Precursor of Pro-apoptotic Cytokine Modulates Aminoacylation Activity of tRNA Synthetase

Park, Sang Gyu; Jung, Keum Hee; Lee, Jong Sang; Jo, Yeong Joon; Motegi, Hiromi; Kim, Sung Hoon; Shiba, Kiyotaka

doi:10.1074/jbc.274.24.16673

Cited by 87 publications

(101 citation statements)

References 28 publications

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“…By similar reasoning, the combination of cross-linking and protein interaction studies suggests that one upper domain of the structure contains ArgRS and LysRS and so the remaining enzymes are in the other domain. The auxiliary protein p43 has been shown to interact with ArgRS (11) and is near the center of the structure (12). Thus, the general location of tRNA Arg is likely to be near area 3, which may also include tRNA Lys .…”

Section: Resultsmentioning

confidence: 99%

“…Evidence that this is appropriate comes from data showing that ArgRS is stabilized within the complex by the N-terminal portion of p43 (10). In addition, it is thought that a major function of complex-associated p43, a known tRNA-binding protein, is to facilitate enzymatic activities within the complex, in particular ArgRS (11). However, when working with individual purified proteins (10) no catalytic enhancement of ArgRS due to association with p43 was seen.…”

Section: Discussionmentioning

confidence: 99%

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A Three-dimensional Working Model of the Multienzyme Complex of Aminoacyl-tRNA Synthetases Based on Electron Microscopic Placements of tRNA and Proteins

Wolfe

Warrington

Treadwell

et al. 2005

Journal of Biological Chemistry

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It has become evident that the process of protein synthesis is performed by many cellular polypeptides acting in concert within the structural confines of protein complexes. In multicellular eukaryotes, one of these assemblies is a multienzyme complex composed of eight proteins that have aminoacyl-tRNA synthetase activities as well as three non-synthetase proteins (p43, p38, and p18) with diverse functions. This study uses electron microscopy and three-dimensional reconstruction to explore the arrangement of proteins and tRNA substrates within this "core" multisynthetase complex. Binding of unfractionated tRNA establishes that these molecules are widely distributed on the exterior of the structure. Binding of gold-labeled tRNALeu places leucyl-tRNA synthetase and the bifunctional glutamyl-/prolyl-tRNA synthetase at the base of this asymmetric "V"-shaped particle. A stable cell line has been produced that incorporates hexahistidine-labeled p43 into the multisynthetase complex. Using a gold-labeled nickel-nitrilotriacetic acid probe, the polypeptides of the p43 dimer have been located along one face of the particle. The results of this and previous studies are combined into an initial three-dimensional working model of the multisynthetase complex. This is the first conceptualization of how the protein constituents and tRNA substrates are arrayed within the structural confines of this multiprotein assembly.It has been known for many years that a "core" complex of aminoacyltRNA synthetases can be isolated from all multicellular eukaryotes (1). Its characteristic composition is three non-synthetase proteins and eight polypeptides having nine aminoacyl-tRNA synthetase activities. With the enzymes abbreviated as the three-letter amino acid name plus RS for the enzyme, the components are ArgRS, AspRS, GluProRS, GlnRS, IleRS, LeuRS, LysRS, MetRS, p43, p38, and p18. Several of these are known dimers, so the total polypeptide count in the multisynthetase complex is at least fifteen. This is a particularly intriguing protein assembly as all of the enzymes catalyze the same reaction, albeit with individual and highly specific substrates. The reaction catalyzed is the covalent attachment of an amino acid to either the 2Ј-or 3Ј-hydroxyl of the 3Ј-terminal adenosine of tRNA. Recent increased interest in these enzymes has been generated by studies indicating that they have roles in a variety of other cellular processes (2-4). Such activities range from cytokine-mediated chemoattraction to priming of reverse transcription of the human immunodeficiency virus, type 1 genome. These enzymes are also viewed as targets in the development of new antimicrobial agents (5). The multisynthetase complex also contains three non-synthetase proteins. The first of these, p18, has been shown to interact with EF-1␥, which may facilitate transfer of aminoacyl-tRNAs to the ribosome (6). Data from yeast two-hybrid screens (7), in vitro binding assays (8), and deletion analysis (9) indicate that p38 functions as a scaffolding protein and appears to be...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

A Three-dimensional Working Model of the Multienzyme Complex of Aminoacyl-tRNA Synthetases Based on Electron Microscopic Placements of tRNA and Proteins

Wolfe

Warrington

Treadwell

et al. 2005

Journal of Biological Chemistry

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“…Rabbit polyclonal antibody was then raised against these proteins as described previously (20). The IgG from antiserum was purified by protein A affinity chromatography according to the manufacturer's protocol (Bio-Rad).…”

Section: Methodsmentioning

confidence: 99%

“…Thus, tyrosyl-tRNA synthetase has a potent apoptosis-inducing activity after proteolytic cleavage, since their split polypepetides stimulate the production of TNF and tissue factor from target cells and have leukocyte chemotaxis activity to scavenge apoptotic corpses. The precursor of endothelial monocyte-activating polypeptide II is associated with the N-terminal noncatalytic extension of arginyl-tRNA synthetase and enhances aminoacylation activity (20). Like human tyrosyl-tRNA synthetase, the cytokine domain of this precursor is released upon apoptosis and exerts its proapoptotic function (21,22).…”

mentioning

confidence: 99%

Glutamine-dependent Antiapoptotic Interaction of Human Glutaminyl-tRNA Synthetase with Apoptosis Signal-regulating Kinase 1

Ko¹,

Kim²,

Kim³

et al. 2001

Journal of Biological Chemistry

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182

123

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Glutamine has been known to be an apoptosis suppressor, since it blocks apoptosis induced by heat shock, irradiation, and c-Myc overexpression. Here, we demonstrated that HeLa cells were susceptible to Fas-mediated apoptosis under the condition of glutamine deprivation. Fas ligation activated apoptosis signalregulating kinase 1 (ASK1) and c-Jun N-terminal kinase (JNK; also known as stress-activated protein kinase (SAPK)) in Gln-deprived cells but not in normal cells, suggesting that Gln might be involved in the activity control of ASK1 and JNK/SAPK. As one of the possible mechanisms for the suppressive effect of Gln on ASK1, we investigated the molecular interaction between human glutaminyl-tRNA synthetase (QRS) and ASK1 and found the Gln-dependent association of the two molecules. While their association was enhanced by the elevation of Gln concentration, they were dissociated by Fas ligation within 5 min. The association involved the catalytic domains of the two enzymes. The ASK1 activity was inhibited by the interaction with QRS as determined by in vitro kinase and transcription assays. Finally, we have shown that QRS inhibited the cell death induced by ASK1, and this antiapoptotic function of QRS was weakened by the deprivation of Gln. Thus, the antiapoptotic interaction of QRS with ASK1 is controlled positively by the cellular concentration of Gln and negatively by Fas ligation. The results of this work provide one possible explanation for the working mechanism of the antiapoptotic activity of Gln and suggest a novel function of mammalian ARSs.

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“…Many of these complex-forming ARSs, as well as AIMPs, play diverse regulatory roles that are not directly related to protein synthesis (2). Among the three AIMPs, AIMP1 is secreted as a cytokine working in immune, angiogenesis, and wound-healing processes (3)(4)(5)(6)(7) and also functions as a hormone controlling glucose homeostasis (8). AIMP3 is a tumor suppressor required for chromosome integrity (9,10).…”

mentioning

confidence: 99%

AIMP2/p38, the scaffold for the multi-tRNA synthetase complex, responds to genotoxic stresses via p53

Han¹,

Park²,

Park³

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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107

108

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AIMP2/p38 is a scaffolding protein required for the assembly of the macromolecular tRNA synthetase complex. Here, we describe a previously unknown function for AIMP2 as a positive regulator of p53 in response to genotoxic stresses. Depletion of AIMP2 increased resistance to DNA damage-induced apoptosis, and introduction of AIMP2 into AIMP2-deficient cells restored the susceptibility to apoptosis. Upon DNA damage, AIMP2 was phosphorylated, dissociated from the multi-tRNA synthetase complex, and translocated into the nuclei of cells. AIMP2 directly interacts with p53, thereby preventing MDM2-mediated ubiquitination and degradation of p53. Mutations in AIMP2, affecting its interaction with p53, hampered its ability to activate p53. Nutlin-3 recovered the level of p53 and the susceptibility to UV-induced cell death in AIMP2-deficient cells. This work demonstrates that AIMP2, a component of the translational machinery, functions as proapoptotic factor via p53 in response to DNA damage.A minoacyl-tRNA synthetases (ARSs) are the enzymes that ligate specific amino acids to tRNAs before protein synthesis. In higher eukaryotic systems, nine different ARSs form an intriguing macromolecular complex with three nonenzymatic factors called ARS-interacting, multifunctional proteins (AIMPs) (1, 2). Many of these complex-forming ARSs, as well as AIMPs, play diverse regulatory roles that are not directly related to protein synthesis (2). Among the three AIMPs, AIMP1 is secreted as a cytokine working in immune, angiogenesis, and wound-healing processes (3-7) and also functions as a hormone controlling glucose homeostasis (8). AIMP3 is a tumor suppressor required for chromosome integrity (9, 10). Although AIMP2 is critical for the assembly of the multi-ARS complex (11), it also suppresses cell proliferation via down-regulation of c-Myc (12). In addition, AIMP2 was shown to be involved in Parkinson's disease, inducing neural cell death (13). However, it is yet to be determined how AIMP2 is involved in the control of cell death. In this work, we investigated the functional significance and molecular behavior of AIMP2 during the control of cell death and the relationship of AIMP2 associated with the multi-ARS complex and its proapoptotic activity. Results AIMP2-Deficient Cells AreResistant to Cell Death. To see the importance of AIMP2 during the control of cell death, we subjected 12.5-d AIMP2 ϩ/ϩ and AIMP2 Ϫ/Ϫ mouse embryonic fibroblasts (MEFs) to UV irradiation and compared their apoptotic sensitivity. The apoptotic cells, indicated by the subG1 portion, were increased Ϸ3-fold by UV irradiation in AIMP2 ϩ/ϩ but not in AIMP2 Ϫ/Ϫ cells (Fig. 1A). Transfection of AIMP2 into AIMP2 Ϫ/Ϫ MEFs restored the apoptotic sensitivity to UV irradiation (Fig. 1B). We also compared the apoptotic response of AIMP2 ϩ/ϩ and AIMP2 Ϫ/Ϫ MEFs to UV irradiation by monitoring caspase-3 activation. Procaspase-3 cleavage resulting in caspase-3 generation was observed in AIMP2 ϩ/ϩ but not in AIMP2 Ϫ/Ϫ cells (Fig. 1C). Suppression of AIMP2 via gene-specific siRNA...

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Precursor of Pro-apoptotic Cytokine Modulates Aminoacylation Activity of tRNA Synthetase

Cited by 87 publications

References 28 publications

A Three-dimensional Working Model of the Multienzyme Complex of Aminoacyl-tRNA Synthetases Based on Electron Microscopic Placements of tRNA and Proteins

A Three-dimensional Working Model of the Multienzyme Complex of Aminoacyl-tRNA Synthetases Based on Electron Microscopic Placements of tRNA and Proteins

Glutamine-dependent Antiapoptotic Interaction of Human Glutaminyl-tRNA Synthetase with Apoptosis Signal-regulating Kinase 1

AIMP2/p38, the scaffold for the multi-tRNA synthetase complex, responds to genotoxic stresses via p53

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