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Zou C, Gu C, Zhao M, Zhu D, Wang N, Yu J, Yao Y, Chen Y, Shi M, Gu Q, Qian Y, Qiu Q, Zheng Z. The Role of the AIMP1 Pathway in Diabetic Retinopathy: AIMP1-Targeted Intervention Study in Diabetic Retinopathy. Ophthalmic Res 2020; 63:122-132. [PMID: 31962335 DOI: 10.1159/000503637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 09/24/2019] [Indexed: 11/19/2022]
Abstract
INTRODUCTION We characterized the role of aminoacyl-tRNA synthetase-interacting multifunctional protein 1 (AIMP1) in retinal inflammation and apoptosis regulation, both in vivo and in vitro. In addition, we used clinical specimens to show the relationship between AIMP1 and the development of diabetic retinopathy (DR). OBJECTIVE To elucidate the role of AIMP1 in DR. METHODS A diabetic AIMP1-specific knockout (KO) C57 mouse model was used. Human retinal microvascular endothelial cells (HRMECs) were incubated with normal glucose, high glucose (HG), and HG + AIMP1-small interfering RNA (siRNA). The expression of AIMP1 and relative inflammatory and apoptotic cytokines in diabetic mice retina and HRMECs were measured using Western blotting and polymerase chain reaction. The apoptosis of HRMECs was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. The levels of AIMP1 in the vitreous humor and serum were determined using ELISA. Possible correlations between the intravitreal level of AIMP1 and blood glucose, glycosylated hemoglobin HbA1c, intravitreal levels of IL-1β, and caspase-3 were determined. RESULTS The expression of inflammatory and apoptotic proteins was inhibited in the AIMP1 KO mice and HRMECs incubated with AIMP1-siRNA. The apoptosis of HRMECs was decreased in the AIMP1-siRNA group. The intravitreal level of AIMP1 in DR patients was significantly higher than that in nondiabetic patients (p < 0.01). There was a positive correlation between intravitreal AIMP1 and HbA1c and intravitreal IL-1β and caspase-3 (p < 0.05). CONCLUSIONS HG induced increased expression of AIMP1 in HRMECs and retinas from diabetic C57 mice, thereby increasing the expression of inflammatory and apoptotic cytokines, which promoted DR progression. A decrease in AIMP1 expression prevented the development of DR by inhibiting the activation of inflammatory and apoptotic signaling. Therefore, AIMP1 is an effective interfering target for the prevention and treatment of DR.
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Affiliation(s)
- Chen Zou
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Chufeng Gu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Minjie Zhao
- Department of Ophthalmology, Yixing People's Hospital, Jiangsu University, Yixing, China
| | - Dandan Zhu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Na Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Jingjing Yu
- Department of Ophthalmology, Changshu 2nd People's Hospital, Changshu, China
| | - Yuan Yao
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Ye Chen
- Department of Nursing, Shanghai General Hospital, Shanghai, China
| | - Min Shi
- Department of Nursing, Shanghai General Hospital, Shanghai, China
| | - Qi Gu
- Department of Nursing, Shanghai General Hospital, Shanghai, China
| | - Yingying Qian
- Department of Nursing, Shanghai General Hospital, Shanghai, China
| | - Qinghua Qiu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
| | - Zhi Zheng
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China,
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Motzik A, Amir E, Erlich T, Wang J, Kim BG, Han JM, Kim JH, Nechushtan H, Guo M, Razin E, Tshori S. Post-translational modification of HINT1 mediates activation of MITF transcriptional activity in human melanoma cells. Oncogene 2017; 36:4732-4738. [DOI: 10.1038/onc.2017.81] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/21/2016] [Accepted: 01/24/2017] [Indexed: 12/23/2022]
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3
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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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Lee SW, Kim G, Kim S. Aminoacyl-tRNA synthetase-interacting multi-functional protein 1/p43: an emerging therapeutic protein working at systems level. Expert Opin Drug Discov 2013; 3:945-57. [PMID: 23484969 DOI: 10.1517/17460441.3.8.945] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Drug discovery programs are based on the presumption of one drug-one action-one disease, which is frustrated by the complexity of biological systems. Because the aberration of a single gene often leads to multiple pathological symptoms, we should understand the functional network of the disease-related proteins to develop effective therapy. OBJECTIVES To describe how activities of proteins are reflected in phenotypes and their pathological implications using aminoacyl-tRNA synthetase-interacting multi-functional protein 1 (AIMP1). METHODS The physiological activities of AIMP1 are unveiled through in vitro approaches and in vivo phenotyptic investigation. Bioinformatics tool was used to combine all AIMP1-target proteins. CONCLUSION Although a cytosolic protein, AIMP1 can be secreted as a cytokine to control immune response, angiogenesis and wound healing, and as a glucagon-like hormone for glucose homeostasis. It is involved in the regulation of autoimmune control and TGF-β signaling within the cells. AIMP1-deficient mice developed multiple phenotypes in immune systems, metabolism and body growth. The therapeutic potential of this multi-functional protein with associated biological activities are discussed.
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Affiliation(s)
- Sang Won Lee
- Seoul National University of Education, Department of Science and Technology Education for Life, 1650, Seocho-dong, Seocho-gu, Seoul 137-742, Korea
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5
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Park SG, Kang YS, Kim JY, Lee CS, Ko YG, Lee WJ, Lee KU, Yeom YI, Kim S. Hormonal activity of AIMP1/p43 for glucose homeostasis. Proc Natl Acad Sci U S A 2006; 103:14913-8. [PMID: 17001013 PMCID: PMC1595450 DOI: 10.1073/pnas.0602045103] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
AIMP1/p43 is known as a cytokine working in the control of angiogenesis, inflammation, and wound healing. Here we report its enrichment in pancreatic alpha cells and glucagon-like hormonal activity. AIMP1 is secreted from the pancreas upon glucose starvation. Exogenous infusion of AIMP1 increased plasma levels of glucose, glucagon, and fatty acid, and AIMP1-deficient mice showed reduced plasma glucose levels compared with the wild-type mice under fasting conditions. Thus, AIMP1 plays a glucagon-like role in glucose homeostasis.
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Affiliation(s)
- Sang Gyu Park
- *National Creative Research Initiatives Center for ARS Network, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Young Sun Kang
- *National Creative Research Initiatives Center for ARS Network, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Jin Young Kim
- *National Creative Research Initiatives Center for ARS Network, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Chang Seok Lee
- Division of Life Sciences and Graduate School of Biotechnology, Korea University, 1, 5-ga, Anam-dong, Sungbuk-gu, Seoul 136-701, Korea
| | - Young Gyu Ko
- Division of Life Sciences and Graduate School of Biotechnology, Korea University, 1, 5-ga, Anam-dong, Sungbuk-gu, Seoul 136-701, Korea
| | - Woo Je Lee
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea; and
| | - Ki-Up Lee
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea; and
| | - Young Il Yeom
- Genome Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejon 305-333, Korea
| | - Sunghoon Kim
- *National Creative Research Initiatives Center for ARS Network, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
- Genome Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejon 305-333, Korea
- To whom correspondence should be addressed. E-mail:
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Han JM, Kim JY, Kim S. Molecular network and functional implications of macromolecular tRNA synthetase complex. Biochem Biophys Res Commun 2003; 303:985-93. [PMID: 12684031 DOI: 10.1016/s0006-291x(03)00485-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Understanding the complex network and multi-functionality of proteins is one of the main objectives of post-genome research. Aminoacyl-tRNA synthetases (ARSs) are the family of enzymes that are essential for cellular protein synthesis and viability that catalyze the attachment of specific amino acids to their cognate tRNAs. However, a lot of evidence has shown that these enzymes are multi-functional proteins that are involved in diverse cellular processes, such as tRNA processing, RNA splicing and trafficking, rRNA synthesis, apoptosis, angiogenesis, and inflammation. In addition, mammalian ARSs form a macromolecular complex with three auxiliary factors or with the elongation factor complex. Although the functional meaning and physiological significance of these complexes are poorly understood, recent data on the molecular interactions among the components for the multi-ARS complex are beginning to provide insights into the structural organization and cellular functions. In this review, the molecular mechanism for the assembly and functional implications of the multi-ARS complex will be discussed.
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Affiliation(s)
- Jung Min Han
- Imagene Co. Biotechnology Incubating Center, Golden Helix, Seoul National University, San 56-1, Shillim-dong, Kwanak-Gu, Republic of Korea
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Abstract
The vast number of proteins that sustain the currently living organisms have been generated from a relatively small number of ancestral genes that has involved a variety of processes. Lysozyme is an ancient protein whose origin goes back an estimated 400 to 600 million years. This protein was originally a bacteriolytic defensive agent and has been adapted to serve a digestive function on at least two occasions, separated by nearly 40 million years. The origins of the related goose type and T4 phage lysozyme that are distinct from the more common C type are obscure. They share no discernable amino acid sequence identity and yet they possess common secondary and tertiary structures. Lysozyme C gene also gave rise, after gene duplication 300 to 400 million years ago, to a gene that currently codes for alpha-lactalbumin, a protein expressed only in the lactating mammary gland of all but a few species of mammals. It is required for the synthesis of lactose, the sugar secreted in milk. alpha-Lactalbumin shares only 40% identity in amino acid sequence with lysozyme C, but it has a closer spatial structure and gene organization. Although structurally similar, functionally they are quite distinct. Specific amino acid substitutions in alpha-lactalbumin account for the loss of the enzyme activity of lysozyme and the acquisition of the features necessary for its role in lactose synthesis. Evolutionary implications are as yet unclear but are being unraveled in many laboratories.
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Affiliation(s)
- P K Qasba
- Structural Glycobiology Section, National Cancer Institute, N.I.H., Frederick, MD 21702-1201, USA.
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8
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Affiliation(s)
- D C Yang
- Department of Chemistry, Georgetown University, Washington DC 20057, USA
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9
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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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10
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Abstract
The size distribution of aminoacyl-tRNA synthetase activity was investigated in cell extracts prepared from Saccharomyces cerevisiae. Bio-Gel A-5M chromatography of 105,000 g supernatants separated isoleucyl-tRNA synthetase activity into three peaks, with apparent molecular masses (Da) of about 100,000, 350,000 and 10(6) or greater. Similar results were obtained with synthetases specific for glutamic acid, serine and tyrosine. Sucrose-density-gradient centrifugation of yeast supernatants also provided evidence for the existence of synthetase complexes. These data provide the first evidence for the existence of a high-molecular-mass aminoacyl-tRNA synthetase complex in yeast, perhaps similar to those reported in higher eukaryotes.
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Affiliation(s)
- C L Harris
- Department of Biochemistry, West Virginia University, Robert C. Byrd Health Sciences Center, Morgantown 26506-9142, USA
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11
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Characterization of a novel N-terminal peptide in human aspartyl-tRNA synthetase. Roles in the transfer of aminoacyl-tRNA from aminoacyl-tRNA synthetase to the elongation factor 1 alpha. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(20)30081-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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12
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Mechanisms of the transfer of aminoacyl-tRNA from aminoacyl-tRNA synthetase to the elongation factor 1 alpha. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(20)30080-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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13
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Escalante C, Qasba PK, Yang DC. Expression of human aspartyl-tRNA synthetase in COS cells. Mol Cell Biochem 1994; 140:55-63. [PMID: 7877598 DOI: 10.1007/bf00928366] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Mammalian aspartyl-tRNA synthetase (DRS) occurs in a multi-enzyme complex of aminoacyl-tRNA synthetases, while DRS exists as free soluble enzymes in bacteria and yeast. The properties of human DRS transient expressed in COS cells were examined. After transfection of COS cells with the recombinant plasmids pSVL-63 that contained hDRS cDNA coding and non-coding sequences, and pSV-hDRS where the non-coding sequences were deleted, DRS in the transfected COS cells significantly increased compared to mock transfected cells. COS cells transfected with pSV-hDRS delta 32 that contained N-terminal 32 residue-coding sequence deleted hDRS cDNA showed no increase in DRS activity. Northern blot analysis showed that concentrations of corresponding mRNAs of hDRS and hDRS delta 32 were greatly enhanced in transfected cells. The increases in the level of the transcripts were much higher than those of the corresponding proteins. Gel filtration analysis showed that hDRS in pSV-hDRS transfected cells expressed as a low molecular weight form of hDRS and pSV-hDRS delta 32 transfected cells did not. Epitope tagging and indirect immunofluorescence microscopy was used to localize hDRS. Both hDRSmyc and hDRS delta 32myc were localized in the cytoplasm and showed diffused patterns. These results showed that hDRS has little tendency to aggregate in vivo and suggested that the N-terminal extension in hDRS was not involved in the expression and sub-cellular localization of hDRS, but may play a role in the maintenance of enzymatic activity of hDRS in COS cells.
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Affiliation(s)
- C Escalante
- Department of Chemistry, Georgetown University, Washington, DC 20057
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14
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Nada S, Chang P, Dignam J. Primary structure of the gene for glycyl-tRNA synthetase from Bombyx mori. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53008-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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15
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Ting S, Bogner P, Dignam J. Isolation of prolyl-tRNA synthetase as a free form and as a form associated with glutamyl-tRNA synthetase. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)37099-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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17
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Motorin YA, Wolfson AD, Löhr D, Orlovsky AF, Gladilin KL. Purification and properties of a high-molecular-mass complex between Val-tRNA synthetase and the heavy form of elongation factor 1 from mammalian cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 201:325-31. [PMID: 1935929 DOI: 10.1111/j.1432-1033.1991.tb16289.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In extracts of various mammalian tissues obtained in the presence of protease inhibitors Val-tRNA synthetase exists exclusively as a complex with a molecular mass of about 800 kDa. This complex was purified by gel filtration and two HPLC steps and contained five different polypeptides with molecular masses of 140, 50, 50, 40 and 30 kDa. The complex seems to have no tissue or species specificity, because preparations with identical polypeptide composition were obtained by the same method from rabbit liver and reticulocytes, and rat and beef liver. Four low-molecular-mass polypeptides were identified by two-dimensional electrophoresis as subunits of the heavy form of elongation factor 1 (EF-1H). The complex possesses the activity of EF-1 in the poly(U)-directed translation system, indicating that EF-1H is an integral part of the complex. Gel filtration of the tissue extracts reveals three different peaks of EF-1 activity, corresponding to EF-1 alpha, EF-1H and the high-molecular-mass complex of Val-tRNA synthetase and EF-1H. All activity of Val-tRNA synthetase and about 25% of EF-1 activity are associated with the complex. Different forms of EF-1 revealed no significant differences in the nucleotide-binding properties, but the complex of Val-tRNA synthetase with EF-1H was 10 times more active in the poly(U)-directed binding of Phe-tRNAPhe to ribosomes than EF-1H. These results strongly suggest that the complex of Val-tRNA synthetase with EF-1H is a novel functionally active individual form of EF-1.
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Affiliation(s)
- Y A Motorin
- A. N. Bakh Institute of Biochemistry, Academy of Sciences of USSR, Moscow
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18
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Norcum M. Structural analysis of the high molecular mass aminoacyl-tRNA synthetase complex. Effects of neutral salts and detergents. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98629-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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19
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Nucleotide and deduced amino acid sequence of human threonyl-tRNA synthetase reveals extensive homology to the Escherichia coli and yeast enzymes. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)92906-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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20
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Venema RC, Traugh JA. Protein kinase C phosphorylates glutamyl-tRNA synthetase in rabbit reticulocytes stimulated by tumor promoting phorbol esters. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)67787-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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21
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Sivaram P, Deutscher MP. Existence of two forms of rat liver arginyl-tRNA synthetase suggests channeling of aminoacyl-tRNA for protein synthesis. Proc Natl Acad Sci U S A 1990; 87:3665-9. [PMID: 2187187 PMCID: PMC53963 DOI: 10.1073/pnas.87.10.3665] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Arginyl-tRNA synthetase (arginine-tRNA ligase, EC 6.1.1.19) is found in extracts of mammalian cells both as a free protein (Mr = 60,000) and as a component (Mr approximately 72,000) of the high molecular weight aminoacyl-tRNA synthetase complex (Mr greater than 10(6). Several pieces of evidence indicate that the low molecular weight free form is not a proteolytic degradation product of the complex-bound enzyme but that it preexists in vivo: (i) the endogenous free form differs in size from the active proteolytic fragment generated in vitro, (ii) conditions expected to increase or decrease the amount of proteolysis do not alter the ratio of the two forms of the enzyme, and (iii) the free form contains an NH2-terminal methionine residue. A model is presented that provides a rationale for the existence of two forms of arginyl-tRNA synthetase in cells. In this model the complexed enzyme supplies arginyl-tRNA for protein synthesis, whereas the free enzyme provides arginyl-tRNA for the NH2-terminal arginine modification of proteins by arginyl-tRNA:protein arginyltransferase. This latter process targets certain proteins for removal by the ubiquitin-dependent protein degradation pathway. The necessity for an additional pool of arginyl-tRNA for the modification reaction leads to the conclusion that the arginyl-tRNA destined for protein synthesis (and/or protein modification) is channeled and unavailable for other processes. Other evidence supporting channeling in protein synthesis is discussed.
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Affiliation(s)
- P Sivaram
- Department of Biochemistry, University of Connecticut Health Center, Farmington 06032
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22
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Harris CL. High-molecular-weight forms of aminoacyl-tRNA synthetases and tRNA modification enzymes in Escherichia coli. J Bacteriol 1990; 172:1798-803. [PMID: 2180904 PMCID: PMC208671 DOI: 10.1128/jb.172.4.1798-1803.1990] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The presence of high-molecular-weight complexes of aminoacyl-tRNA synthetases in Escherichia coli has been reported (C. L. Harris, J. Bacteriol. 169:2718-2723, 1987). In the current study, Bio-Gel A-5M gel chromatography of 105,000 x g supernatant preparations from E. coli Q13 indicated high molecular weights for both tRNA methylase (300,000) and tRNA sulfurtransferase (450,000). These tRNA modification enzymes did not appear to exist in the same multienzymic complex. On the other hand, 4-thiouridine sulfurtransferase eluted with aminoacyl-tRNA synthetase activity on Bio-Gel A-5M, and both of these activities were cosedimented after further centrifugation of cell supernatants at 160,000 x g for 18 h. Despite this evidence for association of the sulfurtransferase with the synthetase complex, isoleucyl-tRNA synthetase and tRNA sulfurtransferase were totally resolved from each other by DEAE-Sephacel chromatography. Subsequent gel chromatography showed little change in their elution positions on agarose. Hence, either nonspecific aggregation occurred here, or the modification enzymes studied are not members of the aminoacyl-tRNA synthetase complex in E. coli. These findings do suggest that some bacterial tRNA modification enzymes are present in multiprotein complexes of high molecular weight.
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Affiliation(s)
- C L Harris
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown 26506
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23
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Sivaram P, Deutscher MP. Free fatty acids associated with the high molecular weight aminoacyl-tRNA synthetase complex influence its structure and function. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39430-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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24
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Norcum MT. Isolation and Electron Microscopic Characterization of the High Molecular Mass Aminoacyl-tRNA Synthetase Complex from Murine Erythroleukemia Cells. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)63808-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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25
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Sivaram P, Vellekamp G, Deutscher MP. A role for lipids in the functional and structural properties of the rat liver aminoacyl-tRNA synthetase complex. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37366-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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26
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Godar DE, Yang DC. Mammalian high molecular weight and monomeric forms of valyl-tRNA synthetase. Biochemistry 1988; 27:2181-6. [PMID: 3378054 DOI: 10.1021/bi00406a055] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Valyl-tRNA synthetase from rat liver sediments at 15.5 S with a Stokes radius of 90 A, corresponding to a native molecular weight of 585,000. Purification of valyl-tRNA synthetase to homogeneity by a combination of conventional and affinity column chromatography yields a fully active monomeric form of valyl-tRNA synthetase with a sedimentation coefficient of 7.7 S and a Stokes radius of 45 A. The subunit molecular weight of the monomeric valyl-tRNA synthetase is 140,000, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. In the presence of 400 mM KCl, the purified monomeric valyl-tRNA synthetase associates to a high molecular weight form. The high molecular weight valyl-tRNA synthetase in the homogenate can be readily converted to the monomeric form by controlled trypsinization. The kinetic parameters of the two forms are nearly identical. The results suggest that the high molecular weight valyl-tRNA synthetase is a homotypic tetramer and converts to the monomeric valyl-tRNA synthetase after the cleavage of a small peptide.
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Affiliation(s)
- D E Godar
- Department of Chemistry, Georgetown University, Washington, D.C. 20057
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27
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Vellekamp G, Deutscher M. A basic NH2-terminal extension of rat liver arginyl-tRNA synthetase required for its association with high molecular weight complexes. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)61051-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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