Innate immune and chemically triggered oxidative stress modifies translational fidelity

Nir Netzer, Jeffrey M. Goodenbour, Alexandre David, Kimberly A. Dittmar, Richard B. Jones, Jeffrey R. Schneider, David Boone, Eva M. Eves, Marsha R. Rosner, James S. Gibbs, Alan Embry, Brian Dolan, Suman Das, Heather D. Hickman, Peter Berglund, Jack R. Bennink, Jonathan W. Yewdell, Tao Pan

Research output: Contribution to journalArticlepeer-review

260 Scopus citations

Abstract

Translational fidelity, essential for protein and cell function, requires accurate transfer RNA (tRNA) aminoacylation. Purified aminoacyl-tRNA synthetases exhibit a fidelity of one error per 10,000 to 100,000 couplings. The accuracy of tRNA aminoacylation in vivo is uncertain, however, and might be considerably lower. Here we show that in mammalian cells, approximately 1% of methionine (Met) residues used in protein synthesis are aminoacylated to non-methionyl-tRNAs. Remarkably, Met-misacylation increases up to tenfold upon exposing cells to live or non-infectious viruses, toll-like receptor ligands or chemically induced oxidative stress. Met is misacylated to specific non-methionyl-tRNA families, and these Met-misacylated tRNAs are used in translation. Met-misacylation is blocked by an inhibitor of cellular oxidases, implicating reactive oxygen species (ROS) as the misacylation trigger. Among six amino acids tested, tRNA misacylation occurs exclusively with Met. As Met residues are known to protect proteins against ROS-mediated damage, we propose that Met-misacylation functions adaptively to increase Met incorporation into proteins to protect cells against oxidative stress. In demonstrating an unexpected conditional aspect of decoding mRNA, our findings illustrate the importance of considering alternative iterations of the genetic code.

Original languageEnglish (US)
Pages (from-to)522-526
Number of pages5
JournalNature
Volume462
Issue number7272
DOIs
StatePublished - Nov 26 2009

ASJC Scopus subject areas

  • General

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