Ontology highlight
ABSTRACT:
PROVIDER: PRJNA757010 | ENA |
REPOSITORIES: ENA
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Project description:GCN2 adapts the proteome to scavenging-dependent growth
| PRJNA634769 | ENA
Project description:Cellular signaling controls translation through cis regulatory elements found in mRNAs. Gcn2 is the master regulator of translation during nutrient limitation in normal and cancer cells. Activated Gcn2 phosphorylates eIF2a, thereby repressing general translation while activating translation of specific mRNAs with upstream ORFs (uORFs) in its leader regions. Here we performed genome-wide measurement of mRNA translation during histidine starvation in fission yeast Schizosaccharomyces pombe. Polysomal microarray hybridization experiments identified a group of 1779 genes whose translation is up-regulated in Gcn2-dependent manner. We find that translation is reprogrammed to enhance organellar synthesis and transcription and repress ribosome synthesis. The 1779 genes included gcn5 and hri2 shown to promote growth under histidine starvation. They encode histone acetyl transferase and heme-binding eIF2a kinase activated by oxidative stress, and their 5’-leader contains 3 or 4 uORFs, respectively. Our reporter studies show that uORFs in gcn5 and hri2 operate similarly to those found in S. cerevisiae GCN4, the founding case for uORF-dependent regulation. Moreover, motif analysis identified 5’-UGA(C/G)GG-3’ as a motif promoting translation during starvation. Using hrd1 5’UTR with such a motif, we demonstrated its requirement in Gcn2-dependent translational control. To our knowledge, this is the first nucleotide motif found to be responsible for translational control by Gcn2. We propose that Gcn2 mediates translational control of more specific mRNAs than previously anticipated
2020-09-23 | GSE143299 | GEO
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
Project description:Ataxin-2 adapts ribosomal mRNA levels and S6 phosphorylation to nutrient availability, with effects on protein synthesis and growth
| PRJNA238815 | ENA
Project description:Compared protein synthesis in Gcn2 WT vs Gcn2 KO murine PDAC cells (KRPC) in amino acid-replete or leucine-free media.
2022-10-13 | PXD028143 | Pride
Project description:A MYC/GCN2/eIF2alpha negative feedback loop limits protein synthesis to prevent MYC-dependent apoptosis in colorectal cancer
| PRJNA418238 | ENA
Project description:Using ribosome profiling, we find globally reduced translation efficiency during mitotic / replicative aging in budding yeast. Two mechanisms contribute to this: Firstly, the mRNA binding protein Ssd1 is induced during aging, sequestering mRNAs to P-bodies and stress granules that are abundant in old cells. Indeed, overexpression of Ssd1 reduced protein synthesis in young cells and extended lifespan, while loss of Ssd1 reduced the translational deficit of old cells and shortened lifespan. Secondly, the Gcn2 kinase is activated in old cells, phosphorylating and inactivating the translational initiation factor eIF2α. Accordingly, deletion of GCN2 reduced the translational defect of old cells. Furthermore, overexpressing an uncharged tRNA to fully activate Gcn2, or overexpression of its downstream mediator, Gcn4, extended replicative lifespan in a manner that was mostly dependent on autophagy without inhibiting the TOR pathway. As such, Ssd1 induction, activation of the integrated stress response or autophagy are favorable TOR-independent therapeutic targets for lifespan extension.
2018-08-10 | GSE104506 | GEO
Project description:Tumours depend on altered rates of protein synthesis for growth and survival, suggesting that mechanisms controlling mRNA translation may be exploitable for therapy. Here, we show that loss of APC, which occurs almost universally in colorectal tumours, strongly enhances the dependence on the translation initiation factor eIF2B5. Depletion of eIF2B5 induces an integrated stress response and enhances translation of MYC via an internal ribosomal entry site. This perturbs cellular amino acid and nucleotide pools and strains energy resources and causes MYC-dependent apoptosis. eIF2B5 limits MYC expression and prevents apoptosis in APC-deficient murine and patient-derived organoids and in APC-deficient murine intestinal epithelia in vivo. Conversely, the high MYC levels present in APC-deficient cells induce phosphorylation of eIF2alpha via the GCN2 and PKR kinases. Pharmacological inhibition of GCN2 phenocopies eIF2B5 depletion and has therapeutic efficacy in tumour organoids, demonstrating that a negative MYC/eIF2alpha feedback loop constitutes a targetable vulnerability of colorectal tumours.
2019-11-04 | GSE106858 | GEO
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.
2010-08-01 | GSE22452 | GEO
Project description:La-related protein 1 (LARP1) has been identified as a key translational inhibitor of terminal oligopyrimidine tract (TOP) mRNAs downstream of the nutrient sensing protein kinase complex, mTORC1. LARP1 exerts this inhibitory effect on TOP mRNA translation by binding to the mRNA cap and the adjacent 5’TOP motif, resulting in the displacement of the eIF4E complex from TOP mRNAs. In the present study, we identify a second nutrient sensing kinase GCN2 that converges on LARP1 to control TOP mRNA translation. GCN2 inhibits TOP mRNA translation via ATF4-dependent transcriptional induction of LARP1 mRNAs and GCN1-mediated recruitment of LARP1 to stalled ribosomes. We performed ATF4 ChIP-seq experiments in both WT and GCN2 KO MEFs with or without leucine deprivation.
2022-08-31 | GSE166590 | GEO