Initiation Factor Eif5b Catalyzes Second GTP-Dependent Step in Eukaryotic Translation Initiation
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Translational Resistance of Late Alphavirus Mrna to Eif2␣ Phosphorylation: a Strategy to Overcome the Antiviral Effect of Protein Kinase PKR
Downloaded from genesdev.cshlp.org on September 29, 2021 - Published by Cold Spring Harbor Laboratory Press Translational resistance of late alphavirus mRNA to eIF2␣ phosphorylation: a strategy to overcome the antiviral effect of protein kinase PKR Iván Ventoso,1,3 Miguel Angel Sanz,2 Susana Molina,2 Juan José Berlanga,2 Luis Carrasco,2 and Mariano Esteban1 1Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología/CSIC, Cantoblanco, E-28049 Madrid, Spain; 2Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Facultad de Ciencias, Cantoblanco, E-28049 Madrid, Spain The double-stranded RNA-dependent protein kinase (PKR) is one of the four mammalian kinases that phosphorylates the translation initiation factor 2␣ in response to virus infection. This kinase is induced by interferon and activated by double-stranded RNA (dsRNA). Phosphorylation of eukaryotic initiation factor 2␣ (eIF2␣) blocks translation initiation of both cellular and viral mRNA, inhibiting virus replication. To counteract this effect, most viruses express inhibitors that prevent PKR activation in infected cells. Here we report that PKR is highly activated following infection with alphaviruses Sindbis (SV) and Semliki Forest virus (SFV), leading to the almost complete phosphorylation of eIF2␣. Notably, subgenomic SV 26S mRNA is translated efficiently in the presence of phosphorylated eIF2␣. This modification of eIF2 does not restrict viral replication; SV 26S mRNA initiates translation with canonical methionine in the presence of high levels of phosphorylated eIF2␣. Genetic and biochemical data showed a highly stable RNA hairpin loop located downstream of the AUG initiator codon that is necessary to provide translational resistance to eIF2␣ phosphorylation. This structure can stall the ribosomes on the correct site to initiate translation of SV 26S mRNA, thus bypassing the requirement for a functional eIF2. -
Amino Acid Specificity in Translation
Opinion TRENDS in Biochemical Sciences Vol.30 No.12 December 2005 Amino acid specificity in translation Taraka Dale and Olke C. Uhlenbeck Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, IL 60208, USA Recent structural and biochemical experiments indicate For example, in the course of deducing the recognition that bacterial elongation factor Tu and the ribosomal rules of aaRSs, several amber-suppressor tRNA bodies A-site show specificity for both the amino acid and the were deliberately mutated such that they were amino- tRNA portions of their aminoacyl-tRNA (aa-tRNA) acylated by a different aaRS, and the resulting ‘identity- substrates. These data are inconsistent with the swapped’ tRNAs were shown to insert the new amino acid traditional view that tRNAs are generic adaptors in into protein [7,8]. In addition, suppressor tRNAs esterified translation. We hypothesize that each tRNA sequence with O30 different unnatural amino acids have been has co-evolved with its cognate amino acid, such that all successfully incorporated into protein [9]. Together, these aa-tRNAs are translated uniformly. data suggest that the translational apparatus lacks specificity for different amino acids, once they are Introduction esterified onto tRNA. The mechanism of protein synthesis is traditionally In a few isolated cases, however, the translation considered to have two phases with different specificities machinery seems to show specificity for the esterified towards the 20 amino acid side chains (Figure 1). In the amino acid. A prominent example occurs in the transami- first phase, each amino acid is specifically recognized by dation pathway, which is used as an alternative to GlnRS its cognate aminoacyl-tRNA synthetase (aaRS) and to produce Gln-tRNAGln in many bacteria and archaea esterified to the appropriate tRNA to form an aminoacyl- [10,11]. -
From Thermus Thermophilus HB8
Crystal Structure of Elongation Factor P from Thermus thermophilus HB8 Genetic information encoded in messenger RNA molecules. Several proteins were found to possess is translated into protein by the ribosome, which is a domain(s) similar to a portion of tRNA, by which they large ribonucleoprotein complex. It has been clarified interact with the ribosome. The C-terminal domain of that diverse proteins called translation factors and elongation factor G (EF-G) has a shape similar to that RNAs are involved in genetic translation. Translation of the anticodon-stem loop in the elongation factor Tu elongation factor P (EF-P) is one of the translation (EF-Tu)• tRNA• GDPNP ternary complex. Release factors and stimulates the first peptidyl transferase factor 2 (RF2) and ribosome recycling factor (RRF) activity of the ribosome [1]. EF-P is conserved in were also found to possess a protruding domain, by bacteria, and is essential for their viability. Eukarya which they are believed to bind to the ribosome A site and Archaea have an EF-P homologue, eukaryotic [3]. In contrast with these factors, the entire structure initiation factor 5A (eIF-5A). of the EF-P mimics the overall shape of the tRNA We succeeded in the determination of the crystal molecule (Fig. 2). In addition, it is notable that EF-P is structure of EF-P from Thermus thermophilus HB8 at an acidic protein and most of its surface is negatively 1.65 Å resolution, using beamline BL45PX [2]. The charged. The overall tRNA-like shape of the EF-P crystallographic asymmetric unit contains two nearly molecule and the charge distribution seem to be identical EF-P monomers (Fig. -
A Helicase-Independent Activity of Eif4a in Promoting Mrna Recruitment to the Human Ribosome
A helicase-independent activity of eIF4A in promoting mRNA recruitment to the human ribosome Masaaki Sokabea and Christopher S. Frasera,1 aDepartment of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA 95616 Edited by Alan G. Hinnebusch, National Institutes of Health, Bethesda, MD, and approved May 5, 2017 (received for review December 12, 2016) In the scanning model of translation initiation, the decoding site and at the solvent side of the mRNA entry channel (14). Importantly, latch of the 40S subunit must open to allow the recruitment and that study showed that a short mRNA that does not extend into the migration of messenger RNA (mRNA); however, the precise molec- entry channel fails to displace eIF3j. A similar observation was also ular details for how initiation factors regulate mRNA accommodation found for initiation mediated by the hepatitis C virus internal ribo- into the decoding site have not yet been elucidated. Eukaryotic some entry site, where an mRNA truncated after the initiation co- initiation factor (eIF) 3j is a subunit of eIF3 that binds to the mRNA don failed to displace eIF3j (11). Taken together, these studies entry channel and A-site of the 40S subunit. Previous studies have suggest a model in which a full accommodation of mRNA in the shown that a reduced affinity of eIF3j for the 43S preinitiation mRNA entry channel of the 40S subunit corresponds to a reduced complex (PIC) occurs on eIF4F-dependent mRNA recruitment. Because affinity of eIF3j for the 40S subunit. This model has allowed us to eIF3j and mRNA bind anticooperatively to the 43S PIC, reduced eIF3j exploit the change in eIF3j affinity for the 43S PIC to quantitatively affinity likely reflects a state of full accommodation of mRNA into the monitor the process of mRNA recruitment. -
EF-Tu and Rnase E Are Functionally Connected
Till min familj List of Papers This thesis is based on the following papers, which are referred to in the text by their Roman numerals. I Hammarlöf, D.L., Hughes, D. (2008) Mutants of the RNA- processing enzyme RNase E reverse the extreme slow-growth phenotype caused by a mutant translation factor EF-Tu. Molecular Microbiology, 70(5), 1194-1209 II †Bergman, J., †Hammarlöf, D.L., Hughes D. (2011) Reducing ppGpp levels rescues the extreme growth defect of mutant EF-Tu. Manuscript III Hammarlöf, D.L., Liljas, L., Hughes, D. (2011) Temperature- sensitive mutants of RNase E in Salmonella enterica. Journal of Bacteriology. In press IV †Hammarlöf, D.L., †Bergman, J., Hughes, D. (2011) Extragenic suppressors of RNase E. Manuscript †These authors contributed equally. Reprints were made with permission from the respective publishers. Contents Introduction ................................................................................................... 11 Bacterial growth ....................................................................................... 11 Translation in bacteria .............................................................................. 12 The ribosome ....................................................................................... 12 The translation cycle ............................................................................ 13 Elongation Factor Tu ................................................................................ 14 The most abundant protein in the cell ................................................. -
Ten Commandments for a Good Scientist
Unravelling the mechanism of differential biological responses induced by food-borne xeno- and phyto-estrogenic compounds Ana María Sotoca Covaleda Wageningen 2010 Thesis committee Thesis supervisors Prof. dr. ir. Ivonne M.C.M. Rietjens Professor of Toxicology Wageningen University Prof. dr. Albertinka J. Murk Personal chair at the sub-department of Toxicology Wageningen University Thesis co-supervisor Dr. ir. Jacques J.M. Vervoort Associate professor at the Laboratory of Biochemistry Wageningen University Other members Prof. dr. Michael R. Muller, Wageningen University Prof. dr. ir. Huub F.J. Savelkoul, Wageningen University Prof. dr. Everardus J. van Zoelen, Radboud University Nijmegen Dr. ir. Toine F.H. Bovee, RIKILT, Wageningen This research was conducted under the auspices of the Graduate School VLAG Unravelling the mechanism of differential biological responses induced by food-borne xeno- and phyto-estrogenic compounds Ana María Sotoca Covaleda Thesis submitted in fulfillment of the requirements for the degree of doctor at Wageningen University by the authority of the Rector Magnificus Prof. dr. M.J. Kropff, in the presence of the Thesis Committee appointed by the Academic Board to be defended in public on Tuesday 14 September 2010 at 4 p.m. in the Aula Unravelling the mechanism of differential biological responses induced by food-borne xeno- and phyto-estrogenic compounds. Ana María Sotoca Covaleda Thesis Wageningen University, Wageningen, The Netherlands, 2010, With references, and with summary in Dutch. ISBN: 978-90-8585-707-5 “Caminante no hay camino, se hace camino al andar. Al andar se hace camino, y al volver la vista atrás se ve la senda que nunca se ha de volver a pisar” - Antonio Machado – A mi madre. -
Archaeal Translation Initiation Revisited: the Initiation Factor 2 and Eukaryotic Initiation Factor 2B ␣--␦ Subunit Families
Proc. Natl. Acad. Sci. USA Vol. 95, pp. 3726–3730, March 1998 Evolution Archaeal translation initiation revisited: The initiation factor 2 and eukaryotic initiation factor 2B a-b-d subunit families NIKOS C. KYRPIDES* AND CARL R. WOESE Department of Microbiology, University of Illinois at Urbana-Champaign, B103 Chemical and Life Sciences, MC 110, 407 S. Goodwin, Urbana, IL 61801 Contributed by Carl R. Woese, December 31, 1997 ABSTRACT As the amount of available sequence data bacterial and eukaryotic translation initiation mechanisms, increases, it becomes apparent that our understanding of although mechanistically generally similar, were molecularly translation initiation is far from comprehensive and that unrelated and so had evolved independently. The Methano- prior conclusions concerning the origin of the process are coccus jannaschii genome (7–9), which gave us our first wrong. Contrary to earlier conclusions, key elements of trans- comprehensive look at the componentry of archaeal transla- lation initiation originated at the Universal Ancestor stage, for tion initiation, revealed that archaeal translation initiation homologous counterparts exist in all three primary taxa. showed considerable homology with eukaryotic initiation, Herein, we explore the evolutionary relationships among the which, if anything, reinforced the divide between bacterial components of bacterial initiation factor 2 (IF-2) and eukary- initiation and that seen in the other domains. We recently have otic IF-2 (eIF-2)/eIF-2B, i.e., the initiation factors involved in shown, however, that bacterial translation initiation factor 1 introducing the initiator tRNA into the translation mecha- (IF-1), contrary to previously accepted opinion, is related in nism and performing the first step in the peptide chain sequence to its eukaryotic/archaeal (functional) counterpart, elongation cycle. -
Universal Conservation in Translation Initiation Revealed By
Proc. Natl. Acad. Sci. USA Vol. 96, pp. 4342–4347, April 1999 Biochemistry Universal conservation in translation initiation revealed by human and archaeal homologs of bacterial translation initiation factor IF2 (eukaryotic translation initiation factoryFUN12yinitiator tRNA) JOON H. LEE*, SANG KI CHOI*, ANTONINA ROLL-MECAK†,STEPHEN K. BURLEY†‡, AND THOMAS E. DEVER*§ *Laboratory of Eukaryotic Gene Regulation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2716; and †Laboratories of Molecular Biophysics and ‡Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10021 Communicated by Igor B. Dawid, National Institute of Child Health and Human Development, Bethesda, MD, February 11, 1999 (received for review September 22, 1998) ABSTRACT Binding of initiator methionyl-tRNA to ribo- romyces cerevisiae (7) revealed the presence of IF2 homologs somes is catalyzed in prokaryotes by initiation factor (IF) IF2 in addition to all three eIF2 subunits in this archaeon and and in eukaryotes by eIF2. The discovery of both IF2 and eIF2 eukaryote, respectively. The identification of both IF2 and homologs in yeast and archaea suggested that these microbes eIF2 homologs in archaea was surprising and contributed to possess an evolutionarily intermediate protein synthesis ap- speculation that archaea may possess a translation apparatus paratus. We describe the identification of a human IF2 intermediate between prokaryotes and eukaryotes (8). The homolog, and we demonstrate by using in vivo and in vitro presence of the IF2 homolog in yeast suggests instead that IF2 assays that human IF2 functions as a translation factor. In has been conserved throughout the evolution of microbes from addition, we show that archaea IF2 can substitute for its yeast bacteria to the lower eukaryotes. -
Ribosomal Initiation Complex-Driven Changes in the Stability and Dynamics of Initiation Factor 2 Regulate the Fidelity of Translation Initiation
Article Ribosomal Initiation Complex-Driven Changes in the Stability and Dynamics of Initiation Factor 2 Regulate the Fidelity of Translation Initiation Jiangning Wang, Kelvin Caban and Ruben L. Gonzalez Jr. Department of Chemistry, Columbia University, 3000 Broadway, MC3126, New York, NY 10027, USA Correspondence to Ruben L. Gonzalez: [email protected] http://dx.doi.org/10.1016/j.jmb.2014.12.025 Edited by S. A. Woodson Abstract Joining of the large, 50S, ribosomal subunit to the small, 30S, ribosomal subunit initiation complex (IC) during bacterial translation initiation is catalyzed by the initiation factor (IF) IF2. Because the rate of subunit joining is coupled to the IF, transfer RNA (tRNA), and mRNA codon compositions of the 30S IC, the subunit joining reaction functions as a kinetic checkpoint that regulates the fidelity of translation initiation. Recent structural studies suggest that the conformational dynamics of the IF2·tRNA sub-complex forming on the intersubunit surface of the 30S IC may play a significant role in the mechanisms that couple the rate of subunit joining to the IF, tRNA, and codon compositions of the 30S IC. To test this hypothesis, we have developed a single-molecule fluorescence resonance energy transfer signal between IF2 and tRNA that has enabled us to monitor the conformational dynamics of the IF2·tRNA sub-complex across a series of 30S ICs. Our results demonstrate that 30S ICs undergoing rapid subunit joining display a high affinity for IF2 and an IF2·tRNA sub-complex that primarily samples a single conformation. In contrast, 30S ICs that undergo slower subunit joining exhibit a decreased affinity for IF2 and/or a change in the conformational dynamics of the IF2·tRNA sub-complex. -
Eif4a Is Stimulated by the Pre-Initiation Complex and Enhances Recruitment of Mrnas Regardless of Structural Complexity
bioRxiv preprint doi: https://doi.org/10.1101/147959; this version posted June 13, 2017. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 1 eIF4A is stimulated by the pre-initiation complex and enhances recruitment of mRNAs regardless of structural 2 complexity 3 Paul Yourik1, Colin Echeverría Aitken1, Fujun Zhou1, Neha Gupta1,2, Alan G. Hinnebusch2,3, Jon R. Lorsch1,3 4 5 1Laboratory on the Mechanism and Regulation of Protein Synthesis, Eunice Kennedy Shriver National Institute of Child 6 Health and Development, National Institutes of Health, Bethesda, MD 20892 7 2Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and 8 Human Development, National Institutes of Health, Bethesda, MD 20892, USA 9 3Corresponding Author 10 11 ABSTRACT 12 eIF4A is a DEAD-box RNA-dependent ATPase thought to unwind RNA secondary structure in the 5'-untranslated 13 regions (UTRs) of mRNAs to promote their recruitment to the eukaryotic translation pre-initiation complex (PIC). We 14 show that the PIC stimulates the ATPase of eIF4A, indicating that the factor acts in association with initiating ribosomal 15 complexes rather than exclusively on isolated mRNAs. ATP hydrolysis by eIF4A accelerates the rate of recruitment for 16 all mRNAs tested, regardless of their degree of secondary structure, indicating that the factor plays important roles 17 beyond unwinding mRNA structure. Structures in the 5'-UTR and 3' of the start codon synergistically inhibit mRNA 18 recruitment, in a manner relieved by eIF4A, suggesting that the factor resolves global mRNA structure rather than just 19 secondary structures in the 5'-UTR. -
Whole Exome Sequencing in Families at High Risk for Hodgkin Lymphoma: Identification of a Predisposing Mutation in the KDR Gene
Hodgkin Lymphoma SUPPLEMENTARY APPENDIX Whole exome sequencing in families at high risk for Hodgkin lymphoma: identification of a predisposing mutation in the KDR gene Melissa Rotunno, 1 Mary L. McMaster, 1 Joseph Boland, 2 Sara Bass, 2 Xijun Zhang, 2 Laurie Burdett, 2 Belynda Hicks, 2 Sarangan Ravichandran, 3 Brian T. Luke, 3 Meredith Yeager, 2 Laura Fontaine, 4 Paula L. Hyland, 1 Alisa M. Goldstein, 1 NCI DCEG Cancer Sequencing Working Group, NCI DCEG Cancer Genomics Research Laboratory, Stephen J. Chanock, 5 Neil E. Caporaso, 1 Margaret A. Tucker, 6 and Lynn R. Goldin 1 1Genetic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD; 2Cancer Genomics Research Laboratory, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD; 3Ad - vanced Biomedical Computing Center, Leidos Biomedical Research Inc.; Frederick National Laboratory for Cancer Research, Frederick, MD; 4Westat, Inc., Rockville MD; 5Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD; and 6Human Genetics Program, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD, USA ©2016 Ferrata Storti Foundation. This is an open-access paper. doi:10.3324/haematol.2015.135475 Received: August 19, 2015. Accepted: January 7, 2016. Pre-published: June 13, 2016. Correspondence: [email protected] Supplemental Author Information: NCI DCEG Cancer Sequencing Working Group: Mark H. Greene, Allan Hildesheim, Nan Hu, Maria Theresa Landi, Jennifer Loud, Phuong Mai, Lisa Mirabello, Lindsay Morton, Dilys Parry, Anand Pathak, Douglas R. Stewart, Philip R. Taylor, Geoffrey S. Tobias, Xiaohong R. Yang, Guoqin Yu NCI DCEG Cancer Genomics Research Laboratory: Salma Chowdhury, Michael Cullen, Casey Dagnall, Herbert Higson, Amy A. -
The Solution Structure of the Guanine Nucleotide Exchange Domain Of
View metadata, citation and similar papers at core.ac.uk brought to you by CORE Researchprovided Articleby Elsevier -217 Publisher Connector The solution structure of the guanine nucleotide exchange domain of human elongation factor 1b reveals a striking resemblance to that of EF-Ts from Escherichia coli Janice MJ Pérez1,2‡, Gregg Siegal2*‡, Jan Kriek1, Karl Hård2†, Jan Dijk1, Gerard W Canters2 and Wim Möller1 Background: In eukaryotic protein synthesis, the multi-subunit elongation Addresses: 1Department of Molecular Cell Biology, factor 1 (EF-1) plays an important role in ensuring the fidelity and regulating the Sylvius Laboratory, University of Leiden, Wassenaarseweg 72, NL-2333 AL Leiden, The rate of translation. EF-1α, which transports the aminoacyl tRNA to the Netherlands and 2Leiden Institute of Chemistry, β ribosome, is a member of the G-protein superfamily. EF-1 regulates the activity Gorlaeus Laboratory, University of Leiden, of EF-1α by catalyzing the exchange of GDP for GTP and thereby regenerating Einsteinweg 55, NL-2333 CC Leiden, The the active form of EF-1α. The structure of the bacterial analog of EF-1α, EF-Tu Netherlands. has been solved in complex with its GDP exchange factor, EF-Ts. These †Present address: Astra Structural Chemistry structures indicate a mechanism for GDP–GTP exchange in prokaryotes. Laboratory, S-43183 Mölndal, Sweden. Although there is good sequence conservation between EF-1α and EF-Tu, there is essentially no sequence similarity between EF-1β and EF-Ts. We ‡These two authors contributed equally to this work. wished to explore whether the prokaryotic exchange mechanism could shed any *Corresponding author.