1
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Fernandez SG, Ferguson L, Ingolia NT. Ribosome rescue factor PELOTA modulates translation start site choice for C/EBPα protein isoforms. Life Sci Alliance 2024; 7:e202302501. [PMID: 38803235 PMCID: PMC11109482 DOI: 10.26508/lsa.202302501] [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: 11/28/2023] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 05/29/2024] Open
Abstract
Translation initiation at alternative start sites can dynamically control the synthesis of two or more functionally distinct protein isoforms from a single mRNA. Alternate isoforms of the developmental transcription factor CCAAT/enhancer-binding protein α (C/EBPα) produced from different start sites exert opposing effects during myeloid cell development. This choice between alternative start sites depends on sequence features of the CEBPA transcript, including a regulatory uORF, but the molecular basis is not fully understood. Here, we identify the factors that affect C/EBPα isoform choice using a sensitive and quantitative two-color fluorescent reporter coupled with CRISPRi screening. Our screen uncovered a role of the ribosome rescue factor PELOTA (PELO) in promoting the expression of the longer C/EBPα isoform by directly removing inhibitory unrecycled ribosomes and through indirect effects mediated by the mechanistic target of rapamycin kinase. Our work uncovers further links between ribosome recycling and translation reinitiation that regulate a key transcription factor, with implications for normal hematopoiesis and leukemogenesis.
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Affiliation(s)
- Samantha G Fernandez
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Lucas Ferguson
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- https://ror.org/01an7q238 Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
| | - Nicholas T Ingolia
- https://ror.org/01an7q238 Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- https://ror.org/01an7q238 Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
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2
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van den Akker GGH, Chabronova A, Housmans BAC, van der Vloet L, Surtel DAM, Cremers A, Marchand V, Motorin Y, Caron MMJ, Peffers MJ, Welting TJM. TGF-β2 Induces Ribosome Activity, Alters Ribosome Composition and Inhibits IRES-Mediated Translation in Chondrocytes. Int J Mol Sci 2024; 25:5031. [PMID: 38732249 PMCID: PMC11084827 DOI: 10.3390/ijms25095031] [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: 03/12/2024] [Revised: 04/29/2024] [Accepted: 05/01/2024] [Indexed: 05/13/2024] Open
Abstract
Alterations in cell fate are often attributed to (epigenetic) regulation of gene expression. An emerging paradigm focuses on specialized ribosomes within a cell. However, little evidence exists for the dynamic regulation of ribosome composition and function. Here, we stimulated a chondrocytic cell line with transforming growth factor beta (TGF-β2) and mapped changes in ribosome function, composition and ribosomal RNA (rRNA) epitranscriptomics. 35S Met/Cys incorporation was used to evaluate ribosome activity. Dual luciferase reporter assays were used to assess ribosomal modus. Ribosomal RNA expression and processing were determined by RT-qPCR, while RiboMethSeq and HydraPsiSeq were used to determine rRNA modification profiles. Label-free protein quantification of total cell lysates, isolated ribosomes and secreted proteins was done by LC-MS/MS. A three-day TGF-β2 stimulation induced total protein synthesis in SW1353 chondrocytic cells and human articular chondrocytes. Specifically, TGF-β2 induced cap-mediated protein synthesis, while IRES-mediated translation was not (P53 IRES) or little affected (CrPv IGR and HCV IRES). Three rRNA post-transcriptional modifications (PTMs) were affected by TGF-β2 stimulation (18S-Gm1447 downregulated, 18S-ψ1177 and 28S-ψ4598 upregulated). Proteomic analysis of isolated ribosomes revealed increased interaction with eIF2 and tRNA ligases and decreased association of eIF4A3 and heterogeneous nuclear ribonucleoprotein (HNRNP)s. In addition, thirteen core ribosomal proteins were more present in ribosomes from TGF-β2 stimulated cells, albeit with a modest fold change. A prolonged stimulation of chondrocytic cells with TGF-β2 induced ribosome activity and changed the mode of translation. These functional changes could be coupled to alterations in accessory proteins in the ribosomal proteome.
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Affiliation(s)
- Guus G. H. van den Akker
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Alzbeta Chabronova
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
- Department of Musculoskeletal Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Bas A. C. Housmans
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Laura van der Vloet
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Don A. M. Surtel
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Andy Cremers
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Virginie Marchand
- UAR2008 IBSLor CNRS-INSERM, Université de Lorraine, BioPole, F54000 Nancy, France; (V.M.); (Y.M.)
| | - Yuri Motorin
- UAR2008 IBSLor CNRS-INSERM, Université de Lorraine, BioPole, F54000 Nancy, France; (V.M.); (Y.M.)
- UMR7365 IMoPA, CNRS, Université de Lorraine, BioPole, F54000 Nancy, France
| | - Marjolein M. J. Caron
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Mandy J. Peffers
- Department of Musculoskeletal Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Tim J. M. Welting
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University Medical Center +, 6229 HX Maastricht, The Netherlands
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3
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Tanaka M, Yokoyama T, Saito H, Nishimoto M, Tsuda K, Sotta N, Shigematsu H, Shirouzu M, Iwasaki S, Ito T, Fujiwara T. Boric acid intercepts 80S ribosome migration from AUG-stop by stabilizing eRF1. Nat Chem Biol 2024; 20:605-614. [PMID: 38267667 DOI: 10.1038/s41589-023-01513-0] [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: 02/11/2022] [Accepted: 11/24/2023] [Indexed: 01/26/2024]
Abstract
In response to environmental changes, cells flexibly and rapidly alter gene expression through translational controls. In plants, the translation of NIP5;1, a boric acid diffusion facilitator, is downregulated in response to an excess amount of boric acid in the environment through upstream open reading frames (uORFs) that consist of only AUG and stop codons. However, the molecular details of how this minimum uORF controls translation of the downstream main ORF in a boric acid-dependent manner have remained unclear. Here, by combining ribosome profiling, translation complex profile sequencing, structural analysis with cryo-electron microscopy and biochemical assays, we show that the 80S ribosome assembled at AUG-stop migrates into the subsequent RNA segment, followed by downstream translation initiation, and that boric acid impedes this process by the stable confinement of eukaryotic release factor 1 on the 80S ribosome on AUG-stop. Our results provide molecular insight into translation regulation by a minimum and environment-responsive uORF.
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Affiliation(s)
- Mayuki Tanaka
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takeshi Yokoyama
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Hironori Saito
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- RIKEN Cluster for Pioneering Research, Wako, Japan
| | - Madoka Nishimoto
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, Japan
| | - Kengo Tsuda
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, Japan
| | - Naoyuki Sotta
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Hideki Shigematsu
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, Japan
- Life Science Research Infrastructure Group, RIKEN SPring-8 Center, Sayo, Japan
| | - Mikako Shirouzu
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, Japan
| | - Shintaro Iwasaki
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
- RIKEN Cluster for Pioneering Research, Wako, Japan.
| | - Takuhiro Ito
- RIKEN Center for Biosystems Dynamics Research, Tsurumi-ku, Yokohama, Japan.
| | - Toru Fujiwara
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
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4
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Pacheco M, D’Orazio KN, Lessen LN, Veltri AJ, Neiman Z, Loll-Krippleber R, Brown GW, Green R. Genetic screens in Saccharomyces cerevisiae identify a role for 40S ribosome recycling factors Tma20 and Tma22 in nonsense-mediated decay. G3 (BETHESDA, MD.) 2024; 14:jkad295. [PMID: 38198768 PMCID: PMC10917514 DOI: 10.1093/g3journal/jkad295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 08/29/2023] [Accepted: 12/06/2023] [Indexed: 01/12/2024]
Abstract
The decay of messenger RNA with a premature termination codon by nonsense-mediated decay (NMD) is an important regulatory pathway for eukaryotes and an essential pathway in mammals. NMD is typically triggered by the ribosome terminating at a stop codon that is aberrantly distant from the poly-A tail. Here, we use a fluorescence screen to identify factors involved in NMD in Saccharomyces cerevisiae. In addition to the known NMD factors, including the entire UPF family (UPF1, UPF2, and UPF3), as well as NMD4 and EBS1, we identify factors known to function in posttermination recycling and characterize their contribution to NMD. These observations in S. cerevisiae expand on data in mammals indicating that the 60S recycling factor ABCE1 is important for NMD by showing that perturbations in factors implicated in 40S recycling also correlate with a loss of NMD.
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Affiliation(s)
- Miguel Pacheco
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Karole N D’Orazio
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Laura N Lessen
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Anthony J Veltri
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zachary Neiman
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Raphael Loll-Krippleber
- Department of Biochemistry and Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Grant W Brown
- Department of Biochemistry and Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Rachel Green
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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5
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Brito Querido J, Díaz-López I, Ramakrishnan V. The molecular basis of translation initiation and its regulation in eukaryotes. Nat Rev Mol Cell Biol 2024; 25:168-186. [PMID: 38052923 DOI: 10.1038/s41580-023-00624-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2023] [Indexed: 12/07/2023]
Abstract
The regulation of gene expression is fundamental for life. Whereas the role of transcriptional regulation of gene expression has been studied for several decades, it has been clear over the past two decades that post-transcriptional regulation of gene expression, of which translation regulation is a major part, can be equally important. Translation can be divided into four main stages: initiation, elongation, termination and ribosome recycling. Translation is controlled mainly during its initiation, a process which culminates in a ribosome positioned with an initiator tRNA over the start codon and, thus, ready to begin elongation of the protein chain. mRNA translation has emerged as a powerful tool for the development of innovative therapies, yet the detailed mechanisms underlying the complex process of initiation remain unclear. Recent studies in yeast and mammals have started to shed light on some previously unclear aspects of this process. In this Review, we discuss the current state of knowledge on eukaryotic translation initiation and its regulation in health and disease. Specifically, we focus on recent advances in understanding the processes involved in assembling the 43S pre-initiation complex and its recruitment by the cap-binding complex eukaryotic translation initiation factor 4F (eIF4F) at the 5' end of mRNA. In addition, we discuss recent insights into ribosome scanning along the 5' untranslated region of mRNA and selection of the start codon, which culminates in joining of the 60S large subunit and formation of the 80S initiation complex.
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Affiliation(s)
- Jailson Brito Querido
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Irene Díaz-López
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
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6
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Grove DJ, Russell PJ, Kearse MG. To initiate or not to initiate: A critical assessment of eIF2A, eIF2D, and MCT-1·DENR to deliver initiator tRNA to ribosomes. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1833. [PMID: 38433101 PMCID: PMC11260288 DOI: 10.1002/wrna.1833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 03/05/2024]
Abstract
Selection of the correct start codon is critical for high-fidelity protein synthesis. In eukaryotes, this is typically governed by a multitude of initiation factors (eIFs), including eIF2·GTP that directly delivers the initiator tRNA (Met-tRNAi Met ) to the P site of the ribosome. However, numerous reports, some dating back to the early 1970s, have described other initiation factors having high affinity for the initiator tRNA and the ability of delivering it to the ribosome, which has provided a foundation for further work demonstrating non-canonical initiation mechanisms using alternative initiation factors. Here we provide a critical analysis of current understanding of eIF2A, eIF2D, and the MCT-1·DENR dimer, the evidence surrounding their ability to initiate translation, their implications in human disease, and lay out important key questions for the field. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes Translation > Mechanisms Translation > Regulation.
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Affiliation(s)
- Daisy J. Grove
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Paul J. Russell
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- The Cellular, Molecular, Biochemical Sciences Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Michael G. Kearse
- The Ohio State Biochemistry Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- The Cellular, Molecular, Biochemical Sciences Program, Department of Biological Chemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
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7
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Schubert K, Karousis ED, Ban I, Lapointe CP, Leibundgut M, Bäumlin E, Kummerant E, Scaiola A, Schönhut T, Ziegelmüller J, Puglisi JD, Mühlemann O, Ban N. Universal features of Nsp1-mediated translational shutdown by coronaviruses. Mol Cell 2023; 83:3546-3557.e8. [PMID: 37802027 PMCID: PMC10575594 DOI: 10.1016/j.molcel.2023.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/16/2023] [Accepted: 09/06/2023] [Indexed: 10/08/2023]
Abstract
Nonstructural protein 1 (Nsp1) produced by coronaviruses inhibits host protein synthesis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Nsp1 C-terminal domain was shown to bind the ribosomal mRNA channel to inhibit translation, but it is unclear whether this mechanism is broadly used by coronaviruses, whether the Nsp1 N-terminal domain binds the ribosome, or how Nsp1 allows viral RNAs to be translated. Here, we investigated Nsp1 from SARS-CoV-2, Middle East respiratory syndrome coronavirus (MERS-CoV), and Bat-Hp-CoV coronaviruses using structural, biophysical, and biochemical experiments, revealing a conserved role for the C-terminal domain. Additionally, the N-terminal domain of Bat-Hp-CoV Nsp1 binds to the decoding center of the 40S subunit, where it would prevent mRNA and eIF1A accommodation. Structure-based experiments demonstrated the importance of decoding center interactions in all three coronaviruses and showed that the same regions of Nsp1 are necessary for the selective translation of viral RNAs. Our results provide a mechanistic framework to understand how Nsp1 controls preferential translation of viral RNAs.
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Affiliation(s)
- Katharina Schubert
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Evangelos D Karousis
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland; Multidisciplinary Center for Infectious Diseases, University of Bern, Bern 3012, Switzerland.
| | - Ivo Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Emilie Bäumlin
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland; Multidisciplinary Center for Infectious Diseases, University of Bern, Bern 3012, Switzerland
| | - Eric Kummerant
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Alain Scaiola
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Tanja Schönhut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland
| | - Jana Ziegelmüller
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich 8049, Switzerland.
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8
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Sherlock ME, Baquero Galvis L, Vicens Q, Kieft JS, Jagannathan S. Principles, mechanisms, and biological implications of translation termination-reinitiation. RNA (NEW YORK, N.Y.) 2023; 29:865-884. [PMID: 37024263 PMCID: PMC10275272 DOI: 10.1261/rna.079375.122] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 03/28/2023] [Indexed: 06/11/2023]
Abstract
The gene expression pathway from DNA sequence to functional protein is not as straightforward as simple depictions of the central dogma might suggest. Each step is highly regulated, with complex and only partially understood molecular mechanisms at play. Translation is one step where the "one gene-one protein" paradigm breaks down, as often a single mature eukaryotic mRNA leads to more than one protein product. One way this occurs is through translation reinitiation, in which a ribosome starts making protein from one initiation site, translates until it terminates at a stop codon, but then escapes normal recycling steps and subsequently reinitiates at a different downstream site. This process is now recognized as both important and widespread, but we are only beginning to understand the interplay of factors involved in termination, recycling, and initiation that cause reinitiation events. There appear to be several ways to subvert recycling to achieve productive reinitiation, different types of stresses or signals that trigger this process, and the mechanism may depend in part on where the event occurs in the body of an mRNA. This perspective reviews the unique characteristics and mechanisms of reinitiation events, highlights the similarities and differences between three major scenarios of reinitiation, and raises outstanding questions that are promising avenues for future research.
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Affiliation(s)
- Madeline E Sherlock
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Laura Baquero Galvis
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Sujatha Jagannathan
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
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9
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Schubert K, Karousis ED, Ban I, Lapointe CP, Leibundgut M, Bäumlin E, Kummerant E, Scaiola A, Schönhut T, Ziegelmüller J, Puglisi JD, Mühlemann O, Ban N. Universal features of Nsp1-mediated translational shutdown by coronaviruses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543022. [PMID: 37398176 PMCID: PMC10312502 DOI: 10.1101/2023.05.31.543022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Nonstructural protein 1 (Nsp1) produced by coronaviruses shuts down host protein synthesis in infected cells. The C-terminal domain of SARS-CoV-2 Nsp1 was shown to bind to the small ribosomal subunit to inhibit translation, but it is not clear whether this mechanism is broadly used by coronaviruses, whether the N-terminal domain of Nsp1 binds the ribosome, or how Nsp1 specifically permits translation of viral mRNAs. Here, we investigated Nsp1 from three representative Betacoronaviruses - SARS-CoV-2, MERS-CoV, and Bat-Hp-CoV - using structural, biophysical, and biochemical assays. We revealed a conserved mechanism of host translational shutdown across the three coronaviruses. We further demonstrated that the N-terminal domain of Bat-Hp-CoV Nsp1 binds to the decoding center of the 40S subunit, where it would prevent mRNA and eIF1A binding. Structure-based biochemical experiments identified a conserved role of these inhibitory interactions in all three coronaviruses and showed that the same regions of Nsp1 are responsible for the preferential translation of viral mRNAs. Our results provide a mechanistic framework to understand how Betacoronaviruses overcome translational inhibition to produce viral proteins.
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Affiliation(s)
- Katharina Schubert
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Evangelos D Karousis
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Ivo Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Christopher P Lapointe
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Emilie Bäumlin
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Eric Kummerant
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Alain Scaiola
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Tanja Schönhut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Jana Ziegelmüller
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Oliver Mühlemann
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
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10
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Ikeuchi K, Ivic N, Buschauer R, Cheng J, Fröhlich T, Matsuo Y, Berninghausen O, Inada T, Becker T, Beckmann R. Molecular basis for recognition and deubiquitination of 40S ribosomes by Otu2. Nat Commun 2023; 14:2730. [PMID: 37169754 PMCID: PMC10175282 DOI: 10.1038/s41467-023-38161-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 04/19/2023] [Indexed: 05/13/2023] Open
Abstract
In actively translating 80S ribosomes the ribosomal protein eS7 of the 40S subunit is monoubiquitinated by the E3 ligase Not4 and deubiquitinated by Otu2 upon ribosomal subunit recycling. Despite its importance for translation efficiency the exact role and structural basis for this translational reset is poorly understood. Here, structural analysis by cryo-electron microscopy of native and reconstituted Otu2-bound ribosomal complexes reveals that Otu2 engages 40S subunits mainly between ribosome recycling and initiation stages. Otu2 binds to several sites on the intersubunit surface of the 40S that are not occupied by any other 40S-binding factors. This binding mode explains the discrimination against 80S ribosomes via the largely helical N-terminal domain of Otu2 as well as the specificity for mono-ubiquitinated eS7 on 40S. Collectively, this study reveals mechanistic insights into the Otu2-driven deubiquitination steps for translational reset during ribosome recycling/(re)initiation.
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Affiliation(s)
- Ken Ikeuchi
- Department of Biochemistry, Gene Center, Feodor-Lynen-Str. 25, University of Munich, 81377, Munich, Germany
| | - Nives Ivic
- Division of Physical Chemistry, Rudjer Boskovic Institute, Bijenicka cesta 54, 10000, Zagreb, Croatia
| | - Robert Buschauer
- Department of Biochemistry, Gene Center, Feodor-Lynen-Str. 25, University of Munich, 81377, Munich, Germany
| | - Jingdong Cheng
- Department of Biochemistry, Gene Center, Feodor-Lynen-Str. 25, University of Munich, 81377, Munich, Germany
- Institutes of biomedical science, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Fudan university, Dong'an Road 131, 200032, Shanghai, China
| | - Thomas Fröhlich
- LAFUGA, Laboratory for Functional Genome Analysis, Gene Center, Feodor-Lynen-Str. 25, University of Munich, 81377, Munich, Germany
| | - Yoshitaka Matsuo
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-ku, 108-8639, Japan
| | - Otto Berninghausen
- Department of Biochemistry, Gene Center, Feodor-Lynen-Str. 25, University of Munich, 81377, Munich, Germany
| | - Toshifumi Inada
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Minato-ku, 108-8639, Japan
| | - Thomas Becker
- Department of Biochemistry, Gene Center, Feodor-Lynen-Str. 25, University of Munich, 81377, Munich, Germany.
| | - Roland Beckmann
- Department of Biochemistry, Gene Center, Feodor-Lynen-Str. 25, University of Munich, 81377, Munich, Germany.
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11
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Fernandez SG, Ferguson L, Ingolia NT. Ribosome rescue factor PELOTA modulates translation start site choice and protein isoform levels of transcription factor C/EBP α. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.16.524343. [PMID: 36711859 PMCID: PMC9882168 DOI: 10.1101/2023.01.16.524343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Translation initiation at alternative start sites can dynamically control the synthesis of two or more functionally distinct protein isoforms from a single mRNA. Alternate isoforms of the hematopoietic transcription factor CCAAT-enhancer binding protein α (C/EBPα) produced from different start sites exert opposing effects during myeloid cell development. This alternative initiation depends on sequence features of the CEBPA transcript, including a regulatory upstream open reading frame (uORF), but the molecular basis is not fully understood. Here we identify trans-acting factors that affect C/EBPα isoform choice using a sensitive and quantitative two-color fluorescence reporter coupled with CRISPRi screening. Our screen uncovered a role for the ribosome rescue factor PELOTA (PELO) in promoting expression of the longer C/EBPα isoform, by directly removing inhibitory unrecycled ribosomes and through indirect effects mediated by the mechanistic target of rapamycin (mTOR) kinase. Our work provides further mechanistic insights into coupling between ribosome recycling and translation reinitiation in regulation of a key transcription factor, with implications for normal hematopoiesis and leukemiagenesis.
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Affiliation(s)
| | - Lucas Ferguson
- Department of Molecular and Cell Biology, University of California, Berkeley
| | - Nicholas T. Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley
- Center for Computational Biology and California Institute for Quantitative Biosciences, University of California, Berkeley
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12
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Makeeva DS, Riggs CL, Burakov AV, Ivanov PA, Kushchenko AS, Bykov DA, Popenko VI, Prassolov VS, Ivanov PV, Dmitriev SE. Relocalization of Translation Termination and Ribosome Recycling Factors to Stress Granules Coincides with Elevated Stop-Codon Readthrough and Reinitiation Rates upon Oxidative Stress. Cells 2023; 12:259. [PMID: 36672194 PMCID: PMC9856671 DOI: 10.3390/cells12020259] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/27/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
Upon oxidative stress, mammalian cells rapidly reprogram their translation. This is accompanied by the formation of stress granules (SGs), cytoplasmic ribonucleoprotein condensates containing untranslated mRNA molecules, RNA-binding proteins, 40S ribosomal subunits, and a set of translation initiation factors. Here we show that arsenite-induced stress causes a dramatic increase in the stop-codon readthrough rate and significantly elevates translation reinitiation levels on uORF-containing and bicistronic mRNAs. We also report the recruitment of translation termination factors eRF1 and eRF3, as well as ribosome recycling and translation reinitiation factors ABCE1, eIF2D, MCT-1, and DENR to SGs upon arsenite treatment. Localization of these factors to SGs may contribute to a rapid resumption of mRNA translation after stress relief and SG disassembly. It may also suggest the presence of post-termination, recycling, or reinitiation complexes in SGs. This new layer of translational control under stress conditions, relying on the altered spatial distribution of translation factors between cellular compartments, is discussed.
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Affiliation(s)
- Desislava S. Makeeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Claire L. Riggs
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Anton V. Burakov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Pavel A. Ivanov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Artem S. Kushchenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Dmitri A. Bykov
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Vladimir I. Popenko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Vladimir S. Prassolov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Pavel V. Ivanov
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sergey E. Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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13
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Hossain A, Akter S, Rashid AA, Khair S, Alam ASMRU. Unique mutations in SARS-CoV-2 omicron subvariants' non-spike proteins: Potential impact on viral pathogenesis and host immune evasion. Microb Pathog 2022; 170:105699. [PMID: 35944840 PMCID: PMC9356572 DOI: 10.1016/j.micpath.2022.105699] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 12/20/2022]
Affiliation(s)
- Anamica Hossain
- Department of Microbiology, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Shammi Akter
- Department of Microbiology, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Alfi Anjum Rashid
- Department of Microbiology, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Sabik Khair
- Department of Microbiology, University of Dhaka, Dhaka, 1000, Bangladesh
| | - A S M Rubayet Ul Alam
- Department of Microbiology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh.
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14
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Brown ZP, Abaeva IS, De S, Hellen CUT, Pestova TV, Frank J. Molecular architecture of 40S translation initiation complexes on the hepatitis C virus IRES. EMBO J 2022; 41:e110581. [PMID: 35822879 DOI: 10.15252/embj.2022110581] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/01/2022] [Accepted: 06/14/2022] [Indexed: 02/05/2023] Open
Abstract
Hepatitis C virus mRNA contains an internal ribosome entry site (IRES) that mediates end-independent translation initiation, requiring a subset of eukaryotic initiation factors (eIFs). Biochemical studies revealed that direct binding of the IRES to the 40S ribosomal subunit places the initiation codon into the P site, where it base pairs with eIF2-bound Met-tRNAiMet forming a 48S initiation complex. Subsequently, eIF5 and eIF5B mediate subunit joining, yielding an elongation-competent 80S ribosome. Initiation can also proceed without eIF2, in which case Met-tRNAiMet is recruited directly by eIF5B. However, the structures of initiation complexes assembled on the HCV IRES, the transitions between different states, and the accompanying conformational changes have remained unknown. To fill these gaps, we now obtained cryo-EM structures of IRES initiation complexes, at resolutions up to 3.5 Å, that cover all major stages from the initial ribosomal association, through eIF2-containing 48S initiation complexes, to eIF5B-containing complexes immediately prior to subunit joining. These structures provide insights into the dynamic network of 40S/IRES contacts, highlight the role of IRES domain II, and reveal conformational changes that occur during the transition from eIF2- to eIF5B-containing 48S complexes and prepare them for subunit joining.
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Affiliation(s)
- Zuben P Brown
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Irina S Abaeva
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Swastik De
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.,Department of Biological Sciences, Columbia University, New York, NY, USA
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15
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Young DJ, Guydosh NR. Rebirth of the translational machinery: The importance of recycling ribosomes. Bioessays 2022; 44:e2100269. [PMID: 35147231 PMCID: PMC9270684 DOI: 10.1002/bies.202100269] [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: 11/10/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/10/2022]
Abstract
Translation of the genetic code occurs in a cycle where ribosomes engage mRNAs, synthesize protein, and then disengage in order to repeat the process again. The final part of this process-ribosome recycling, where ribosomes dissociate from mRNAs-involves a complex molecular choreography of specific protein factors to remove the large and small subunits of the ribosome in a coordinated fashion. Errors in this process can lead to the accumulation of ribosomes at stop codons or translation of downstream open reading frames (ORFs). Ribosome recycling is also critical when a ribosome stalls during the elongation phase of translation and must be rescued to allow continued translation of the mRNA. Here we discuss the molecular interactions that drive ribosome recycling, and their regulation in the cell. We also examine the consequences of inefficient recycling with regards to disease, and its functional roles in synthesis of novel peptides, regulation of gene expression, and control of mRNA-associated proteins. Alterations in ribosome recycling efficiency have the potential to impact many cellular functions but additional work is needed to understand how this regulatory power is utilized.
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Affiliation(s)
- David J Young
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
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16
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Sepich-Poore C, Zheng Z, Schmitt E, Wen K, Zhang ZS, Cui XL, Dai Q, Zhu AC, Zhang L, Sanchez Castillo A, Tan H, Peng J, Zhuang X, He C, Nachtergaele S. The METTL5-TRMT112 N 6-methyladenosine methyltransferase complex regulates mRNA translation via 18S rRNA methylation. J Biol Chem 2022; 298:101590. [PMID: 35033535 PMCID: PMC8857481 DOI: 10.1016/j.jbc.2022.101590] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 01/03/2022] [Accepted: 01/05/2022] [Indexed: 12/13/2022] Open
Abstract
Ribosomal RNAs (rRNAs) have long been known to carry chemical modifications, including 2'O-methylation, pseudouridylation, N6-methyladenosine (m6A), and N6,6-dimethyladenosine. While the functions of many of these modifications are unclear, some are highly conserved and occur in regions of the ribosome critical for mRNA decoding. Both 28S rRNA and 18S rRNA carry single m6A sites, and while the methyltransferase ZCCHC4 has been identified as the enzyme responsible for the 28S rRNA m6A modification, the methyltransferase responsible for the 18S rRNA m6A modification has remained unclear. Here, we show that the METTL5-TRMT112 methyltransferase complex installs the m6A modification at position 1832 of human 18S rRNA. Our work supports findings that TRMT112 is required for METTL5 stability and reveals that human METTL5 mutations associated with microcephaly and intellectual disability disrupt this interaction. We show that loss of METTL5 in human cancer cell lines and in mice regulates gene expression at the translational level; additionally, Mettl5 knockout mice display reduced body size and evidence of metabolic defects. While recent work has focused heavily on m6A modifications in mRNA and their roles in mRNA processing and translation, we demonstrate here that deorphanizing putative methyltransferase enzymes can reveal previously unappreciated regulatory roles for m6A in noncoding RNAs.
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Affiliation(s)
- Caraline Sepich-Poore
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA; Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA; University of Chicago Medical Scientist Training Program, Chicago, Illinois, USA
| | - Zhong Zheng
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
| | - Emily Schmitt
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
| | - Kailong Wen
- Department of Neurobiology, University of Chicago, Chicago, Illinois, USA
| | - Zijie Scott Zhang
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
| | - Xiao-Long Cui
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
| | - Qing Dai
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA
| | - Allen C Zhu
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA; Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA; University of Chicago Medical Scientist Training Program, Chicago, Illinois, USA
| | - Linda Zhang
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
| | - Arantxa Sanchez Castillo
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA
| | - Haiyan Tan
- Center for Proteomics and Metabolomics, St Jude Children's Research Hospital, Memphis, Tennessee, USA; Departments of Structural Biology and Developmental Neurobiology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Junmin Peng
- Center for Proteomics and Metabolomics, St Jude Children's Research Hospital, Memphis, Tennessee, USA; Departments of Structural Biology and Developmental Neurobiology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Xiaoxi Zhuang
- Department of Neurobiology, University of Chicago, Chicago, Illinois, USA
| | - Chuan He
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA; Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA; Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois, USA.
| | - Sigrid Nachtergaele
- Department of Chemistry, University of Chicago, Chicago, Illinois, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, USA.
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17
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Lai SH, Tamara S, Heck AJ. Single-particle mass analysis of intact ribosomes by mass photometry and Orbitrap-based charge detection mass spectrometry. iScience 2021; 24:103211. [PMID: 34712917 PMCID: PMC8529500 DOI: 10.1016/j.isci.2021.103211] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/04/2021] [Accepted: 09/29/2021] [Indexed: 12/28/2022] Open
Abstract
Standard methods for mass analysis measure ensembles of thousand to millions of molecules. This approach enables analysis of monodisperse recombinant proteins, whereas some heterogeneous protein assemblies pose a significant challenge, whereby co-occurring stoichiometries, sub-complexes, and modifications hamper analysis using native mass spectrometry. To tackle the challenges posed by mass heterogeneity, single-particle methods may come to the rescue. Recently, two such approaches have been introduced, namely, mass photometry (MP) and Orbitrap-based charge detection mass spectrometry (CDMS). Both methods assess masses of individual molecules, albeit adhering to distinct physical principles. To evaluate these methods side by side, we analyzed a set of ribosomal particles, representing polydisperse ribonucleoprotein assemblies in the MDa range. MP and CDMS provide accurate masses for intact ribosomes and enable quantitative analysis of concomitant distinct particles within each ribosome sample. Here, we discuss pros and cons of these single-molecule techniques, also in the context of other techniques used for mass analysis.
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Affiliation(s)
- Szu-Hsueh Lai
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands
- Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Sem Tamara
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands
- Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Albert J.R. Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands
- Netherlands Proteomics Center, Padualaan 8, 3584 CH Utrecht, The Netherlands
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18
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Sorokin II, Vassilenko KS, Terenin IM, Kalinina NO, Agol VI, Dmitriev SE. Non-Canonical Translation Initiation Mechanisms Employed by Eukaryotic Viral mRNAs. BIOCHEMISTRY. BIOKHIMIIA 2021; 86:1060-1094. [PMID: 34565312 PMCID: PMC8436584 DOI: 10.1134/s0006297921090042] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/04/2021] [Accepted: 08/04/2021] [Indexed: 12/12/2022]
Abstract
Viruses exploit the translation machinery of an infected cell to synthesize their proteins. Therefore, viral mRNAs have to compete for ribosomes and translation factors with cellular mRNAs. To succeed, eukaryotic viruses adopt multiple strategies. One is to circumvent the need for m7G-cap through alternative instruments for ribosome recruitment. These include internal ribosome entry sites (IRESs), which make translation independent of the free 5' end, or cap-independent translational enhancers (CITEs), which promote initiation at the uncapped 5' end, even if located in 3' untranslated regions (3' UTRs). Even if a virus uses the canonical cap-dependent ribosome recruitment, it can still perturb conventional ribosomal scanning and start codon selection. The pressure for genome compression often gives rise to internal and overlapping open reading frames. Their translation is initiated through specific mechanisms, such as leaky scanning, 43S sliding, shunting, or coupled termination-reinitiation. Deviations from the canonical initiation reduce the dependence of viral mRNAs on translation initiation factors, thereby providing resistance to antiviral mechanisms and cellular stress responses. Moreover, viruses can gain advantage in a competition for the translational machinery by inactivating individual translational factors and/or replacing them with viral counterparts. Certain viruses even create specialized intracellular "translation factories", which spatially isolate the sites of their protein synthesis from cellular antiviral systems, and increase availability of translational components. However, these virus-specific mechanisms may become the Achilles' heel of a viral life cycle. Thus, better understanding of the unconventional mechanisms of viral mRNA translation initiation provides valuable insight for developing new approaches to antiviral therapy.
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Affiliation(s)
- Ivan I Sorokin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Konstantin S Vassilenko
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Ilya M Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Natalia O Kalinina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Vadim I Agol
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Institute of Poliomyelitis, Chumakov Center for Research and Development of Immunobiological Products, Russian Academy of Sciences, Moscow, 108819, Russia
| | - Sergey E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
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19
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Mancera-Martínez E, Dong Y, Makarian J, Srour O, Thiébeauld O, Jamsheer M, Chicher J, Hammann P, Schepetilnikov M, Ryabova LA. Phosphorylation of a reinitiation supporting protein, RISP, determines its function in translation reinitiation. Nucleic Acids Res 2021; 49:6908-6924. [PMID: 34133725 PMCID: PMC8266674 DOI: 10.1093/nar/gkab501] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 05/14/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022] Open
Abstract
Reinitiation supporting protein, RISP, interacts with 60S (60S ribosomal subunit) and eIF3 (eukaryotic initiation factor 3) in plants. TOR (target-of-rapamycin) mediates RISP phosphorylation at residue Ser267, favoring its binding to eL24 (60S ribosomal protein L24). In a viral context, RISP, when phosphorylated, binds the CaMV transactivator/ viroplasmin, TAV, to assist in an exceptional mechanism of reinitiation after long ORF translation. Moreover, we show here that RISP interacts with eIF2 via eIF2β and TOR downstream target 40S ribosomal protein eS6. A RISP phosphorylation knockout, RISP-S267A, binds preferentially eIF2β, and both form a ternary complex with eIF3a in vitro. Accordingly, transient overexpression in plant protoplasts of RISP-S267A, but not a RISP phosphorylation mimic, RISP-S267D, favors translation initiation. In contrast, RISP-S267D preferentially binds eS6, and, when bound to the C-terminus of eS6, can capture 60S in a highly specific manner in vitro, suggesting that it mediates 60S loading during reinitiation. Indeed, eS6-deficient plants are highly resistant to CaMV due to their reduced reinitiation capacity. Strikingly, an eS6 phosphomimic, when stably expressed in eS6-deficient plants, can fully restore the reinitiation deficiency of these plants in cellular and viral contexts. These results suggest that RISP function in translation (re)initiation is regulated by phosphorylation at Ser267.
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Affiliation(s)
- Eder Mancera-Martínez
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Yihan Dong
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Joelle Makarian
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Ola Srour
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Odon Thiébeauld
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Muhammed Jamsheer
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Johana Chicher
- Plateforme protéomique Strasbourg Esplanade FRC1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Philippe Hammann
- Plateforme protéomique Strasbourg Esplanade FRC1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Mikhail Schepetilnikov
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Lyubov A Ryabova
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
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20
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Alghoul F, Laure S, Eriani G, Martin F. Translation inhibitory elements from Hoxa3 and Hoxa11 mRNAs use uORFs for translation inhibition. eLife 2021; 10:e66369. [PMID: 34076576 PMCID: PMC8172242 DOI: 10.7554/elife.66369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/20/2021] [Indexed: 01/20/2023] Open
Abstract
During embryogenesis, Hox mRNA translation is tightly regulated by a sophisticated molecular mechanism that combines two RNA regulons located in their 5'UTR. First, an internal ribosome entry site (IRES) enables cap-independent translation. The second regulon is a translation inhibitory element or TIE, which ensures concomitant cap-dependent translation inhibition. In this study, we deciphered the molecular mechanisms of mouse Hoxa3 and Hoxa11 TIEs. Both TIEs possess an upstream open reading frame (uORF) that is critical to inhibit cap-dependent translation. However, the molecular mechanisms used are different. In Hoxa3 TIE, we identify an uORF which inhibits cap-dependent translation and we show the requirement of the non-canonical initiation factor eIF2D for this process. The mode of action of Hoxa11 TIE is different, it also contains an uORF but it is a minimal uORF formed by an uAUG followed immediately by a stop codon, namely a 'start-stop'. The 'start-stop' sequence is species-specific and in mice, is located upstream of a highly stable stem loop structure which stalls the 80S ribosome and thereby inhibits cap-dependent translation of Hoxa11 main ORF.
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Affiliation(s)
- Fatima Alghoul
- Institut de Biologie Moléculaire et Cellulaire, “Architecture et Réactivité de l’ARN” CNRS UPR9002, Université de StrasbourgStrasbourgFrance
| | - Schaeffer Laure
- Institut de Biologie Moléculaire et Cellulaire, “Architecture et Réactivité de l’ARN” CNRS UPR9002, Université de StrasbourgStrasbourgFrance
| | - Gilbert Eriani
- Institut de Biologie Moléculaire et Cellulaire, “Architecture et Réactivité de l’ARN” CNRS UPR9002, Université de StrasbourgStrasbourgFrance
| | - Franck Martin
- Institut de Biologie Moléculaire et Cellulaire, “Architecture et Réactivité de l’ARN” CNRS UPR9002, Université de StrasbourgStrasbourgFrance
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21
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An K, Zhou JB, Xiong Y, Han W, Wang T, Ye ZQ, Wu YD. Computational Studies of the Structural Basis of Human RPS19 Mutations Associated With Diamond-Blackfan Anemia. Front Genet 2021; 12:650897. [PMID: 34108988 PMCID: PMC8181406 DOI: 10.3389/fgene.2021.650897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/28/2021] [Indexed: 11/13/2022] Open
Abstract
Diamond-Blackfan Anemia (DBA) is an inherited rare disease characterized with severe pure red cell aplasia, and it is caused by the defective ribosome biogenesis stemming from the impairment of ribosomal proteins. Among all DBA-associated ribosomal proteins, RPS19 affects most patients and carries most DBA mutations. Revealing how these mutations lead to the impairment of RPS19 is highly demanded for understanding the pathogenesis of DBA, but a systematic study is currently lacking. In this work, based on the complex structure of human ribosome, we comprehensively studied the structural basis of DBA mutations of RPS19 by using computational methods. Main structure elements and five conserved surface patches involved in RPS19-18S rRNA interaction were identified. We further revealed that DBA mutations would destabilize RPS19 through disrupting the hydrophobic core or breaking the helix, or perturb the RPS19-18S rRNA interaction through destroying hydrogen bonds, introducing steric hindrance effect, or altering surface electrostatic property at the interface. Moreover, we trained a machine-learning model to predict the pathogenicity of all possible RPS19 mutations. Our work has laid a foundation for revealing the pathogenesis of DBA from the structural perspective.
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Affiliation(s)
- Ke An
- State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Jing-Bo Zhou
- State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Yao Xiong
- State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Wei Han
- State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Tao Wang
- Shenzhen Bay Laboratory, Shenzhen, China
| | - Zhi-Qiang Ye
- State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
- Shenzhen Bay Laboratory, Shenzhen, China
| | - Yun-Dong Wu
- State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
- Shenzhen Bay Laboratory, Shenzhen, China
- College of Chemistry and Molecular Engineering, Peking University, Beijing, China
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22
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Young DJ, Meydan S, Guydosh NR. 40S ribosome profiling reveals distinct roles for Tma20/Tma22 (MCT-1/DENR) and Tma64 (eIF2D) in 40S subunit recycling. Nat Commun 2021; 12:2976. [PMID: 34016977 PMCID: PMC8137927 DOI: 10.1038/s41467-021-23223-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 04/14/2021] [Indexed: 12/21/2022] Open
Abstract
The recycling of ribosomes at stop codons for use in further rounds of translation is critical for efficient protein synthesis. Removal of the 60S subunit is catalyzed by the ATPase Rli1 (ABCE1) while removal of the 40S is thought to require Tma64 (eIF2D), Tma20 (MCT-1), and Tma22 (DENR). However, it remains unclear how these Tma proteins cause 40S removal and control reinitiation of downstream translation. Here we used a 40S ribosome footprinting strategy to directly observe intermediate steps of ribosome recycling in cells. Deletion of the genes encoding these Tma proteins resulted in broad accumulation of unrecycled 40S subunits at stop codons, directly establishing their role in 40S recycling. Furthermore, the Tma20/Tma22 heterodimer was responsible for a majority of 40S recycling events while Tma64 played a minor role. Introduction of an autism-associated mutation into TMA22 resulted in a loss of 40S recycling activity, linking ribosome recycling and neurological disease.
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Affiliation(s)
- David J Young
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sezen Meydan
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
- Postdoctoral Research Associate Training Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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23
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Chen Y, Shen L, Chen B, Han X, Yu Y, Yuan X, Zhong L. The predictive prognostic values of CBFA2T3, STX3, DENR, EGLN1, FUT4, and PCDH7 in lung cancer. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:843. [PMID: 34164477 PMCID: PMC8184469 DOI: 10.21037/atm-21-1392] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background Lung cancer is one of the most malignant tumors. However, neither the pathogenesis of lung cancer nor the prognosis markers are completely clear. The purpose of this study is to screen the diagnostic or prognostic markers of lung cancer. Methods TCGA and GEO datasets were used to analyze the relationship between lung cancer-related genes and lung cancer samples. Common differential genes were screened, and a univariate Cox regression analysis was used to screen survival related genes. A univariable Cox proportional hazards regression analysis was used to verify the genes and construct risk model. The key factors affecting the prognosis of lung cancer were determined by univariate and multivariate regression analyses. The ROC curve, AUC and the survival of each risk gene was analyzed. Finally, the biological functions of high- and low-risk patients were explored by GSEA and an immune-infiltration analysis. Results Based on the common differential genes, 13 genes significantly related to lung cancer survival were identified. Eight risk genes (CBFA2T3, DENR, EGLN1, FUT2, FUT4, PCDH7, PHF14, and STX3) were screened out. The results showed that risk status may be an independent prognostic factor, and the risk score predicted the prognosis of lung cancer. CBFA2T3 and STX3 are protective genes, while DENR, EGLN1, FUT4 and PCDH7 are dangerous genes. These 6 genes can be used as independent lung cancer prognosis markers. The corresponding biological functions of genes expressed in high-risk patients were mostly related to tumor proliferation and inflammatory infiltration. Neutrophil, CD8+T, Macrophage M0, Macrophage M1- and mDC-activated cells were high in high-risk status samples. Conclusions CBFA2T3, STX3, DENR, EGLN1, FUT4, and PCDH7 are important participants in the occurrence and development of lung cancer. High-risk patients display serious inflammatory infiltration. This study not only provides insight into the mechanism of occurrence and development of lung cancer, but also provides potential targets for targeted therapy of lung cancer.
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Affiliation(s)
- Yuhao Chen
- Department of Thoracic Surgery, Affiliated Hospital of Nantong University, Nantong, China
| | - Lu Shen
- Department of Thoracic Surgery, Affiliated Hospital of Nantong University, Nantong, China
| | - Bairong Chen
- Department of Medical Laboratory, School of Public Health, Nantong University, Nantong, China
| | - Xiao Han
- Department of Thoracic Surgery, Affiliated Hospital of Nantong University, Nantong, China
| | - Yunchi Yu
- Department of Thoracic Surgery, Affiliated Hospital of Nantong University, Nantong, China
| | - Xiaosa Yuan
- Department of Thoracic Surgery, Affiliated Hospital of Nantong University, Nantong, China
| | - Lou Zhong
- Department of Thoracic Surgery, Affiliated Hospital of Nantong University, Nantong, China
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24
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Shyrokova EY, Prassolov VS, Spirin PV. The Role of the MCTS1 and DENR Proteins in Regulating the Mechanisms Associated with Malignant Cell Transformation. Acta Naturae 2021; 13:98-105. [PMID: 34377560 PMCID: PMC8327141 DOI: 10.32607/actanaturae.11181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 09/28/2020] [Indexed: 02/05/2023] Open
Abstract
The mutations associated with malignant cell transformation are believed to disrupt the expression of a significant number of normal, non-mutant genes. The proteins encoded by these genes are involved in the regulation of many signaling pathways that are responsible for differentiation and proliferation, as well as sensitivity to apoptotic signals, growth factors, and cytokines. Abnormalities in the balance of signaling pathways can lead to the transformation of a normal cell, which results in tumor formation. Detection of the target genes and the proteins they encode and that are involved in the malignant transformation is one of the major evolutions in anti-cancer biomedicine. Currently, there is an accumulation of data that shed light on the role of the MCTS1 and DENR proteins in oncogenesis.
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Affiliation(s)
- E. Y. Shyrokova
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, Moscow, 119991 Russia
- Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Moscow Region, 141701 Russia
| | - V. S. Prassolov
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, Moscow, 119991 Russia
| | - P. V. Spirin
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, Moscow, 119991 Russia
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25
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Gaikwad S, Ghobakhlou F, Young DJ, Visweswaraiah J, Zhang H, Hinnebusch AG. Reprogramming of translation in yeast cells impaired for ribosome recycling favors short, efficiently translated mRNAs. eLife 2021; 10:e64283. [PMID: 33764298 PMCID: PMC7993997 DOI: 10.7554/elife.64283] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/04/2021] [Indexed: 12/21/2022] Open
Abstract
In eukaryotes, 43S preinitiation complex (PIC) formation is a rate-determining step of translation. Ribosome recycling following translation termination produces free 40S subunits for re-assembly of 43S PICs. Yeast mutants lacking orthologs of mammalian eIF2D (Tma64), and either MCT-1 (Tma20) or DENR (Tma22), are broadly impaired for 40S recycling; however, it was unknown whether this defect alters the translational efficiencies (TEs) of particular mRNAs. Here, we conducted ribosome profiling of a yeast tma64∆/tma20∆ double mutant and observed a marked reprogramming of translation, wherein the TEs of the most efficiently translated ('strong') mRNAs increase, while those of 'weak' mRNAs generally decline. Remarkably, similar reprogramming was seen on reducing 43S PIC assembly by inducing phosphorylation of eIF2α or by decreasing total 40S subunit levels by depleting Rps26. Our findings suggest that strong mRNAs outcompete weak mRNAs in response to 43S PIC limitation achieved in various ways, in accordance with previous mathematical modeling.
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Affiliation(s)
- Swati Gaikwad
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Fardin Ghobakhlou
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - David J Young
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Jyothsna Visweswaraiah
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Hongen Zhang
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
| | - Alan G Hinnebusch
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of HealthBethesdaUnited States
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26
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Vasudevan D, Neuman SD, Yang A, Lough L, Brown B, Bashirullah A, Cardozo T, Ryoo HD. Translational induction of ATF4 during integrated stress response requires noncanonical initiation factors eIF2D and DENR. Nat Commun 2020; 11:4677. [PMID: 32938929 PMCID: PMC7495428 DOI: 10.1038/s41467-020-18453-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 08/17/2020] [Indexed: 01/25/2023] Open
Abstract
The Integrated Stress Response (ISR) helps metazoan cells adapt to cellular stress by limiting the availability of initiator methionyl-tRNA for translation. Such limiting conditions paradoxically stimulate the translation of ATF4 mRNA through a regulatory 5' leader sequence with multiple upstream Open Reading Frames (uORFs), thereby activating stress-responsive gene expression. Here, we report the identification of two critical regulators of such ATF4 induction, the noncanonical initiation factors eIF2D and DENR. Loss of eIF2D and DENR in Drosophila results in increased vulnerability to amino acid deprivation, susceptibility to retinal degeneration caused by endoplasmic reticulum (ER) stress, and developmental defects similar to ATF4 mutants. eIF2D requires its RNA-binding motif for regulation of 5' leader-mediated ATF4 translation. Consistently, eIF2D and DENR deficient human cells show impaired ATF4 protein induction in response to ER stress. Altogether, our findings indicate that eIF2D and DENR are critical mediators of ATF4 translational induction and stress responses in vivo.
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Affiliation(s)
- Deepika Vasudevan
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Sarah D Neuman
- Department of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Amy Yang
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Lea Lough
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Brian Brown
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Arash Bashirullah
- Department of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Hyung Don Ryoo
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, 10016, USA.
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27
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SARS-CoV-2 Nsp1 binds the ribosomal mRNA channel to inhibit translation. Nat Struct Mol Biol 2020; 27:959-966. [DOI: 10.1038/s41594-020-0511-8] [Citation(s) in RCA: 298] [Impact Index Per Article: 74.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 08/26/2020] [Indexed: 12/13/2022]
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28
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Renz PF, Valdivia-Francia F, Sendoel A. Some like it translated: small ORFs in the 5'UTR. Exp Cell Res 2020; 396:112229. [PMID: 32818479 DOI: 10.1016/j.yexcr.2020.112229] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 07/28/2020] [Accepted: 08/07/2020] [Indexed: 01/06/2023]
Abstract
The 5' untranslated region (5'UTR) is critical in determining post-transcriptional control, which is partly mediated by short upstream open reading frames (uORFs) present in half of mammalian transcripts. uORFs are generally considered to provide functionally important repression of the main-ORF by engaging initiating ribosomes, but under specific environmental conditions such as cellular stress, uORFs can become essential to activate the translation of the main coding sequence. In addition, a growing number of uORF-encoded bioactive microproteins have been described, which have the potential to significantly increase cellular protein diversity. Here we review the diverse cellular contexts in which uORFs play a critical role and discuss the molecular mechanisms underlying their function and regulation. The progress over the last decades in dissecting uORF function suggests that the 5'UTR remains an exciting frontier towards understanding how the cellular proteome is shaped in health and disease.
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Affiliation(s)
- Peter F Renz
- Institute for Regenerative Medicine (IREM), University of Zurich, Wagistrasse 12, CH-8952 Schlieren, Switzerland
| | - Fabiola Valdivia-Francia
- Institute for Regenerative Medicine (IREM), University of Zurich, Wagistrasse 12, CH-8952 Schlieren, Switzerland; Life Science Zurich Graduate School, Molecular Life Science Program, University of Zurich/ ETH Zurich, Switzerland
| | - Ataman Sendoel
- Institute for Regenerative Medicine (IREM), University of Zurich, Wagistrasse 12, CH-8952 Schlieren, Switzerland.
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29
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Tian C, Zeng S, Luo J. MCTS1 Directly Binds to TWF1 and Synergistically Modulate Cyclin D1 and C-Myc Translation in Luminal A/B Breast Cancer Cells. Onco Targets Ther 2020; 13:5353-5361. [PMID: 32606753 PMCID: PMC7293984 DOI: 10.2147/ott.s255675] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/14/2020] [Indexed: 01/04/2023] Open
Abstract
Purpose MCTS1 re-initiation and release factor (MCTS1) is a ribosome-binding protein and shows multiple oncogenic properties in multiple cancers. This study aimed to investigate the expression, prognostic significance and transcription profile of MCTS1 in the PAM50 subtypes of breast cancer, as well as proteins with functional interactions with MCTS1 in luminal A/B breast cancer cells. Materials and Methods Data from The Cancer Genome Atlas (TCGA)-Breast Carcinoma (BRCA) and Gene Expression Omnibus (GEO) and normal breast epithelial tissue data from the Genotype-Tissue Expression (GTEx) project were extracted and integrated for bioinformatic analysis. BT-474 and MCF-7 cells were used for in-vitro studies. Results MCTS1 expression varied significantly among PAM50 subtypes. Its expression might independently predict unfavorable overall survival (OS) in luminal A and B cases, but not in other subtypes. ENST00000371317.9 is the dominant isoform of MCTS1 transcripts and showed a step increase from normal, adjacent normal to breast cancer tissues. The protein encoded by this isoform directly bound to TWF1 and synergistically modulated cyclin D1 and C-Myc translation in BT-474 and MCF-7 cells. Conclusion MCTS1 expression might serve as a potential prognostic biomarker of unfavorable OS in luminal A and luminal B cases. The novel direct interaction between MCTS1 and TWF1 might be necessary for the translation of some downstream genes in common in luminal A/B breast cancer cells.
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Affiliation(s)
- Chao Tian
- Department of Breast Surgery, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610041, Sichuan, People's Republic of China
| | - Shiyan Zeng
- Department of Breast Surgery, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610041, Sichuan, People's Republic of China
| | - Jing Luo
- Department of Breast Surgery, Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan, People's Republic of China
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30
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Simonetti A, Guca E, Bochler A, Kuhn L, Hashem Y. Structural Insights into the Mammalian Late-Stage Initiation Complexes. Cell Rep 2020; 31:107497. [PMID: 32268096 PMCID: PMC7166083 DOI: 10.1016/j.celrep.2020.03.061] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/17/2020] [Accepted: 03/18/2020] [Indexed: 12/12/2022] Open
Abstract
In higher eukaryotes, the mRNA sequence in the direct vicinity of the start codon, called the Kozak sequence (CRCCaugG, where R is a purine), is known to influence the rate of the initiation process. However, the molecular basis underlying its role remains poorly understood. Here, we present the cryoelectron microscopy (cryo-EM) structures of mammalian late-stage 48S initiation complexes (LS48S ICs) in the presence of two different native mRNA sequences, β-globin and histone 4, at overall resolution of 3 and 3.5 Å, respectively. Our high-resolution structures unravel key interactions from the mRNA to eukaryotic initiation factors (eIFs): 1A, 2, 3, 18S rRNA, and several 40S ribosomal proteins. In addition, we are able to study the structural role of ABCE1 in the formation of native 48S ICs. Our results reveal a comprehensive map of ribosome/eIF-mRNA and ribosome/eIF-tRNA interactions and suggest the impact of mRNA sequence on the structure of the LS48S IC.
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MESH Headings
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Codon, Initiator/genetics
- Codon, Initiator/ultrastructure
- Cryoelectron Microscopy/methods
- Enhancer Elements, Genetic/genetics
- Eukaryotic Initiation Factor-1/genetics
- Eukaryotic Initiation Factor-1/metabolism
- Eukaryotic Initiation Factor-2/genetics
- Eukaryotic Initiation Factor-2/metabolism
- Eukaryotic Initiation Factor-3/genetics
- Eukaryotic Initiation Factor-3/metabolism
- Eukaryotic Initiation Factors/metabolism
- Eukaryotic Initiation Factors/ultrastructure
- Humans
- Mice
- Peptide Chain Initiation, Translational
- Protein Biosynthesis
- RNA, Messenger/metabolism
- RNA, Ribosomal, 18S/genetics
- RNA, Ribosomal, 18S/metabolism
- RNA, Transfer/metabolism
- Ribosomal Proteins/metabolism
- Ribosomes/metabolism
- Transcription Initiation, Genetic/physiology
- beta-Globins/genetics
- beta-Globins/ultrastructure
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Affiliation(s)
- Angelita Simonetti
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, Strasbourg 67000, France
| | - Ewelina Guca
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France
| | - Anthony Bochler
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, Strasbourg 67000, France; INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France
| | - Lauriane Kuhn
- Proteomic Platform Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, Université de Strasbourg, Strasbourg 67000, France
| | - Yaser Hashem
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France.
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31
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Hepatitis C Virus Translation Regulation. Int J Mol Sci 2020; 21:ijms21072328. [PMID: 32230899 PMCID: PMC7178104 DOI: 10.3390/ijms21072328] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 03/18/2020] [Accepted: 03/25/2020] [Indexed: 12/12/2022] Open
Abstract
Translation of the hepatitis C virus (HCV) RNA genome is regulated by the internal ribosome entry site (IRES), located in the 5’-untranslated region (5′UTR) and part of the core protein coding sequence, and by the 3′UTR. The 5′UTR has some highly conserved structural regions, while others can assume different conformations. The IRES can bind to the ribosomal 40S subunit with high affinity without any other factors. Nevertheless, IRES activity is modulated by additional cis sequences in the viral genome, including the 3′UTR and the cis-acting replication element (CRE). Canonical translation initiation factors (eIFs) are involved in HCV translation initiation, including eIF3, eIF2, eIF1A, eIF5, and eIF5B. Alternatively, under stress conditions and limited eIF2-Met-tRNAiMet availability, alternative initiation factors such as eIF2D, eIF2A, and eIF5B can substitute for eIF2 to allow HCV translation even when cellular mRNA translation is downregulated. In addition, several IRES trans-acting factors (ITAFs) modulate IRES activity by building large networks of RNA-protein and protein–protein interactions, also connecting 5′- and 3′-ends of the viral RNA. Moreover, some ITAFs can act as RNA chaperones that help to position the viral AUG start codon in the ribosomal 40S subunit entry channel. Finally, the liver-specific microRNA-122 (miR-122) stimulates HCV IRES-dependent translation, most likely by stabilizing a certain structure of the IRES that is required for initiation.
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32
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Lomakin IB, De S, Wang J, Borkar AN, Steitz TA. Crystal structure of the C-terminal domain of DENR. Comput Struct Biotechnol J 2020; 18:696-704. [PMID: 32257053 PMCID: PMC7114459 DOI: 10.1016/j.csbj.2020.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/09/2020] [Accepted: 03/11/2020] [Indexed: 02/04/2023] Open
Abstract
The density regulated protein (DENR) forms a stable heterodimer with malignant T-cell-amplified sequence 1 (MCT-1). DENR-MCT-1 heterodimer then participates in regulation of non-canonical translation initiation and ribosomal recycling. The N-terminal domain of DENR interacts with MCT-1 and carries a classical tetrahedral zinc ion-binding site, which is crucial for the dimerization. DENR-MCT-1 binds the small (40S) ribosomal subunit through interactions between MCT-1 and helix h24 of the 18S rRNA, and through interactions between the C-terminal domain of DENR and helix h44 of the 18S rRNA. This later interaction occurs in the vicinity of the P site that is also the binding site for canonical translation initiation factor eIF1, which plays the key role in initiation codon selection and scanning. Sequence homology modeling and a low-resolution crystal structure of the DENR-MCT-1 complex with the human 40S subunit suggests that the C-terminal domain of DENR and eIF1 adopt a similar fold. Here we present the crystal structure of the C-terminal domain of DENR determined at 1.74 Å resolution, which confirms its resemblance to eIF1 and advances our understanding of the mechanism by which DENR-MCT-1 regulates non-canonical translation initiation and ribosomal recycling.
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Affiliation(s)
- Ivan B. Lomakin
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
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33
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Komar AA, Merrick WC. A Retrospective on eIF2A-and Not the Alpha Subunit of eIF2. Int J Mol Sci 2020; 21:E2054. [PMID: 32192132 PMCID: PMC7139343 DOI: 10.3390/ijms21062054] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/29/2020] [Accepted: 03/13/2020] [Indexed: 12/31/2022] Open
Abstract
Initiation of protein synthesis in eukaryotes is a complex process requiring more than 12 different initiation factors, comprising over 30 polypeptide chains. The functions of many of these factors have been established in great detail; however, the precise role of some of them and their mechanism of action is still not well understood. Eukaryotic initiation factor 2A (eIF2A) is a single chain 65 kDa protein that was initially believed to serve as the functional homologue of prokaryotic IF2, since eIF2A and IF2 catalyze biochemically similar reactions, i.e., they stimulate initiator Met-tRNAi binding to the small ribosomal subunit. However, subsequent identification of a heterotrimeric 126 kDa factor, eIF2 (α,β,γ) showed that this factor, and not eIF2A, was primarily responsible for the binding of Met-tRNAi to 40S subunit in eukaryotes. It was found however, that eIF2A can promote recruitment of Met-tRNAi to 40S/mRNA complexes under conditions of inhibition of eIF2 activity (eIF2α-phosphorylation), or its absence. eIF2A does not function in major steps in the initiation process, but is suggested to act at some minor/alternative initiation events such as re-initiation, internal initiation, or non-AUG initiation, important for translational control of specific mRNAs. This review summarizes our current understanding of the eIF2A structure and function.
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Affiliation(s)
- Anton A. Komar
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA;
| | - William C. Merrick
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA;
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Nürenberg-Goloub E, Tampé R. Ribosome recycling in mRNA translation, quality control, and homeostasis. Biol Chem 2019; 401:47-61. [DOI: 10.1515/hsz-2019-0279] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023]
Abstract
Abstract
Protein biosynthesis is a conserved process, essential for life. Ongoing research for four decades has revealed the structural basis and mechanistic details of most protein biosynthesis steps. Numerous pathways and their regulation have recently been added to the translation system describing protein quality control and messenger ribonucleic acid (mRNA) surveillance, ribosome-associated protein folding and post-translational modification as well as human disorders associated with mRNA and ribosome homeostasis. Thus, translation constitutes a key regulatory process placing the ribosome as a central hub at the crossover of numerous cellular pathways. Here, we describe the role of ribosome recycling by ATP-binding cassette sub-family E member 1 (ABCE1) as a crucial regulatory step controlling the biogenesis of functional proteins and the degradation of aberrant nascent chains in quality control processes.
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Affiliation(s)
- Elina Nürenberg-Goloub
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt/Main , Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt , Max-von-Laue-Str. 9 , D-60438 Frankfurt/Main , Germany
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Weisser M, Ban N. Extensions, Extra Factors, and Extreme Complexity: Ribosomal Structures Provide Insights into Eukaryotic Translation. Cold Spring Harb Perspect Biol 2019; 11:11/9/a032367. [PMID: 31481454 DOI: 10.1101/cshperspect.a032367] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Although the basic aspects of protein synthesis are preserved in all kingdoms of life, there are many important structural and functional differences between bacterial and the more complex eukaryotic ribosomes. High-resolution cryo-electron microscopy (cryo-EM) and X-ray crystallography structures of eukaryotic ribosomes have revealed the complex architectures of eukaryotic ribosomes and species-specific variations in protein and ribosomal RNA (rRNA) extensions. They also enabled structural studies of a range of eukaryotic ribosomal complexes involved in translation initiation, elongation, and termination, revealing unique mechanistic features of the eukaryotic translation process, especially with respect to the identification and recognition of translation start and stop codons on messenger RNAs (mRNAs). Most recently, structural biology has provided insights into the eukaryotic ribosomal biogenesis pathway by visualizing several of its complex intermediates. This review highlights the past decade's structural work on eukaryotic ribosomes and its implications on our understanding of eukaryotic translation.
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Affiliation(s)
- Melanie Weisser
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Nenad Ban
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
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36
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Janapala Y, Preiss T, Shirokikh NE. Control of Translation at the Initiation Phase During Glucose Starvation in Yeast. Int J Mol Sci 2019; 20:E4043. [PMID: 31430885 PMCID: PMC6720308 DOI: 10.3390/ijms20164043] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/10/2019] [Accepted: 08/15/2019] [Indexed: 12/13/2022] Open
Abstract
Glucose is one of the most important sources of carbon across all life. Glucose starvation is a key stress relevant to all eukaryotic cells. Glucose starvation responses have important implications in diseases, such as diabetes and cancer. In yeast, glucose starvation causes rapid and dramatic effects on the synthesis of proteins (mRNA translation). Response to glucose deficiency targets the initiation phase of translation by different mechanisms and with diverse dynamics. Concomitantly, translationally repressed mRNAs and components of the protein synthesis machinery may enter a variety of cytoplasmic foci, which also form with variable kinetics and may store or degrade mRNA. Much progress has been made in understanding these processes in the last decade, including with the use of high-throughput/omics methods of RNA and RNA:protein detection. This review dissects the current knowledge of yeast reactions to glucose starvation systematized by the stage of translation initiation, with the focus on rapid responses. We provide parallels to mechanisms found in higher eukaryotes, such as metazoans, for the most critical responses, and point out major remaining gaps in knowledge and possible future directions of research on translational responses to glucose starvation.
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Affiliation(s)
- Yoshika Janapala
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Preiss
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia.
- Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
| | - Nikolay E Shirokikh
- EMBL-Australia Collaborating Group, Department of Genome Sciences, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia.
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Gilabert-Juan J, López-Campos G, Sebastiá-Ortega N, Guara-Ciurana S, Ruso-Julve F, Prieto C, Crespo-Facorro B, Sanjuán J, Moltó MD. Time dependent expression of the blood biomarkers EIF2D and TOX in patients with schizophrenia. Brain Behav Immun 2019; 80:909-915. [PMID: 31078689 DOI: 10.1016/j.bbi.2019.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/05/2019] [Accepted: 05/08/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND During last years, there has been an intensive search for blood biomarkers in schizophrenia to assist in diagnosis, prognosis and clinical management of the disease. METHODS In this study, we first conducted a weighted gene coexpression network analysis to address differentially expressed genes in peripheral blood from patients with chronic schizophrenia (n = 30) and healthy controls (n = 15). The discriminating performance of the candidate genes was further tested in an independent cohort of patients with first-episode schizophrenia (n = 124) and healthy controls (n = 54), and in postmortem brain samples (cingulate and prefrontal cortices) from patients with schizophrenia (n = 34) and healthy controls (n = 35). RESULTS The expression of the Eukaryotic Translation Initiation Factor 2D (EIF2D) gene, which is involved in protein synthesis regulation, was increased in the chronic patients of schizophrenia. On the contrary, the expression of the Thymocyte Selection-Associated High Mobility Group Box (TOX) gene, involved in immune function, was reduced. EIF2D expression was also altered in first-episode schizophrenia patients, but showing reduced levels. Any of the postmortem brain areas studied did not show differences of expression of both genes. CONCLUSIONS EIF2D and TOX are putative blood markers of chronic patients of schizophrenia, which expression change from the onset to the chronic disease, unraveling new biological pathways that can be used for the development of new intervention strategies in the diagnosis and prognosis of schizophrenia disease.
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Affiliation(s)
- Javier Gilabert-Juan
- Department of Genetics, Universitat de València, Valencia, Spain; Neurobiology Unit, Cell Biology Department, Interdisciplinary Research Structure for Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Valencia, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; INCLIVA, Valencia, Spain.
| | | | - Noelia Sebastiá-Ortega
- Department of Genetics, Universitat de València, Valencia, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; INCLIVA, Valencia, Spain
| | | | - Fulgencio Ruso-Julve
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; University Hospital Marqués de Valdecilla, IDIVAL, Department of Psychiatry, School of Medicine, University of Cantabria, Santander, Spain
| | - Carlos Prieto
- Servicio de Bioinformática, Nucleus, Universidad de Salamanca, Salamanca, Spain
| | - Benedicto Crespo-Facorro
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; University Hospital Marqués de Valdecilla, IDIVAL, Department of Psychiatry, School of Medicine, University of Cantabria, Santander, Spain
| | - Julio Sanjuán
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; INCLIVA, Valencia, Spain; Unit of Psychiatry, Universitat de València, Valencia, Spain
| | - María Dolores Moltó
- Department of Genetics, Universitat de València, Valencia, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; INCLIVA, Valencia, Spain
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Monestier A, Lazennec-Schurdevin C, Coureux PD, Mechulam Y, Schmitt E. Role of aIF1 in Pyrococcus abyssi translation initiation. Nucleic Acids Res 2019; 46:11061-11074. [PMID: 30239976 PMCID: PMC6237735 DOI: 10.1093/nar/gky850] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/11/2018] [Indexed: 01/06/2023] Open
Abstract
In archaeal translation initiation, a preinitiation complex (PIC) made up of aIF1, aIF1A, the ternary complex (TC, e/aIF2-GTP-Met-tRNAiMet) and mRNA bound to the small ribosomal subunit is responsible for start codon selection. Many archaeal mRNAs contain a Shine-Dalgarno (SD) sequence allowing the PIC to be prepositioned in the vicinity of the start codon. Nevertheless, cryo-EM studies have suggested local scanning to definitely establish base pairing of the start codon with the tRNA anticodon. Here, using fluorescence anisotropy, we show that aIF1 and mRNA have synergistic binding to the Pyrococcus abyssi 30S. Stability of 30S:mRNA:aIF1 strongly depends on the SD sequence. Further, toeprinting experiments show that aIF1-containing PICs display a dynamic conformation with the tRNA not firmly accommodated in the P site. AIF1-induced destabilization of the PIC is favorable for proofreading erroneous initiation complexes. After aIF1 departure, the stability of the PIC increases reflecting initiator tRNA fully base-paired to the start codon. Altogether, our data support the idea that some of the main events governing start codon selection in eukaryotes and archaea occur within a common structural and functional core. However, idiosyncratic features in loop 1 sequence involved in 30S:mRNA binding suggest adjustments of e/aIF1 functioning in the two domains.
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Affiliation(s)
- Auriane Monestier
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
| | | | - Pierre-Damien Coureux
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
| | - Yves Mechulam
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
| | - Emmanuelle Schmitt
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau cedex, France
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Castelo-Szekely V, De Matos M, Tusup M, Pascolo S, Ule J, Gatfield D. Charting DENR-dependent translation reinitiation uncovers predictive uORF features and links to circadian timekeeping via Clock. Nucleic Acids Res 2019; 47:5193-5209. [PMID: 30982898 PMCID: PMC6547434 DOI: 10.1093/nar/gkz261] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 03/25/2019] [Accepted: 04/08/2019] [Indexed: 02/05/2023] Open
Abstract
The non-canonical initiation factor DENR promotes translation reinitiation on mRNAs harbouring upstream open reading frames (uORFs). Moreover, DENR depletion shortens circadian period in mouse fibroblasts, suggesting involvement of uORF usage and reinitiation in clock regulation. To identify DENR-regulated translation events transcriptome-wide and, in particular, specific core clock transcripts affected by this mechanism, we have used ribosome profiling in DENR-deficient NIH3T3 cells. We uncovered 240 transcripts with altered translation rate, and used linear regression analysis to extract 5' UTR features predictive of DENR dependence. Among core clock genes, we identified Clock as a DENR target. Using Clock 5' UTR mutants, we mapped the specific uORF through which DENR acts to regulate CLOCK protein biosynthesis. Notably, these experiments revealed an alternative downstream start codon, likely representing the bona fide CLOCK N-terminus. Our findings provide insights into uORF-mediated translational regulation that can regulate the mammalian circadian clock and gene expression at large.
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Affiliation(s)
- Violeta Castelo-Szekely
- Center for Integrative Genomics, University of Lausanne, Genopode, 1015 Lausanne, Switzerland
| | - Mara De Matos
- Center for Integrative Genomics, University of Lausanne, Genopode, 1015 Lausanne, Switzerland
| | - Marina Tusup
- Department of Dermatology, University Hospital of Zurich, Gloriastrasse 31, 8091 Zurich, Switzerland
- Faculty of Medicine, University of Zurich, 8091 Zurich, Switzerland
| | - Steve Pascolo
- Department of Dermatology, University Hospital of Zurich, Gloriastrasse 31, 8091 Zurich, Switzerland
- Faculty of Medicine, University of Zurich, 8091 Zurich, Switzerland
| | - Jernej Ule
- Department of Neuromuscular Diseases, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David Gatfield
- Center for Integrative Genomics, University of Lausanne, Genopode, 1015 Lausanne, Switzerland
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40
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Weng YS, Tseng HY, Chen YA, Shen PC, Al Haq AT, Chen LM, Tung YC, Hsu HL. MCT-1/miR-34a/IL-6/IL-6R signaling axis promotes EMT progression, cancer stemness and M2 macrophage polarization in triple-negative breast cancer. Mol Cancer 2019; 18:42. [PMID: 30885232 PMCID: PMC6421700 DOI: 10.1186/s12943-019-0988-0] [Citation(s) in RCA: 249] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 02/26/2019] [Indexed: 02/07/2023] Open
Abstract
Background Triple-negative breast cancer (TNBC) is a poor prognostic breast cancer with the highest mutations and limited therapeutic choices. Cytokine networking between cancer cells and the tumor microenvironment (TME) maintains the self-renewing subpopulation of breast cancer stem cells (BCSCs) that mediate tumor heterogeneity, resistance and recurrence. Immunotherapy of those factors combined with targeted therapy or chemoagents may advantage TNBC treatment. Results We found that the oncogene Multiple Copies in T-cell Malignancy 1 (MCT-1/MCTS1) expression is a new poor-prognosis marker in patients with aggressive breast cancers. Overexpressing MCT-1 perturbed the oncogenic breast epithelial acini morphogenesis and stimulated epithelial-mesenchymal transition and matrix metalloproteinase activation in invasive TNBC cells, which were repressed after MCT-1 gene silencing. As mammary tumor progression was promoted by oncogenic MCT-1 activation, tumor-promoting M2 macrophages were enriched in TME, whereas M2 macrophages were decreased and tumor-suppressive M1 macrophages were increased as the tumor was repressed via MCT-1 knockdown. MCT-1 stimulated interleukin-6 (IL-6) secretion that promoted monocytic THP-1 polarization into M2-like macrophages to increase TNBC cell invasiveness. In addition, MCT-1 elevated the soluble IL-6 receptor levels, and thus, IL-6R antibodies antagonized the effect of MCT-1 on promoting M2-like polarization and cancer cell invasion. Notably, MCT-1 increased the features of BCSCs, which were further advanced by IL-6 but prevented by tocilizumab, a humanized IL-6R antibody, thus MCT-1 knockdown and tocilizumab synergistically inhibited TNBC stemness. Tumor suppressor miR-34a was induced upon MCT-1 knockdown that inhibited IL-6R expression and activated M1 polarization. Conclusions The MCT-1 pathway is a novel and promising therapeutic target for TNBC. Electronic supplementary material The online version of this article (10.1186/s12943-019-0988-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yueh-Shan Weng
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Hong-Yu Tseng
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Yen-An Chen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Pei-Chun Shen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Aushia Tanzih Al Haq
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Li-Mei Chen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Yi-Chung Tung
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Hsin-Ling Hsu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan.
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Makeeva DS, Lando AS, Anisimova A, Egorov AA, Logacheva MD, Penin AA, Andreev DE, Sinitcyn PG, Terenin IM, Shatsky IN, Kulakovskiy IV, Dmitriev SE. Translatome and transcriptome analysis of TMA20 (MCT-1) and TMA64 (eIF2D) knockout yeast strains. Data Brief 2019; 23:103701. [PMID: 30815525 PMCID: PMC6378902 DOI: 10.1016/j.dib.2019.103701] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/15/2018] [Accepted: 01/21/2019] [Indexed: 02/05/2023] Open
Abstract
TMA20 (MCT-1), TMA22 (DENR) and TMA64 (eIF2D) are eukaryotic translation factors involved in ribosome recycling and re-initiation. They operate with P-site bound tRNA in post-termination or (re-)initiation translation complexes, thus participating in the removal of 40S ribosomal subunit from mRNA stop codons after termination and controlling translation re-initiation on mRNAs with upstream open reading frames (uORFs), as well as de novo initiation on some specific mRNAs. Here we report ribosomal profiling data of S.cerevisiae strains with individual deletions of TMA20, TMA64 or both TMA20 and TMA64 genes. We provide RNA-Seq and Ribo-Seq data from yeast strains grown in the rich YPD or minimal SD medium. We illustrate our data by plotting differential distribution of ribosomal-bound mRNA fragments throughout uORFs in 5'-untranslated region (5' UTR) of GCN4 mRNA and on mRNA transcripts encoded in MAT locus in the mutant and wild-type strains, thus providing a basis for investigation of the role of these factors in the stress response, mating and sporulation. We also document a shift of transcription start site of the APC4 gene which occurs when the neighboring TMA64 gene is replaced by the standard G418-resistance cassette used for the creation of the Yeast Deletion Library. This shift results in dramatic deregulation of the APC4 gene expression, as revealed by our Ribo-Seq data, which can be probably used to explain strong genetic interactions of TMA64 with genes involved in the cell cycle and mitotic checkpoints. Raw RNA-Seq and Ribo-Seq data as well as all gene counts are available in NCBI Gene Expression Omnibus (GEO) repository under GEO accession GSE122039 (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE122039).
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Affiliation(s)
- Desislava S Makeeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia.,School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234 Russia
| | - Andrey S Lando
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia
| | - Aleksandra Anisimova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia.,School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234 Russia
| | - Artyom A Egorov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia.,Department of Medical Physics, Faculty of Physics, Lomonosov Moscow State University, Moscow, 119991 Russia
| | - Maria D Logacheva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia.,Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
| | - Alexey A Penin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia.,Department of Genetics, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991 Russia.,Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Dmitry E Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia
| | - Pavel G Sinitcyn
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234 Russia
| | - Ilya M Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, 119991 Russia
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia
| | - Ivan V Kulakovskiy
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia.,Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia.,Institute of Mathematical Problems of Biology RAS - the Branch of Keldysh Institute of Applied Mathematics of Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.,Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Sergey E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234 Russia.,School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234 Russia.,Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia.,Department of Biochemistry, Biological Faculty, Lomonosov Moscow State University, Moscow, 119234 Russia
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Crystal structure of the DENR-MCT-1 complex revealed zinc-binding site essential for heterodimer formation. Proc Natl Acad Sci U S A 2018; 116:528-533. [PMID: 30584092 DOI: 10.1073/pnas.1809688116] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The density-regulated protein (DENR) and the malignant T cell-amplified sequence 1 (MCT-1/MCTS1) oncoprotein support noncanonical translation initiation, promote translation reinitiation on a specific set of mRNAs with short upstream reading frames, and regulate ribosome recycling. DENR and MCT-1 form a heterodimer, which binds to the ribosome. We determined the crystal structure of the heterodimer formed by human MCT-1 and the N-terminal domain of DENR at 2.0-Å resolution. The structure of the heterodimer reveals atomic details of the mechanism of DENR and MCT-1 interaction. Four conserved cysteine residues of DENR (C34, C37, C44, C53) form a classical tetrahedral zinc ion-binding site, which preserves the structure of the DENR's MCT-1-binding interface that is essential for the dimerization. Substitution of all four cysteines by alanine abolished a heterodimer formation. Our findings elucidate further the mechanism of regulation of DENR-MCT-1 activities in unconventional translation initiation, reinitiation, and recycling.
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43
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Control of mRNA Translation by Versatile ATP-Driven Machines. Trends Biochem Sci 2018; 44:167-180. [PMID: 30527974 DOI: 10.1016/j.tibs.2018.11.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 10/29/2018] [Accepted: 11/01/2018] [Indexed: 12/13/2022]
Abstract
Translation is organized in a cycle that requires ribosomal subunits, mRNA, aminoacylated transfer RNAs, and myriad regulatory factors. As soon as translation reaches a stop codon or stall, a termination or surveillance process is launched via the release factors eRF1 or Pelota, respectively. The ATP-binding cassette (ABC) protein ABCE1 interacts with release factors and coordinates the recycling process in Eukarya and Archaea. After splitting, ABCE1 stays with the small ribosomal subunit and emerges as an integral part of translation initiation complexes. In addition, eEF3 and ABCF proteins control translation by binding at the E-site. In this review, we highlight advances in the fundamental role of ABC systems in mRNA translation in view of their collective inner mechanics.
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44
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Merrick WC, Pavitt GD. Protein Synthesis Initiation in Eukaryotic Cells. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a033092. [PMID: 29735639 DOI: 10.1101/cshperspect.a033092] [Citation(s) in RCA: 197] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review summarizes our current understanding of the major pathway for the initiation phase of protein synthesis in eukaryotic cells, with a focus on recent advances. We describe the major scanning or messenger RNA (mRNA) m7G cap-dependent mechanism, which is a highly coordinated and stepwise regulated process that requires the combined action of at least 12 distinct translation factors with initiator transfer RNA (tRNA), ribosomes, and mRNAs. We limit our review to studies involving either mammalian or budding yeast cells and factors, as these represent the two best-studied experimental systems, and only include a reference to other organisms where particular insight has been gained. We close with a brief description of what we feel are some of the major unknowns in eukaryotic initiation.
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Affiliation(s)
- William C Merrick
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Graham D Pavitt
- Division of Molecular and Cellular Function, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, United Kingdom
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45
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Akulich KA, Sinitcyn PG, Makeeva DS, Andreev DE, Terenin IM, Anisimova AS, Shatsky IN, Dmitriev SE. A novel uORF-based regulatory mechanism controls translation of the human MDM2 and eIF2D mRNAs during stress. Biochimie 2018; 157:92-101. [PMID: 30419262 DOI: 10.1016/j.biochi.2018.11.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/06/2018] [Indexed: 01/02/2023]
Abstract
Short upstream open reading frames (uORFs) are the most prevalent cis-acting regulatory elements in the mammalian transcriptome which can orchestrate mRNA translation. Apart from being "passive roadblocks" that decrease expression of the main coding regions, particular uORFs can serve as specific sensors for changing conditions, thus regulating translation in response to cell stress. Here we report a novel uORF-based regulatory mechanism that is employed under conditions of hyperosmotic stress by at least two human mRNAs, coding for translation reinitiation/recycling factor eIF2D and E3 ubiquitin ligase MDM2. This novel mode of translational control selectively downregulates their expression and requires as few as one uORF. Using a set of reporter mRNAs and fleeting mRNA transfection (FLERT) technique, we provide evidence that the phenomenon does not rely on delayed reinitiation, altered AUG recognition, ribosome stalling, mRNA destabilization or other known mechanisms. Instead, it is based on events taking place at uORF stop codon or immediately downstream. Functional aspects and implications of the novel regulatory mechanism to cell physiology are discussed.
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Affiliation(s)
- Kseniya A Akulich
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Pavel G Sinitcyn
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Desislava S Makeeva
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Dmitry E Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Ilya M Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia; Sechenov First Moscow State Medical University, Institute of Molecular Medicine, 119991, Moscow, Russia
| | - Aleksandra S Anisimova
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Sergey E Dmitriev
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia; Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia; Department of Biochemistry, Biological Faculty, Lomonosov Moscow State University, Moscow, 119991, Russia.
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46
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Hellen CUT. Translation Termination and Ribosome Recycling in Eukaryotes. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a032656. [PMID: 29735640 DOI: 10.1101/cshperspect.a032656] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Termination of mRNA translation occurs when a stop codon enters the A site of the ribosome, and in eukaryotes is mediated by release factors eRF1 and eRF3, which form a ternary eRF1/eRF3-guanosine triphosphate (GTP) complex. eRF1 recognizes the stop codon, and after hydrolysis of GTP by eRF3, mediates release of the nascent peptide. The post-termination complex is then disassembled, enabling its constituents to participate in further rounds of translation. Ribosome recycling involves splitting of the 80S ribosome by the ATP-binding cassette protein ABCE1 to release the 60S subunit. Subsequent dissociation of deacylated transfer RNA (tRNA) and messenger RNA (mRNA) from the 40S subunit may be mediated by initiation factors (priming the 40S subunit for initiation), by ligatin (eIF2D) or by density-regulated protein (DENR) and multiple copies in T-cell lymphoma-1 (MCT1). These events may be subverted by suppression of termination (yielding carboxy-terminally extended read-through polypeptides) or by interruption of recycling, leading to reinitiation of translation near the stop codon.
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Affiliation(s)
- Christopher U T Hellen
- Department of Cell Biology, State University of New York, Downstate Medical Center, New York, New York 11203
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47
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Young DJ, Makeeva DS, Zhang F, Anisimova AS, Stolboushkina EA, Ghobakhlou F, Shatsky IN, Dmitriev SE, Hinnebusch AG, Guydosh NR. Tma64/eIF2D, Tma20/MCT-1, and Tma22/DENR Recycle Post-termination 40S Subunits In Vivo. Mol Cell 2018; 71:761-774.e5. [PMID: 30146315 PMCID: PMC6225905 DOI: 10.1016/j.molcel.2018.07.028] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 06/11/2018] [Accepted: 07/21/2018] [Indexed: 02/05/2023]
Abstract
The recycling of ribosomal subunits after translation termination is critical for efficient gene expression. Tma64 (eIF2D), Tma20 (MCT-1), and Tma22 (DENR) function as 40S recycling factors in vitro, but it is unknown whether they perform this function in vivo. Ribosome profiling of tma deletion strains revealed 80S ribosomes queued behind the stop codon, consistent with a block in 40S recycling. We found that unrecycled ribosomes could reinitiate translation at AUG codons in the 3' UTR, as evidenced by peaks in the footprint data and 3' UTR reporter analysis. In vitro translation experiments using reporter mRNAs containing upstream open reading frames (uORFs) further established that reinitiation increased in the absence of these proteins. In some cases, 40S ribosomes appeared to rejoin with 60S subunits and undergo an 80S reinitiation process in 3' UTRs. These results support a crucial role for Tma64, Tma20, and Tma22 in recycling 40S ribosomal subunits at stop codons and translation reinitiation.
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Affiliation(s)
- David J Young
- Laboratory of Gene Regulation & Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA; Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Desislava S Makeeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia; School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Fan Zhang
- Laboratory of Gene Regulation & Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Aleksandra S Anisimova
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Elena A Stolboushkina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Russia
| | - Fardin Ghobakhlou
- Laboratory of Gene Regulation & Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
| | - Ivan N Shatsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Sergey E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia; Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia; Department of Biochemistry, Biological Faculty, Lomonosov Moscow State University, Moscow 119234, Russia.
| | - Alan G Hinnebusch
- Laboratory of Gene Regulation & Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
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48
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Unique features of mammalian mitochondrial translation initiation revealed by cryo-EM. Nature 2018; 560:263-267. [PMID: 30089917 DOI: 10.1038/s41586-018-0373-y] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/17/2018] [Indexed: 11/09/2022]
Abstract
Mitochondria maintain their own specialized protein synthesis machinery, which in mammals is used exclusively for the synthesis of the membrane proteins responsible for oxidative phosphorylation1,2. The initiation of protein synthesis in mitochondria differs substantially from bacterial or cytosolic translation systems. Mitochondrial translation initiation lacks initiation factor 1, which is essential in all other translation systems from bacteria to mammals3,4. Furthermore, only one type of methionyl transfer RNA (tRNAMet) is used for both initiation and elongation4,5, necessitating that the initiation factor specifically recognizes the formylated version of tRNAMet (fMet-tRNAMet). Lastly, most mitochondrial mRNAs do not possess 5' leader sequences to promote mRNA binding to the ribosome2. There is currently little mechanistic insight into mammalian mitochondrial translation initiation, and it is not clear how mRNA engagement, initiator-tRNA recruitment and start-codon selection occur. Here we determine the cryo-EM structure of the complete translation initiation complex from mammalian mitochondria at 3.2 Å. We describe the function of an additional domain insertion that is present in the mammalian mitochondrial initiation factor 2 (mtIF2). By closing the decoding centre, this insertion stabilizes the binding of leaderless mRNAs and induces conformational changes in the rRNA nucleotides involved in decoding. We identify unique features of mtIF2 that are required for specific recognition of fMet-tRNAMet and regulation of its GTPase activity. Finally, we observe that the ribosomal tunnel in the initiating ribosome is blocked by insertion of the N-terminal portion of mitochondrial protein mL45, which becomes exposed as the ribosome switches to elongation mode and may have an additional role in targeting of mitochondrial ribosomes to the protein-conducting pore in the inner mitochondrial membrane.
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49
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Ryoo HD, Vasudevan D. Two distinct nodes of translational inhibition in the Integrated Stress Response. BMB Rep 2018; 50:539-545. [PMID: 28803610 PMCID: PMC5720466 DOI: 10.5483/bmbrep.2017.50.11.157] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Indexed: 12/21/2022] Open
Abstract
The Integrated Stress Response (ISR) refers to a signaling pathway initiated by stress-activated eIF2α kinases. Once activated, the pathway causes attenuation of global mRNA translation while also paradoxically inducing stress response gene expression. A detailed analysis of this pathway has helped us better understand how stressed cells coordinate gene expression at translational and transcriptional levels. The translational attenuation associated with this pathway has been largely attributed to the phosphorylation of the translational initiation factor eIF2α. However, independent studies are now pointing to a second translational regulation step involving a downstream ISR target, 4E-BP, in the inhibition of eIF4E and specifically cap-dependent translation. The activation of 4E-BP is consistent with previous reports implicating the roles of 4E-BP resistant, Internal Ribosome Entry Site (IRES) dependent translation in ISR active cells. In this review, we provide an overview of the translation inhibition mechanisms engaged by the ISR and how they impact the translation of stress response genes.
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Affiliation(s)
- Hyung Don Ryoo
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Deepika Vasudevan
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
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50
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van de Waterbeemd M, Tamara S, Fort KL, Damoc E, Franc V, Bieri P, Itten M, Makarov A, Ban N, Heck AJR. Dissecting ribosomal particles throughout the kingdoms of life using advanced hybrid mass spectrometry methods. Nat Commun 2018; 9:2493. [PMID: 29950687 PMCID: PMC6021402 DOI: 10.1038/s41467-018-04853-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/28/2018] [Indexed: 11/08/2022] Open
Abstract
Biomolecular mass spectrometry has matured strongly over the past decades and has now reached a stage where it can provide deep insights into the structure and composition of large cellular assemblies. Here, we describe a three-tiered hybrid mass spectrometry approach that enables the dissection of macromolecular complexes in order to complement structural studies. To demonstrate the capabilities of the approach, we investigate ribosomes, large ribonucleoprotein particles consisting of a multitude of protein and RNA subunits. We identify sites of sequence processing, protein post-translational modifications, and the assembly and stoichiometry of individual ribosomal proteins in four distinct ribosomal particles of bacterial, plant and human origin. Amongst others, we report extensive cysteine methylation in the zinc finger domain of the human S27 protein, the heptameric stoichiometry of the chloroplastic stalk complex, the heterogeneous composition of human 40S ribosomal subunits and their association to the CrPV, and HCV internal ribosome entry site RNAs.
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Affiliation(s)
- Michiel van de Waterbeemd
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, 3584CH, The Netherlands
- Netherlands Proteomics Center, 3584CH, Utrecht, The Netherlands
| | - Sem Tamara
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, 3584CH, The Netherlands
- Netherlands Proteomics Center, 3584CH, Utrecht, The Netherlands
| | - Kyle L Fort
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, 3584CH, The Netherlands
- Netherlands Proteomics Center, 3584CH, Utrecht, The Netherlands
- Thermo Fisher Scientific, 28199, Bremen, Germany
| | - Eugen Damoc
- Thermo Fisher Scientific, 28199, Bremen, Germany
| | - Vojtech Franc
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, 3584CH, The Netherlands
- Netherlands Proteomics Center, 3584CH, Utrecht, The Netherlands
| | - Philipp Bieri
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland
| | - Martin Itten
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland
| | - Alexander Makarov
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, 3584CH, The Netherlands
- Thermo Fisher Scientific, 28199, Bremen, Germany
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, 3584CH, The Netherlands.
- Netherlands Proteomics Center, 3584CH, Utrecht, The Netherlands.
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