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Gupta S, Jani J, Vijayasurya, Mochi J, Tabasum S, Sabarwal A, Pappachan A. Aminoacyl-tRNA synthetase - a molecular multitasker. FASEB J 2023; 37:e23219. [PMID: 37776328 DOI: 10.1096/fj.202202024rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 08/31/2023] [Accepted: 09/12/2023] [Indexed: 10/02/2023]
Abstract
Aminoacyl-tRNA synthetases (AaRSs) are valuable "housekeeping" enzymes that ensure the accurate transmission of genetic information in living cells, where they aminoacylated tRNA molecules with their cognate amino acid and provide substrates for protein biosynthesis. In addition to their translational or canonical function, they contribute to nontranslational/moonlighting functions, which are mediated by the presence of other domains on the proteins. This was supported by several reports which claim that AaRS has a significant role in gene transcription, apoptosis, translation, and RNA splicing regulation. Noncanonical/ nontranslational functions of AaRSs also include their roles in regulating angiogenesis, inflammation, cancer, and other major physio-pathological processes. Multiple AaRSs are also associated with a broad range of physiological and pathological processes; a few even serve as cytokines. Therefore, the multifunctional nature of AaRSs suggests their potential as viable therapeutic targets as well. Here, our discussion will encompass a range of noncanonical functions attributed to Aminoacyl-tRNA Synthetases (AaRSs), highlighting their links with a diverse array of human diseases.
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Affiliation(s)
- Swadha Gupta
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
| | - Jaykumar Jani
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
| | - Vijayasurya
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
| | - Jigneshkumar Mochi
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
| | - Saba Tabasum
- Dana Farber Cancer Institute, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Akash Sabarwal
- Harvard Medical School, Boston, Massachusetts, USA
- Boston Children's Hospital, Boston, Massachusetts, USA
| | - Anju Pappachan
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
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2
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Mutation in KARS: A novel mechanism for severe anaphylaxis. J Allergy Clin Immunol 2020; 147:1855-1864.e9. [PMID: 33385443 DOI: 10.1016/j.jaci.2020.12.637] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 11/23/2020] [Accepted: 12/02/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Anaphylaxis is a severe allergic reaction that can be lethal if not treated adequately. The underlying molecular mechanisms responsible for the severity are mostly unknown. OBJECTIVE This study is based on a clinical case of a patient with extremely severe anaphylaxis to paper wasp venom. This patient has a mutation in the KARS gene, which encodes lysyl-tRNA synthetase (LysRS), a moonlight protein with a canonical function in protein synthesis and a noncanonical function in antigen dependent-FcεRI activation in mast cells. In this study, the objective was to characterize the mutation at the molecular level. METHODS Analysis of the KARS mutation was carried out using biochemical and functional approaches, cell transfection, Western blot, confocal microscopy, cell degranulation, prostaglandin D2 secretion, and proteases gene transcription. Structural analysis using molecular dynamics simulations and well-tempered metadynamics was also performed. RESULTS The mutation found, P542R (proline was replaced by arginine at aminoacid 542), affects the location of the protein as we show in biochemical and structural analyses. The mutation resembles active LysRS and causes a constitutive activation of the microphthalmia transcription factor, which is involved in critical mast cell functions such as synthesis of mediators and granule biogenesis. Moreover, the structural analysis provides insights into how LysRS works in mast cell activation. CONCLUSIONS A link between the aberrant LysRS-P542R function and mast cell-exacerbated activation with increase in proinflammatory mediator release after antigen-IgE-dependent response could be established.
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3
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Ballotti R, Cheli Y, Bertolotto C. The complex relationship between MITF and the immune system: a Melanoma ImmunoTherapy (response) Factor? Mol Cancer 2020; 19:170. [PMID: 33276788 PMCID: PMC7718690 DOI: 10.1186/s12943-020-01290-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/29/2020] [Indexed: 12/18/2022] Open
Abstract
The clinical benefit of immune checkpoint inhibitory therapy (ICT) in advanced melanomas is limited by primary and acquired resistance. The molecular determinants of the resistance have been extensively studied, but these discoveries have not yet been translated into therapeutic benefits. As such, a paradigm shift in melanoma treatment, to surmount the therapeutic impasses linked to the resistance, is an important ongoing challenge.This review outlines the multifaceted interplay between microphthalmia-associated transcription factor (MITF), a major determinant of the biology of melanoma cells, and the immune system. In melanomas, MITF functions downstream oncogenic pathways and microenvironment stimuli that restrain the immune responses. We highlight how MITF, by controlling differentiation and genome integrity, may regulate melanoma-specific antigen expression by interfering with the endolysosomal pathway, KARS1, and antigen processing and presentation. MITF also modulates the expression of coinhibitory receptors, i.e., PD-L1 and HVEM, and the production of an inflammatory secretome, which directly affects the infiltration and/or activation of the immune cells.Furthermore, MITF is also a key determinant of melanoma cell plasticity and tumor heterogeneity, which are undoubtedly one of the major hurdles for an effective immunotherapy. Finally, we briefly discuss the role of MITF in kidney cancer, where it also plays a key role, and in immune cells, establishing MITF as a central mediator in the regulation of immune responses in melanoma and other cancers.We propose that a better understanding of MITF and immune system intersections could help in the tailoring of current ICT in melanomas and pave the way for clinical benefits and long-lasting responses.
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Affiliation(s)
- Robert Ballotti
- Université Côte d'Azur, Nice, France
- Inserm, Biology and Pathologies of melanocytes, team1, Equipe labellisée Ligue 2020 and Equipe labellisée ARC 2019, Centre Méditerranéen de Médecine Moléculaire, Nice, France
| | - Yann Cheli
- Université Côte d'Azur, Nice, France
- Inserm, Biology and Pathologies of melanocytes, team1, Equipe labellisée Ligue 2020 and Equipe labellisée ARC 2019, Centre Méditerranéen de Médecine Moléculaire, Nice, France
| | - Corine Bertolotto
- Université Côte d'Azur, Nice, France.
- Inserm, Biology and Pathologies of melanocytes, team1, Equipe labellisée Ligue 2020 and Equipe labellisée ARC 2019, Centre Méditerranéen de Médecine Moléculaire, Nice, France.
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Levi O, Garin S, Arava Y. RNA mimicry in post-transcriptional regulation by aminoacyl tRNA synthetases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1564. [PMID: 31414576 DOI: 10.1002/wrna.1564] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/10/2019] [Accepted: 07/25/2019] [Indexed: 12/15/2022]
Abstract
Aminoacyl tRNA synthetases (aaRS) are well studied for their roles in tRNA charging with cognate amino acid. Nevertheless, numerous lines of evidence indicate that these proteins have roles other than tRNA charging. These include coordination of cellular signaling cascades, induction of cytokines outside the cell and transcription regulation. Herein, we focus on their roles in post-transcriptional regulation of mRNA expression. We describe functions that are related to antitermination of transcription, RNA splicing and mRNA translation. Cases were recognition of mRNA by the aaRS involves recognition of tRNA-like structures are described. Such recognition may be achieved by repurposing tRNA-binding domains or through domains added to the aaRS later in evolution. Furthermore, we describe cases in which binding by aaRS is implicated in autogenous regulation of expression. Overall, we propose RNA-mimicry as a common mode of interaction between aaRS and mRNA which allows efficient expression regulation. This article is categorized under: RNA Processing > tRNA Processing RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Translation Regulation.
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Affiliation(s)
- Ofri Levi
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Shahar Garin
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Yoav Arava
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
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5
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Rémion A, Khoder-Agha F, Cornu D, Argentini M, Redeker V, Mirande M. Identification of protein interfaces within the multi-aminoacyl-tRNA synthetase complex: the case of lysyl-tRNA synthetase and the scaffold protein p38. FEBS Open Bio 2016; 6:696-706. [PMID: 27398309 PMCID: PMC4932449 DOI: 10.1002/2211-5463.12074] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/23/2016] [Accepted: 04/19/2016] [Indexed: 11/06/2022] Open
Abstract
Human cytoplasmic lysyl-tRNA synthetase (LysRS) is associated within a multi-aminoacyl-tRNA synthetase complex (MSC). Within this complex, the p38 component is the scaffold protein that binds the catalytic domain of LysRS via its N-terminal region. In addition to its translational function when associated to the MSC, LysRS is also recruited in nontranslational roles after dissociation from the MSC. The balance between its MSC-associated and MSC-dissociated states is essential to regulate the functions of LysRS in cellular homeostasis. With the aim of understanding the rules that govern association of LysRS in the MSC, we analyzed the protein interfaces between LysRS and the full-length version of p38, the scaffold protein of the MSC. In a previous study, the cocrystal structure of LysRS with a N-terminal peptide of p38 was reported [Ofir-Birin Y et al. (2013) Mol Cell 49, 30-42]. In order to identify amino acid residues involved in interaction of the two proteins, the non-natural, photo-cross-linkable amino acid p-benzoyl-l-phenylalanine (Bpa) was incorporated at 27 discrete positions within the catalytic domain of LysRS. Among the 27 distinct LysRS mutants, only those with Bpa inserted in place of Lys356 or His364 were cross-linked with p38. Using mass spectrometry, we unambiguously identified the protein interface of the cross-linked complex and showed that Lys356 and His364 of LysRS interact with the peptide from Pro8 to Arg26 in native p38, in agreement with the published cocrystal structure. This interface, which in LysRS is located on the opposite side of the dimer to the site of interaction with its tRNA substrate, defines the core region of the MSC. The residues identified herein in human LysRS are not conserved in yeast LysRS, an enzyme that does not associate within the MSC, and contrast with the residues proposed to be essential for LysRS:p38 association in the earlier work.
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Affiliation(s)
- Azaria Rémion
- Laboratoire d'Enzymologie et Biochimie Structurales (LEBS) CNRS Gif-sur-Yvette France
| | - Fawzi Khoder-Agha
- Laboratoire d'Enzymologie et Biochimie Structurales (LEBS) CNRS Gif-sur-Yvette France; Institute for Integrative Biology of the Cell (I2BC) CEACNRS Univ. Paris-Sud, Université Paris-Saclay Gif-sur-Yvette France
| | - David Cornu
- Service d'identification et de Caractérisation des Protéines par Spectrométrie de Masse (SICaPS) CEA CNRS Univ. Paris-Sud, Université Paris-Saclay Gif-sur-Yvette France
| | - Manuela Argentini
- Service d'identification et de Caractérisation des Protéines par Spectrométrie de Masse (SICaPS) CEA CNRS Univ. Paris-Sud, Université Paris-Saclay Gif-sur-Yvette France
| | - Virginie Redeker
- Laboratoire d'Enzymologie et Biochimie Structurales (LEBS) CNRSGif-sur-Yvette France; Service d'identification et de Caractérisation des Protéines par Spectrométrie de Masse (SICaPS) CEACNRS Univ. Paris-Sud, Université Paris-Saclay Gif-sur-Yvette France; Present address: Paris-Saclay Institute of Neuroscience (Neuro-PSI) CNRS 1 avenue de la Terrasse 91190 Gif-sur-Yvette France
| | - Marc Mirande
- Laboratoire d'Enzymologie et Biochimie Structurales (LEBS) CNRS Gif-sur-Yvette France; Institute for Integrative Biology of the Cell (I2BC) CEACNRS Univ. Paris-Sud, Université Paris-Saclay Gif-sur-Yvette France
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Marriott AS, Copeland NA, Cunningham R, Wilkinson MC, McLennan AG, Jones NJ. Diadenosine 5', 5'''-P(1),P(4)-tetraphosphate (Ap4A) is synthesized in response to DNA damage and inhibits the initiation of DNA replication. DNA Repair (Amst) 2015. [PMID: 26204256 DOI: 10.1016/j.dnarep.2015.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The level of intracellular diadenosine 5', 5'''-P(1),P(4)-tetraphosphate (Ap4A) increases several fold in mammalian cells treated with non-cytotoxic doses of interstrand DNA-crosslinking agents such as mitomycin C. It is also increased in cells lacking DNA repair proteins including XRCC1, PARP1, APTX and FANCG, while >50-fold increases (up to around 25 μM) are achieved in repair mutants exposed to mitomycin C. Part of this induced Ap4A is converted into novel derivatives, identified as mono- and di-ADP-ribosylated Ap4A. Gene knockout experiments suggest that DNA ligase III is primarily responsible for the synthesis of damage-induced Ap4A and that PARP1 and PARP2 can both catalyze its ADP-ribosylation. Degradative proteins such as aprataxin may also contribute to the increase. Using a cell-free replication system, Ap4A was found to cause a marked inhibition of the initiation of DNA replicons, while elongation was unaffected. Maximum inhibition of 70-80% was achieved with 20 μM Ap4A. Ap3A, Ap5A, Gp4G and ADP-ribosylated Ap4A were without effect. It is proposed that Ap4A acts as an important inducible ligand in the DNA damage response to prevent the replication of damaged DNA.
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Affiliation(s)
- Andrew S Marriott
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Nikki A Copeland
- Division of Biomedical and Life Sciences, University of Lancaster, Lancaster LA1 4YG, UK
| | - Ryan Cunningham
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Mark C Wilkinson
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Alexander G McLennan
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
| | - Nigel J Jones
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
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7
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Motzik A, Nechushtan H, Foo SY, Razin E. Non-canonical roles of lysyl-tRNA synthetase in health and disease. Trends Mol Med 2013; 19:726-31. [DOI: 10.1016/j.molmed.2013.07.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 07/16/2013] [Accepted: 07/26/2013] [Indexed: 01/26/2023]
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8
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Guo M, Schimmel P. Essential nontranslational functions of tRNA synthetases. Nat Chem Biol 2013; 9:145-53. [PMID: 23416400 DOI: 10.1038/nchembio.1158] [Citation(s) in RCA: 282] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 11/28/2012] [Indexed: 12/25/2022]
Abstract
Nontranslational functions of vertebrate aminoacyl tRNA synthetases (aaRSs), which catalyze the production of aminoacyl-tRNAs for protein synthesis, have recently been discovered. Although these new functions were thought to be 'moonlighting activities', many are as critical for cellular homeostasis as their activity in translation. New roles have been associated with their cytoplasmic forms as well as with nuclear and secreted extracellular forms that affect pathways for cardiovascular development and the immune response and mTOR, IFN-γ and p53 signaling. The associations of aaRSs with autoimmune disorders, cancers and neurological disorders further highlight nontranslational functions of these proteins. New architecture elaborations of the aaRSs accompany their functional expansion in higher organisms and have been associated with the nontranslational functions for several aaRSs. Although a general understanding of how these functions developed is limited, the expropriation of aaRSs for essential nontranslational functions may have been initiated by co-opting the amino acid-binding site for another purpose.
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Affiliation(s)
- Min Guo
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, Florida, USA
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9
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Wang J, Fang P, Schimmel P, Guo M. Side chain independent recognition of aminoacyl adenylates by the Hint1 transcription suppressor. J Phys Chem B 2012; 116:6798-805. [PMID: 22329685 PMCID: PMC3375047 DOI: 10.1021/jp212457w] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Human Hint1 suppresses specific gene transcription by
interacting with the transcription factor MITF in mast cells. Hint1
activity is connected to lysyl-tRNA synthetase (LysRS), a member of
the universal aminoacyl tRNA synthetase family that catalyzes specific
aminoacylation of their cognate tRNAs, through an aminoacyl adenylate
(aa-AMP) intermediate. During immune activation, LysRS produces a
side-product diadenosine tetraphosphate (Ap4A) from the
condensation of Lys-AMP with ATP. The pleiotropic signaling molecule
Ap4A then binds Hint1 to promote activation of MITF-target
gene transcription. Earlier work showed that Hint1 can also bind and
hydrolyze Lys-AMP, possibly to constrain Ap4A production.
Because Ap4A can result from condensation of other aa-AMP's
with ATP, the specificity of the Hint1 aa-AMP–hydrolysis activity
is of interest. Here we show that Hint1 has broad specificity for
adenylate hydrolysis, whose structural basis we revealed through high-resolution
structures of Hint1 in complex with three different aa-AMP analogues.
Hint1 recognizes only the common main chain of the aminoacyl moiety,
and has no contact with the aa side chain. The α-amino group
is anchored by a cation-pi interaction with Trp123 at the C-terminus
of Hint1. These results reveal the structural basis for the remarkable
adenylate surveillance activity of Hint1, to potentially control Ap4A levels in the cell.
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Affiliation(s)
- Jing Wang
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, 130 Scripps Way, Jupiter, Florida 33458, USA
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10
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Dias J, Octobre G, Kobbi L, Comisso M, Flisiak S, Mirande M. Activation of human mitochondrial lysyl-tRNA synthetase upon maturation of its premitochondrial precursor. Biochemistry 2012; 51:909-16. [PMID: 22235746 DOI: 10.1021/bi201337b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The cytoplasmic and mitochondrial species of human lysyl-tRNA synthetase are encoded by a single gene by means of alternative splicing of the KARS1 gene. The cytosolic enzyme possesses a eukaryote-specific N-terminal polypeptide extension that confers on the native enzyme potent tRNA binding properties required for the vectorial transfer of tRNA from the synthetase to elongation factor EF1A within the eukaryotic translation machinery. The mitochondrial enzyme matures from its precursor upon being targeted to that organelle. To understand how the cytosolic and mitochondrial enzymes are adapted to participate in two distinct translation machineries, of eukaryotic or bacterial origin, we characterized the mitochondrial LysRS species. Here we report that cleavage of the precursor of mitochondrial LysRS leads to a mature enzyme with reduced tRNA binding properties compared to those of the cytoplasmic counterpart. This adaptation mechanism may prevent inhibition of translation through sequestration of lysyl-tRNA on the synthetase in a compartment where the bacterial-like elongation factor EF-Tu could not assist in its dissociation from the synthetase. We also observed that the RxxxKRxxK tRNA-binding motif of mitochondrial LysRS is not functional in the precursor form of that enzyme and becomes operational after cleavage of the mitochondrial targeting sequence. The finding that maturation of the precursor is needed to reveal the potent tRNA binding properties of this enzyme has strong implications for the spatiotemporal regulation of its activities and is consistent with previous studies suggesting that the only LysRS species able to promote packaging of tRNA(Lys) into HIV-1 viral particles is the mature form of the mitochondrial enzyme.
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Affiliation(s)
- José Dias
- Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, Gif-sur-Yvette, France
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11
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Fraga H, Fontes R. Enzymatic synthesis of mono and dinucleoside polyphosphates. Biochim Biophys Acta Gen Subj 2011; 1810:1195-204. [PMID: 21978831 DOI: 10.1016/j.bbagen.2011.09.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 09/09/2011] [Accepted: 09/19/2011] [Indexed: 01/08/2023]
Abstract
BACKGROUND Mono and dinucleoside polyphosphates (p(n)Ns and Np(n)Ns) exist in living organisms and induce diverse biological effects through interaction with intracellular and cytoplasmic membrane proteins. The source of these compounds is associated with secondary activities of a diverse group of enzymes. SCOPE OF REVIEW Here we discuss the mechanisms that can promote their synthesis at a molecular level. Although all the enzymes described in this review are able to catalyse the in vitro synthesis of Np(n)Ns (and/or p(n)N), it is not clear which ones are responsible for their in vivo accumulation. MAJOR CONCLUSIONS Despite the large amount of knowledge already available, important questions remain to be answered and a more complete understanding of p(n)Ns and Np(n)Ns synthesis mechanisms is required. With the possible exception of (GTP:GTP guanylyltransferase of Artemia), all enzymes able to catalyse the synthesis of p(n)Ns and Np(n)Ns are unspecific and the factors that can promote their synthesis relative to the canonical enzyme activities are unclear. GENERAL SIGNIFICANCE The fact that p(n)Ns and Np(n)Ns syntheses are promiscuous activities of housekeeping enzymes does not reduce its physiological or pathological importance. Here we resume the current knowledge regarding their enzymatic synthesis and point the open questions on the field.
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Affiliation(s)
- Hugo Fraga
- Department of Biochemistry, Universitat Autonoma de Barcelona, Spain
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12
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Martin J, St-Pierre MV, Dufour JF. Hit proteins, mitochondria and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:626-32. [PMID: 21316334 DOI: 10.1016/j.bbabio.2011.02.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 02/02/2011] [Accepted: 02/02/2011] [Indexed: 11/30/2022]
Abstract
The histidine triad (HIT) superfamily comprises proteins that share the histidine triad motif, His-ϕ-His-ϕ-His-ϕ-ϕ, where ϕ is a hydrophobic amino acid. HIT proteins are ubiquitous in prokaryotes and eukaryotes. HIT proteins bind nucleotides and exert dinucleotidyl hydrolase, nucleotidylyl transferase or phosphoramidate hydrolase enzymatic activity. In humans, 5 families of HIT proteins are recognized. The accumulated epidemiological and experimental evidence indicates that two branches of the superfamily, the HINT (Histidine Triad Nucleotide Binding) members and FHIT (Fragile Histidine Triad), have tumor suppressor properties but a conclusive physiological role can still not be assigned to these proteins. Aprataxin forms another discrete branch of the HIT superfamily, is implicated in DNA repair mechanisms and unlike the HINT and FHIT members, a defective protein can be conclusively linked to a disease, ataxia with oculomotor apraxia type 1. The scavenger mRNA decapping enzyme, DcpS, forms a fourth branch of the HIT superfamily. Finally, the GalT enzymes, which exert specific nucleoside monophosphate transferase activity, form a fifth branch that is not implicated in tumorigenesis. The molecular mechanisms by which the HINT and FHIT proteins participate in bioenergetics of cancer are just beginning to be unraveled. Their purported actions as tumor suppressors are highlighted in this review.
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Affiliation(s)
- Juliette Martin
- Institute of Clinical Pharmacology and Visceral Research, University of Bern, Switzerland
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13
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Ul-Haq Z, Khan W, Zarina S, Sattar R, Moin ST. Template-based structure prediction and molecular dynamics simulation study of two mammalian Aspartyl-tRNA synthetases. J Mol Graph Model 2010; 28:401-12. [DOI: 10.1016/j.jmgm.2009.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2009] [Revised: 09/14/2009] [Accepted: 09/23/2009] [Indexed: 10/20/2022]
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14
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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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15
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Yannay-Cohen N, Carmi-Levy I, Kay G, Yang CM, Han JM, Kemeny DM, Kim S, Nechushtan H, Razin E. LysRS serves as a key signaling molecule in the immune response by regulating gene expression. Mol Cell 2009; 34:603-11. [PMID: 19524539 DOI: 10.1016/j.molcel.2009.05.019] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 12/31/2008] [Accepted: 05/26/2009] [Indexed: 11/28/2022]
Abstract
Lysyl-tRNA synthetase (LysRS) was found to produce diadenosine tetraphosphate (Ap(4)A) in vitro more than two decades ago. Here, we used LysRS silencing in mast cells in combination with transfected normal and mutated LysRS to demonstrate in vivo the critical role played by LysRS in the production of Ap(4)A in response to immunological challenge. Upon such challenge, LysRS was phosphorylated on serine 207 in a MAPK-dependent manner, released from the multisynthetase complex, and translocated into the nucleus. We previously demonstrated that LysRS forms a complex with MITF and its repressor Hint-1, which is released from the complex by its binding to Ap(4)A, enabling MITF to transcribe its target genes. Here, silencing LysRS led to reduced Ap(4)A production in immunologically activated cells, which resulted in a lower level of MITF inducible genes. Our data demonstrate that specific LysRS serine 207 phosphorylation regulates Ap(4)A production in immunologically stimulated mast cells, thus implying that LysRS is a key mediator in gene regulation.
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Affiliation(s)
- Nurit Yannay-Cohen
- Department of Biochemistry, The Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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16
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Nechushtan H, Kim S, Kay G, Razin E. Chapter 1 The Physiological Role of Lysyl tRNA Synthetase in the Immune System. Adv Immunol 2009; 103:1-27. [DOI: 10.1016/s0065-2776(09)03001-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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17
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Diadenosine tetraphosphate hydrolase is part of the transcriptional regulation network in immunologically activated mast cells. Mol Cell Biol 2008; 28:5777-84. [PMID: 18644867 DOI: 10.1128/mcb.00106-08] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously discovered that microphthalmia transcription factor (MITF) and upstream stimulatory factor 2 (USF2) each forms a complex with its inhibitor histidine triad nucleotide-binding 1 (Hint-1) and with lysyl-tRNA synthetase (LysRS). Moreover, we showed that the dinucleotide diadenosine tetraphosphate (Ap(4)A), previously shown to be synthesized by LysRS, binds to Hint-1, and as a result the transcription factors are released from their suppression. Thus, transcriptional activity is regulated by Ap(4)A, suggesting that Ap(4)A is a second messenger in this context. For Ap(4)A to be unambiguously established as a second messenger, several criteria have to be fulfilled, including the presence of a metabolizing enzyme. Since several enzymes are able to hydrolyze Ap(4)A, we provided here evidence that the "Nudix" type 2 gene product, Ap(4)A hydrolase, is responsible for Ap(4)A degradation following the immunological activation of mast cells. The knockdown of Ap(4)A hydrolase modulated Ap(4)A accumulation, resulting in changes in the expression of MITF and USF2 target genes. Moreover, our observations demonstrated that the involvement of Ap(4)A hydrolase in gene regulation is not a phenomenon exclusive to mast cells but can also be found in cardiac cells activated with the beta-agonist isoproterenol. Thus, we have provided concrete evidence establishing Ap(4)A as a second messenger in the regulation of gene expression.
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18
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Yiadom KPAB, Hammamieh R, Ukpabi N, Tsang P, Yang DCH. A peptide from the extension of Lys-tRNA synthetase binds to transfer RNA and DNA. Peptides 2003; 24:987-98. [PMID: 14499277 DOI: 10.1016/s0196-9781(03)00188-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eukaryotic aminoacyl-tRNA synthetases have dispensable extensions appended at the amino- or carboxyl-terminus as compared to their bacterial counterparts. While a synthetic peptide corresponding to the basic amino-terminal extension in yeast Asp-tRNA synthetase binds to DNA, the extension in the intact protein evidently binds to tRNA and enhances the tRNA specificity of Asp-tRNA synthetase. On the other hand, the amino-terminal extension in human Asp-tRNA synthetase, both within the intact protein and as a synthetic peptide, binds to tRNA. Here, the tRNA binding of a synthetic peptide, hKRS(Arg(25)-Glu(42)), corresponding to the amino-terminal extension of human Lys-tRNA synthetase (hKRS) was analyzed. This basic peptide bound to tRNA(Phe) and the apparent-binding constant increased with increasing concentrations of Mg(2+). The hKRS peptide also bound to DNA and polyphosphate; however, the apparent DNA-binding constants decreased at increasing concentrations of Mg(2+). The ability of the hKRS peptide to adopt alpha-helical conformation was demonstrated by NMR and circular dichroism. A Lys-rich peptide derived from the elongation factor 1alpha was also examined and bound to DNA but not to tRNA.
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MESH Headings
- Amino Acid Sequence
- Cations, Divalent/chemistry
- Circular Dichroism
- DNA/chemistry
- DNA/metabolism
- DNA-Binding Proteins/chemical synthesis
- DNA-Binding Proteins/chemistry
- DNA-Binding Proteins/metabolism
- Humans
- Hydrogen-Ion Concentration
- Lysine-tRNA Ligase/chemistry
- Magnesium Chloride/chemistry
- Magnetic Resonance Spectroscopy
- Models, Molecular
- Molecular Sequence Data
- Molecular Weight
- Peptide Elongation Factor 1/chemistry
- Peptides/chemical synthesis
- Peptides/chemistry
- Peptides/metabolism
- Polyphosphates/chemistry
- Protein Binding
- Protein Structure, Secondary
- RNA, Transfer/chemistry
- RNA, Transfer/metabolism
- RNA, Transfer, Met/chemistry
- RNA, Transfer, Met/metabolism
- RNA, Transfer, Phe/chemistry
- RNA, Transfer, Phe/metabolism
- RNA-Binding Proteins/chemical synthesis
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/metabolism
- Sodium Chloride/chemistry
- Spectrometry, Fluorescence
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Trifluoroethanol/chemistry
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19
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The Transcription of Genes. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50031-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Affiliation(s)
- D C Yang
- Department of Chemistry, Georgetown University, Washington DC 20057, USA
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21
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Abstract
Lysyl-tRNA synthetase catalyses the formation of lysyl-transfer RNA, Lys-tRNA(Lys), which then is ready to insert lysine into proteins. Lysine is important for proteins since it is one of only two proteinogenic amino acids carrying an alkaline functional group. Seven genes of lysyl-tRNA synthetases have been localized in five organisms, and the nucleotide and the amino acid sequences have been established. The lysyl-tRNA synthetase molecules are of average chain lengths among the aminoacyl-tRNA synthetases, which range from about 300 to 1100 amino acids. Lysyl-tRNA synthetases act as dimers; in eukaryotes they can be localized in multienzyme complexes and can contain carbohydrates or lipids. Lysine tRNA is recognized by lysyl-tRNA synthetase via standard identity elements, namely anticodon region and acceptor stem. The aminoacylation follows the standard two-step mechanism. However the accuracy of selecting lysine against the other amino acids is less than average. The first threedimensional structure of a lysyl-tRNA synthetase worked out very recently, using the enzyme from the Escherichia coli lysU gene which binds one molecule of lysine, is similar to those of other class II synthetases. However, none of the reaction steps catalyzed by the enzyme is clarified to atomic resolution. Thus surprising findings might be possible. Lysyl-tRNA synthetase and its precursors as well as its substrates and products are targets and starting points of many regulation circuits, e.g. in multienzyme complex formation and function, dinucleoside polyphosphate synthesis, heat shock regulation, activation or deactivation by phosphorylation/dephosphorylation, inhibition by amino acid analogs, and generation of antibodies against lysyl-tRNA synthetase. None of these pathways is clarified completely.
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Affiliation(s)
- W Freist
- Max-Planck-Institut für Experimentelle Medizin, Göttingen, Germany
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22
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Onesti S, Miller AD, Brick P. The crystal structure of the lysyl-tRNA synthetase (LysU) from Escherichia coli. Structure 1995; 3:163-76. [PMID: 7735833 DOI: 10.1016/s0969-2126(01)00147-2] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Lysyl-tRNA synthetase catalyzes the attachment of the amino acid lysine to the cognate tRNA. The enzyme is a member of the class II amino-acyl-tRNA synthetases; the crystal structures of the seryl- and aspartyl-tRNA synthetases from this class are already known. Lysyl-tRNA synthetase shows extensive sequence homology with aspartyl-tRNA synthetase. In Escherichia coli there are two isoforms of the enzyme, LysS and LysU. Unlike LysS, which is synthesized under normal growth conditions, LysU is the product of a normally silent gene which is overexpressed under extreme physiological conditions (such as heat-shock), and can synthesize a number of adenyl dinucleotides (in particular AppppA). These dinucleotides have been proposed to act as modulators of the heat-shock response and stress response. RESULTS The crystal structure of E. coli LysU has been determined to 2.8 A resolution, with lysine bound to the active site. The protein is a homodimer, with a rather extended dimer interface spanning the entire length of the molecule. Each monomer consists of two domains: a smaller N-terminal domain which binds the tRNA anticodon, and a larger C-terminal domain with the topology characteristic of the catalytic domain found in class II synthetases. CONCLUSIONS A comparison of the LysU crystal structure with the structures of seryl- and aspartyl-tRNA synthetases enables a conserved core to be identified. The structural homology with the aspartyl-tRNA synthetase extends to include the anticodon-binding domain. When the active sites of lysyl-, aspartyl- and seryl-tRNA synthetases are compared, a number of catalytically important residues are conserved and a similar extended network of hydrogen bonds can be observed in the amino acid binding pocket in all three structures, although the details may differ. The lysine substrate is involved in an extended network of hydrogen bonds and polar interactions, with the side chain amino group forming a salt bridge with Glu428. The binding of ATP to LysU can be modelled on the basis of the aspartyl-tRNA synthetase-ATP complex, but the tRNA acceptor stem interaction for LysU cannot be easily modelled by similar extrapolation.
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Affiliation(s)
- S Onesti
- Blackett Laboratory, Imperial College, London, UK
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23
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Escalante C, Yang D. Expression of human aspartyl-tRNA synthetase in Escherichia coli. Functional analysis of the N-terminal putative amphiphilic helix. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53420-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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24
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García-Agúndez J, Cameselle JC, Costas MJ, Sillero MA, Sillero A. Particulate diadenosine 5',5"'-P1,P3-triphosphate hydrolases in rat brain: two specific dinucleoside triphosphatases and two phosphodiesterase I-like hydrolases. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1073:402-9. [PMID: 1849011 DOI: 10.1016/0304-4165(91)90149-b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Rat liver and brain differ in the distribution pattern of the total hydrolytic activity on diadenosine 5',5"'-P1,P3-triphosphate (Ap3A) between the soluble and particulate fractions. The Ap3A-hydrolase activity in both the soluble and particulate liver fractions and in the brain soluble fraction had been previously studied in detail. We report now on the brain particulate fraction which, unlike liver, showed a low unspecific phosphodiesterase I-like (PDEaseI, EC 3.1.4.1) activity relative to the specific dinucleoside triphosphatase (Ap3Aase, EC 3.6.1.29). Two PDEaseI-like forms (PDEaseI-A and PDEaseI-B), with different apparent Mrs and kinetic properties, and two Ap3Aases (Ap3Aase-alpha and Ap3Aase-beta) were solubilized with 0.5% Triton X-100 from the particulate fraction. Ap3Aase-alpha resembled the cytosolic Ap3Aase (Ap3Aase-c), a known situation in liver. Comparative to Ap3Aase-alpha, Ap3Aase-beta showed a slightly higher Km (35 vs. 15 micron) and lower isoelectric point (5.25 vs. 5.45); Ap3Aase-beta was absent from the soluble fraction, and its recovery was unaffected by proteinase inhibitors, strongly arguing for distinct soluble and particulate turnover pathways for dinucleoside polyphosphates.
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Affiliation(s)
- J García-Agúndez
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Medicina, Universidad de Extremadura, Badajoz, Spain
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25
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Mirande M. Aminoacyl-tRNA synthetase family from prokaryotes and eukaryotes: structural domains and their implications. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1991; 40:95-142. [PMID: 2031086 DOI: 10.1016/s0079-6603(08)60840-5] [Citation(s) in RCA: 200] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- M Mirande
- Laboratoire d'Enzymologie, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
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26
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Kimball SR, Antonetti DA, Brawley RM, Jefferson LS. Mechanism of inhibition of peptide chain initiation by amino acid deprivation in perfused rat liver. Regulation involving inhibition of eukaryotic initiation factor 2 alpha phosphatase activity. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52387-5] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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27
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Okada N. Transfer RNA-like structure of the human Alu family: implications of its generation mechanism and possible functions. J Mol Evol 1990; 31:500-10. [PMID: 1702838 DOI: 10.1007/bf02102077] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Structural resemblance of the human Alu family with a subset of vertebrate tRNAs was detected. Of four tRNAs, tRNA(Lys), tRNA(Ile), tRNA(Thr), and tRNA(Tyr), which comprise a structurally related family, tRNA(Lys) is the most similar to the human Alu family. Of the 76 nucleotides in lysine tRNA (including the CCA tail), 47 are similar to the human Alu family (60% identity). The secondary structure of the human Alu family corresponding to the D-stem and anticodon stem regions of the tRNA appears to be very stable. The 7SL RNA, which is a progenitor of the human Alu family, is less similar to lysine tRNA (55% identity), and the secondary structure of the 7SL RNA folded like a tRNA is less stable than that of the human Alu family folded likewise. Insertion of the tetranucleotide GAGA, which is an important region of the second promoter for RNA polymerase III in the Alu sequence, occurred during the deletion and ligation process to generate the Alu sequence from the parental 7SL RNA. These results suggest that the human Alu family was generated from the 7SL RNA by deletion, insertion, and mutations, which thus modified the ancestral 7SL sequence so that it could form a structure more closely resembling lysine tRNA. The similarities of several short interspersed sequences to the lysine tRNA were also examined. The Galago type 2 family, which was reported to be derived from a methionine initiator tRNA, was also found to be similar to the lysine tRNA. Thus lysine tRNA-like structures are widespread in genomes in the animal kingdom. The implications of these findings in relation to the mechanism of generation of the human Alu family and its possible functions are discussed.
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MESH Headings
- Animals
- Base Sequence
- Deoxyribonucleases, Type II Site-Specific/metabolism
- Humans
- Molecular Sequence Data
- Mutation
- Nucleic Acid Conformation
- RNA, Transfer, Amino Acid-Specific/genetics
- RNA, Transfer, Amino Acid-Specific/metabolism
- RNA, Transfer, Amino Acid-Specific/physiology
- RNA, Transfer, Lys/genetics
- RNA-Directed DNA Polymerase/metabolism
- Repetitive Sequences, Nucleic Acid
- Rodentia
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Affiliation(s)
- N Okada
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan
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28
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Meyer D, Moris G, Wolff CM, Befort N, Remy P. Significance of dinucleoside tetraphosphate production by cultured tumor cells exposed to the presence of ethanol. Biochimie 1990; 72:57-64. [PMID: 2160288 DOI: 10.1016/0300-9084(90)90173-e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The use of 30 to 50% ethanol solutions to extract the nucleotides from HTC and A-459 cells results in dinucleoside tetraphosphate (Ap4X) levels 3-30-fold as high as those obtained by 5% classical trichloracetic acid extraction, while ATP levels are identical in both cases. The amplification factor varies with the percentage of ethanol and duration of contact between the cells and the extraction mixture. It remains constant for the HTC cells during cell growth, but exhibits a maximum for the A-459 cells towards the end of the exponential growth period. The incorporation of radioactivity in Ap4X when [alpha-32P]ATP is added to the extraction mixture suggests an Ap4X neosynthesis in the presence of ethanol. The results carried out in the presence of pyrophosphate, EDTA and zinc acetate strongly suggest that aminoacyl-tRNA synthetases could be responsible for the increase in Ap4A content with ethanol treatment. Nevertheless, the effect of ethanol is probably not the result of an activation of these enzymes, but rather, as already suggested by earlier results in our laboratory, the result of a fast inactivation of the degradation enzymes.
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Affiliation(s)
- D Meyer
- Institut de Biologie Moléculaire et Cellulaire du Centre National de la Recherche Scientifique, Strasbourg, France
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29
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Berbeć H, Paszkowska A. Comparison of the thermolability and hydrophobic properties of high- and low-molecular-weight forms of rabbit liver arginyl-tRNA synthetase. Mol Cell Biochem 1989; 86:125-33. [PMID: 2770710 DOI: 10.1007/bf00222612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Two preparations with arginyl-tRNA synthetase activity have been obtained from rabbit liver post-microsomal fraction: a) a high-molecular-weight containing the multienzyme aminoacyl-tRNA synthetase complex and b) a low-molecular-weight preparation containing free enzymes. Thermal inactivation of arginyl-tRNA synthetase in both preparations has been compared in a solution which was successively supplemented with tRNA, reduced glutathione, L-ascorbic acid, ZnCl2 and Triton X 100. Moreover, hydrophobic properties of both enzyme preparations have been compared. It was found that the complexed arginyl-tRNA synthetase is more stable than the free enzyme. A role of hydrophobic interactions in the maintenance of the complexed enzyme stability is suggested.
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Affiliation(s)
- H Berbeć
- Department of Physiological Chemistry, Medical School, Lublin, Poland
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30
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31
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Freist W. Isoleucyl-tRNA Synthetase: An Enzyme with Several Catalytic Cycles Displaying Variation in Specificity and Energy Consumption. ACTA ACUST UNITED AC 1988. [DOI: 10.1002/anie.198807731] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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32
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Freist W. Isoleucyl-tRNA-Synthetase: Ein Enzym mit mehreren Katalysewegen, variabel in Spezifität und Energieverbrauch. Angew Chem Int Ed Engl 1988. [DOI: 10.1002/ange.19881000605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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33
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SHIMADA HIRAKU. DNA Replication and Its Regulation in Cleavage Embryos of Sea Urchin. (DNA replication/cytoplasmic factor/cleavage embryo/sea urchin). Dev Growth Differ 1987. [DOI: 10.1111/j.1440-169x.1987.00417.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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34
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Coste H, Brevet A, Plateau P, Blanquet S. Non-adenylylated bis(5'-nucleosidyl) tetraphosphates occur in Saccharomyces cerevisiae and in Escherichia coli and accumulate upon temperature shift or exposure to cadmium. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)45321-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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35
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Hilderman RH, Ortwerth BJ. A preferential role for lysyl-tRNA4 in the synthesis of diadenosine 5',5'''-P1,P4-tetraphosphate by an arginyl-tRNA synthetase-lysyl-tRNA synthetase complex from rat liver. Biochemistry 1987; 26:1586-91. [PMID: 3647796 DOI: 10.1021/bi00380a015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The synthesis of diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) can be catalyzed in vitro by a tetrameric tRNA synthetase complex from rat liver containing two lysyl-tRNA synthetase and two arginyl-tRNA synthetase subunits. This reaction required ATP, AMP, 50-100 microM zinc, and inorganic pyrophosphatase. We show here that AMP can be omitted from the reaction and that the zinc levels can be markedly reduced provided catalytic amounts of tRNA(Lys) are added to the reaction mixture. Ap4A synthesis with purified tRNA(Lys) isoacceptors showed that the minor species, tRNA(4Lys), was 3-fold more active than either of the two major tRNA(Lys) species, tRNA(2Lys) and tRNA(5Lys). No activity could be demonstrated with tRNA(Lys) from Escherichia coli or with tRNA(Lys) or tRNA(Phe) from yeast. Aminoacylation of tRNA(4Lys) was strictly required as determined by the fact that Ap4A synthesis was not observed until aminoacylation was nearly complete, inhibitors of aminoacylation blocked Ap4A synthesis, and there was a strict requirement for added lysine. None of the above observations could be demonstrated, however, when lysyl-tRNA(Lys) was directly supplied to the reaction mixture. Optimum Ap4A synthesis was obtained by the addition of 1 mol of tRNA(Lys)/mol of the synthetase complex. This reaction is unique because it does not require the prior formation of an aminoacyl-AMP intermediate and because it can actively synthesize Ap4A at physiological zinc concentrations. The preferential role for tRNA(4Lys) in Ap4A synthesis is consistent with its prior implication in cell division.
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36
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Wahab SZ, Yang DC. Comparison of the enzymatic behavior of high molecular weight and free lysyl-tRNA synthetase from rat liver: kinetic analysis of lysylation of tRNA. Arch Biochem Biophys 1986; 249:407-17. [PMID: 3753009 DOI: 10.1016/0003-9861(86)90017-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Lysyl-tRNA synthetase occurs in the high molecular weight form in rat liver. The high molecular weight lysyl-tRNA synthetase has been previously demonstrated to exist as multienzyme complexes of aminoacyl-tRNA synthetases. The multienzyme complexes can be dissociated by hydrophobic interaction chromatography and yield fully active, free lysyl-tRNA synthetase. The free form is found to be twice as active as the complexed form in lysylation. Bisubstrate and product inhibition kinetics of lysylation are systematically carried out for highly purified free lysyl-tRNA synthetase and the 18 S synthetase complex. Surprisingly, the two enzyme forms exhibit distinctly different kinetic patterns in bisubstrate and product inhibition kinetics under identical conditions. The 18 S synthetase complex shows kinetic patterns consistent with an ordered bi uni uni bi ping pong mechanism, while the results of free lysyl-tRNA synthetase do not. We conclude that structural organization of lysyl-tRNA synthetase beyond quaternary structure of proteins may alter the enzyme behavior.
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37
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Dang CV, Dang CV. Higher eukaryotic aminoacyl-tRNA synthetases in physiologic and pathologic states. Mol Cell Biochem 1986; 71:107-20. [PMID: 3534543 DOI: 10.1007/bf00214769] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The aminoacyl-tRNA synthetases play a dual role in cell metabolism by synthesizing aminoacyl-tRNAs and an odd dinucleotide diadenosine-5', 5''-P1, P4-tetraphosphate which appears to be involved in DNA replication and the control of cell proliferation. This review is a synthesis of recent results on the structure, genetics, cell biology, physiology, role in neoplasia, and role in autoimmune myositis of the higher eukaryotic aminoacyl-tRNA synthetases.
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Robinson AK, Barnes LD. Three diadenosine 5',5''-P1,P4-tetraphosphate hydrolytic enzymes from Physarum polycephalum with differential effects by calcium: a specific dinucleoside polyphosphate pyrophosphohydrolase, a nucleotide pyrophosphatase, and a phosphodiesterase. Arch Biochem Biophys 1986; 248:502-15. [PMID: 3017212 DOI: 10.1016/0003-9861(86)90503-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Two new enzymes that hydrolyze diadenosine tetraphosphate (Ap4A) have been isolated from the acellular slime mold Physarum polycephalum. Both enzymes are different from the Physarum Ap4A symmetrical pyrophosphohydrolase previously described on the basis of their substrate specificities, reaction products, molecular weights, and divalent cation requirements. One enzyme is a nucleotide pyrophosphatase that asymmetrically hydrolyzes Ap4A to AMP and ATP. This enzyme hydrolyzes several mono- and dinucleotides with the corresponding nucleotide monophosphate as one of the products. The percentage hydrolysis of NAD+, Ap4A, and Ap4G, each at 10 microM, was 100, 56, and 51, respectively. A divalent cation is required for activity, with Ca2+ yielding 20-30 times greater activity than Mg2+ or Mn2+. Values of Km for Ap4A and Vmax are similar to the corresponding values for Ap4A symmetrical pyrophosphohydrolase. The second enzyme is a phosphodiesterase I with broad substrate reactivity. This enzyme also asymmetrically hydrolyzes Ap4A, but it does not hydrolyze NAD+. Activity of the phosphodiesterase I is stimulated by divalent cations, with Ca2+ being 50-60 times more stimulatory than Mg2+ or Mn2+. The apparent molecular weights of the nucleotide pyrophosphatase and phosphodiesterase are 184,000 and 45,000, respectively. In contrast, the Ap4A pyrophosphohydrolase hydrolyzes Ap4A to ADP, is inhibited by Ca2+ and other divalent cations, and has an apparent molecular weight of 26,000 as previously reported.
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