Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Translation in amino acid-poor environments is limited by tRNAGln charging

ABSTRACT: An inadequate supply of amino acids leads to accumulation of uncharged tRNAs, which can bind and activate GCN2 kinase to reduce translation. Here, we show that glutamine-specific tRNAs selectively become uncharged when extracellular amino acid availability is compromised. In contrast, all other tRNAs retain charging of their cognate amino acids in a manner that is dependent upon intact lysosomal function. In addition to GCN2 activation and reduced total translation, the reduced charging of tRNAGln in amino acid-deprived cells also leads to specific depletion of proteins containing polyglutamine tracts including core binding factor α1, mediator subunit 12, transcriptional coactivator CBP and TATA-box binding protein. Treating amino acid-deprived cells with exogenous glutamine or glutaminase inhibitors restores tRNAGln charging and the levels of polyglutamine-containing proteins. Together, these results demonstrate that the activation of GCN2 and the translation of polyglutamine-encoding transcripts serve as the key sensors of glutamine availability in mammalian cells.

ORGANISM(S): Mus musculus

PROVIDER: GSE157276 | GEO | 2020/12/14

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Selective control of metabolism by the GCN2 eIF2 kinase pathway in Saccharomyces cerevisiae

Project description:When eukaryotic cells are deprived of amino acids, uncharged tRNAs accumulate and activate the conserved GCN2 protein kinase. We examine how yeast growth and tRNA charging or aminoacylation is affected during amino acid depletion in the presence and absence of GCN2. tRNA charging is measured using a microarray technique which allows for simultaneous measurement of all cytosolic tRNAs. A fully prototrophic and its isogenic GCN2 deletion strain were used. We measured relative tRNA charging levels in yeast strains with an intact and deleted GCN2.

2010-08-01 | E-GEOD-22452 | biostudies-arrayexpress

Selective control of metabolism by the GCN2 eIF2 kinase pathway in Saccharomyces cerevisiae

2010-08-01 | GSE22452 | GEO

Multiple mechanisms activate GCN2 eIF2 kinase in response to diverse stress conditions

Project description:Diverse environmental insults induce the integrated stress response (ISR), which features eIF2 phosphorylation and translational control that serves to restore protein homeostasis. The eIF2 kinase GCN2 is a first responder in the ISR that is activated by amino acid depletion and other unrelated stresses. Two processes are suggested to trigger an ordered process of GCN2 activation during stress: GCN2 monitoring stress via accumulating uncharged tRNAs or by stalled and colliding ribosomes. Our results suggest that while ribosomal collisions are indeed essential for GCN2 activation in response to translational elongation inhibitors, conditions that trigger deacylation of tRNAs activate GCN2 via its direct association with affected tRNAs. Both process require the GCN2 regulatory domain related to histidyl tRNA synthetases. GCN2 activation by UV irradiation features lowered amino acids and increased uncharged tRNAs and ribosome collisions are dispensable. We conclude that there are multiple mechanisms that activate GCN2 during diverse stresses.

2024-03-06 | GSE239867 | GEO

The HisRS-like domain of GCN2 is a pseudoenzyme that can bind uncharged tRNA - HX-MS Data

Project description:GCN2 is a stress response kinase that phosphorylates the translation initiation factor eIF2to inhibit general protein synthesis when activated by uncharged tRNA and stalled ribosomes. The presence of a HisRS-like domain in GCN2, normally associated with the ability to bind and aminoacylate tRNAs, led to the hypothesis that eIF2 kinase activity is regulated by the direct binding of this domain to uncharged tRNA. Here we solved the structure of the HisRS-like domain in the context of full-length GCN2 by cryoEM. Structure and function analysis shows the HisRS-like domain of GCN2 has lost tRNA charging, ATP binding, and histidine binding activity but retains the ability to bind tRNA. Hydrogen deuterium exchange mass spectrometry (HX-MS), site-directed mutagenesis and computational docking experiments support a tRNA binding model that overlaps with but is partially shifted from that employed by bona fide HisRS enzymes. These results demonstrate that the HisRS-like domain of GCN2 is a pseudoenzyme and advance our understanding of GCN2 regulation and function.

2024-02-01 | PXD049090 | Pride

Growth Optimized Aminoacyl-tRNA Synthetase Levels Prevent Maximal tRNA Charging

Project description:Summary Aminoacyl-tRNA synthetases (aaRSs) serve a dual role in charging tRNAs. Their enzymatic activities both provide protein synthesis flux and reduce uncharged tRNA levels. Although uncharged tRNAs can negatively impact bacterial growth, substantial concentrations of tRNAs remain deacylated even under nutrient-rich conditions. Here we show that tRNA charging in Bacillus subtilis is not maximized due to optimization of aaRS production during rapid growth, which prioritizes demands in protein synthesis over charging levels. The presence of uncharged tRNAs is alleviated by precisely tuned translation kinetics and the stringent response, both insensitive to aaRS overproduction but sharply responsive to underproduction, allowing for just-enough aaRS production atop a “fitness cliff”. Notably, we find that the stringent response mitigates fitness defects at all aaRS underproduction levels even without external starvation. Thus, adherence to minimal, flux-satisfying protein production drives limited tRNA charging and provides a basis for the sensitivity and setpoints of an integrated growth-control network.

2020-07-20 | GSE141389 | GEO

Yeast glutamine tRNA synthetase doxycycline shut-off

Project description:During protein synthesis, charged tRNAs deliver amino acids to translating ribosomes, and are then re-charged by tRNA synthetases (aaRS). In humans, mutant aaRS cause a diversity of neurological disorders, but their molecular aetiologies are incompletely characterised. To understand system responses to aaRS depletion, the yeast glutamine aaRS gene (GLN4) was transcriptionally regulated using doxycycline by tet-off control. Depletion of Gln4p inhibited growth, and induced a transcriptional GCN4 amino acid starvation response, indicative of uncharged tRNA accumulation and Gcn2 kinase activation. The GCN4 response was confirmed using SILAC proteomics, using heavy isotope labelling to identify changes in protein expression during glutamine tRNA synthetase depletion.

2020-02-12 | PXD017140 | Pride

Effects of single amino acid deficiency on mRNA translation are markedly different for methionine versus leucine

Project description:Amino acid availability regulates translation through the action of the GCN2 and mTORC1 pathways. Low amino acids activate the eIF2α kinase GCN2 through binding of uncharged tRNAs to a histidyl-tRNA synthetase−related regulatory domain. Once activated GCN2 phosphorylates eIF2α, inhibiting ternary complex formation and translation initiation. Recent studies show that mTORC1 is particularly sensitive to arginine and leucine status, with a deprivation of these amino acids leading to a strong inhibition of mTORC1 that prevents the phosphorylation and inactivation of the translational repressor 4EBP1. Though amino acids are known regulators of translation, the effects that deficiencies of specific amino acids have on translation have yet to be determined. We demonstrate that deprivation of leucine or methionine results in large inhibitory effects on translation initiation and on polysome formation that are not replicated by overexpressing non-phosphorylatable 4EBP1 or a phosphomimetic eIF2α. Our results demonstrate that a lack of either leucine or methionine has a major impact on mRNA translation, though they act by quite different mechanisms. Leucine deprivation appears to primarily inhibit ribosome loading, whereas methionine deprivation appears to primarily impair start site recognition. These data point to a unique regulatory effect that methionine status has on translation initiation.

2018-04-04 | GSE112643 | GEO

Translational control through differential ribosome pausing during amino acid limitation in mammalian cells

Project description:Limitation for amino acids is thought to regulate translation in mammalian cells primarily by signaling through the kinases mTORC1 and GCN2. We find that limitation for the amino acid arginine causes a selective loss of tRNA charging, which regulates translation through ribosome pausing at two of six arginine codons. Interestingly, limitation for leucine, an essential and abundant amino acid in protein, results in little or no ribosome pausing. Chemical and genetic perturbation of mTORC1 and GCN2 signaling revealed that their robust response to leucine limitation prevents ribosome pausing, while an insufficient response to arginine limitation led to loss of arginine tRNA charging and ribosome pausing. Codon-specific ribosome pausing decreased protein production and triggered premature ribosome termination without significantly reducing mRNA levels. Together, our results suggest that amino acids which are not optimally sensed by the mTORC1 and GCN2 pathways still regulate translation through an evolutionarily conserved mechanism based on synonymous codon usage.

2018-07-19 | GSE113751 | GEO

tRNA senses cellular nutrient status and senescence via amino acid acylation

Project description:We profiled the cellular tRNA charging landscape using next-generation sequencing and identified a subset of tRNA that sense nutrients. The charging levels of tRNAGln were exclusively and significantly decreased in response to amino acid starvation.

2022-11-30 | GSE157510 | GEO

Uncharged tRNAGln as an indicator of intracellular amino acid level upregulates UBC expression to maintain its charging level V

2022-11-30 | GSE188860 | GEO