GCN2 kinase-mediated upregulation of ubiquitin C maintains intracellular glutamine level and tRNAGln (CUG) charging under amino acid starvation.

Each tRNA is aminoacylated (charged) with a genetic codon-specific amino acid. It remains unclear what factors are associated with tRNA charging and how tRNA charging is maintained. By using the individual tRNA acylation PCR method, we found that the charging ratio of tRNAGln (CUG) reflects cellular glutamine level. When uncharged tRNAGln (CUG) increased under amino acid starvation, the kinase GCN2, which is a key stimulator of the integrated stress response, was activated. Activation of GCN2 led to the upregulation of ubiquitin C (UBC) expression. Upregulated UBC, in turn, suppressed the further reduction in tRNAGln (CUG) charging levels. Thus, tRNA charging is sensitive to intracellular nutrient status and is an important initiator of intracellular signaling. © 2023 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

Citation

Yusuke Tsukamoto, Yumi Nakamura, Makoto Hirata, Daisuke Okuzaki, Ryuichi Sakate, Tomonori Kimura. GCN2 kinase-mediated upregulation of ubiquitin C maintains intracellular glutamine level and tRNAGln (CUG) charging under amino acid starvation. FEBS letters. 2023 Jun;597(12):1638-1650

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PMID: 37079003

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