The human mitochondrial translation release factor HMRF1L is methylated in the GGQ motif by the methyltransferase HMPrmC

Toshihiro Ishizawa, Yusuke Nozaki, Takuya Ueda, Nono Takeuchi

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We have recently identified the human mitochondrial release factor, HMRF1L, which is responsible for decoding of UAA/UAG termination codons. Here, we identified human mitochondrial methyltransferase, HMPrmC, which methylates the glutamine residue in the GGQ tripeptide motif of HMRF1L. We demonstrate that HMPrmC is targeted to mitochondria and the glutamine residue in the GGQ motif of HMRF1L is methylated in vivo. HMPrmC depletion in HeLa cells leads to decreased mitochondrial translation activity in the presence of the translation fidelity antibiotic streptomycin in galactose containing medium. These results suggest that the methylation of HMRF1L by HMPrmC in human mitochondria is involved in the control of the translation termination process, probably by preventing the undesired suppression of termination codons and/or abortive termination events at sense codons under such conditions, as observed in prokaryotes and eukaryotes systems.

Original languageEnglish
Pages (from-to)99-103
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - 2008 Aug 15



  • Mammalian mitochondria
  • Methyltransferase
  • Translation release factor

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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