scholarly journals Nucleolar Localization of Human Methionyl–Trna Synthetase and Its Role in Ribosomal RNA Synthesis

2000 ◽  
Vol 149 (3) ◽  
pp. 567-574 ◽  
Author(s):  
Young-Gyu Ko ◽  
Young-Sun Kang ◽  
Eun-Kyoung Kim ◽  
Sang Gyu Park ◽  
Sunghoon Kim
Keyword(s):  
Protein Synthesis ◽  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Trna Synthetase ◽  
Nucleolar Localization ◽  
Trna Synthetases ◽  
Quiescent Cells ◽  
Aminoacyl Trna Synthetases ◽  
Polymerase I ◽  
Methionyl Trna Synthetase

Human aminoacyl–tRNA synthetases (ARSs) are normally located in cytoplasm and are involved in protein synthesis. In the present work, we found that human methionyl–tRNA synthetase (MRS) was translocated to nucleolus in proliferative cells, but disappeared in quiescent cells. The nucleolar localization of MRS was triggered by various growth factors such as insulin, PDGF, and EGF. The presence of MRS in nucleoli depended on the integrity of RNA and the activity of RNA polymerase I in the nucleolus. The ribosomal RNA synthesis was specifically decreased by the treatment of anti-MRS antibody as determined by nuclear run-on assay and immunostaining with anti-Br antibody after incorporating Br-UTP into nascent RNA. Thus, human MRS plays a role in the biogenesis of rRNA in nucleoli, while it is catalytically involved in protein synthesis in cytoplasm.

scholarly journals Oxidation of cellular amino acid pools leads to cytotoxic mistranslation of the genetic code

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Tammy J Bullwinkle ◽  
Noah M Reynolds ◽  
Medha Raina ◽  
Adil Moghal ◽  
Eleftheria Matsa ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Genetic Code ◽  
Trna Synthetase ◽  
Control Mechanisms ◽  
Cellular Toxicity ◽  
Trna Synthetases ◽  
Aminoacyl Trna Synthetases ◽  
The Cost

Aminoacyl-tRNA synthetases use a variety of mechanisms to ensure fidelity of the genetic code and ultimately select the correct amino acids to be used in protein synthesis. The physiological necessity of these quality control mechanisms in different environments remains unclear, as the cost vs benefit of accurate protein synthesis is difficult to predict. We show that in Escherichia coli, a non-coded amino acid produced through oxidative damage is a significant threat to the accuracy of protein synthesis and must be cleared by phenylalanine-tRNA synthetase in order to prevent cellular toxicity caused by mis-synthesized proteins. These findings demonstrate how stress can lead to the accumulation of non-canonical amino acids that must be excluded from the proteome in order to maintain cellular viability.

scholarly journals A Novel Aminoacyl-tRNA Synthetase Appended Domain Can Supply the Core Synthetase with Its Amino Acid Substrate

Genes ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1320
Author(s):  
Marc Muraski ◽  
Emil Nilsson ◽  
Benjamin Weekley ◽  
Sandhya Bharti Sharma ◽  
Rebecca W. Alexander
Keyword(s):  
Trna Synthetase ◽  
Mycoplasma Species ◽  
Intracellular Pathogen ◽  
Aminoacyl Trna Synthetase ◽  
Trna Synthetases ◽  
Aminoacyl Trna Synthetases ◽  
Acid Analog ◽  
Methionyl Trna Synthetase ◽  
Acid Substrate ◽  
Amino Acid Substrate

The structural organization and functionality of aminoacyl-tRNA synthetases have been expanded through polypeptide additions to their core aminoacylation domain. We have identified a novel domain appended to the methionyl-tRNA synthetase (MetRS) of the intracellular pathogen Mycoplasma penetrans. Sequence analysis of this N-terminal region suggests the appended domain is an aminotransferase, which we demonstrate here. The aminotransferase domain of MpMetRS is capable of generating methionine from its α-keto acid analog, 2-keto-4-methylthiobutyrate (KMTB). The methionine thus produced can be subsequently attached to cognate tRNAMet in the MpMetRS aminoacylation domain. Genomic erosion in the Mycoplasma species has impaired many canonical biosynthetic pathways, causing them to rely on their host for numerous metabolites. It is still unclear if this bifunctional MetRS is a key part of pathogen life cycle or is a neutral consequence of the reductive evolution experienced by Mycoplasma species.

scholarly journals An Archaeal Aminoacyl-tRNA Synthetase Missing from Genomic Analysis

1999 ◽  
Vol 181 (18) ◽  
pp. 5880-5884 ◽  
Author(s):  
Christian S. Hamann ◽  
Kevin R. Sowers ◽  
Richard S. A. Lipman ◽  
Ya-Ming Hou
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Genomic Analysis ◽  
Trna Synthetase ◽  
Genomic Sequencing ◽  
Aminoacyl Trna Synthetase ◽  
Trna Synthetases ◽  
Cell Lysate ◽  
Aminoacyl Trna Synthetases ◽  
Complete Genomic

ABSTRACT The complete genomic sequencing of Methanococcus jannaschii cannot identify the gene for the cysteine-specific member of aminoacyl-tRNA synthetases. However, we show here that enzyme activity is present in the cell lysate of M. jannaschii. The demonstration of this activity suggests a direct pathway for the synthesis of cysteinyl-tRNACys during protein synthesis.

scholarly journals Cloning and sequencing of cDNA encoding the rice methionyl-tRNA synthetase.

1998 ◽  
Vol 45 (3) ◽  
pp. 669-676 ◽  
Author(s):  
M Deniziak ◽  
M Mirande ◽  
J Barciszewski
Keyword(s):  
Trna Synthetase ◽  
Great Similarity ◽  
High Homology ◽  
Yeast Protein ◽  
Cloning And Sequencing ◽  
Trna Synthetases ◽  
Aminoacyl Trna Synthetases ◽  
C Terminus ◽  
Signature Sequences ◽  
Methionyl Trna Synthetase

Three overlapping clones of cDNA, Mos43, Mos28 and Mos60, coding for methionyl-tRNA synthetase were obtained by screening the Oryza sativa lambda gt11 library. Their nucleotide sequence of 2850 bp was determined. The deduced amino-acid sequence of the isolated clones contains a HLGN and KFSKS motifs, which are conserved for this family of enzymes and have been proposed to be the signature sequences for class I aminoacyl-tRNA synthetases. A comparison of the rice MetRS primary structure with those deposited in EMBL/GenBank points to its high homology to yeast, human and Caenorhabditis elegans MetRSs. Interestingly, a great similarity of its C terminus to endothelial-monocyte-activating polypeptide II (EMAPII) and yeast protein G4p1 was observed.

scholarly journals Regulation of ex-translational activities is the primary function of the multi-tRNA synthetase complex

2020 ◽  
Author(s):  
Haissi Cui ◽  
Mridu Kapur ◽  
Jolene K Diedrich ◽  
John R Yates III ◽  
Susan L Ackerman ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Mammalian Cells ◽  
Mrna Translation ◽  
Trna Synthetase ◽  
Stress Conditions ◽  
Aminoacyl Trna Synthetase ◽  
Trna Synthetases ◽  
Aminoacyl Trna Synthetases ◽  
Alternative Function ◽  
Ribosome Pausing

Abstract During mRNA translation, tRNAs are charged by aminoacyl-tRNA synthetases and subsequently used by ribosomes. A multi-enzyme aminoacyl-tRNA synthetase complex (MSC) has been proposed to increase protein synthesis efficiency by passing charged tRNAs to ribosomes. An alternative function is that the MSC repurposes specific synthetases that are released from the MSC upon cues for functions independent of translation. To explore this, we generated mammalian cells in which arginyl-tRNA synthetase and/or glutaminyl-tRNA synthetase were absent from the MSC. Protein synthesis, under a variety of stress conditions, was unchanged. Most strikingly, levels of charged tRNAArg and tRNAGln remained unchanged and no ribosome pausing was observed at codons for arginine and glutamine. Thus, increasing or regulating protein synthesis efficiency is not dependent on arginyl-tRNA synthetase and glutaminyl-tRNA synthetase in the MSC. Alternatively, and consistent with previously reported ex-translational roles requiring changes in synthetase cellular localizations, our manipulations of the MSC visibly changed localization.

scholarly journals Relaxed Substrate Specificity Leads to Extensive tRNA Mischarging by Streptococcus pneumoniae Class I and Class II Aminoacyl-tRNA Synthetases

mBio ◽  
2014 ◽  
Vol 5 (5) ◽  
Author(s):  
Jennifer Shepherd ◽  
Michael Ibba
Keyword(s):  
Quality Control ◽  
Cell Wall ◽  
Protein Synthesis ◽  
Streptococcus Pneumoniae ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Trna Synthetase ◽  
Content Type ◽  
Trna Synthetases ◽  
Aminoacyl Trna Synthetases

ABSTRACTAminoacyl-tRNA synthetases provide the first step in protein synthesis quality control by discriminating cognate from noncognate amino acid and tRNA substrates. While substrate specificity is enhanced in many instances bycis-andtrans-editing pathways, it has been revealed that in organisms such asStreptococcus pneumoniaesome aminoacyl-tRNA synthetases display significant tRNA mischarging activity. To investigate the extent of tRNA mischarging in this pathogen, the aminoacylation profiles of class I isoleucyl-tRNA synthetase (IleRS) and class II lysyl-tRNA synthetase (LysRS) were determined. Pneumococcal IleRS mischarged tRNAIlewith both Val, as demonstrated in other bacteria, and Leu in a tRNA sequence-dependent manner. IleRS substrate specificity was achieved in an editing-independent manner, indicating that tRNA mischarging would only be significant under growth conditions where Ile is depleted. Pneumococcal LysRS was found to misaminoacylate tRNALyswith Ala and to a lesser extent Thr and Ser, with mischarging efficiency modulated by the presence of an unusual U4:G69 wobble pair in the acceptor stems of both pneumococcal tRNALysisoacceptors. Addition of thetrans-editing factor MurM, which also functions in peptidoglycan synthesis, reduced Ala-tRNALysproduction by LysRS, providing evidence for cross talk between the protein synthesis and cell wall biogenesis pathways. Mischarging of tRNALysby AlaRS was also observed, and this would provide additional potential MurM substrates. More broadly, the extensive mischarging activities now described for a number ofStreptococcus pneumoniaeaminoacyl-tRNA synthetases suggest that adaptive misaminoacylation may contribute significantly to the viability of this pathogen during amino acid starvation.IMPORTANCEStreptococcus pneumoniaeis a common causative agent of several debilitating and potentially life-threatening infections, such as pneumonia, meningitis, and infectious endocarditis. Such infections are increasingly difficult to treat due to widespread development of penicillin resistance. High-level penicillin resistance is known to depend in part upon MurM, a protein involved in both aminoacyl-tRNA-dependent synthesis of indirect amino acid cross-linkages within cell wall peptidoglycan and in translation quality control. The involvement of MurM in both protein synthesis and antibiotic resistance identify it as a potential target for the development of new and potent antibiotics for pneumococcal infections. The goals of this work were to identify and characterizeS. pneumoniaepathways that can synthesize mischarged tRNAs and to relate these activities to expected changes in protein and peptidoglycan biosynthesis during antibiotic and nutritional stress.

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