1
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Cui H, Diedrich JK, Wu DC, Lim JJ, Nottingham RM, Moresco JJ, Yates JR, Blencowe BJ, Lambowitz AM, Schimmel P. Arg-tRNA synthetase links inflammatory metabolism to RNA splicing and nuclear trafficking via SRRM2. Nat Cell Biol 2023; 25:592-603. [PMID: 37059883 DOI: 10.1038/s41556-023-01118-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 02/27/2023] [Indexed: 04/16/2023]
Abstract
Cells respond to perturbations such as inflammation by sensing changes in metabolite levels. Especially prominent is arginine, which has known connections to the inflammatory response. Aminoacyl-tRNA synthetases, enzymes that catalyse the first step of protein synthesis, can also mediate cell signalling. Here we show that depletion of arginine during inflammation decreased levels of nuclear-localized arginyl-tRNA synthetase (ArgRS). Surprisingly, we found that nuclear ArgRS interacts and co-localizes with serine/arginine repetitive matrix protein 2 (SRRM2), a spliceosomal and nuclear speckle protein, and that decreased levels of nuclear ArgRS correlated with changes in condensate-like nuclear trafficking of SRRM2 and splice-site usage in certain genes. These splice-site usage changes cumulated in the synthesis of different protein isoforms that altered cellular metabolism and peptide presentation to immune cells. Our findings uncover a mechanism whereby an aminoacyl-tRNA synthetase cognate to a key amino acid that is metabolically controlled during inflammation modulates the splicing machinery.
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Affiliation(s)
- Haissi Cui
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Jolene K Diedrich
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Douglas C Wu
- Institute for Cellular and Molecular Biology and Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX, USA
| | - Justin J Lim
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Ryan M Nottingham
- Institute for Cellular and Molecular Biology and Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX, USA
| | - James J Moresco
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
- Center for the Genetics of Host Defense, UT Southwestern Medical Center, Dallas, TX, USA
| | - John R Yates
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Benjamin J Blencowe
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology and Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX, USA.
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.
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2
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Istvan ES, Guerra F, Abraham M, Huang KS, Rocamora F, Zhao H, Xu L, Pasaje C, Kumpornsin K, Luth MR, Cui H, Yang T, Diaz SP, Gomez-Lorenzo MG, Qahash T, Mittal N, Ottilie S, Niles J, Lee MCS, Llinas M, Kato N, Okombo J, Fidock DA, Schimmel P, Gamo FJ, Goldberg DE, Winzeler EA. Cytoplasmic isoleucyl tRNA synthetase as an attractive multistage antimalarial drug target. Sci Transl Med 2023; 15:eadc9249. [PMID: 36888694 PMCID: PMC10286833 DOI: 10.1126/scitranslmed.adc9249] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 02/17/2023] [Indexed: 03/10/2023]
Abstract
Development of antimalarial compounds into clinical candidates remains costly and arduous without detailed knowledge of the target. As resistance increases and treatment options at various stages of disease are limited, it is critical to identify multistage drug targets that are readily interrogated in biochemical assays. Whole-genome sequencing of 18 parasite clones evolved using thienopyrimidine compounds with submicromolar, rapid-killing, pan-life cycle antiparasitic activity showed that all had acquired mutations in the P. falciparum cytoplasmic isoleucyl tRNA synthetase (cIRS). Engineering two of the mutations into drug-naïve parasites recapitulated the resistance phenotype, and parasites with conditional knockdowns of cIRS became hypersensitive to two thienopyrimidines. Purified recombinant P. vivax cIRS inhibition, cross-resistance, and biochemical assays indicated a noncompetitive, allosteric binding site that is distinct from that of known cIRS inhibitors mupirocin and reveromycin A. Our data show that Plasmodium cIRS is an important chemically and genetically validated target for next-generation medicines for malaria.
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Affiliation(s)
- Eva S. Istvan
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Francisco Guerra
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Matthew Abraham
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | | | - Frances Rocamora
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | | | - Lan Xu
- The Global Health Drug Discovery Institute, Tsinghua University 30 Shuangqing Rd, Haidian District, Beijing, China
| | - Charisse Pasaje
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Madeline R. Luth
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Haissi Cui
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tuo Yang
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Sara Palomo Diaz
- Global Health Medicines, GlaxoSmithKline, Severo Ochoa 2, 28760 Tres Cantos, Spain
| | | | - Tarrick Qahash
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
- Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
| | - Nimisha Mittal
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Sabine Ottilie
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Jacquin Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Marcus C. S. Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, CB10 1SA, UK
| | - Manuel Llinas
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
- Huck Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Nobutaka Kato
- The Global Health Drug Discovery Institute, Tsinghua University 30 Shuangqing Rd, Haidian District, Beijing, China
| | - John Okombo
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York 10032, USA
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, New York 10032, USA
- Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, New York 10032, USA
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Daniel E. Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Elizabeth A. Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
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3
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Tye MA, Payne NC, Johansson C, Singh K, Santos SA, Fagbami L, Pant A, Sylvester K, Luth MR, Marques S, Whitman M, Mota MM, Winzeler EA, Lukens AK, Derbyshire ER, Oppermann U, Wirth DF, Mazitschek R. Elucidating the path to Plasmodium prolyl-tRNA synthetase inhibitors that overcome halofuginone resistance. Nat Commun 2022; 13:4976. [PMID: 36008486 PMCID: PMC9403976 DOI: 10.1038/s41467-022-32630-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 08/10/2022] [Indexed: 02/07/2023] Open
Abstract
The development of next-generation antimalarials that are efficacious against the human liver and asexual blood stages is recognized as one of the world's most pressing public health challenges. In recent years, aminoacyl-tRNA synthetases, including prolyl-tRNA synthetase, have emerged as attractive targets for malaria chemotherapy. We describe the development of a single-step biochemical assay for Plasmodium and human prolyl-tRNA synthetases that overcomes critical limitations of existing technologies and enables quantitative inhibitor profiling with high sensitivity and flexibility. Supported by this assay platform and co-crystal structures of representative inhibitor-target complexes, we develop a set of high-affinity prolyl-tRNA synthetase inhibitors, including previously elusive aminoacyl-tRNA synthetase triple-site ligands that simultaneously engage all three substrate-binding pockets. Several compounds exhibit potent dual-stage activity against Plasmodium parasites and display good cellular host selectivity. Our data inform the inhibitor requirements to overcome existing resistance mechanisms and establish a path for rational development of prolyl-tRNA synthetase-targeted anti-malarial therapies.
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Affiliation(s)
- Mark A Tye
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA, USA
- Harvard Graduate School of Arts and Sciences, Cambridge, MA, USA
- Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - N Connor Payne
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Catrine Johansson
- Botnar Research Centre, NIHR Oxford Biomedical Research Unit, University of Oxford, Oxford, UK
- Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | - Kritika Singh
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Sofia A Santos
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Lọla Fagbami
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA, USA
- Harvard Graduate School of Arts and Sciences, Cambridge, MA, USA
- Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Akansha Pant
- Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | | | - Madeline R Luth
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Sofia Marques
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Malcolm Whitman
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Elizabeth A Winzeler
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | | | | | - Udo Oppermann
- Botnar Research Centre, NIHR Oxford Biomedical Research Unit, University of Oxford, Oxford, UK
- Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | - Dyann F Wirth
- Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ralph Mazitschek
- Center for Systems Biology, Massachusetts General Hospital, Boston, MA, USA.
- Harvard T.H. Chan School of Public Health, Boston, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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4
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Abstract
Charcot-Marie-Tooth disease (CMT) is a devastating motor and sensory neuropathy with an estimated 100,000 afflicted individuals in the US. Unexpectedly, aminoacyl-tRNA synthetases are the largest disease-associated protein family. A natural explanation is that the disease is associated with weak translation or mistranslation (caused by editing defects). However, our results with six different disease-causing mutants in AlaRS ruled out defects in aminoacylation or editing as causal factors. Instead, specific mutant proteins gained a neuropilin 1 (Nrp1)-AlaRS interaction. Previously a gain of Nrp1 interaction with a different disease-causing tRNA synthetase was mechanistically linked to the pathology of CMT. Thus, our results raise the possibility that pathological engagement of Nrp1 is common to at least a subset of tRNA synthetase-associated cases of CMT. Through dominant mutations, aminoacyl-tRNA synthetases constitute the largest protein family linked to Charcot-Marie-Tooth disease (CMT). An example is CMT subtype 2N (CMT2N), caused by individual mutations spread out in AlaRS, including three in the aminoacylation domain, thereby suggesting a role for a tRNA-charging defect. However, here we found that two are aminoacylation defective but that the most widely distributed R329H is normal as a purified protein in vitro and in unfractionated patient cell samples. Remarkably, in contrast to wild-type (WT) AlaRS, all three mutant proteins gained the ability to interact with neuropilin 1 (Nrp1), the receptor previously linked to CMT pathogenesis in GlyRS. The aberrant AlaRS-Nrp1 interaction is further confirmed in patient samples carrying the R329H mutation. However, CMT2N mutations outside the aminoacylation domain do not induce the Nrp1 interaction. Detailed biochemical and biophysical investigations, including X-ray crystallography, small-angle X-ray scattering, hydrogen-deuterium exchange (HDX), switchSENSE hydrodynamic diameter determinations, and protease digestions reveal a mutation-induced structural loosening of the aminoacylation domain that correlates with the Nrp1 interaction. The b1b2 domains of Nrp1 are responsible for the interaction with R329H AlaRS. The results suggest Nrp1 is more broadly associated with CMT-associated members of the tRNA synthetase family. Moreover, we revealed a distinct structural loosening effect induced by a mutation in the editing domain and a lack of conformational impact with C-Ala domain mutations, indicating mutations in the same protein may cause neuropathy through different mechanisms. Our results show that, as with other CMT-associated tRNA synthetases, aminoacylation per se is not relevant to the pathology.
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5
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Shi Y, Liu Z, Zhang Q, Vallee I, Mo Z, Kishi S, Yang XL. Phosphorylation of seryl-tRNA synthetase by ATM/ATR is essential for hypoxia-induced angiogenesis. PLoS Biol 2020; 18:e3000991. [PMID: 33351793 PMCID: PMC7755189 DOI: 10.1371/journal.pbio.3000991] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 11/19/2020] [Indexed: 01/09/2023] Open
Abstract
Hypoxia-induced angiogenesis maintains tissue oxygen supply and protects against ischemia but also enhances tumor progression and malignancy. This is mediated through activation of transcription factors like hypoxia-inducible factor 1 (HIF-1) and c-Myc, yet the impact of hypoxia on negative regulators of angiogenesis is unknown. During vascular development, seryl-tRNA synthetase (SerRS) regulates angiogenesis through a novel mechanism by counteracting c-Myc and transcriptionally repressing vascular endothelial growth factor A (VEGFA) expression. Here, we reveal that the transcriptional repressor role of SerRS is inactivated under hypoxia through phosphorylation by ataxia telangiectasia mutated (ATM) and ataxia telangiectasia mutated and RAD3-related (ATR) at Ser101 and Ser241 to attenuate its DNA binding capacity. In zebrafish, SerRSS101D/S241D, a phosphorylation-mimicry mutant, cannot suppress VEGFA expression to support normal vascular development. Moreover, expression of SerRSS101A/S241A, a phosphorylation-deficient and constitutively active mutant, prevents hypoxia-induced binding of c-Myc and HIF-1 to the VEGFA promoter, and activation of VEGFA expression. Consistently, SerRSS101A/S241A strongly inhibits normal and tumor-derived angiogenesis in mice. Therefore, we reveal a key step regulating hypoxic angiogenesis and highlight the importance of nuclear SerRS in post-developmental angiogenesis regulation in addition to vascular development. The role of nuclear SerRS in inhibiting both c-Myc and HIF-1 may provide therapeutic opportunities to correct dysregulation of angiogenesis in pathological settings.
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Affiliation(s)
- Yi Shi
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
- School of Medicine, Nankai University, Tianjin, China
- * E-mail: (YS); (X-LY)
| | - Ze Liu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Qian Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Ingrid Vallee
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Zhongying Mo
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Shuji Kishi
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida, United States of America
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail: (YS); (X-LY)
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6
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Abstract
Aminoacyl-tRNA synthetases (ARSs) are essential enzymes for protein synthesis with evolutionarily conserved enzymatic mechanisms. Despite their similarity across organisms, scientists have been able to generate effective anti-infective agents based on the structural differences in the catalytic clefts of ARSs from pathogens and humans. However, recent genomic, proteomic and functionomic advances have unveiled unexpected disease-associated mutations and altered expression, secretion and interactions in human ARSs, revealing hidden biological functions beyond their catalytic roles in protein synthesis. These studies have also brought to light their potential as a rich and unexplored source for new therapeutic targets and agents through multiple avenues, including direct targeting of the catalytic sites, controlling disease-associated protein-protein interactions and developing novel biologics from the secreted ARS proteins or their parts. This Review addresses the emerging biology and therapeutic applications of human ARSs in diseases including autoimmune and rare diseases, and cancer.
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7
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CMT disease severity correlates with mutation-induced open conformation of histidyl-tRNA synthetase, not aminoacylation loss, in patient cells. Proc Natl Acad Sci U S A 2019; 116:19440-19448. [PMID: 31501329 DOI: 10.1073/pnas.1908288116] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Aminoacyl-transfer RNA (tRNA) synthetases (aaRSs) are the largest protein family causatively linked to neurodegenerative Charcot-Marie-Tooth (CMT) disease. Dominant mutations cause the disease, and studies of CMT disease-causing mutant glycyl-tRNA synthetase (GlyRS) and tyrosyl-tRNA synthetase (TyrRS) showed their mutations create neomorphic structures consistent with a gain-of-function mechanism. In contrast, based on a haploid yeast model, loss of aminoacylation function was reported for CMT disease mutants in histidyl-tRNA synthetase (HisRS). However, neither that nor prior work of any CMT disease-causing aaRS investigated the aminoacylation status of tRNAs in the cellular milieu of actual patients. Using an assay that interrogated aminoacylation levels in patient cells, we investigated a HisRS-linked CMT disease family with the most severe disease phenotype. Strikingly, no difference in charged tRNA levels between normal and diseased family members was found. In confirmation, recombinant versions of 4 other HisRS CMT disease-causing mutants showed no correlation between activity loss in vitro and severity of phenotype in vivo. Indeed, a mutation having the most detrimental impact on activity was associated with a mild disease phenotype. In further work, using 3 independent biophysical analyses, structural opening (relaxation) of mutant HisRSs at the dimer interface best correlated with disease severity. In fact, the HisRS mutation in the severely afflicted patient family caused the largest degree of structural relaxation. These data suggest that HisRS-linked CMT disease arises from open conformation-induced mechanisms distinct from loss of aminoacylation.
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8
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Buckner FS, Ranade RM, Gillespie JR, Shibata S, Hulverson MA, Zhang Z, Huang W, Choi R, Verlinde CLMJ, Hol WGJ, Ochida A, Akao Y, Choy RKM, Van Voorhis WC, Arnold SLM, Jumani RS, Huston CD, Fan E. Optimization of Methionyl tRNA-Synthetase Inhibitors for Treatment of Cryptosporidium Infection. Antimicrob Agents Chemother 2019; 63:e02061-18. [PMID: 30745384 PMCID: PMC6437504 DOI: 10.1128/aac.02061-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/01/2019] [Indexed: 02/07/2023] Open
Abstract
Cryptosporidiosis is one of the leading causes of moderate to severe diarrhea in children in low-resource settings. The therapeutic options for cryptosporidiosis are limited to one drug, nitazoxanide, which unfortunately has poor activity in the most needy populations of malnourished children and HIV-infected persons. We describe here the discovery and early optimization of a class of imidazopyridine-containing compounds with potential for treating Cryptosporidium infections. The compounds target the Cryptosporidium methionyl-tRNA synthetase (MetRS), an enzyme that is essential for protein synthesis. The most potent compounds inhibited the enzyme with Ki values in the low picomolar range. Cryptosporidium cells in culture were potently inhibited with 50% effective concentrations as low as 7 nM and >1,000-fold selectivity over mammalian cells. A parasite persistence assay indicates that the compounds act by a parasiticidal mechanism. Several compounds were demonstrated to control infection in two murine models of cryptosporidiosis without evidence of toxicity. Pharmacological and physicochemical characteristics of compounds were investigated to determine properties that were associated with higher efficacy. The results indicate that MetRS inhibitors are excellent candidates for development for anticryptosporidiosis therapy.
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Affiliation(s)
| | - Ranae M Ranade
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - J Robert Gillespie
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Sayaka Shibata
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | | | - Zhongsheng Zhang
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Wenlin Huang
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | - Ryan Choi
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | | | - Wim G J Hol
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
| | | | | | - Robert K M Choy
- Drug Development Program, PATH, San Francisco, California, USA
| | | | - Sam L M Arnold
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Rajiv S Jumani
- Department of Medicine, University of Vermont, Burlington, Vermont, USA
| | | | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
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9
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Abstract
Aminoacyl-tRNA synthetases (aaRSs) establish the rules to express the universal genetic code. During aminoacylation, each of the 20 aaRSs associates 1 of 20 amino acids with a specific trinucleotide known as anticodon. Remarkably, for alanyl-tRNAs, the synthetase makes no contact with the anticodon. Instead, it uses a “second genetic code” by picking out a single G3:U70 base pair in the tRNA acceptor stem, which is close to the amino acid attachment site, but 76 Å away from the anticodon. Here, we show that, while in the three kingdoms of life, alanyl-tRNA synthetases use G3:U70 to identify alanyl-tRNAs, surprisingly, they use three different mechanisms to achieve this. We thus suggest that, in evolution, the genetic code had a powerful and persistent preference for associating G:U with alanine. Throughout three domains of life, alanyl-tRNA synthetases (AlaRSs) recognize a G3:U70 base pair in the acceptor stem of tRNAAla as the major identity determinant of tRNAAla. The crystal structure of the archaeon Archaeoglobus fulgidus AlaRS in complex with tRNAAla provided the basis for G3:U70 recognition with residues (Asp and Asn) that are conserved in the three domains [Naganuma M, et al. (2014) Nature 510:507–511]. The recognition mode is unprecedented, with specific accommodation of the dyad asymmetry of the G:U wobble pair and exclusion of the dyad symmetry of a Watson–Crick pair. With this conserved mode, specificity is based more on “fit” than on direct recognition of specific atomic groups. Here, we show that, in contrast to the archaeal complex, the Escherichia coli enzyme uses direct positive (energetically favorable) minor groove recognition of the unpaired 2-amino of G3 by Asp and repulsion of a competing base pair by Asn. Strikingly, mutations that disrupted positive recognition by the E. coli enzyme had little or no effect on G:U recognition by the human enzyme. Alternatively, Homo sapiens AlaRS selects G:U without positive recognition and uses Asp instead to repel a competitor. Thus, the widely conserved Asp-plus-Asn architecture of AlaRSs can select G:U in a straightforward (bacteria) or two different unconventional (eukarya/archaea) ways. The adoption of different modes for recognition of a widely conserved G:U pair in alanine tRNAs suggests an early and insistent role for G:U in the development of the genetic code.
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10
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Vo MN, Terrey M, Lee JW, Roy B, Moresco JJ, Sun L, Fu H, Liu Q, Weber TG, Yates JR, Fredrick K, Schimmel P, Ackerman SL. ANKRD16 prevents neuron loss caused by an editing-defective tRNA synthetase. Nature 2018; 557:510-515. [PMID: 29769718 PMCID: PMC5973781 DOI: 10.1038/s41586-018-0137-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 04/09/2018] [Indexed: 11/29/2022]
Abstract
Editing domains of aminoacyl tRNA synthetases correct tRNA charging errors to maintain translational fidelity. A mutation in the editing domain of alanyl tRNA synthetase (AlaRS) in Aars sti mutant mice results in an increase in the production of serine-mischarged tRNAAla and the degeneration of cerebellar Purkinje cells. Here, using positional cloning, we identified Ankrd16, a gene that acts epistatically with the Aars sti mutation to attenuate neurodegeneration. ANKRD16, a vertebrate-specific protein that contains ankyrin repeats, binds directly to the catalytic domain of AlaRS. Serine that is misactivated by AlaRS is captured by the lysine side chains of ANKRD16, which prevents the charging of serine adenylates to tRNAAla and precludes serine misincorporation in nascent peptides. The deletion of Ankrd16 in the brains of Aarssti/sti mice causes widespread protein aggregation and neuron loss. These results identify an amino-acid-accepting co-regulator of tRNA synthetase editing as a new layer of the machinery that is essential to the prevention of severe pathologies that arise from defects in editing.
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Affiliation(s)
- My-Nuong Vo
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA
| | - Markus Terrey
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA
- Section of Neurobiology, University of California San Diego, La Jolla, CA, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - Jeong Woong Lee
- The Jackson Laboratory, Bar Harbor, ME, USA
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Bappaditya Roy
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - James J Moresco
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA, USA
- Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Litao Sun
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA
| | - Hongjun Fu
- The Jackson Laboratory, Bar Harbor, ME, USA
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Qi Liu
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
- Sharklet Technologies, Aurora, CO, USA
| | | | - John R Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA, USA
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Paul Schimmel
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA.
- The Scripps Research Institute, Jupiter, FL, USA.
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA.
- Section of Neurobiology, University of California San Diego, La Jolla, CA, USA.
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.
- The Jackson Laboratory, Bar Harbor, ME, USA.
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11
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Double mimicry evades tRNA synthetase editing by toxic vegetable-sourced non-proteinogenic amino acid. Nat Commun 2017; 8:2281. [PMID: 29273753 PMCID: PMC5741666 DOI: 10.1038/s41467-017-02201-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 11/13/2017] [Indexed: 01/29/2023] Open
Abstract
Hundreds of non-proteinogenic (np) amino acids (AA) are found in plants and can in principle enter human protein synthesis through foods. While aminoacyl-tRNA synthetase (AARS) editing potentially provides a mechanism to reject np AAs, some have pathological associations. Co-crystal structures show that vegetable-sourced azetidine-2-carboxylic acid (Aze), a dual mimic of proline and alanine, is activated by both human prolyl- and alanyl-tRNA synthetases. However, it inserts into proteins as proline, with toxic consequences in vivo. Thus, dual mimicry increases odds for mistranslation through evasion of one but not both tRNA synthetase editing systems.
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12
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Two crystal structures reveal design for repurposing the C-Ala domain of human AlaRS. Proc Natl Acad Sci U S A 2016; 113:14300-14305. [PMID: 27911835 DOI: 10.1073/pnas.1617316113] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The 20 aminoacyl tRNA synthetases (aaRSs) couple each amino acid to their cognate tRNAs. During evolution, 19 aaRSs expanded by acquiring novel noncatalytic appended domains, which are absent from bacteria and many lower eukaryotes but confer extracellular and nuclear functions in higher organisms. AlaRS is the single exception, with an appended C-terminal domain (C-Ala) that is conserved from prokaryotes to humans but with a wide sequence divergence. In human cells, C-Ala is also a splice variant of AlaRS. Crystal structures of two forms of human C-Ala, and small-angle X-ray scattering of AlaRS, showed that the large sequence divergence of human C-Ala reshaped C-Ala in a way that changed the global architecture of AlaRS. This reshaping removes the role of C-Ala in prokaryotes for docking tRNA and instead repurposes it to form a dimer interface presenting a DNA-binding groove. This groove cannot form with the bacterial ortholog. Direct DNA binding by human C-Ala, but not by bacterial C-Ala, was demonstrated. Thus, instead of acquiring a novel appended domain like other human aaRSs, which engendered novel functions, a new AlaRS architecture was created by diversifying a preexisting appended domain.
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13
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Spectrophotometric assays for monitoring tRNA aminoacylation and aminoacyl-tRNA hydrolysis reactions. Methods 2016; 113:3-12. [PMID: 27780756 DOI: 10.1016/j.ymeth.2016.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/17/2016] [Accepted: 10/21/2016] [Indexed: 11/22/2022] Open
Abstract
Aminoacyl-tRNA synthetases play a central role in protein synthesis, catalyzing the attachment of amino acids to their cognate tRNAs. Here, we describe a spectrophotometric assay for tyrosyl-tRNA synthetase in which the Tyr-tRNA product is cleaved, regenerating the tRNA substrate. As tRNA is the limiting substrate in the assay, recycling it substantially increases the sensitivity of the assay while simultaneously reducing its cost. The tRNA aminoacylation reaction is monitored spectrophotometrically by coupling the production of AMP to the conversion of NAD+ to NADH. We have adapted the tyrosyl-tRNA synthetase assay to monitor: (1) aminoacylation of tRNA by l- or d-tyrosine, (2) cyclodipeptide formation by cyclodipeptide synthases, (3) hydrolysis of d-aminoacyl-tRNAs by d-tyrosyl-tRNA deacylase, and (4) post-transfer editing by aminoacyl-tRNA synthetases. All of these assays are continuous and homogenous, making them amenable for use in high-throughput screens of chemical libraries. In the case of the cyclodipeptide synthase, d-tyrosyl-tRNA deacylase, and post-transfer editing assays, the aminoacyl-tRNAs are generated in situ, avoiding the need to synthesize and purify aminoacyl-tRNA substrates prior to performing the assays. Lastly, we describe how the tyrosyl-tRNA synthetase assay can be adapted to monitor the activity of other aminoacyl-tRNA synthetases and how the approach to regenerating the tRNA substrate can be used to increase the sensitivity and decrease the cost of commercially available aminoacyl-tRNA synthetase assays.
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14
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Structural characterization of antibiotic self-immunity tRNA synthetase in plant tumour biocontrol agent. Nat Commun 2016; 7:12928. [PMID: 27713402 PMCID: PMC5059758 DOI: 10.1038/ncomms12928] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 08/16/2016] [Indexed: 01/08/2023] Open
Abstract
Antibiotic-producing microbes evolved self-resistance mechanisms to avoid suicide. The biocontrol Agrobacterium radiobacter K84 secretes the Trojan Horse antibiotic agrocin 84 that is selectively transported into the plant pathogen A. tumefaciens and processed into the toxin TM84. We previously showed that TM84 employs a unique tRNA-dependent mechanism to inhibit leucyl-tRNA synthetase (LeuRS), while the TM84-producer prevents self-poisoning by expressing a resistant LeuRS AgnB2. We now identify a mechanism by which the antibiotic-producing microbe resists its own toxin. Using a combination of structural, biochemical and biophysical approaches, we show that AgnB2 evolved structural changes so as to resist the antibiotic by eliminating the tRNA-dependence of TM84 binding. Mutagenesis of key resistance determinants results in mutants adopting an antibiotic-sensitive phenotype. This study illuminates the evolution of resistance in self-immunity genes and provides mechanistic insights into a fascinating tRNA-dependent antibiotic with applications for the development of anti-infectives and the prevention of biocontrol emasculation.
The bacterium Agrobacterium radiobacter K84 secretes an antibiotic that is transported into the plant pathogen A. tumefaciens and processed into the toxin TM84. Here, the authors identify a mechanism whereby the antibiotic-producing microbe resists its own toxin.
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15
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Melo Czekster C, Robertson WE, Walker AS, Söll D, Schepartz A. In Vivo Biosynthesis of a β-Amino Acid-Containing Protein. J Am Chem Soc 2016; 138:5194-7. [PMID: 27086674 DOI: 10.1021/jacs.6b01023] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It has recently been reported that ribosomes from erythromycin-resistant Escherichia coli strains, when isolated in S30 extracts and incubated with chemically mis-acylated tRNA, can incorporate certain β-amino acids into full length DHFR in vitro. Here we report that wild-type E. coli EF-Tu and phenylalanyl-tRNA synthetase collaborate with these mutant ribosomes and others to incorporate β(3)-Phe analogs into full length DHFR in vivo. E. coli harboring the most active mutant ribosomes are robust, with a doubling time only 14% longer than wild-type. These results reveal the unexpected tolerance of E. coli and its translation machinery to the β(3)-amino acid backbone and should embolden in vivo selections for orthogonal translational machinery components that incorporate diverse β-amino acids into proteins and peptides. E. coli harboring mutant ribosomes may possess the capacity to incorporate many non-natural, non-α-amino acids into proteins and other sequence-programmed polymeric materials.
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Affiliation(s)
- Clarissa Melo Czekster
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Wesley E Robertson
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Allison S Walker
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Dieter Söll
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Alanna Schepartz
- Department of Chemistry, ‡Department of Molecular, Cellular, and Developmental Biology, and §Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States
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16
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Niehues S, Bussmann J, Steffes G, Erdmann I, Köhrer C, Sun L, Wagner M, Schäfer K, Wang G, Koerdt SN, Stum M, Jaiswal S, RajBhandary UL, Thomas U, Aberle H, Burgess RW, Yang XL, Dieterich D, Storkebaum E. Impaired protein translation in Drosophila models for Charcot-Marie-Tooth neuropathy caused by mutant tRNA synthetases. Nat Commun 2015; 6:7520. [PMID: 26138142 PMCID: PMC4506996 DOI: 10.1038/ncomms8520] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 05/16/2015] [Indexed: 01/06/2023] Open
Abstract
Dominant mutations in five tRNA synthetases cause Charcot-Marie-Tooth (CMT) neuropathy, suggesting that altered aminoacylation function underlies the disease. However, previous studies showed that loss of aminoacylation activity is not required to cause CMT. Here we present a Drosophila model for CMT with mutations in glycyl-tRNA synthetase (GARS). Expression of three CMT-mutant GARS proteins induces defects in motor performance and motor and sensory neuron morphology, and shortens lifespan. Mutant GARS proteins display normal subcellular localization but markedly reduce global protein synthesis in motor and sensory neurons, or when ubiquitously expressed in adults, as revealed by FUNCAT and BONCAT. Translational slowdown is not attributable to altered tRNA(Gly) aminoacylation, and cannot be rescued by Drosophila Gars overexpression, indicating a gain-of-toxic-function mechanism. Expression of CMT-mutant tyrosyl-tRNA synthetase also impairs translation, suggesting a common pathogenic mechanism. Finally, genetic reduction of translation is sufficient to induce CMT-like phenotypes, indicating a causal contribution of translational slowdown to CMT.
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Affiliation(s)
- Sven Niehues
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany [2] Faculty of Medicine, University of Münster, 48149 Münster, Germany
| | - Julia Bussmann
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany [2] Faculty of Medicine, University of Münster, 48149 Münster, Germany
| | - Georg Steffes
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany [2] Faculty of Medicine, University of Münster, 48149 Münster, Germany
| | - Ines Erdmann
- 1] Research Group Neuralomics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany [2] Institute for Pharmacology and Toxicology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Caroline Köhrer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Litao Sun
- The Scripps Research Institute, La Jolla, California 92037, USA
| | - Marina Wagner
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany [2] Faculty of Medicine, University of Münster, 48149 Münster, Germany
| | - Kerstin Schäfer
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany [2] Faculty of Medicine, University of Münster, 48149 Münster, Germany
| | - Guangxia Wang
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany [2] Faculty of Medicine, University of Münster, 48149 Münster, Germany
| | - Sophia N Koerdt
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany [2] Faculty of Medicine, University of Münster, 48149 Münster, Germany
| | - Morgane Stum
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA
| | | | - Uttam L RajBhandary
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Ulrich Thomas
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Hermann Aberle
- Functional Cell Morphology Lab, Heinrich Heine University, 40225 Düsseldorf, Germany
| | | | - Xiang-Lei Yang
- The Scripps Research Institute, La Jolla, California 92037, USA
| | - Daniela Dieterich
- 1] Research Group Neuralomics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany [2] Institute for Pharmacology and Toxicology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Erik Storkebaum
- 1] Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany [2] Faculty of Medicine, University of Münster, 48149 Münster, Germany
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17
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Deficiencies in tRNA synthetase editing activity cause cardioproteinopathy. Proc Natl Acad Sci U S A 2014; 111:17570-5. [PMID: 25422440 DOI: 10.1073/pnas.1420196111] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Misfolded proteins are an emerging hallmark of cardiac diseases. Although some misfolded proteins, such as desmin, are associated with mutations in the genes encoding these disease-associated proteins, little is known regarding more general mechanisms that contribute to the generation of misfolded proteins in the heart. Reduced translational fidelity, caused by a hypomorphic mutation in the editing domain of alanyl-tRNA synthetase (AlaRS), resulted in accumulation of misfolded proteins in specific mouse neurons. By further genetic modulation of the editing activity of AlaRS, we generated mouse models with broader phenotypes, the severity of which was directly related to the degree of compromised editing. Severe disruption of the editing activity of AlaRS caused embryonic lethality, whereas an intermediate reduction in AlaRS editing efficacy resulted in ubiquitinated protein aggregates and mitochondrial defects in cardiomyocytes that were accompanied by progressive cardiac fibrosis and dysfunction. In addition, autophagic vacuoles accumulated in mutant cardiomyocytes, suggesting that autophagy is insufficient to eliminate misfolded proteins. These findings demonstrate that the pathological consequences of diminished tRNA synthetase editing activity, and thus translational infidelity, are dependent on the cell type and the extent of editing disruption, and provide a previously unidentified mechanism underlying cardiac proteinopathy.
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18
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Kim DG, Lee JY, Kwon NH, Fang P, Zhang Q, Wang J, Young NL, Guo M, Cho HY, Mushtaq AU, Jeon YH, Choi JW, Han JM, Kang HW, Joo JE, Hur Y, Kang W, Yang H, Nam DH, Lee MS, Lee JW, Kim ES, Moon A, Kim K, Kim D, Kang EJ, Moon Y, Rhee KH, Han BW, Yang JS, Han G, Yang WS, Lee C, Wang MW, Kim S. Chemical inhibition of prometastatic lysyl-tRNA synthetase-laminin receptor interaction. Nat Chem Biol 2013; 10:29-34. [PMID: 24212136 DOI: 10.1038/nchembio.1381] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 09/18/2013] [Indexed: 01/11/2023]
Abstract
Lysyl-tRNA synthetase (KRS), a protein synthesis enzyme in the cytosol, relocates to the plasma membrane after a laminin signal and stabilizes a 67-kDa laminin receptor (67LR) that is implicated in cancer metastasis; however, its potential as an antimetastatic therapeutic target has not been explored. We found that the small compound BC-K-YH16899, which binds KRS, impinged on the interaction of KRS with 67LR and suppressed metastasis in three different mouse models. The compound inhibited the KRS-67LR interaction in two ways. First, it directly blocked the association between KRS and 67LR. Second, it suppressed the dynamic movement of the N-terminal extension of KRS and reduced membrane localization of KRS. However, it did not affect the catalytic activity of KRS. Our results suggest that specific modulation of a cancer-related KRS-67LR interaction may offer a way to control metastasis while avoiding the toxicities associated with inhibition of the normal functions of KRS.
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Affiliation(s)
- Dae Gyu Kim
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea. [3]
| | - Jin Young Lee
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea. [3]
| | - Nam Hoon Kwon
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Pengfei Fang
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, USA
| | - Qian Zhang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Jing Wang
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, USA
| | - Nicolas L Young
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA
| | - Min Guo
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, USA
| | - Hye Young Cho
- College of Pharmacy, Korea University, Sejong, Korea
| | | | - Young Ho Jeon
- College of Pharmacy, Korea University, Sejong, Korea
| | - Jin Woo Choi
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jung Min Han
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | | | | | - Youn Hur
- Yuhan Research Institute, Yongin, Korea
| | - Wonyoung Kang
- Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Heekyoung Yang
- Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Do-Hyun Nam
- Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Mi-Sook Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Jung Weon Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Eun-Sook Kim
- College of Pharmacy, Duksung Women's University, Seoul, Korea
| | - Aree Moon
- College of Pharmacy, Duksung Women's University, Seoul, Korea
| | - Kibom Kim
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Doyeun Kim
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Eun Joo Kang
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea
| | - Youngji Moon
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea
| | - Kyung Hee Rhee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Byung Woo Han
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Jee Sun Yang
- Translational Research Center for Protein Function Control, Department of Biotechnology and WCU Department of Biomedical Sciences, Yonsei University, Seoul, Korea
| | - Gyoonhee Han
- Translational Research Center for Protein Function Control, Department of Biotechnology and WCU Department of Biomedical Sciences, Yonsei University, Seoul, Korea
| | - Won Suk Yang
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Cheolju Lee
- BRI, Korea Institute of Science and Technology, Seoul, Korea
| | - Ming-Wei Wang
- The National Center for Drug Screening, Zhangjiang High-Tech Park, Shanghai, China
| | - Sunghoon Kim
- 1] Medicinal Bioconvergence Research Center, Seoul National University, Seoul, Korea. [2] Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Korea. [3] World Class University Department of Molecular Medicine and Biopharmaceutical Sciences, Seoul National University, Seoul, Korea
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19
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Xu X, Shi Y, Yang XL. Crystal structure of human Seryl-tRNA synthetase and Ser-SA complex reveals a molecular lever specific to higher eukaryotes. Structure 2013; 21:2078-86. [PMID: 24095058 DOI: 10.1016/j.str.2013.08.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/07/2013] [Accepted: 08/26/2013] [Indexed: 01/13/2023]
Abstract
Seryl-tRNA synthetase (SerRS), an essential enzyme for translation, also regulates vascular development. This "gain-of-function" has been linked to the UNE-S domain added to vertebrate SerRS during evolution. However, the significance of two insertions also specific to higher eukaryotic SerRS remains elusive. Here, we determined the crystal structure of human SerRS in complex with Ser-SA, an aminoacylation reaction intermediate analog, at 2.9 Å resolution. Despite a 70 Å distance, binding of Ser-SA in the catalytic domain dramatically leverages the position of Insertion I in the tRNA binding domain. Importantly, this leverage is specific to higher eukaryotes and not seen in bacterial, archaeal, and lower eukaryotic SerRSs. Deletion of Insertion I does not affect tRNA binding but instead reduce the catalytic efficiency of the synthetase. Thus, a long-range conformational and functional communication specific to higher eukaryotes is found in human SerRS, possibly to coordinate translation with vasculogenesis.
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Affiliation(s)
- Xiaoling Xu
- Departments of Chemical Physiology and Cell and Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang Province 310036, China
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20
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Hirano T, Kobayashi N, Matsuhashi T, Watanabe D, Watanabe T, Takasuga A, Sugimoto M, Sugimoto Y. Mapping and exome sequencing identifies a mutation in the IARS gene as the cause of hereditary perinatal weak calf syndrome. PLoS One 2013; 8:e64036. [PMID: 23700453 PMCID: PMC3660308 DOI: 10.1371/journal.pone.0064036] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 04/08/2013] [Indexed: 11/29/2022] Open
Abstract
We identified an IARS (isoleucyl-tRNA synthetase) c.235G>C (p.Val79Leu) substitution as the causative mutation for neonatal weakness with intrauterine growth retardation (perinatal weak calf syndrome). In Japanese Black cattle, the syndrome was frequently found in calves sired by Bull A. Hence, we employed homozygosity mapping and linkage analysis. In order to identify the perinatal weak calf syndrome locus in a 4.04-Mb region of BTA 8, we analysed a paternal half-sibling family with a BovineSNP50 BeadChip and microsatellites. In this critical region, we performed exome sequencing to identify a causative mutation. Three variants were detected as possible candidates for causative mutations that were predicted to disrupt the protein function, including a G>C (p.Val79Leu) mutation in IARS c.235. The IARS c.235G>C mutation was not a homozygous risk allele in the 36 healthy offspring of Bull A. Moreover, the IARS Val79 residue and its flanking regions were evolutionarily and highly conserved. The IARS mutant (Leu79) had decreased aminoacylation activity. Additionally, the homozygous mutation was not found in any of 1526 healthy cattle. Therefore, we concluded that the IARS c.235G>C mutation was the cause of hereditary perinatal weak calf syndrome.
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Affiliation(s)
- Takashi Hirano
- Shirakawa Institute of Animal Genetics, Fukushima, Japan.
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21
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Chopra S, Palencia A, Virus C, Tripathy A, Temple BR, Velazquez-Campoy A, Cusack S, Reader JS. Plant tumour biocontrol agent employs a tRNA-dependent mechanism to inhibit leucyl-tRNA synthetase. Nat Commun 2013; 4:1417. [PMID: 23361008 DOI: 10.1038/ncomms2421] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 12/20/2012] [Indexed: 11/08/2022] Open
Abstract
Leucyl-tRNA synthetases (LeuRSs) have an essential role in translation and are promising targets for antibiotic development. Agrocin 84 is a LeuRS inhibitor produced by the biocontrol agent Agrobacterium radiobacter K84 that targets pathogenic strains of A. tumefaciens, the causative agent of plant tumours. Agrocin 84 acts as a molecular Trojan horse and is processed inside the pathogen into a toxic moiety (TM84). Here we show using crystal structure, thermodynamic and kinetic analyses, that this natural antibiotic employs a unique and previously undescribed mechanism to inhibit LeuRS. TM84 requires tRNA(Leu) for tight binding to the LeuRS synthetic active site, unlike any previously reported inhibitors. TM84 traps the enzyme-tRNA complex in a novel 'aminoacylation-like' conformation, forming novel interactions with the KMSKS loop and the tRNA 3'-end. Our findings reveal an intriguing tRNA-dependent inhibition mechanism that may confer a distinct evolutionary advantage in vivo and inform future rational antibiotic design.
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Affiliation(s)
- Shaileja Chopra
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, 536 Taylor Hall, CB# 7090, Chapel Hill, North Carolina 27599-7090, USA
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22
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ATP-directed capture of bioactive herbal-based medicine on human tRNA synthetase. Nature 2012; 494:121-4. [PMID: 23263184 PMCID: PMC3569068 DOI: 10.1038/nature11774] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 11/09/2012] [Indexed: 12/17/2022]
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23
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Unique domain appended to vertebrate tRNA synthetase is essential for vascular development. Nat Commun 2012; 3:681. [PMID: 22353712 PMCID: PMC3293412 DOI: 10.1038/ncomms1686] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 01/16/2012] [Indexed: 11/08/2022] Open
Abstract
New domains were progressively added to cytoplasmic aminoacyl transfer RNA (tRNA) synthetases during evolution. One example is the UNE-S domain, appended to seryl-tRNA synthetase (SerRS) in species that developed closed circulatory systems. Here we show using solution and crystal structure analyses and in vitro and in vivo functional studies that UNE-S harbours a robust nuclear localization signal (NLS) directing SerRS to the nucleus where it attenuates vascular endothelial growth factor A expression. We also show that SerRS mutants previously linked to vasculature abnormalities either deleted the NLS or have the NLS sequestered in an alternative conformation. A structure-based second-site mutation, designed to release the sequestered NLS, restored normal vasculature. Thus, the essential function of SerRS in vascular development depends on UNE-S. These results are the first to show an essential role for a tRNA synthetase-associated appended domain at the organism level, and suggest that acquisition of UNE-S has a role in the establishment of the closed circulatory systems of vertebrates.
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24
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Fu G, Xu T, Shi Y, Wei N, Yang XL. tRNA-controlled nuclear import of a human tRNA synthetase. J Biol Chem 2012; 287:9330-4. [PMID: 22291016 DOI: 10.1074/jbc.c111.325902] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aminoacyl-tRNA synthetases, essential components of the cytoplasmic translation apparatus, also have nuclear functions that continue to be elucidated. However, little is known about how the distribution between cytoplasmic and nuclear compartments is controlled. Using a combination of methods, here we showed that human tyrosyl-tRNA synthetase (TyrRS) distributes to the nucleus and that the nuclear import of human TyrRS is regulated by its cognate tRNA(Tyr). We identified a hexapeptide motif in the anticodon recognition domain that is critical for nuclear import of the synthetase. Remarkably, this nuclear localization signal (NLS) sequence motif is also important for interacting with tRNA(Tyr). As a consequence, mutational alteration of the hexapeptide simultaneously attenuated aminoacylation and nuclear localization. Because the NLS is sterically blocked when the cognate tRNA is bound to TyrRS, we hypothesized that the nuclear distribution of TyrRS is regulated by tRNA(Tyr). This expectation was confirmed by RNAi knockdown of tRNA(Tyr) expression, which led to robust nuclear import of TyrRS. Further bioinformatics analysis showed that to have nuclear import of TyrRS directly controlled by tRNA(Tyr) in higher organisms, the NLS of lower eukaryotes was abandoned, whereas the new NLS was evolved from an anticodon-binding hexapeptide motif. Thus, higher organisms developed a strategy to make tRNA a regulator of the nuclear trafficking of its cognate synthetase. The design in principle should coordinate nuclear import of a tRNA synthetase with the demands of protein synthesis in the cytoplasm.
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Affiliation(s)
- Guangsen Fu
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
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Charcot-Marie-Tooth-linked mutant GARS is toxic to peripheral neurons independent of wild-type GARS levels. PLoS Genet 2011; 7:e1002399. [PMID: 22144914 PMCID: PMC3228828 DOI: 10.1371/journal.pgen.1002399] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 10/13/2011] [Indexed: 01/19/2023] Open
Abstract
Charcot-Marie-Tooth disease type 2D (CMT2D) is a dominantly inherited peripheral neuropathy caused by missense mutations in the glycyl-tRNA synthetase gene (GARS). In addition to GARS, mutations in three other tRNA synthetase genes cause similar neuropathies, although the underlying mechanisms are not fully understood. To address this, we generated transgenic mice that ubiquitously over-express wild-type GARS and crossed them to two dominant mouse models of CMT2D to distinguish loss-of-function and gain-of-function mechanisms. Over-expression of wild-type GARS does not improve the neuropathy phenotype in heterozygous Gars mutant mice, as determined by histological, functional, and behavioral tests. Transgenic GARS is able to rescue a pathological point mutation as a homozygote or in complementation tests with a Gars null allele, demonstrating the functionality of the transgene and revealing a recessive loss-of-function component of the point mutation. Missense mutations as transgene-rescued homozygotes or compound heterozygotes have a more severe neuropathy than heterozygotes, indicating that increased dosage of the disease-causing alleles results in a more severe neurological phenotype, even in the presence of a wild-type transgene. We conclude that, although missense mutations of Gars may cause some loss of function, the dominant neuropathy phenotype observed in mice is caused by a dose-dependent gain of function that is not mitigated by over-expression of functional wild-type protein.
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p23H implicated as cis/trans regulator of AlaXp-directed editing for mammalian cell homeostasis. Proc Natl Acad Sci U S A 2011; 108:2723-8. [PMID: 21285375 DOI: 10.1073/pnas.1019400108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The toxicity of mistranslation of serine for alanine appears to be universal, and is prevented in part by the editing activities of alanyl-tRNA synthetases (AlaRSs), which remove serine from mischarged tRNA(Ala). The problem of serine mistranslation is so acute that free-standing, genome-encoded fragments of the editing domain of AlaRSs are found throughout evolution. These AlaXps are thought to provide functional redundancy of editing. Indeed, archaeal versions rescue the conditional lethality of bacterial cells harboring an editing-inactive AlaRS. In mammals, AlaXps are encoded by a gene that fuses coding sequences of a homolog of the HSP90 cochaperone p23 (p23(H)) to those of AlaXp, to create p23(H)AlaXp. Not known is whether this fusion protein, or various potential splice variants, are expressed as editing-proficient proteins in mammalian cells. Here we show that both p23(H)AlaXp and AlaXp alternative splice variants can be detected as proteins in mammalian cells. The variant that ablated p23(H) and encoded just AlaXp was active in vitro. In contrast, neither the p23(H)AlaXp fusion protein, nor the mixture of free p23(H) with AlaXp, was active. Further experiments in a mammalian cell-based system showed that RNAi-directed suppression of sequences encoding AlaXp led to a serine-sensitive increase in the accumulation of misfolded proteins. The results demonstrate the dependence of mammalian cell homeostasis on AlaXp, and implicate p23(H) as a cis- and trans-acting regulator of its activity.
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Guo RT, Chong YE, Guo M, Yang XL. Crystal structures and biochemical analyses suggest a unique mechanism and role for human glycyl-tRNA synthetase in Ap4A homeostasis. J Biol Chem 2009; 284:28968-76. [PMID: 19710017 PMCID: PMC2781443 DOI: 10.1074/jbc.m109.030692] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Aminoacyl-tRNA synthetases catalyze the attachment of amino acids to their cognate tRNAs for protein synthesis. However, the aminoacylation reaction can be diverted to produce diadenosine tetraphosphate (Ap4A), a universal pleiotropic signaling molecule needed for cell regulation pathways. The only known mechanism for Ap4A production by a tRNA synthetase is through the aminoacylation reaction intermediate aminoacyl-AMP, thus making Ap4A synthesis amino acid-dependent. Here, we demonstrate a new mechanism for Ap4A synthesis. Crystal structures and biochemical analyses show that human glycyl-tRNA synthetase (GlyRS) produces Ap4A by direct condensation of two ATPs, independent of glycine concentration. Interestingly, whereas the first ATP-binding pocket is conserved for all class II tRNA synthetases, the second ATP pocket is formed by an insertion domain that is unique to GlyRS, suggesting that GlyRS is the only tRNA synthetase catalyzing direct Ap4A synthesis. A special role for GlyRS in Ap4A homeostasis is proposed.
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Affiliation(s)
- Rey-Ting Guo
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Yeeting E. Chong
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Min Guo
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Xiang-Lei Yang
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, To whom correspondence should be addressed: Scripps Research Inst., BCC110, North Torrey Pines Rd., La Jolla, CA 92037. Tel.: 858-784-8976; Fax: 858-784-7250; E-mail:
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Bruzzese FJ, Tsu CA, Ma J, Loke HK, Wu D, Li Z, Tayber O, Dick LR. Development of a charcoal paper adenosine triphosphate:pyrophosphate exchange assay: kinetic characterization of NEDD8 activating enzyme. Anal Biochem 2009; 394:24-9. [PMID: 19602421 DOI: 10.1016/j.ab.2009.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 07/02/2009] [Accepted: 07/08/2009] [Indexed: 01/11/2023]
Abstract
Ubiquitin activating enzyme (UAE, UBE1, or E1) and seven known homologous "E1s" initiate the conjugation pathways for ubiquitin and 16 other ubiquitin-like modifiers (ULMs) found in humans. The initial step catalyzed by E1s uses adenosine triphosphate (ATP) to adenylate the C terminus of the appropriate ULM and results in the production of inorganic pyrophosphate (PPi). The mechanism of these enzymes can be studied with assays that measure the rate of ULM-dependent ATP:PPi exchange. The traditional method follows the initial velocity of [32P]PPi incorporation into ATP by capturing the nucleotide on activated charcoal powder to separate it from excess [32P]PPi and then measuring [32P]ATP in a scintillation counter. We have modified the method by using charcoal paper to capture the nucleotide and a phosphorimager to quantify the [32P]ATP. The significant increase in throughput that these modifications provide is accomplished without any sacrifice in sensitivity or accuracy compared with the traditional method. To demonstrate this, we reproduce and extend the characterization of the NEDD8 activating enzyme.
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Affiliation(s)
- Frank J Bruzzese
- Discovery, Millennium Pharmaceuticals, Cambridge, MA 02139, USA.
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Chong YE, Yang XL, Schimmel P. Natural homolog of tRNA synthetase editing domain rescues conditional lethality caused by mistranslation. J Biol Chem 2008; 283:30073-8. [PMID: 18723508 DOI: 10.1074/jbc.m805943200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AlaXp is a widely distributed (from bacteria to humans) genome-encoded homolog of the editing domain of alanyl-tRNA synthetases. Editing repairs the confusion of serine and glycine for alanine through clearance of mischarged (with Ser or Gly) tRNA(Ala). Because genome-encoded fragments of editing domains of other synthetases are scarce, the AlaXp redundancy of the editing domain of alanyl-tRNA synthetase is thought to reflect an unusual sensitivity of cells to mistranslation at codons for Ala. Indeed, a small defect in the editing activity of alanyl-tRNA synthetase is causally linked to neurodegeneration in the mouse. Although limited earlier studies demonstrated that AlaXp deacylated mischarged tRNA(Ala) in vitro, the significance of this activity in vivo has not been clear. Here we describe a bacterial system specifically designed to investigate activity of AlaXp in vivo. Serine toxicity, experienced by a strain harboring an editing-defective alanyl-tRNA synthetase, was rescued by an AlaXp-encoding transgene. Rescue was dependent on amino acid residues in AlaXp that are needed for its in vitro catalytic activity. Thus, the editing activity per se of AlaXp was essential for suppressing mistranslation. The results support the idea that the unique widespread distribution of AlaXp arises from the singular difficulties, for translation, poised by alanine.
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Affiliation(s)
- Yeeting E Chong
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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30
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Distinct domains of tRNA synthetase recognize the same base pair. Nature 2008; 451:90-3. [PMID: 18172502 DOI: 10.1038/nature06454] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 11/07/2007] [Indexed: 11/08/2022]
Abstract
Synthesis of proteins containing errors (mistranslation) is prevented by aminoacyl transfer RNA synthetases through their accurate aminoacylation of cognate tRNAs and their ability to correct occasional errors of aminoacylation by editing reactions. A principal source of mistranslation comes from mistaking glycine or serine for alanine, which can lead to serious cell and animal pathologies, including neurodegeneration. A single specific G.U base pair (G3.U70) marks a tRNA for aminoacylation by alanyl-tRNA synthetase. Mistranslation occurs when glycine or serine is joined to the G3.U70-containing tRNAs, and is prevented by the editing activity that clears the mischarged amino acid. Previously it was assumed that the specificity for recognition of tRNA(Ala) for editing was provided by the same structural determinants as used for aminoacylation. Here we show that the editing site of alanyl-tRNA synthetase, as an artificial recombinant fragment, targets mischarged tRNA(Ala) using a structural motif unrelated to that for aminoacylation so that, remarkably, two motifs (one for aminoacylation and one for editing) in the same enzyme independently can provide determinants for tRNA(Ala) recognition. The structural motif for editing is also found naturally in genome-encoded protein fragments that are widely distributed in evolution. These also recognize mischarged tRNA(Ala). Thus, through evolution, three different complexes with the same tRNA can guard against mistaking glycine or serine for alanine.
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31
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Splan KE, Musier-Forsyth K, Boniecki MT, Martinis SA. In vitro assays for the determination of aminoacyl-tRNA synthetase editing activity. Methods 2008; 44:119-28. [PMID: 18241793 PMCID: PMC2270698 DOI: 10.1016/j.ymeth.2007.10.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 10/29/2007] [Indexed: 11/21/2022] Open
Abstract
Aminoacyl-tRNA synthetases are essential enzymes that help to ensure the fidelity of protein translation by accurately aminoacylating (or "charging") specific tRNA substrates with cognate amino acids. Many synthetases have an additional catalytic activity to confer amino acid editing or proofreading. This activity relieves ambiguities during translation of the genetic code that result from one synthetase activating multiple amino acid substrates. In this review, we describe methods that have been developed for assaying both pre- and post-transfer editing activities. Pre-transfer editing is defined as hydrolysis of a misactivated aminoacyl-adenylate prior to transfer to the tRNA. This reaction has been reported to occur either in the aminoacylation active site or in a separate editing domain. Post-transfer editing refers to the hydrolysis reaction that cleaves the aminoacyl-ester linkage formed between the carbonyl carbon of the amino acid and the 2' or 3' hydroxyl group of the ribose on the terminal adenosine. Post-transfer editing takes place in a hydrolytic active site that is distinct from the site of amino acid activation. Here, we focus on methods for determination of steady-state reaction rates using editing assays developed for both classes of synthetases.
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Affiliation(s)
- Kathryn E Splan
- Department of Chemistry, Macalester College, St. Paul, MN 55105, USA
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32
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Auld D, Simeonov A, Thomas C. Literature Search and Review. Assay Drug Dev Technol 2007. [DOI: 10.1089/adt.2006.9989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Doug Auld
- National Institutes of Health, Bethesda, MD
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