 PMCID: PMC3919601 DOI: 10.1093/nar/gkt1107] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ribosomes transit between two conformational states, non-rotated and rotated, through the elongation cycle. Here, we present evidence that an internal loop in the essential yeast ribosomal protein rpL10 is a central controller of this process. Mutations in this loop promote opposing effects on the natural equilibrium between these two extreme conformational states. rRNA chemical modification analyses reveals allosteric interactions involved in coordinating intersubunit rotation originating from rpL10 in the core of the large subunit (LSU) through both subunits, linking all the functional centers of the ribosome. Mutations promoting rotational disequilibria showed catalytic, biochemical and translational fidelity defects. An rpL3 mutation promoting opposing structural and biochemical effects, suppressed an rpL10 mutant, re-establishing rotational equilibrium. The rpL10 loop is also involved in Sdo1p recruitment, suggesting that rotational status is important for ensuring late-stage maturation of the LSU, supporting a model in which pre-60S subunits undergo a ‘test drive’ before final maturation.
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Affiliation(s)
- Sergey O Sulima
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA, Section of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA and Department of Biotechnology and Microbiology, Vilnius University, Vilnius LT-03101, Lithuania
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26
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Protein methylation at the surface and buried deep: thinking outside the histone box. Trends Biochem Sci 2013; 38:243-52. [PMID: 23490039 DOI: 10.1016/j.tibs.2013.02.004] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 01/31/2013] [Accepted: 02/05/2013] [Indexed: 01/08/2023]
Abstract
Methylated lysine and arginine residues in histones represent a crucial part of the histone code, and recognition of these methylated residues by protein interaction domains modulates transcription. Although some methylating enzymes appear to be histone specific, many can modify histone and non-histone substrates and an increasing number are specific for non-histone substrates. Some of the non-histone substrates can also be involved in transcription, but a distinct subset of protein methylation reactions occurs at residues buried deeply in ribosomal proteins that may function in protein-RNA interactions rather than protein-protein interactions. Additionally, recent work has identified enzymes that catalyze protein methylation reactions at new sites in ribosomal and other proteins. These reactions include modifications of histidine and cysteine residues as well as the N terminus.
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27
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On the segregation of protein ionic residues by charge type. Amino Acids 2012; 43:2231-47. [PMID: 23081700 DOI: 10.1007/s00726-012-1418-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 10/06/2012] [Indexed: 10/27/2022]
Abstract
Based on ubiquitous presence of large ionic motifs and clusters in proteins involved in gene transcription and protein synthesis, we analyzed the distribution of ionizable sidechains in a broad selection of proteins with regulatory, metabolic, structural and adhesive functions, in agonist, antagonist, toxin and antimicrobial peptides, and in self-excising inteins and intron-derived proteins and sequence constructs. All tested groups, regardless of taxa or sequence size, show considerable segregation of ionizable sidechains into same type charge (homoionic) tracts. These segments in most cases exceed half of the sequence length and comprise more than two-thirds of all ionizable sidechains. This distribution of ionic residues apparently reflects a fundamental advantage of sorted electrostatic contacts in association of sequence elements within and between polypeptides, as well as in interaction with polynucleotides. While large ionic densities are encountered in highly interactive proteins, the average ionic density in most sets does not change appreciably with size of the homoionic segments, which supports the segregation as a modular feature favoring association.
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28
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Wang Y, Shen JK, Schroeder SJ. Nucleotide Dynamics at the A-Site Cleft in the Peptidyltransferase Center of H. marismortui 50S Ribosomal Subunits. J Phys Chem Lett 2012; 3:1007-1010. [PMID: 26286564 DOI: 10.1021/jz3001882] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Resistance mutations to antibiotics targeting rRNA can be far from the drug-binding site. Crystallography studies revealed that the antibiotic resistance mutation G2482A (G2447A in E. coli ) in Haloarcula marismortui 50S ribosomes does not directly contact the drug or introduce changes to the ribosomal structure except for losing a potassium ion coordinated to a base triple at the drug-binding site. Using molecular dynamics simulations, we tested hypotheses regarding the effects of the G2482A mutation and ion coordination on the conformational dynamics of the 50S ribosome. Simulations show that the mutation enhances conformational fluctuation at the antibiotic binding site, weakens the hydrogen-bonding network, and increases flexibility at the 50S peptidyl transferase center (PTC). Our data supports the view that distant mutations can perturb the dynamic network in the ribosomal PTC, thereby raising the entropic cost of antibiotic binding. These results underscore the importance of considering conformational dynamics in rational drug design.
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Affiliation(s)
- Yuhang Wang
- †Department of Chemistry and Biochemistry, ‡School of Chemical, Biological, and Materials Engineering, and ξDepartment of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma, United States
| | - Jana K Shen
- †Department of Chemistry and Biochemistry, ‡School of Chemical, Biological, and Materials Engineering, and ξDepartment of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma, United States
| | - Susan J Schroeder
- †Department of Chemistry and Biochemistry, ‡School of Chemical, Biological, and Materials Engineering, and ξDepartment of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma, United States
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29
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Jack K, Bellodi C, Landry DM, Niederer RO, Meskauskas A, Musalgaonkar S, Kopmar N, Krasnykh O, Dean AM, Thompson SR, Ruggero D, Dinman JD. rRNA pseudouridylation defects affect ribosomal ligand binding and translational fidelity from yeast to human cells. Mol Cell 2012; 44:660-6. [PMID: 22099312 DOI: 10.1016/j.molcel.2011.09.017] [Citation(s) in RCA: 230] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 05/17/2011] [Accepted: 09/01/2011] [Indexed: 01/04/2023]
Abstract
How pseudouridylation (Ψ), the most common and evolutionarily conserved modification of rRNA, regulates ribosome activity is poorly understood. Medically, Ψ is important because the rRNA Ψ synthase, DKC1, is mutated in X-linked dyskeratosis congenita (X-DC) and Hoyeraal-Hreidarsson (HH) syndrome. Here, we characterize ribosomes isolated from a yeast strain in which Cbf5p, the yeast homolog of DKC1, is catalytically impaired through a D95A mutation (cbf5-D95A). Ribosomes from cbf5-D95A cells display decreased affinities for tRNA binding to the A and P sites as well as the cricket paralysis virus internal ribosome entry site (IRES), which interacts with both the P and the E sites of the ribosome. This biochemical impairment in ribosome activity manifests as decreased translational fidelity and IRES-dependent translational initiation, which are also evident in mouse and human cells deficient for DKC1 activity. These findings uncover specific roles for Ψ modification in ribosome-ligand interactions that are conserved in yeast, mouse, and humans.
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Affiliation(s)
- Karen Jack
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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30
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Leshin JA, Heselpoth R, Belew AT, Dinman J. High throughput structural analysis of yeast ribosomes using hSHAPE. RNA Biol 2011; 8:478-87. [PMID: 21508682 DOI: 10.4161/rna.8.3.14453] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Global mapping of rRNA structure by traditional methods is prohibitive in terms of time, labor and expense. High throughput selective 2' hydroxyl acylation analyzed by primer extension (hSHAPE) bypasses these problems by using fluorescently labeled primers to perform primer extension reactions, the products of which can be separated by capillary electrophoresis, thus enabling long read lengths in a cost effective manner. The data so generated is analyzed in a quantitative fashion using SHAPEFinder. This approach was used to map the flexibility of nearly the entire sequences of the 3 largest rRNAs from intact, empty yeast ribosomes. Mapping of these data onto near-atomic resolution yeast ribosome structures revealed the binding sites of known trans-acting factors, as well as previously unknown highly flexible regions of yeast rRNA. Refinement of this technology will enable nucleotide-specific mapping of changes in rRNA structure depending on the status of tRNA occupancy, the presence or absence of other trans-acting factors, due to mutations of intrinsic ribosome components or extrinsic factors affecting ribosome biogenesis, or in the presence of translational inhibitors.
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Affiliation(s)
- Jonathan A Leshin
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
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31
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Rakauskaite R, Dinman JD. Mutations of highly conserved bases in the peptidyltransferase center induce compensatory rearrangements in yeast ribosomes. RNA (NEW YORK, N.Y.) 2011; 17:855-864. [PMID: 21441349 PMCID: PMC3078735 DOI: 10.1261/rna.2593211] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 02/18/2011] [Indexed: 05/30/2023]
Abstract
Molecular dynamics simulation identified three highly conserved rRNA bases in the large subunit of the ribosome that form a three-dimensional (3D) "gate" that induces pausing of the aa-tRNA acceptor stem during accommodation into the A-site. A nearby fourth base contacting the "tryptophan finger" of yeast protein L3, which is involved in the coordinating elongation factor recruitment to the ribosome with peptidyltransfer, is also implicated in this process. To better understand the functional importance of these bases, single base substitutions as well as deletions at all four positions were constructed and expressed as the sole forms of ribosomes in yeast Saccharomyces cerevisiae. None of the mutants had strong effects on cell growth, translational fidelity, or on the interactions between ribosomes and tRNAs. However, the mutants did promote strong effects on cell growth in the presence of translational inhibitors, and differences in viability between yeast and Escherichia coli mutants at homologous positions suggest new targets for antibacterial therapeutics. Mutant ribosomes also promoted changes in 25S rRNA structure, all localized to the core of peptidyltransferase center (i.e., the proto-ribosome area). We suggest that a certain degree of structural plasticity is built into the ribosome, enabling it to ensure accurate translation of the genetic code while providing it with the flexibility to adapt and evolve.
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Affiliation(s)
- Rasa Rakauskaite
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
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32
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Belew AT, Advani VM, Dinman JD. Endogenous ribosomal frameshift signals operate as mRNA destabilizing elements through at least two molecular pathways in yeast. Nucleic Acids Res 2010; 39:2799-808. [PMID: 21109528 PMCID: PMC3074144 DOI: 10.1093/nar/gkq1220] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although first discovered in viruses, previous studies have identified operational −1 ribosomal frameshifting (−1 RF) signals in eukaryotic genomic sequences, and suggested a role in mRNA stability. Here, four yeast −1 RF signals are shown to promote significant mRNA destabilization through the nonsense mediated mRNA decay pathway (NMD), and genetic evidence is presented suggesting that they may also operate through the no-go decay pathway (NGD) as well. Yeast EST2 mRNA is highly unstable and contains up to five −1 RF signals. Ablation of the −1 RF signals or of NMD stabilizes this mRNA, and changes in −1 RF efficiency have opposing effects on the steady-state abundance of the EST2 mRNA. These results demonstrate that endogenous −1 RF signals function as mRNA destabilizing elements through at least two molecular pathways in yeast. Consistent with current evolutionary theory, phylogenetic analyses suggest that −1 RF signals are rapidly evolving cis-acting regulatory elements. Identification of high confidence −1 RF signals in ∼10% of genes in all eukaryotic genomes surveyed suggests that −1 RF is a broadly used post-transcriptional regulator of gene expression.
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Affiliation(s)
- Ashton T Belew
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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