1
|
Zhong Y, Feng J, Koh AF, Kotecha A, Greber BJ, Ataide S. Cryo-EM structure of SRP68/72 reveals an extended dimerization domain with RNA-binding activity. Nucleic Acids Res 2024; 52:5285-5300. [PMID: 38366771 PMCID: PMC11109942 DOI: 10.1093/nar/gkae107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/31/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024] Open
Abstract
The signal recognition particle (SRP) is a critical component in protein sorting pathways in all domains of life. Human SRP contains six proteins bound to the 7S RNA and their structures and functions have been mostly elucidated. The SRP68/72 dimer is the largest SRP component and is essential for SRP function. Although the structures of the SRP68/72 RNA binding and dimerization domains have been previously reported, the structure and function of large portions of the SRP68/72 dimer remain unknown. Here, we analyse full-length SRP68/72 using cryo-EM and report that SRP68/72 depend on each other for stability and form an extended dimerization domain. This newly observed dimerization domain is both a protein- and RNA-binding domain. Comparative analysis with current structural models suggests that this dimerization domain undergoes dramatic translocation upon SRP docking onto SRP receptor and eventually comes close to the Alu domain. We propose that the SRP68/72 dimerization domain functions by binding and detaching the Alu domain and SRP9/14 from the ribosomal surface, thus releasing elongation arrest upon docking onto the ER membrane.
Collapse
Affiliation(s)
- Yichen Zhong
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Junjie Feng
- Division of Structural Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Adrian F Koh
- Materials and Structural Analysis Division, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 Eindhoven, The Netherlands
| | - Abhay Kotecha
- Materials and Structural Analysis Division, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 Eindhoven, The Netherlands
| | - Basil J Greber
- Division of Structural Biology, The Institute of Cancer Research, London SW3 6JB, UK
| | - Sandro F Ataide
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| |
Collapse
|
2
|
He TT, Xu YF, Li X, Wang X, Li JY, Ou-Yang D, Cheng HS, Li HY, Qin J, Huang Y, Wang HY. A linear and circular dual-conformation noncoding RNA involved in oxidative stress tolerance in Bacillus altitudinis. Nat Commun 2023; 14:5722. [PMID: 37714854 PMCID: PMC10504365 DOI: 10.1038/s41467-023-41491-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 09/06/2023] [Indexed: 09/17/2023] Open
Abstract
Circular RNAs have been extensively studied in eukaryotes, but their presence and/or biological functionality in bacteria are unclear. Here, we show that a regulatory noncoding RNA (DucS) exists in both linear and circular conformation in Bacillus altitudinis. The linear forms promote B. altitudinis tolerance to H2O2 stress, partly through increased translation of a stress-responsive gene, htrA. The 3' end sequences of the linear forms are crucial for RNA circularization, and formation of circular forms can decrease the levels of the regulatory linear cognates. Bioinformatic analysis of available RNA-seq datasets from 30 bacterial species revealed multiple circular RNA candidates, distinct from DucS, for all the examined species. Experiments testing for the presence of selected circular RNA candidates in four species successfully validated 7 out of 9 candidates from B. altitudinis and 4 out of 5 candidates from Bacillus paralicheniformis; However, none of the candidates tested for Bacillus subtilis and Escherichia coli were detected. Our work identifies a dual-conformation regulatory RNA in B. altitutidinis, and indicates that circular RNAs exist in diverse bacteria. However, circularization of specific RNAs does not seem to be conserved across species, and the circularization mechanisms and biological functionality of the circular forms remain unclear.
Collapse
Affiliation(s)
- Ting-Ting He
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
- Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yun-Fan Xu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Xiang Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Xia Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Jie-Yu Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Dan Ou-Yang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Han-Sen Cheng
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Hao-Yang Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Jia Qin
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Yu Huang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Hai-Yan Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China.
| |
Collapse
|
3
|
Fromm SA, O'Connor KM, Purdy M, Bhatt PR, Loughran G, Atkins JF, Jomaa A, Mattei S. The translating bacterial ribosome at 1.55 Å resolution generated by cryo-EM imaging services. Nat Commun 2023; 14:1095. [PMID: 36841832 PMCID: PMC9968351 DOI: 10.1038/s41467-023-36742-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 02/15/2023] [Indexed: 02/26/2023] Open
Abstract
Our understanding of protein synthesis has been conceptualised around the structure and function of the bacterial ribosome. This complex macromolecular machine is the target of important antimicrobial drugs, an integral line of defence against infectious diseases. Here, we describe how open access to cryo-electron microscopy facilities combined with bespoke user support enabled structural determination of the translating ribosome from Escherichia coli at 1.55 Å resolution. The obtained structures allow for direct determination of the rRNA sequence to identify ribosome polymorphism sites in the E. coli strain used in this study and enable interpretation of the ribosomal active and peripheral sites at unprecedented resolution. This includes scarcely populated chimeric hybrid states of the ribosome engaged in several tRNA translocation steps resolved at ~2 Å resolution. The current map not only improves our understanding of protein synthesis but also allows for more precise structure-based drug design of antibiotics to tackle rising bacterial resistance.
Collapse
Affiliation(s)
- Simon A Fromm
- EMBL Imaging Centre, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Kate M O'Connor
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Michael Purdy
- Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Pramod R Bhatt
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland. .,MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
| | - Ahmad Jomaa
- Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA. .,Centre for Cell and Membrane Physiology, University of Virginia, Charlottesville, VA, USA.
| | - Simone Mattei
- EMBL Imaging Centre, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany. .,Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany.
| |
Collapse
|
4
|
D'Souza MH, Mrozowich T, Badmalia MD, Geeraert M, Frederickson A, Henrickson A, Demeler B, Wolfinger MT, Patel TR. Biophysical characterisation of human LincRNA-p21 sense and antisense Alu inverted repeats. Nucleic Acids Res 2022; 50:5881-5898. [PMID: 35639511 PMCID: PMC9177966 DOI: 10.1093/nar/gkac414] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/26/2022] [Accepted: 05/09/2022] [Indexed: 12/05/2022] Open
Abstract
Human Long Intergenic Noncoding RNA-p21 (LincRNA-p21) is a regulatory noncoding RNA that plays an important role in promoting apoptosis. LincRNA-p21 is also critical in down-regulating many p53 target genes through its interaction with a p53 repressive complex. The interaction between LincRNA-p21 and the repressive complex is likely dependent on the RNA tertiary structure. Previous studies have determined the two-dimensional secondary structures of the sense and antisense human LincRNA-p21 AluSx1 IRs using SHAPE. However, there were no insights into its three-dimensional structure. Therefore, we in vitro transcribed the sense and antisense regions of LincRNA-p21 AluSx1 Inverted Repeats (IRs) and performed analytical ultracentrifugation, size exclusion chromatography, light scattering, and small angle X-ray scattering (SAXS) studies. Based on these studies, we determined low-resolution, three-dimensional structures of sense and antisense LincRNA-p21. By adapting previously known two-dimensional information, we calculated their sense and antisense high-resolution models and determined that they agree with the low-resolution structures determined using SAXS. Thus, our integrated approach provides insights into the structure of LincRNA-p21 Alu IRs. Our study also offers a viable pipeline for combining the secondary structure information with biophysical and computational studies to obtain high-resolution atomistic models for long noncoding RNAs.
Collapse
Affiliation(s)
- Michael H D'Souza
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Tyler Mrozowich
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Maulik D Badmalia
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Mitchell Geeraert
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Angela Frederickson
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Amy Henrickson
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Borries Demeler
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada.,Department of Chemistry and Biochemistry, University of Montana, Missoula, MT 59812, USA.,NorthWest Biophysics Consortium, University of Lethbridge, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada
| | - Michael T Wolfinger
- Bioinformatics and Computational Biology, Faculty of Computer Science, Währingerstrasse 29, 1090 Vienna, Austria.,Department of Theoretical Chemistry, University of Vienna, Währingerstrasse 17, 1090 Vienna, Austria
| | - Trushar R Patel
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, 4401 University Drive, Lethbridge, AB T1K 3M4, Canada.,Department of Microbiology, Immunology and Infectious Disease, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada.,Li Ka Shing Institute of Virology and Discovery Lab, University of Alberta, Edmonton, AB T6G 2E1, Canada
| |
Collapse
|
5
|
Ribosome-Associated ncRNAs (rancRNAs) Adjust Translation and Shape Proteomes. Noncoding RNA 2022; 8:ncrna8020022. [PMID: 35314615 PMCID: PMC8938821 DOI: 10.3390/ncrna8020022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/05/2022] [Accepted: 03/08/2022] [Indexed: 12/02/2022] Open
Abstract
The regulation of protein synthesis is of extreme importance for cell survival in challenging environmental conditions. Modulating gene expression at the level of translation allows a swift and low-energy-cost response to external stimuli. In the last decade, an emerging class of regulatory ncRNAs, namely ribosome-associated non-coding RNAs (rancRNAs), has been discovered. These rancRNAs have proven to be efficient players in the regulation of translation as a first wave of stress adaptation by directly targeting the ribosome, the central enzyme of protein production. This underlying principle appears to be highly conserved, since rancRNAs are present in all three domains of life. Here, we review the major findings and mechanistic peculiarities of rancRNAs, a class of transcripts that is providing new and broader perspectives on the complexity of the ribosome and translation regulation.
Collapse
|
6
|
Inhibition of SRP-dependent protein secretion by the bacterial alarmone (p)ppGpp. Nat Commun 2022; 13:1069. [PMID: 35217658 PMCID: PMC8881573 DOI: 10.1038/s41467-022-28675-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 02/07/2022] [Indexed: 11/08/2022] Open
Abstract
The stringent response enables bacteria to respond to nutrient limitation and other stress conditions through production of the nucleotide-based second messengers ppGpp and pppGpp, collectively known as (p)ppGpp. Here, we report that (p)ppGpp inhibits the signal recognition particle (SRP)-dependent protein targeting pathway, which is essential for membrane protein biogenesis and protein secretion. More specifically, (p)ppGpp binds to the SRP GTPases Ffh and FtsY, and inhibits the formation of the SRP receptor-targeting complex, which is central for the coordinated binding of the translating ribosome to the SecYEG translocon. Cryo-EM analysis of SRP bound to translating ribosomes suggests that (p)ppGpp may induce a distinct conformational stabilization of the NG domain of Ffh and FtsY in Bacillus subtilis but not in E. coli. Bacterial responses to nutrient limitation and other stress conditions are often modulated by the nucleotide-based second messenger (p)ppGpp. Here, the authors show that (p)ppGpp inhibits the SRP membrane-protein insertion and secretion pathway by binding to GTPases Ffh and FtsY.
Collapse
|
7
|
Soni K, Kempf G, Manalastas-Cantos K, Hendricks A, Flemming D, Guizetti J, Simon B, Frischknecht F, Svergun DI, Wild K, Sinning I. Structural analysis of the SRP Alu domain from Plasmodium falciparum reveals a non-canonical open conformation. Commun Biol 2021; 4:600. [PMID: 34017052 PMCID: PMC8137916 DOI: 10.1038/s42003-021-02132-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/22/2021] [Indexed: 12/25/2022] Open
Abstract
The eukaryotic signal recognition particle (SRP) contains an Alu domain, which docks into the factor binding site of translating ribosomes and confers translation retardation. The canonical Alu domain consists of the SRP9/14 protein heterodimer and a tRNA-like folded Alu RNA that adopts a strictly 'closed' conformation involving a loop-loop pseudoknot. Here, we study the structure of the Alu domain from Plasmodium falciparum (PfAlu), a divergent apicomplexan protozoan that causes human malaria. Using NMR, SAXS and cryo-EM analyses, we show that, in contrast to its prokaryotic and eukaryotic counterparts, the PfAlu domain adopts an 'open' Y-shaped conformation. We show that cytoplasmic P. falciparum ribosomes are non-discriminative and recognize both the open PfAlu and closed human Alu domains with nanomolar affinity. In contrast, human ribosomes do not provide high affinity binding sites for either of the Alu domains. Our analyses extend the structural database of Alu domains to the protozoan species and reveal species-specific differences in the recognition of SRP Alu domains by ribosomes.
Collapse
Affiliation(s)
- Komal Soni
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Georg Kempf
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | | | - Astrid Hendricks
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Dirk Flemming
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Julien Guizetti
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Bernd Simon
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Klemens Wild
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany.
| |
Collapse
|
8
|
Jiang C, Wynne M, Huber D. How Quality Control Systems AID Sec-Dependent Protein Translocation. Front Mol Biosci 2021; 8:669376. [PMID: 33928127 PMCID: PMC8076867 DOI: 10.3389/fmolb.2021.669376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 03/17/2021] [Indexed: 02/01/2023] Open
Abstract
The evolutionarily conserved Sec machinery is responsible for transporting proteins across the cytoplasmic membrane. Protein substrates of the Sec machinery must be in an unfolded conformation in order to be translocated across (or inserted into) the cytoplasmic membrane. In bacteria, the requirement for unfolded proteins is strict: substrate proteins that fold (or misfold) prematurely in the cytoplasm prior to translocation become irreversibly trapped in the cytoplasm. Partially folded Sec substrate proteins and stalled ribosomes containing nascent Sec substrates can also inhibit translocation by blocking (i.e., “jamming”) the membrane-embedded Sec machinery. To avoid these issues, bacteria have evolved a complex network of quality control systems to ensure that Sec substrate proteins do not fold in the cytoplasm. This quality control network can be broken into three branches, for which we have defined the acronym “AID”: (i) avoidance of cytoplasmic intermediates through cotranslationally channeling newly synthesized Sec substrates to the Sec machinery; (ii) inhibition of folding Sec substrate proteins that transiently reside in the cytoplasm by molecular chaperones and the requirement for posttranslational modifications; (iii) destruction of products that could potentially inhibit translocation. In addition, several stress response pathways help to restore protein-folding homeostasis when environmental conditions that inhibit translocation overcome the AID quality control systems.
Collapse
Affiliation(s)
- Chen Jiang
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Max Wynne
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Damon Huber
- School of Biosciences and the Institute for Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
9
|
Crowe-McAuliffe C, Takada H, Murina V, Polte C, Kasvandik S, Tenson T, Ignatova Z, Atkinson GC, Wilson DN, Hauryliuk V. Structural Basis for Bacterial Ribosome-Associated Quality Control by RqcH and RqcP. Mol Cell 2020; 81:115-126.e7. [PMID: 33259810 DOI: 10.1016/j.molcel.2020.11.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/07/2020] [Accepted: 10/29/2020] [Indexed: 12/25/2022]
Abstract
In all branches of life, stalled translation intermediates are recognized and processed by ribosome-associated quality control (RQC) pathways. RQC begins with the splitting of stalled ribosomes, leaving an unfinished polypeptide still attached to the large subunit. Ancient and conserved NEMF family RQC proteins target these incomplete proteins for degradation by the addition of C-terminal "tails." How such tailing can occur without the regular suite of translational components is, however, unclear. Using single-particle cryo-electron microscopy (EM) of native complexes, we show that C-terminal tailing in Bacillus subtilis is mediated by NEMF protein RqcH in concert with RqcP, an Hsp15 family protein. Our structures reveal how these factors mediate tRNA movement across the ribosomal 50S subunit to synthesize polypeptides in the absence of mRNA or the small subunit.
Collapse
Affiliation(s)
- Caillan Crowe-McAuliffe
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany
| | - Hiraku Takada
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden; Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 90187 Umeå, Sweden
| | - Victoriia Murina
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden; Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 90187 Umeå, Sweden
| | - Christine Polte
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany
| | - Sergo Kasvandik
- University of Tartu, Institute of Technology, 50411 Tartu, Estonia
| | - Tanel Tenson
- University of Tartu, Institute of Technology, 50411 Tartu, Estonia
| | - Zoya Ignatova
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany
| | - Gemma C Atkinson
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden
| | - Daniel N Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Pl. 6, 20146 Hamburg, Germany.
| | - Vasili Hauryliuk
- Department of Molecular Biology, Umeå University, 90187 Umeå, Sweden; Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 90187 Umeå, Sweden; University of Tartu, Institute of Technology, 50411 Tartu, Estonia.
| |
Collapse
|
10
|
Mechanism of ribosome shutdown by RsfS in Staphylococcus aureus revealed by integrative structural biology approach. Nat Commun 2020; 11:1656. [PMID: 32245971 PMCID: PMC7125091 DOI: 10.1038/s41467-020-15517-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 03/05/2020] [Indexed: 11/08/2022] Open
Abstract
For the sake of energy preservation, bacteria, upon transition to stationary phase, tone down their protein synthesis. This process is favored by the reversible binding of small stress-induced proteins to the ribosome to prevent unnecessary translation. One example is the conserved bacterial ribosome silencing factor (RsfS) that binds to uL14 protein onto the large ribosomal subunit and prevents its association with the small subunit. Here we describe the binding mode of Staphylococcus aureus RsfS to the large ribosomal subunit and present a 3.2 Å resolution cryo-EM reconstruction of the 50S-RsfS complex together with the crystal structure of uL14-RsfS complex solved at 2.3 Å resolution. The understanding of the detailed landscape of RsfS-uL14 interactions within the ribosome shed light on the mechanism of ribosome shutdown in the human pathogen S. aureus and might deliver a novel target for pharmacological drug development and treatment of bacterial infections.
Collapse
|
11
|
Co-Translational Protein Folding and Sorting in Chloroplasts. PLANTS 2020; 9:plants9020214. [PMID: 32045984 PMCID: PMC7076657 DOI: 10.3390/plants9020214] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 01/22/2023]
Abstract
Cells depend on the continuous renewal of their proteome composition during the cell cycle and in order to replace aberrant proteins or to react to changing environmental conditions. In higher eukaryotes, protein synthesis is achieved by up to five million ribosomes per cell. With the fast kinetics of translation, the large number of newly made proteins generates a substantial burden for protein homeostasis and requires a highly orchestrated cascade of factors promoting folding, sorting and final maturation. Several of the involved factors directly bind to translating ribosomes for the early processing of emerging nascent polypeptides and the translocation of ribosome nascent chain complexes to target membranes. In plant cells, protein synthesis also occurs in chloroplasts serving the expression of a relatively small set of 60–100 protein-coding genes. However, most of these proteins, together with nucleus-derived subunits, form central complexes majorly involved in the essential processes of photosynthetic light reaction, carbon fixation, metabolism and gene expression. Biogenesis of these heterogenic complexes adds an additional level of complexity for protein biogenesis. In this review, we summarize the current knowledge about co-translationally binding factors in chloroplasts and discuss their role in protein folding and ribosome translocation to thylakoid membranes.
Collapse
|
12
|
Abstract
More than a third of all bacterial polypeptides, comprising the 'exportome', are transported to extracytoplasmic locations. Most of the exportome is targeted and inserts into ('membranome') or crosses ('secretome') the plasma membrane. The membranome and secretome use distinct targeting signals and factors, and driving forces, but both use the ubiquitous and essential Sec translocase and its SecYEG protein-conducting channel. Membranome export is co-translational and uses highly hydrophobic N-terminal signal anchor sequences recognized by the signal recognition particle on the ribosome, that also targets C-tail anchor sequences. Translating ribosomes drive movement of these polypeptides through the lateral gate of SecY into the inner membrane. On the other hand, secretome export is post-translational and carries two types of targeting signals: cleavable N-terminal signal peptides and multiple short hydrophobic targeting signals in their mature domains. Secretome proteins remain translocation competent due to occupying loosely folded to completely non-folded states during targeting. This is accomplished mainly by the intrinsic properties of mature domains and assisted by signal peptides and/or chaperones. Secretome proteins bind to the dimeric SecA subunit of the translocase. SecA converts from a dimeric preprotein receptor to a monomeric ATPase motor and drives vectorial crossing of chains through SecY aided by the proton motive force. Signal peptides are removed by signal peptidases and translocated chains fold or follow subsequent trafficking.
Collapse
|
13
|
A Novel Noncoding RNA dsr11 Involved in Heat Stress Tolerance in Deinococcus radiodurans. Biomolecules 2019; 10:biom10010022. [PMID: 31877996 PMCID: PMC7022480 DOI: 10.3390/biom10010022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/11/2019] [Accepted: 12/18/2019] [Indexed: 12/30/2022] Open
Abstract
Deinococcus radiodurans is an extremely resistant bacteria that has evolved masterful strategies to enable survival under various environmental stress conditions. Heat stress is a major environmental stress factor that can cause denaturation of proteins, membrane disruption, and oxidative stress. Previous studies have examined the mechanisms of the heat stress response by analyzing changes in protein levels; however, little is known about the role of small noncoding RNAs (ncRNAs), which are known to play important regulatory functions in bacteria during various environmental stress response. The ncRNA dsr11 of D. radiodurans was previously identified by RNA-seq and Northern blot. In this study, we showed that the transcription level of dsr11 was up-regulated 4.2-fold under heat stress by qRT-PCR analysis. Heat tolerance assay showed that deleting dsr11 significantly inhibited the viability under high temperature conditions. To assess the influence of dsr11 on the D. radiodurans transcriptome, 157 genes were found differentially expressed in the knock-out mutant by RNA-seq experiment. Combining RNA-seq and in silico analysis, we found that trmE (tRNA modification GTPase) and dr_0651 (arginase) were likely to be the direct targets of dsr11. Further microscale thermophoresis results demonstrated that dsr11 can directly bind to the mRNA of trmE and dr_0651. Our results indicated that dsr11 can enhance the tolerance to heat stress of D. radiodurans by binding to trmE and dr_0651 mRNA. Overall, these results extend our understanding of ncRNA regulation and provide new insights into the heat stress response in D. radiodurans.
Collapse
|
14
|
RNA sequencing reveals small RNAs in Bacillus pumilus under different growth phases of the protease fermentation process. Appl Microbiol Biotechnol 2019; 104:833-852. [PMID: 31848654 DOI: 10.1007/s00253-019-10276-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/06/2019] [Accepted: 11/23/2019] [Indexed: 10/25/2022]
Abstract
Bacillus pumilus, an endospore-forming soil bacterium, produces a wide array of extracellular proteins, such as proteases, which are already applied in the chemical, detergent and leather industries. Small noncoding regulatory RNAs (sRNAs) in bacteria are important RNA regulators that act in response to various environmental signals. Here, an RNA-seq-based transcriptome analysis was applied to B. pumilus SCU11, a strain that produces extracellular alkaline protease, across various growth phases of the protease fermentation process. Through bioinformatics screening of the sequencing data and visual inspection, 84 putative regulatory sRNAs were identified in B. pumilus, including 21 antisense sRNAs and 63 sRNAs in intergenic regions. We experimentally validated the expression of 48 intergenic sRNAs by quantitative RT-PCR (qRT-PCR). Meanwhile, the expression of 6 novel sRNAs was confirmed by northern blotting, and the expression profiles of 5 sRNAs showed close correlation with the growth phase. We revealed that the sRNA Bpsr137 was involved in flagellum and biofilm formation in B. pumilus. The identification of a global set of sRNAs increases the inventory of regulatory sRNAs in Bacillus and implies the important regulatory roles of sRNA in B. pumilus. These findings will contribute another dimension to the optimization of crucial metabolic activities of B. pumilus during a productive fermentation process.
Collapse
|
15
|
sRNA OsiA Stabilizes Catalase mRNA during Oxidative Stress Response of Deincoccus radiodurans R1. Microorganisms 2019; 7:microorganisms7100422. [PMID: 31597319 PMCID: PMC6843392 DOI: 10.3390/microorganisms7100422] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 01/04/2023] Open
Abstract
Deinococcus radiodurans adapts to challenging environments by modulating gene expression in response to oxidative stress. Recently, bacterial small noncoding RNAs (sRNAs) have been presumed to participate in the transcriptional or translational regulation of stress-responsive genes. We found 24 sRNAs that may be involved in the oxidative stress response of D. radiodurans by deep RNA sequencing. Moreover, a typical stress-inducible sRNA, IGR_3053, named OsiA, was predicted to bind to the mRNA of katA, katE, and sodC by the bioinformatics method. An osiA knockout of D. radiodurans displayed increased sensitivity to H2O2 and the decreased catalase activity and total antioxidant activity, suggesting that OsiA probably serves as a regulator in the adaptation to oxidative environments. Further microscale thermophoresis results demonstrated that OsiA can directly bind to the mRNA of katA, sodC, and katE. The stability test result of katA mRNA showed that its half-life was 2 min in the osiA mutant compared with 5 min in the wildtype(wt) strain. Our results indicated that OsiA can enhance the stability of katA mRNA and the activity of KatA and consequently the oxidation resistance of D.radiodurans. We are the first one to explore the super-strong oxidative stress resistance of D.radiodurans at the level of post-transcriptional regulation, and found a new pathway that provides a new explanation for the long-term adaptability of D.radiodurans in extreme environments.
Collapse
|
16
|
Hwang Fu YH, Chandrasekar S, Lee JH, Shan SO. A molecular recognition feature mediates ribosome-induced SRP-receptor assembly during protein targeting. J Cell Biol 2019; 218:3307-3319. [PMID: 31537711 PMCID: PMC6781444 DOI: 10.1083/jcb.201901001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 06/28/2019] [Accepted: 08/26/2019] [Indexed: 12/21/2022] Open
Abstract
Molecular recognition features (MoRFs) provide interaction motifs in intrinsically disordered protein regions to mediate diverse cellular functions. Here we report that a MoRF element, located in the disordered linker domain of the mammalian signal recognition particle (SRP) receptor and conserved among eukaryotes, plays an essential role in sensing the ribosome during cotranslational protein targeting to the endoplasmic reticulum. Loss of the MoRF in the SRP receptor (SR) largely abolishes the ability of the ribosome to activate SRP-SR assembly and impairs cotranslational protein targeting. These results demonstrate a novel role for MoRF elements and provide a mechanism for the ribosome-induced activation of the mammalian SRP pathway. Kinetic analyses and comparison with the bacterial SRP further suggest that the SR MoRF functionally replaces the essential GNRA tetraloop in the bacterial SRP RNA, providing an example for the replacement of RNA function by proteins during the evolution of ancient ribonucleoprotein particles.
Collapse
Affiliation(s)
- Yu-Hsien Hwang Fu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Sowmya Chandrasekar
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Jae Ho Lee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA
| |
Collapse
|
17
|
Steinberg R, Knüpffer L, Origi A, Asti R, Koch HG. Co-translational protein targeting in bacteria. FEMS Microbiol Lett 2019; 365:4966980. [PMID: 29790984 DOI: 10.1093/femsle/fny095] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/09/2018] [Indexed: 01/16/2023] Open
Abstract
About 30% of all bacterial proteins execute their function outside of the cytosol and have to be transported into or across the cytoplasmic membrane. Bacteria use multiple protein transport systems in parallel, but the majority of proteins engage two distinct targeting systems. One is the co-translational targeting by two universally conserved GTPases, the signal recognition particle (SRP) and its receptor FtsY, which deliver inner membrane proteins to either the SecYEG translocon or the YidC insertase for membrane insertion. The other targeting system depends on the ATPase SecA, which targets secretory proteins, i.e. periplasmic and outer membrane proteins, to SecYEG for their subsequent ATP-dependent translocation. While SRP selects its substrates already very early during their synthesis, the recognition of secretory proteins by SecA is believed to occur primarily after translation termination, i.e. post-translationally. In this review we highlight recent progress on how SRP recognizes its substrates at the ribosome and how the fidelity of the targeting reaction to SecYEG is maintained. We furthermore discuss similarities and differences in the SRP-dependent targeting to either SecYEG or YidC and summarize recent results that suggest that some membrane proteins are co-translationally targeted by SecA.
Collapse
Affiliation(s)
- Ruth Steinberg
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Lara Knüpffer
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany.,Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestr. 1, Freiburg D-79104, Germany
| | - Rossella Asti
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| |
Collapse
|
18
|
Wild K, Becker MM, Kempf G, Sinning I. Structure, dynamics and interactions of large SRP variants. Biol Chem 2019; 401:63-80. [DOI: 10.1515/hsz-2019-0282] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/09/2019] [Indexed: 12/11/2022]
Abstract
Abstract
Co-translational protein targeting to membranes relies on the signal recognition particle (SRP) system consisting of a cytosolic ribonucleoprotein complex and its membrane-associated receptor. SRP recognizes N-terminal cleavable signals or signal anchor sequences, retards translation, and delivers ribosome-nascent chain complexes (RNCs) to vacant translocation channels in the target membrane. While our mechanistic understanding is well advanced for the small bacterial systems it lags behind for the large bacterial, archaeal and eukaryotic SRP variants including an Alu and an S domain. Here we describe recent advances on structural and functional insights in domain architecture, particle dynamics and interplay with RNCs and translocon and GTP-dependent regulation of co-translational protein targeting stimulated by SRP RNA.
Collapse
Affiliation(s)
- Klemens Wild
- Heidelberg University Biochemistry Center (BZH) , INF 328 , D-69120 Heidelberg , Germany
| | - Matthias M.M. Becker
- Heidelberg University Biochemistry Center (BZH) , INF 328 , D-69120 Heidelberg , Germany
| | - Georg Kempf
- Heidelberg University Biochemistry Center (BZH) , INF 328 , D-69120 Heidelberg , Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH) , INF 328 , D-69120 Heidelberg , Germany
| |
Collapse
|
19
|
Kobayashi K, Jomaa A, Lee JH, Chandrasekar S, Boehringer D, Shan SO, Ban N. Structure of a prehandover mammalian ribosomal SRP·SRP receptor targeting complex. Science 2018; 360:323-327. [PMID: 29567807 PMCID: PMC6309883 DOI: 10.1126/science.aar7924] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/12/2018] [Indexed: 01/13/2023]
Abstract
Signal recognition particle (SRP) targets proteins to the endoplasmic reticulum (ER). SRP recognizes the ribosome synthesizing a signal sequence and delivers it to the SRP receptor (SR) on the ER membrane followed by the transfer of the signal sequence to the translocon. Here, we present the cryo-electron microscopy structure of the mammalian translating ribosome in complex with SRP and SR in a conformation preceding signal sequence handover. The structure visualizes all eukaryotic-specific SRP and SR proteins and reveals their roles in stabilizing this conformation by forming a large protein assembly at the distal site of SRP RNA. We provide biochemical evidence that the guanosine triphosphate hydrolysis of SRP·SR is delayed at this stage, possibly to provide a time window for signal sequence handover to the translocon.
Collapse
Affiliation(s)
- Kan Kobayashi
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, Zurich CH-8093, Switzerland
| | - Ahmad Jomaa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, Zurich CH-8093, Switzerland
| | - Jae Ho Lee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sowmya Chandrasekar
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Daniel Boehringer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, Zurich CH-8093, Switzerland
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Otto-Stern-Weg 5, Zurich CH-8093, Switzerland.
| |
Collapse
|
20
|
Kedrov A, Wickles S, Crevenna AH, van der Sluis EO, Buschauer R, Berninghausen O, Lamb DC, Beckmann R. Structural Dynamics of the YidC:Ribosome Complex during Membrane Protein Biogenesis. Cell Rep 2017; 17:2943-2954. [PMID: 27974208 PMCID: PMC5186731 DOI: 10.1016/j.celrep.2016.11.059] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 10/26/2016] [Accepted: 11/20/2016] [Indexed: 01/30/2023] Open
Abstract
Members of the YidC/Oxa1/Alb3 family universally facilitate membrane protein biogenesis, via mechanisms that have thus far remained unclear. Here, we investigated two crucial functional aspects: the interaction of YidC with ribosome:nascent chain complexes (RNCs) and the structural dynamics of RNC-bound YidC in nanodiscs. We observed that a fully exposed nascent transmembrane domain (TMD) is required for high-affinity YidC:RNC interactions, while weaker binding may already occur at earlier stages of translation. YidC efficiently catalyzed the membrane insertion of nascent TMDs in both fluid and gel phase membranes. Cryo-electron microscopy and fluorescence analysis revealed a conformational change in YidC upon nascent chain insertion: the essential TMDs 2 and 3 of YidC were tilted, while the amphipathic helix EH1 relocated into the hydrophobic core of the membrane. We suggest that EH1 serves as a mechanical lever, facilitating a coordinated movement of YidC TMDs to trigger the release of nascent chains into the membrane.
Collapse
Affiliation(s)
- Alexej Kedrov
- Gene Center Munich, Department of Biochemistry, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, Munich 81377, Germany.
| | - Stephan Wickles
- Gene Center Munich, Department of Biochemistry, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, Munich 81377, Germany
| | - Alvaro H Crevenna
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), the NanoSystems Initiative Munich (NIM), Ludwig-Maximilians-University Munich, Butenandtstrasse 11, Munich 81377, Germany
| | - Eli O van der Sluis
- Gene Center Munich, Department of Biochemistry, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, Munich 81377, Germany
| | - Robert Buschauer
- Gene Center Munich, Department of Biochemistry, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, Munich 81377, Germany
| | - Otto Berninghausen
- Gene Center Munich, Department of Biochemistry, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, Munich 81377, Germany
| | - Don C Lamb
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), the NanoSystems Initiative Munich (NIM), Ludwig-Maximilians-University Munich, Butenandtstrasse 11, Munich 81377, Germany; Center for Integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-University, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Roland Beckmann
- Gene Center Munich, Department of Biochemistry, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, Munich 81377, Germany; Center for Integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-University, Butenandtstrasse 5-13, Munich 81377, Germany.
| |
Collapse
|
21
|
Jomaa A, Fu YHH, Boehringer D, Leibundgut M, Shan SO, Ban N. Structure of the quaternary complex between SRP, SR, and translocon bound to the translating ribosome. Nat Commun 2017; 8:15470. [PMID: 28524878 PMCID: PMC5454536 DOI: 10.1038/ncomms15470] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/29/2017] [Indexed: 01/05/2023] Open
Abstract
During co-translational protein targeting, the signal recognition particle (SRP) binds to the translating ribosome displaying the signal sequence to deliver it to the SRP receptor (SR) on the membrane, where the signal peptide is transferred to the translocon. Using electron cryo-microscopy, we have determined the structure of a quaternary complex of the translating Escherichia coli ribosome, the SRP–SR in the ‘activated' state and the translocon. Our structure, supported by biochemical experiments, reveals that the SRP RNA adopts a kinked and untwisted conformation to allow repositioning of the ‘activated' SRP–SR complex on the ribosome. In addition, we observe the translocon positioned through interactions with the SR in the vicinity of the ribosome exit tunnel where the signal sequence is extending beyond its hydrophobic binding groove of the SRP M domain towards the translocon. Our study provides new insights into the mechanism of signal sequence transfer from the SRP to the translocon. Membrane proteins are inserted co-transnationally through the association between ribosome, the signal recognition particle and its receptor, and the membrane-bound translocon. Here the authors present a cryo-EM reconstruction of this quaternary complex in the activated state and propose a model for signal sequence transfer to the translocon.
Collapse
Affiliation(s)
- Ahmad Jomaa
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH, Zurich CH-8093, Switzerland
| | - Yu-Hsien Hwang Fu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Daniel Boehringer
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH, Zurich CH-8093, Switzerland
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH, Zurich CH-8093, Switzerland
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH, Zurich CH-8093, Switzerland
| |
Collapse
|
22
|
Friesen WJ, Trotta CR, Tomizawa Y, Zhuo J, Johnson B, Sierra J, Roy B, Weetall M, Hedrick J, Sheedy J, Takasugi J, Moon YC, Babu S, Baiazitov R, Leszyk JD, Davis TW, Colacino JM, Peltz SW, Welch EM. The nucleoside analog clitocine is a potent and efficacious readthrough agent. RNA (NEW YORK, N.Y.) 2017; 23:567-577. [PMID: 28096517 PMCID: PMC5340919 DOI: 10.1261/rna.060236.116] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 01/05/2017] [Indexed: 06/01/2023]
Abstract
Nonsense mutations resulting in a premature stop codon in an open reading frame occur in critical tumor suppressor genes in a large number of the most common forms of cancers and are known to cause or contribute to the progression of disease. Low molecular weight compounds that induce readthrough of nonsense mutations offer a new means of treating patients with genetic disorders or cancers resulting from nonsense mutations. We have identified the nucleoside analog clitocine as a potent and efficacious suppressor of nonsense mutations. We determined that incorporation of clitocine into RNA during transcription is a prerequisite for its readthrough activity; the presence of clitocine in the third position of a premature stop codon directly induces readthrough. We demonstrate that clitocine can induce the production of p53 protein in cells harboring p53 nonsense-mutated alleles. In these cells, clitocine restored production of full-length and functional p53 as evidenced by induced transcriptional activation of downstream p53 target genes, progression of cells into apoptosis, and impeded growth of nonsense-containing human ovarian cancer tumors in xenograft tumor models. Thus, clitocine induces readthrough of nonsense mutations by a previously undescribed mechanism and represents a novel therapeutic modality to treat cancers and genetic diseases caused by nonsense mutations.
Collapse
Affiliation(s)
| | | | - Yuki Tomizawa
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - Jin Zhuo
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - Briana Johnson
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - Jairo Sierra
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - Bijoyita Roy
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - Marla Weetall
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - Jean Hedrick
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | | | - James Takasugi
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | | | - Suresh Babu
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - Ramil Baiazitov
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - John D Leszyk
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655-0122, USA
| | - Thomas W Davis
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | | | - Stuart W Peltz
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| | - Ellen M Welch
- PTC Therapeutics, Inc., South Plainfield, New Jersey 07080, USA
| |
Collapse
|
23
|
Gupta S, Roy M, Ghosh A. The Archaeal Signal Recognition Particle: Present Understanding and Future Perspective. Curr Microbiol 2016; 74:284-297. [DOI: 10.1007/s00284-016-1167-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
|
24
|
Becker MMM, Lapouge K, Segnitz B, Wild K, Sinning I. Structures of human SRP72 complexes provide insights into SRP RNA remodeling and ribosome interaction. Nucleic Acids Res 2016; 45:470-481. [PMID: 27899666 PMCID: PMC5224484 DOI: 10.1093/nar/gkw1124] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/21/2016] [Accepted: 10/28/2016] [Indexed: 12/30/2022] Open
Abstract
Co-translational protein targeting and membrane protein insertion is a fundamental process and depends on the signal recognition particle (SRP). In mammals, SRP is composed of the SRP RNA crucial for SRP assembly and function and six proteins. The two largest proteins SRP68 and SRP72 form a heterodimer and bind to a regulatory site of the SRP RNA. Despite their essential roles in the SRP pathway, structural information has been available only for the SRP68 RNA-binding domain (RBD). Here we present the crystal structures of the SRP68 protein-binding domain (PBD) in complex with SRP72-PBD and of the SRP72-RBD bound to the SRP S domain (SRP RNA, SRP19 and SRP68) detailing all interactions of SRP72 within SRP. The SRP72-PBD is a tetratricopeptide repeat, which binds an extended linear motif of SRP68 with high affinity. The SRP72-RBD is a flexible peptide crawling along the 5e- and 5f-loops of SRP RNA. A conserved tryptophan inserts into the 5e-loop forming a novel type of RNA kink-turn stabilized by a potassium ion, which we define as K+-turn. In addition, SRP72-RBD remodels the 5f-loop involved in ribosome binding and visualizes SRP RNA plasticity. Docking of the S domain structure into cryo-electron microscopy density maps reveals multiple contact sites between SRP68/72 and the ribosome, and explains the role of SRP72 in the SRP pathway.
Collapse
Affiliation(s)
- Matthias M M Becker
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | - Karine Lapouge
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | - Bernd Segnitz
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | - Klemens Wild
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| |
Collapse
|
25
|
Abstract
Bacillus subtilis is one of the best-studied organisms. Due to the broad knowledge and annotation and the well-developed genetic system, this bacterium is an excellent starting point for genome minimization with the aim of constructing a minimal cell. We have analyzed the genome of B. subtilis and selected all genes that are required to allow life in complex medium at 37°C. This selection is based on the known information on essential genes and functions as well as on gene and protein expression data and gene conservation. The list presented here includes 523 and 119 genes coding for proteins and RNAs, respectively. These proteins and RNAs are required for the basic functions of life in information processing (replication and chromosome maintenance, transcription, translation, protein folding, and secretion), metabolism, cell division, and the integrity of the minimal cell. The completeness of the selected metabolic pathways, reactions, and enzymes was verified by the development of a model of metabolism of the minimal cell. A comparison of the MiniBacillus genome to the recently reported designed minimal genome of Mycoplasma mycoides JCVI-syn3.0 indicates excellent agreement in the information-processing pathways, whereas each species has a metabolism that reflects specific evolution and adaptation. The blueprint of MiniBacillus presented here serves as the starting point for a successive reduction of the B. subtilis genome.
Collapse
|
26
|
Khusainov I, Marenna A, Cerciat M, Fechter P, Hashem Y, Marzi S, Romby P, Yusupova G, Yusupov M. A glimpse on Staphylococcus aureus translation machinery and its control. Mol Biol 2016. [DOI: 10.1134/s002689331604004x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
27
|
Chartron JW, Hunt KCL, Frydman J. Cotranslational signal-independent SRP preloading during membrane targeting. Nature 2016; 536:224-8. [PMID: 27487213 PMCID: PMC5120976 DOI: 10.1038/nature19309] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 07/18/2016] [Indexed: 12/24/2022]
Abstract
Ribosome-associated factors must faithfully decode the limited information available in nascent polypeptides to direct them to their correct cellular fate1. It is unclear how the low complexity information exposed by the nascent chain suffices for accurate recognition by the many factors competing for the limited surface near the ribosomal exit site2,3. Questions remain even for the well-studied cotranslational targeting cycle to the endoplasmic reticulum (ER), involving recognition of linear hydrophobic Signal Sequences (SS) or Transmembrane Domains (TMD) by the Signal Recognition Particle (SRP)4,5. Intriguingly, SRP is in low abundance relative to the large number of ribosome nascent chain complexes (RNCs), yet it accurately selects those destined to the ER6. Despite their overlapping specificities, SRP and the cotranslational Hsp70 SSB display exquisite mutually exclusive selectivity in vivo for their cognate RNCs7,8. To understand cotranslational nascent chain recognition in vivo, we interrogated the cotranslational membrane targeting cycle using ribosome profiling (herein Ribo-seq)9 coupled with biochemical fractionation of ribosome populations. Unexpectedly, SRP preferentially binds secretory RNCs before targeting signals are translated. We show non-coding mRNA elements can promote this signal-independent SRP pre-recruitment. Our study defines the complex kinetic interplay between elongation and determinants in the polypeptide and mRNA modulating SRP-substrate selection and membrane targeting.
Collapse
|