1
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Gruffaz C, Smirnov A. GTPase Era at the heart of ribosome assembly. Front Mol Biosci 2023; 10:1263433. [PMID: 37860580 PMCID: PMC10582724 DOI: 10.3389/fmolb.2023.1263433] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/21/2023] [Indexed: 10/21/2023] Open
Abstract
Ribosome biogenesis is a key process in all organisms. It relies on coordinated work of multiple proteins and RNAs, including an array of assembly factors. Among them, the GTPase Era stands out as an especially deeply conserved protein, critically required for the assembly of bacterial-type ribosomes from Escherichia coli to humans. In this review, we bring together and critically analyze a wealth of phylogenetic, biochemical, structural, genetic and physiological data about this extensively studied but still insufficiently understood factor. We do so using a comparative and, wherever possible, synthetic approach, by confronting observations from diverse groups of bacteria and eukaryotic organelles (mitochondria and chloroplasts). The emerging consensus posits that Era intervenes relatively early in the small subunit biogenesis and is essential for the proper shaping of the platform which, in its turn, is a prerequisite for efficient translation. The timing of Era action on the ribosome is defined by its interactions with guanosine nucleotides [GTP, GDP, (p)ppGpp], ribosomal RNA, and likely other factors that trigger or delay its GTPase activity. As a critical nexus of the small subunit biogenesis, Era is subject to sophisticated regulatory mechanisms at the transcriptional, post-transcriptional, and post-translational levels. Failure of these mechanisms or a deficiency in Era function entail dramatic generalized consequences for the protein synthesis and far-reaching, pleiotropic effects on the organism physiology, such as the Perrault syndrome in humans.
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Affiliation(s)
- Christelle Gruffaz
- UMR7156- Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France
| | - Alexandre Smirnov
- UMR7156- Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France
- University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France
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2
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Giudice E, Georgeault S, Lavigne R, Pineau C, Trautwetter A, Ermel G, Blanco C, Gillet R. Purification and Characterization of Authentic 30S Ribosomal Precursors Induced by Heat Shock. Int J Mol Sci 2023; 24:ijms24043491. [PMID: 36834906 PMCID: PMC9959188 DOI: 10.3390/ijms24043491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
Ribosome biogenesis is a complex and multistep process that depends on various assembly factors. To understand this process and identify the ribosome assembly intermediates, most studies have set out to delete or deplete these assembly factors. Instead, we took advantage of the impact of heat stress (45 °C) on the late stages of the biogenesis of the 30S ribosomal subunit to explore authentic precursors. Under these conditions, reduced levels of the DnaK chaperone proteins devoted to ribosome assembly lead to the transient accumulation of 21S ribosomal particles, which are 30S precursors. We constructed strains with different affinity tags on one early and one late 30S ribosomal protein and purified the 21S particles that form under heat shock. A combination of relative quantification using mass spectrometry-based proteomics and cryo-electron microscopy (cryo-EM) was then used to determine their protein contents and structures.
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Affiliation(s)
- Emmanuel Giudice
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Sylvie Georgeault
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Régis Lavigne
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, 35000 Rennes, France
- Univ Rennes, CNRS, Inserm, Biosit UAR 3480 US_S 018, Protim Core Facility, 35000 Rennes, France
| | - Charles Pineau
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, 35000 Rennes, France
- Univ Rennes, CNRS, Inserm, Biosit UAR 3480 US_S 018, Protim Core Facility, 35000 Rennes, France
| | - Annie Trautwetter
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Gwennola Ermel
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Carlos Blanco
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Reynald Gillet
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
- Correspondence:
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3
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Maksimova E, Kravchenko O, Korepanov A, Stolboushkina E. Protein Assistants of Small Ribosomal Subunit Biogenesis in Bacteria. Microorganisms 2022; 10:microorganisms10040747. [PMID: 35456798 PMCID: PMC9032327 DOI: 10.3390/microorganisms10040747] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/16/2022] [Accepted: 03/26/2022] [Indexed: 01/27/2023] Open
Abstract
Ribosome biogenesis is a fundamental and multistage process. The basic steps of ribosome assembly are the transcription, processing, folding, and modification of rRNA; the translation, folding, and modification of r-proteins; and consecutive binding of ribosomal proteins to rRNAs. Ribosome maturation is facilitated by biogenesis factors that include a broad spectrum of proteins: GTPases, RNA helicases, endonucleases, modification enzymes, molecular chaperones, etc. The ribosome assembly factors assist proper rRNA folding and protein–RNA interactions and may sense the checkpoints during the assembly to ensure correct order of this process. Inactivation of these factors is accompanied by severe growth phenotypes and accumulation of immature ribosomal subunits containing unprocessed rRNA, which reduces overall translation efficiency and causes translational errors. In this review, we focus on the structural and biochemical analysis of the 30S ribosomal subunit assembly factors RbfA, YjeQ (RsgA), Era, KsgA (RsmA), RimJ, RimM, RimP, and Hfq, which take part in the decoding-center folding.
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Affiliation(s)
| | | | - Alexey Korepanov
- Correspondence: (A.K.); (E.S.); Tel.: +7-925-7180670 (A.K.); +7-915-4791359 (E.S.)
| | - Elena Stolboushkina
- Correspondence: (A.K.); (E.S.); Tel.: +7-925-7180670 (A.K.); +7-915-4791359 (E.S.)
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4
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Black JJ, Johnson AW. Release of the ribosome biogenesis factor Bud23 from small subunit precursors in yeast. RNA (NEW YORK, N.Y.) 2022; 28:371-389. [PMID: 34934010 PMCID: PMC8848936 DOI: 10.1261/rna.079025.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
The two subunits of the eukaryotic ribosome are produced through quasi-independent pathways involving the hierarchical actions of numerous trans-acting biogenesis factors and the incorporation of ribosomal proteins. The factors work together to shape the nascent subunits through a series of intermediate states into their functional architectures. One of the earliest intermediates of the small subunit (SSU or 40S) is the SSU processome which is subsequently transformed into the pre-40S intermediate. This transformation is, in part, facilitated by the binding of the methyltransferase Bud23. How Bud23 is released from the resultant pre-40S is not known. The ribosomal proteins Rps0, Rps2, and Rps21, termed the Rps0-cluster proteins, and several biogenesis factors bind the pre-40S around the time that Bud23 is released, suggesting that one or more of these factors could induce Bud23 release. Here, we systematically examined the requirement of these factors for the release of Bud23 from pre-40S particles. We found that the Rps0-cluster proteins are needed but not sufficient for Bud23 release. The atypical kinase/ATPase Rio2 shares a binding site with Bud23 and is thought to be recruited to pre-40S after the Rps0-cluster proteins. Depletion of Rio2 prevented the release of Bud23 from the pre-40S. More importantly, the addition of recombinant Rio2 to pre-40S particles affinity-purified from Rio2-depleted cells was sufficient for Bud23 release in vitro. The ability of Rio2 to displace Bud23 was independent of nucleotide hydrolysis. We propose a novel role for Rio2 in which its binding to the pre-40S actively displaces Bud23 from the pre-40S.
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Affiliation(s)
- Joshua J Black
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Arlen W Johnson
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
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5
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NMR signal assignments afnd secondary structure determination of the N-terminal domain of the ribosome maturation factor M from Staphylococcus aureus. Russ Chem Bull 2022. [DOI: 10.1007/s11172-021-3365-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Maksimova EM, Korepanov AP, Kravchenko OV, Baymukhametov TN, Myasnikov AG, Vassilenko KS, Afonina ZA, Stolboushkina EA. RbfA Is Involved in Two Important Stages of 30S Subunit Assembly: Formation of the Central Pseudoknot and Docking of Helix 44 to the Decoding Center. Int J Mol Sci 2021; 22:ijms22116140. [PMID: 34200244 PMCID: PMC8201178 DOI: 10.3390/ijms22116140] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 05/28/2021] [Accepted: 06/03/2021] [Indexed: 11/16/2022] Open
Abstract
Ribosome biogenesis is a highly coordinated and complex process that requires numerous assembly factors that ensure prompt and flawless maturation of ribosomal subunits. Despite the increasing amount of data collected, the exact role of most assembly factors and mechanistic details of their operation remain unclear, mainly due to the shortage of high-resolution structural information. Here, using cryo-electron microscopy, we characterized 30S ribosomal particles isolated from an Escherichia coli strain with a deleted gene for the RbfA factor. The cryo-EM maps for pre-30S subunits were divided into six classes corresponding to consecutive assembly intermediates: from the particles with a completely unresolved head domain and unfolded central pseudoknot to almost mature 30S subunits with well-resolved body, platform, and head domains and partially distorted helix 44. The structures of two predominant 30S intermediates belonging to most populated classes obtained at 2.7 Å resolutions indicate that RbfA acts at two distinctive 30S assembly stages: early formation of the central pseudoknot including folding of the head, and positioning of helix 44 in the decoding center at a later stage. Additionally, it was shown that the formation of the central pseudoknot may promote stabilization of the head domain, likely through the RbfA-dependent maturation of the neck helix 28. An update to the model of factor-dependent 30S maturation is proposed, suggesting that RfbA is involved in most of the subunit assembly process.
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Affiliation(s)
- Elena M. Maksimova
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.M.); (A.P.K.); (O.V.K.); (Z.A.A.)
| | - Alexey P. Korepanov
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.M.); (A.P.K.); (O.V.K.); (Z.A.A.)
| | - Olesya V. Kravchenko
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.M.); (A.P.K.); (O.V.K.); (Z.A.A.)
| | - Timur N. Baymukhametov
- National Research Center, “Kurchatov Institute”, Akademika Kurchatova pl. 1, 123182 Moscow, Russia;
| | - Alexander G. Myasnikov
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of NRC “Kurchatov Institute”, 188300 Gatchina, Russia;
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Konstantin S. Vassilenko
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.M.); (A.P.K.); (O.V.K.); (Z.A.A.)
- Correspondence: (K.S.V.); (E.A.S.); Tel.: +7-903-6276710 (K.S.V.); +7-915-4791359 (E.A.S.)
| | - Zhanna A. Afonina
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.M.); (A.P.K.); (O.V.K.); (Z.A.A.)
| | - Elena A. Stolboushkina
- Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Russia; (E.M.M.); (A.P.K.); (O.V.K.); (Z.A.A.)
- Correspondence: (K.S.V.); (E.A.S.); Tel.: +7-903-6276710 (K.S.V.); +7-915-4791359 (E.A.S.)
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7
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Ng Kwan Lim E, Sasseville C, Carrier MC, Massé E. Keeping Up with RNA-Based Regulation in Bacteria: New Roles for RNA Binding Proteins. Trends Genet 2020; 37:86-97. [PMID: 33077249 DOI: 10.1016/j.tig.2020.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 01/06/2023]
Abstract
RNA binding proteins (RBPs) are ubiquitously found in all kingdoms of life. They are involved in a plethora of regulatory events, ranging from direct regulation of gene expression to guiding modification of RNA molecules. As bacterial regulators, RBPs can act alone or in concert with RNA-based regulators, such as small regulatory RNAs (sRNAs), riboswitches, or clustered regularly interspaced short palindromic repeats (CRISPR) RNAs. Various functions of RBPs, whether dependent or not on an RNA regulator, have been described in the past. However, the past decade has been a fertile ground for the development of novel high-throughput methods. These methods acted as stepping-stones for the discovery of new functions of RBPs and helped in the understanding of the molecular mechanisms behind previously described regulatory events. Here, we present an overview of the recently identified roles of major bacterial RBPs from different model organisms. Moreover, the tight relationship between RBPs and RNA-based regulators will be explored.
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Affiliation(s)
- Evelyne Ng Kwan Lim
- Faculty of Medicine and Health Sciences, Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, J1H 5N4, QC, Canada
| | - Charles Sasseville
- Faculty of Medicine and Health Sciences, Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, J1H 5N4, QC, Canada
| | - Marie-Claude Carrier
- Faculty of Medicine and Health Sciences, Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, J1H 5N4, QC, Canada
| | - Eric Massé
- Faculty of Medicine and Health Sciences, Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, J1H 5N4, QC, Canada.
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8
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Sharma H, Anand B. Ribosome assembly defects subvert initiation Factor3 mediated scrutiny of bona fide start signal. Nucleic Acids Res 2020; 47:11368-11386. [PMID: 31586395 PMCID: PMC6868393 DOI: 10.1093/nar/gkz825] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 08/17/2019] [Accepted: 10/03/2019] [Indexed: 12/02/2022] Open
Abstract
In bacteria, the assembly factors tightly orchestrate the maturation of ribosomes whose competency for protein synthesis is validated by translation machinery at various stages of translation cycle. However, what transpires to the quality control measures when the ribosomes are produced with assembly defects remains enigmatic. In Escherichia coli, we show that 30S ribosomes that harbour assembly defects due to the lack of assembly factors such as RbfA and KsgA display suboptimal initiation codon recognition and bypass the critical codon–anticodon proofreading steps during translation initiation. These premature ribosomes on entering the translation cycle compromise the fidelity of decoding that gives rise to errors during initiation and elongation. We show that the assembly defects compromise the binding of initiation factor 3 (IF3), which in turn appears to license the rapid transition of 30S (pre) initiation complex to 70S initiation complex by tempering the validation of codon–anticodon interaction during translation initiation. This suggests that the premature ribosomes harbouring the assembly defects subvert the IF3 mediated proofreading of cognate initiation codon to enter the translation cycle.
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Affiliation(s)
- Himanshu Sharma
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - B Anand
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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9
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Razi A, Davis JH, Hao Y, Jahagirdar D, Thurlow B, Basu K, Jain N, Gomez-Blanco J, Britton RA, Vargas J, Guarné A, Woodson SA, Williamson JR, Ortega J. Role of Era in assembly and homeostasis of the ribosomal small subunit. Nucleic Acids Res 2019; 47:8301-8317. [PMID: 31265110 PMCID: PMC6736133 DOI: 10.1093/nar/gkz571] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/11/2019] [Accepted: 06/27/2019] [Indexed: 01/23/2023] Open
Abstract
Assembly factors provide speed and directionality to the maturation process of the 30S subunit in bacteria. To gain a more precise understanding of how these proteins mediate 30S maturation, it is important to expand on studies of 30S assembly intermediates purified from bacterial strains lacking particular maturation factors. To reveal the role of the essential protein Era in the assembly of the 30S ribosomal subunit, we analyzed assembly intermediates that accumulated in Era-depleted Escherichia coli cells using quantitative mass spectrometry, high resolution cryo-electron microscopy and in-cell footprinting. Our combined approach allowed for visualization of the small subunit as it assembled and revealed that with the exception of key helices in the platform domain, all other 16S rRNA domains fold even in the absence of Era. Notably, the maturing particles did not stall while waiting for the platform domain to mature and instead re-routed their folding pathway to enable concerted maturation of other structural motifs spanning multiple rRNA domains. We also found that binding of Era to the mature 30S subunit destabilized helix 44 and the decoding center preventing binding of YjeQ, another assembly factor. This work establishes Era’s role in ribosome assembly and suggests new roles in maintaining ribosome homeostasis.
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Affiliation(s)
- Aida Razi
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
| | - Joseph H Davis
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yumeng Hao
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Dushyant Jahagirdar
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
| | - Brett Thurlow
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S4K1, Canada
| | - Kaustuv Basu
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
| | - Nikhil Jain
- Department of Molecular Virology and Microbiology, Baylor College of Medicine,Houston, TX 77030, USA.,Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX 77030, USA
| | - Josue Gomez-Blanco
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
| | - Robert A Britton
- Department of Molecular Virology and Microbiology, Baylor College of Medicine,Houston, TX 77030, USA.,Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX 77030, USA
| | - Javier Vargas
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
| | - Alba Guarné
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 0B1 Canada
| | - Sarah A Woodson
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - James R Williamson
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
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10
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Andrade JM, Dos Santos RF, Chelysheva I, Ignatova Z, Arraiano CM. The RNA-binding protein Hfq is important for ribosome biogenesis and affects translation fidelity. EMBO J 2018; 37:embj.201797631. [PMID: 29669858 DOI: 10.15252/embj.201797631] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 02/28/2018] [Accepted: 03/13/2018] [Indexed: 11/09/2022] Open
Abstract
Ribosome biogenesis is a complex process involving multiple factors. Here, we show that the widely conserved RNA chaperone Hfq, which can regulate sRNA-mRNA basepairing, plays a critical role in rRNA processing and ribosome assembly in Escherichia coli Hfq binds the 17S rRNA precursor and facilitates its correct processing and folding to mature 16S rRNA Hfq assists ribosome assembly and associates with pre-30S particles but not with mature 30S subunits. Inactivation of Hfq strikingly decreases the pool of mature 70S ribosomes. The reduction in ribosome levels depends on residues located in the distal face of Hfq but not on residues found in the proximal and rim surfaces which govern interactions with the sRNAs. Our results indicate that Hfq-mediated regulation of ribosomes is independent of its function as sRNA-regulator. Furthermore, we observed that inactivation of Hfq compromises translation efficiency and fidelity, both features of aberrantly assembled ribosomes. Our work expands the functions of the Sm-like protein Hfq beyond its function in small RNA-mediated regulation and unveils a novel role of Hfq as crucial in ribosome biogenesis and translation.
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Affiliation(s)
- José M Andrade
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ricardo F Dos Santos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Irina Chelysheva
- Institute of Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | - Zoya Ignatova
- Institute of Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | - Cecília M Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
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11
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Davis JH, Williamson JR. Structure and dynamics of bacterial ribosome biogenesis. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0181. [PMID: 28138067 DOI: 10.1098/rstb.2016.0181] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2016] [Indexed: 01/28/2023] Open
Abstract
Bacterial ribosome biogenesis has been an active area of research for more than 30 years and has served as a test-bed for the development of new biochemical, biophysical and structural techniques to understand macromolecular assembly generally. Recent work inspecting the process in vivo has advanced our understanding of the role of ribosome biogenesis factors, the co-transcriptional nature of assembly, the kinetics of the process under sub-optimal conditions, and the rRNA folding and ribosome protein binding pathways. Additionally, new structural work enabled by single-particle electron microscopy has helped to connect in vitro ribosomal protein binding maps to the underlying RNA. This review summarizes the state of these in vivo studies, provides a kinetic model for ribosome assembly under sub-optimal conditions, and describes a framework to compare newly emerging assembly intermediate structures.This article is part of the themed issue 'Perspectives on the ribosome'.
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Affiliation(s)
- Joseph H Davis
- Department of Integrative Structural and Computational Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - James R Williamson
- Department of Integrative Structural and Computational Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA .,Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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12
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Razi A, Britton RA, Ortega J. The impact of recent improvements in cryo-electron microscopy technology on the understanding of bacterial ribosome assembly. Nucleic Acids Res 2017; 45:1027-1040. [PMID: 28180306 PMCID: PMC5388408 DOI: 10.1093/nar/gkw1231] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/20/2016] [Accepted: 11/25/2016] [Indexed: 01/14/2023] Open
Abstract
Cryo-electron microscopy (cryo-EM) had played a central role in the study of ribosome structure and the process of translation in bacteria since the development of this technique in the mid 1980s. Until recently cryo-EM structures were limited to ∼10 Å in the best cases. However, the recent advent of direct electron detectors has greatly improved the resolution of cryo-EM structures to the point where atomic resolution is now achievable. This improved resolution will allow cryo-EM to make groundbreaking contributions in essential aspects of ribosome biology, including the assembly process. In this review, we summarize important insights that cryo-EM, in combination with chemical and genetic approaches, has already brought to our current understanding of the ribosomal assembly process in bacteria using previous detector technology. More importantly, we discuss how the higher resolution structures now attainable with direct electron detectors can be leveraged to propose precise testable models regarding this process. These structures will provide an effective platform to develop new antibiotics that target this fundamental cellular process.
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Affiliation(s)
- Aida Razi
- Department of Biochemistry and Biomedical Sciences and M. G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada
| | - Robert A Britton
- Department of Molecular Virology and Microbiology and Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX, USA
| | - Joaquin Ortega
- Department of Biochemistry and Biomedical Sciences and M. G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada
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13
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Ni X, Davis JH, Jain N, Razi A, Benlekbir S, McArthur AG, Rubinstein JL, Britton RA, Williamson JR, Ortega J. YphC and YsxC GTPases assist the maturation of the central protuberance, GTPase associated region and functional core of the 50S ribosomal subunit. Nucleic Acids Res 2016; 44:8442-55. [PMID: 27484475 PMCID: PMC5041480 DOI: 10.1093/nar/gkw678] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/21/2016] [Indexed: 11/12/2022] Open
Abstract
YphC and YsxC are GTPases in Bacillus subtilis that facilitate the assembly of the 50S ribosomal subunit, however their roles in this process are still uncharacterized. To explore their function, we used strains in which the only copy of the yphC or ysxC genes were under the control of an inducible promoter. Under depletion conditions, they accumulated incomplete ribosomal subunits that we named 45SYphC and 44.5SYsxC particles. Quantitative mass spectrometry analysis and the 5–6 Å resolution cryo-EM maps of the 45SYphC and 44.5SYsxC particles revealed that the two GTPases participate in the maturation of the central protuberance, GTPase associated region and key RNA helices in the A, P and E functional sites of the 50S subunit. We observed that YphC and YsxC bind specifically to the two immature particles, suggesting that they represent either on-pathway intermediates or that their structure has not significantly diverged from that of the actual substrate. These results describe the nature of these immature particles, a widely used tool to study the assembly process of the ribosome. They also provide the first insights into the function of YphC and YsxC in 50S subunit assembly and are consistent with this process occurring through multiple parallel pathways, as it has been described for the 30S subunit.
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Affiliation(s)
- Xiaodan Ni
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S4K1, Canada M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario L8S4K1, Canada
| | - Joseph H Davis
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nikhil Jain
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX 77030, USA
| | - Aida Razi
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S4K1, Canada M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario L8S4K1, Canada
| | - Samir Benlekbir
- Molecular Structure and Function Program, The Hospital for Sick Children,Toronto, Ontario M5G 0A4, Canada
| | - Andrew G McArthur
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S4K1, Canada M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario L8S4K1, Canada
| | - John L Rubinstein
- Molecular Structure and Function Program, The Hospital for Sick Children,Toronto, Ontario M5G 0A4, Canada Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Robert A Britton
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA Center for Metagenomics and Microbiome Research, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R Williamson
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Joaquin Ortega
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S4K1, Canada M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario L8S4K1, Canada
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14
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Thurlow B, Davis JH, Leong V, Moraes TF, Williamson JR, Ortega J. Binding properties of YjeQ (RsgA), RbfA, RimM and Era to assembly intermediates of the 30S subunit. Nucleic Acids Res 2016; 44:9918-9932. [PMID: 27382067 PMCID: PMC5175332 DOI: 10.1093/nar/gkw613] [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: 12/22/2015] [Revised: 06/26/2016] [Accepted: 06/27/2016] [Indexed: 11/13/2022] Open
Abstract
Our understanding regarding the function of YjeQ (also called RsgA), RbfA, RimM and Era in ribosome biogenesis has been derived in part from the study of immature 30S particles that accumulate in null strains lacking one of these factors. However, their mechanistic details are still unknown. Here, we demonstrate that these immature particles are not dead-end products of assembly, but progress into mature 30S subunits. Mass spectrometry analysis revealed that in vivo the occupancy level of these factors in these immature 30S particles is below 10% and that the concentration of factors does not increase when immature particles accumulate in cells. We measured by microscale thermophoresis that YjeQ and Era binds to the mature 30S subunit with high affinity. However, the binding affinity of these factors to the immature particles and of RimM and RbfA to mature or immature particles was weak, suggesting that binding is not occurring at physiological concentrations. These results suggest that in the absence of these factors, the immature particles evolve into a thermodynamically stable intermediate that exhibits low affinity for the assembly factors. These results imply that the true substrates of YjeQ, RbfA, RimM and Era are immature particles that precede the ribosomal particles accumulating in the knockouts strains.
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Affiliation(s)
- Brett Thurlow
- Department of Biochemistry and Biomedical Sciences and M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada
| | - Joseph H Davis
- Department of Integrative Computational and Structural Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Vivian Leong
- Department of Biochemistry and Biomedical Sciences and M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada
| | - Trevor F Moraes
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S1A8, Canada
| | - James R Williamson
- Department of Integrative Computational and Structural Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Joaquin Ortega
- Department of Biochemistry and Biomedical Sciences and M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada
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15
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Nord S, Bhatt MJ, Tükenmez H, Farabaugh PJ, Wikström PM. Mutations of ribosomal protein S5 suppress a defect in late-30S ribosomal subunit biogenesis caused by lack of the RbfA biogenesis factor. RNA (NEW YORK, N.Y.) 2015; 21:1454-1468. [PMID: 26089326 PMCID: PMC4509935 DOI: 10.1261/rna.051383.115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 05/04/2015] [Indexed: 06/04/2023]
Abstract
The in vivo assembly of ribosomal subunits requires assistance by maturation proteins that are not part of mature ribosomes. One such protein, RbfA, associates with the 30S ribosomal subunits. Loss of RbfA causes cold sensitivity and defects of the 30S subunit biogenesis and its overexpression partially suppresses the dominant cold sensitivity caused by a C23U mutation in the central pseudoknot of 16S rRNA, a structure essential for ribosome function. We have isolated suppressor mutations that restore partially the growth of an RbfA-lacking strain. Most of the strongest suppressor mutations alter one out of three distinct positions in the carboxy-terminal domain of ribosomal protein S5 (S5) in direct contact with helix 1 and helix 2 of the central pseudoknot. Their effect is to increase the translational capacity of the RbfA-lacking strain as evidenced by an increase in polysomes in the suppressed strains. Overexpression of RimP, a protein factor that along with RbfA regulates formation of the ribosome's central pseudoknot, was lethal to the RbfA-lacking strain but not to a wild-type strain and this lethality was suppressed by the alterations in S5. The S5 mutants alter translational fidelity but these changes do not explain consistently their effect on the RbfA-lacking strain. Our genetic results support a role for the region of S5 modified in the suppressors in the formation of the central pseudoknot in 16S rRNA.
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Affiliation(s)
- Stefan Nord
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Monika J Bhatt
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland 21228, USA
| | - Hasan Tükenmez
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Philip J Farabaugh
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland 21228, USA
| | - P Mikael Wikström
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
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16
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Jeganathan A, Razi A, Thurlow B, Ortega J. The C-terminal helix in the YjeQ zinc-finger domain catalyzes the release of RbfA during 30S ribosome subunit assembly. RNA (NEW YORK, N.Y.) 2015; 21:1203-1216. [PMID: 25904134 PMCID: PMC4436671 DOI: 10.1261/rna.049171.114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 03/22/2015] [Indexed: 06/04/2023]
Abstract
YjeQ (also called RsgA) and RbfA proteins in Escherichia coli bind to immature 30S ribosome subunits at late stages of assembly to assist folding of the decoding center. A key step for the subunit to enter the pool of actively translating ribosomes is the release of these factors. YjeQ promotes dissociation of RbfA during the final stages of maturation; however, the mechanism implementing this functional interplay has not been elucidated. YjeQ features an amino-terminal oligonucleotide/oligosaccharide binding domain, a central GTPase module and a carboxy-terminal zinc-finger domain. We found that the zinc-finger domain is comprised of two functional motifs: the region coordinating the zinc ion and a carboxy-terminal α-helix. The first motif is essential for the anchoring of YjeQ to the 30S subunit and the carboxy-terminal α-helix facilitates the removal of RbfA once the 30S subunit reaches the mature state. Furthermore, the ability of the mature 30S subunit to stimulate YjeQ GTPase activity also depends on the carboxy-terminal α-helix. Our data are consistent with a model in which YjeQ uses this carboxy-terminal α-helix as a sensor to gauge the conformation of helix 44, an essential motif of the decoding center. According to this model, the mature conformation of helix 44 is sensed by the carboxy-terminal α-helix, which in turn stimulates the YjeQ GTPase activity. Hydrolysis of GTP is believed to assist the release of YjeQ from the mature 30S subunit through a still uncharacterized mechanism. These results identify the structural determinants in YjeQ that implement the functional interplay with RbfA.
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Affiliation(s)
- Ajitha Jeganathan
- Department of Biochemistry and Biomedical Sciences, M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - Aida Razi
- Department of Biochemistry and Biomedical Sciences, M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - Brett Thurlow
- Department of Biochemistry and Biomedical Sciences, M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - Joaquin Ortega
- Department of Biochemistry and Biomedical Sciences, M.G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1
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17
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Naganathan A, Wood MP, Moore SD. The large ribosomal subunit protein L9 enables the growth of EF-P deficient cells and enhances small subunit maturation. PLoS One 2015; 10:e0120060. [PMID: 25879934 PMCID: PMC4399890 DOI: 10.1371/journal.pone.0120060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 02/03/2015] [Indexed: 01/08/2023] Open
Abstract
The loss of the large ribosomal protein L9 causes a reduction in translation fidelity by an unknown mechanism. To identify pathways affected by L9, we identified mutants of E. coli that require L9 for fitness. In a prior study, we characterized L9-dependent mutations in the essential GTPase Der (EngA). Here, we describe a second class of L9-dependent mutations that either compromise or inactivate elongation factor P (EF-P, eIF5A in eukaryotes). Without L9, Δefp cells are practically inviable. Cell fractionation studies revealed that, in both the Der and EF-P mutant cases, L9's activity reduces immature 16S rRNA in 30S particles and partially restores the abundance of monosomes. Inspired by these findings, we discovered that L9 also enhances 16S maturation in wild-type cells. Surprisingly, although the amount of immature 16S in 30S particles was found to be elevated in ΔrplI cells, the amount in polysomes was low and inversely correlated with the immature 16S abundance. These findings provide an explanation for the observed fitness increases afforded by L9 in these mutants and reveal particular physiological conditions in which L9 becomes critical. Additionally, L9 may affect the partitioning of small subunits containing immature 16S rRNA.
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Affiliation(s)
- Anusha Naganathan
- The Burnett School of Biomedical Sciences, College of Medicine, The University of Central Florida, Orlando, FL, 32816, United States of America
| | - Matthew P. Wood
- Seattle Biomed, 307 Westlake Ave N, Suite 500, Seattle, WA, 98109, United States of America
- Department of Global Health, University of Washington, 1510 N.E. San Juan Road, Seattle, WA, 98195, United States of America
| | - Sean D. Moore
- The Burnett School of Biomedical Sciences, College of Medicine, The University of Central Florida, Orlando, FL, 32816, United States of America
- * E-mail:
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18
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Abstract
Ribosomal proteins S4 and S5 participate in the decoding and assembly processes on the ribosome and the interaction with specific antibiotic inhibitors of translation. Many of the characterized mutations affecting these proteins decrease the accuracy of translation, leading to a ribosomal-ambiguity phenotype. Structural analyses of ribosomal complexes indicate that the tRNA selection pathway involves a transition between the closed and open conformations of the 30S ribosomal subunit and requires disruption of the interface between the S4 and S5 proteins. In agreement with this observation, several of the mutations that promote miscoding alter residues located at the S4-S5 interface. Here, the Escherichia coli rpsD and rpsE genes encoding the S4 and S5 proteins were targeted for mutagenesis and screened for accuracy-altering mutations. While a majority of the 38 mutant proteins recovered decrease the accuracy of translation, error-restrictive mutations were also recovered; only a minority of the mutant proteins affected rRNA processing, ribosome assembly, or interactions with antibiotics. Several of the mutations affect residues at the S4-S5 interface. These include five nonsense mutations that generate C-terminal truncations of S4. These truncations are predicted to destabilize the S4-S5 interface and, consistent with the domain closure model, all have ribosomal-ambiguity phenotypes. A substantial number of the mutations alter distant locations and conceivably affect tRNA selection through indirect effects on the S4-S5 interface or by altering interactions with adjacent ribosomal proteins and 16S rRNA.
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19
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Domingues S, Moreira RN, Andrade JM, Dos Santos RF, Bárria C, Viegas SC, Arraiano CM. The role of RNase R in trans-translation and ribosomal quality control. Biochimie 2014; 114:113-8. [PMID: 25542646 DOI: 10.1016/j.biochi.2014.12.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 12/18/2014] [Indexed: 01/11/2023]
Abstract
Gene expression not only depends on the rate of transcription but is also largely controlled at the post-transcriptional level. Translation rate and mRNA decay greatly influence the final protein levels. Surveillance mechanisms are essential to ensure the quality of the RNA and proteins produced. Trans-translation is one of the most important systems in the quality control of bacterial translation. This process guarantees the destruction of abnormal proteins and also leads to degradation of the respective defective RNAs through the action of Ribonuclease R (RNase R). This exoribonuclease hydrolyzes RNAs starting from their 3' end. Besides its involvement in trans-translation, RNase R also participates in the quality control of rRNA molecules involved in ribosomal biogenesis. RNase R is thus emerging as a key factor in ensuring translation accuracy. This review focuses on issues related to the quality control of translation, with special emphasis on the role of RNase R.
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Affiliation(s)
- Susana Domingues
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Ricardo N Moreira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - José M Andrade
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Ricardo F Dos Santos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Cátia Bárria
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Sandra C Viegas
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Cecília M Arraiano
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
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