Translation in amino acid-poor environments is limited by tRNAGln charging
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 key sensors of glutamine availability in mammalian cells.
High-throughput sequencing data have been deposited in GEO (accession code GSE157276).
Translation in amino acid-poor environments is limited by tRNAGln chargingNCBI Gene Expression Omnibus, GSE157276.
Article and author information
National Cancer Institute (P30 CA 008748)
- Craig B Thompson
Damon Runyon Cancer Research Foundation (DRG 2234-15)
- Bryan King
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: All animal experiments were conducted in accordance with policies and practices approved by the Memorial Sloan Kettering Cancer Center Institutional Animal Care and Use Committee (IACUC), and were carried out following the NIH guidelines for animal welfare (animal protocol #11-03-007). Every effort was made to minimize suffering.
- Alan G Hinnebusch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, United States
- Received: August 20, 2020
- Accepted: December 7, 2020
- Accepted Manuscript published: December 8, 2020 (version 1)
- Version of Record published: December 16, 2020 (version 2)
© 2020, Pavlova et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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