A unifying model for mTORC1-mediated regulation of mRNA translation
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE36892 | GEO | 2012/05/03
SECONDARY ACCESSION(S): PRJNA157105
REPOSITORIES: GEO
Similar Datasets
Project description:Ribsome profiling analysis of mRNA translation in mouse cells under conditions of mTOR activiation or inhibition. embryonic fibroblasts from 4EBP1/2 p53 mutants treated with Torin1
2012-05-02 | E-GEOD-36892 | biostudies-arrayexpress
Project description:The mTOR complex 1 (mTORC1) kinase nucleates a pathway that promotes cell growth and proliferation and is the target of rapamycin, a drug with many clinical uses. mTORC1 regulates messenger RNA translation, but the overall translational program is poorly defined and no unifying model exists to explain how mTORC1 differentially controls the translation of specific mRNAs. Here we use high-resolution transcriptome-scale ribosome profiling to monitor translation in mouse cells acutely treated with the mTOR inhibitor Torin 1, which, unlike rapamycin, fully inhibits mTORC1 (ref. 2). Our data reveal a surprisingly simple model of the mRNA features and mechanisms that confer mTORC1-dependent translation control. The subset of mRNAs that are specifically regulated by mTORC1 consists almost entirely of transcripts with established 5' terminal oligopyrimidine (TOP) motifs, or, like Hsp90ab1 and Ybx1, with previously unrecognized TOP or related TOP-like motifs that we identified. We find no evidence to support proposals that mTORC1 preferentially regulates mRNAs with increased 5' untranslated region length or complexity. mTORC1 phosphorylates a myriad of translational regulators, but how it controls TOP mRNA translation is unknown. Remarkably, loss of just the 4E-BP family of translational repressors, arguably the best characterized mTORC1 substrates, is sufficient to render TOP and TOP-like mRNA translation resistant to Torin 1. The 4E-BPs inhibit translation initiation by interfering with the interaction between the cap-binding protein eIF4E and eIF4G1. Loss of this interaction diminishes the capacity of eIF4E to bind TOP and TOP-like mRNAs much more than other mRNAs, explaining why mTOR inhibition selectively suppresses their translation. Our results clarify the translational program controlled by mTORC1 and identify 4E-BPs and eIF4G1 as its master effectors.
| S-EPMC3347774 | biostudies-literature
Project description:LARP1 has been proposed to control the translation of TOP mRNAs downstrteam of mTORC1. Here we used ribosome profiling to analyze transcriptome-wide changes in translation following mTOR inhibition in wild-type HEK-293T cells and cells where LARP1 (sgLARP1) or LARP1 and its homologue LARP1B (sgLARP1/1B) have been deleted using CRISPR/Cas9.
2020-02-12 | GSE132703 | GEO
Project description:Roberts syndrome (RBS) is a human developmental disorder caused by mutations in the cohesin acetyltransferase ESCO2. We previously reported that mTORC1 was inhibited and overall translation was reduced in RBS cells. Treatment of RBS cells with L-leucine partially rescued mTOR function and protein synthesis, correlating with increased cell division. In this study, we use RBS as a model for mTOR inhibition and analyze transcription and translation with ribosome profiling to determine genome-wide effects of L-leucine. The translational efficiency of many genes is increased with Lleucine in RBS cells including genes involved in ribosome biogenesis, translation, and mitochondrial function. snoRNAs are strongly upregulated in RBS cells, but decreased with L-leucine. Imprinted genes, including H19 and GTL2, are differentially expressed in RBS cells consistent with contribution to mTORC1 control. This study reveals dramatic effects of L-leucine stimulation of mTORC1 and supports that ESCO2 function is required for normal gene expression and translation. 42 samples of human fibroblast cell lines with various genotypes (wt, corrected, and esco2 mutants) are treated with l-leucine or d-leucine (control) for 3 or 24 hours. Biological replicates are present.
2016-01-15 | E-GEOD-64962 | biostudies-arrayexpress
Project description:We report mTOR inhibitor Rapamycin's specific and genome-wide effect on mRNA translation. Using ribosome footprinting in pancreatic cancer cells that lack 4EBP1 expression we establish the effect of mTOR-S6-dependent mRNA translation, and identify translation programs activated following mTOR inhibition.
2023-02-21 | GSE225683 | GEO
Project description:Roberts syndrome (RBS) is a human developmental disorder caused by mutations in the cohesin acetyltransferase ESCO2. We previously reported that mTORC1 was inhibited and overall translation was reduced in RBS cells. Treatment of RBS cells with L-leucine partially rescued mTOR function and protein synthesis, correlating with increased cell division. In this study, we use RBS as a model for mTOR inhibition and analyze transcription and translation with ribosome profiling to determine genome-wide effects of L-leucine. The translational efficiency of many genes is increased with Lleucine in RBS cells including genes involved in ribosome biogenesis, translation, and mitochondrial function. snoRNAs are strongly upregulated in RBS cells, but decreased with L-leucine. Imprinted genes, including H19 and GTL2, are differentially expressed in RBS cells consistent with contribution to mTORC1 control. This study reveals dramatic effects of L-leucine stimulation of mTORC1 and supports that ESCO2 function is required for normal gene expression and translation.
2016-01-15 | GSE64962 | GEO
Project description:The RNA biding protein, LARP1, has been proposed to function downstream of mTORC1 to positively regulate the translation of 5M-bM-^@M-^YTOP mRNAs such as ribosome protein (RP) mRNAs. However, its regulatory roles in mTORC1-mediated translation remain unclear. PAR-CLIP of LARP1 revealed its direct and dynamic interactions with RP mRNAs through pyrimidine-enriched sequences in the 5M-bM-^@M-^YUTR of RP mRNAs when mTOR activity is inhibited. Importantly, this LARP1 is a direct substrate of mTORC1 and S6K1/Akt, and phosphorylated LARP1 scaffolds mTORC1 on translation-competent mRNAs to facilitate 4EBP1 and S6K1 phosphorylation. Ablation of LARP1 causes multiple defects in the processes of translation including abnormal eIF4G1 interaction with RP mRNAs and inefficient RP mRNA elongation thereby reducing ribosome biogenesis and cell proliferation. These observations illustrate that LARP1 functions both an effector and a regulator for local mTORC1 activity, and acts as a molecular switch for ribosome biogenesis by sensing growth factor/nutrient signaling. LARP1-bound RNA regions were sequenced from HEK293T cells under growing or mTOR-inactive conditions. In parallel, mRNA abundance was quantified, in biological duplicate, from HEK293T cells under the same conditions.
2014-07-31 | E-GEOD-59599 | biostudies-arrayexpress
Project description:Methionine adenosyltransferase (MAT) catalyzes the synthesis of S-adenosylmethionine (SAM). As the sole methyl-donor of methylation of DNA, RNA and proteins, SAM amount affects gene expression by changing their methylation. Expression of MAT2A, the catalytic subunit of isozyme MAT2, is positively correlated with proliferation of cancer cells. However, how MAT2A promotes cell proliferation is largely unknown. Given that the protein synthesis is induced in proliferating cells and that RNA and protein components of translation machinery are methylated, we tested whether MAT2 and SAM are coupled with protein synthesis. By measuring ongoing protein translation with puromycin labeling in HeLa and Hepa1 cells, we revealed that MAT2A depletion by siRNA or chemical inhibition by cycloleucine reduced protein synthesis in mammalian cells. Overexpression of MAT2A enhanced protein synthesis, indicating that SAM is limiting under normal culture conditions. MAT2 inhibition did not accompany a reduction in the mTORC1 activity but reduced polysome formation. Polysome-bound RNA sequencing revealed that MAT2 inhibition decreased translation efficiency of a fraction of mRNAs. MAT2A was also found to interact with the proteins involved in rRNA processing and ribosome biogenesis. Depletion or inhibition of MAT2 reduced 18S rRNA processing. In addition, by quantitative mass spectrometry, we observed that some translation factors were dynamically methylated in response to the activity of MAT2A or the availability of SAM. These observations suggest that cells possess an mTOR-independent regulatory mechanism that tunes translation in response to the amount of SAM. Such a system may acclimate cells for survival when SAM synthesis is reduced whereas it may support proliferation when SAM is sufficient.
2022-12-21 | GSE201299 | GEO
Project description:The cancer cells selectively promote the translation of specific oncogenic transcripts to stimulate cancer progression. Although growing evidence has revealed that tRNA modifications and related genes participate in this process, their roles in head and neck squamous cell carcinoma (HNSCC) remain largely uncharacterized. Here we found that tRNA m7G methyltransferase complex components METTL1/WDR4 were both upregulated in HNSCC and associated with poor prognosis. Functionally, METTL1/WDR4 promoted HNSCC progression and metastasis in cell-based and transgenic mouse models. Mechanistically, ablation of METTL1 reduced m7G levels of 16 tRNAs, causing translational inhibition of a subset of oncogenic transcripts, including the genes related to PI3K/AKT/mTOR signaling pathway. In addition, chemical modulators of PI3K/AKT/mTOR signaling pathway can reverse the effects of Mettl1 in HNSCC. Furthermore, single-cell RNA sequencing results revealed that depletion of Mettl1 in tumor cells altered the immune landscape and cell-cell interaction between tumor and stromal compartment. In summary, this study uncovered the physiological function and mechanism of mis-translation regulation mediated by tRNA m7G modification in HNSCC, and suggested that targeting METTL1 could be a promising treatment strategy for HNSCC patients.
2022-03-23 | GSE172146 | GEO
Project description:mTOR regulates mRNA translation. Whereas ribosome-profiling suggested that mTOR exclusively stimulates translation of TOP (containing a 5â-terminal oligopyrimidine [5âTOP] motif) and TOP-like mRNAs, polysome-profiling implied that mTOR also modulates translation of non-TOP mRNAs. We show that ribosome-, but not polysome-profiling, is biased towards identification of TOP mRNAs as differentially translated while obscuring detection of changes in non-TOP mRNA translation. Transcription start site profiling by Nano-Cap Analysis of Gene Expression (nanoCAGE) revealed that many mTOR-sensitive mRNAs do not have 5âTOP motifs. Moreover, nanoCAGE showed that 5â UTR features distinguish two functionally and translationally distinct subsets of mTOR-sensitive mRNAs: i) those with short 5â UTRs enriched for mitochondrial functions such as respiration, that are translated in an eIF4E, but not eIF4A1-dependent manner and ii) mRNAs encoding proliferation- and survival-promoting proteins, that harbor long 5â UTRs, and require both eIF4E and eIF4A1 for their efficient translation. Selective inhibition of translation of mRNAs harboring long 5â UTRs via suppression of eIF4A leads to uncoupling of expression of proteins involved in respiration (e.g. ATP5O) from those protecting mitochondrial integrity (e.g. BCL-2) ultimately resulting in apoptosis. Conversely, simultaneous translational downregulation of both long and short 5â UTR mRNAs by mTOR inhibitors results in suppression of mitochondrial respiration and predominantly cytostatic effects. Therefore, 5â UTR features define differential modes of translation of functionally distinct mTOR-sensitive mRNAs, which explains discrepancies between the effects of mTOR and eIF4A inhibitors on neoplastic cells. Determination of 5'UTR lengths using nanoCAGE in MCF7 cells
2016-03-14 | E-GEOD-77033 | biostudies-arrayexpress