Mammalian Mitochondrial RNAs Are Degraded in the Mitochondrial Intermembrane Space by RNASET2

Protein Cell. 2017 Oct;8(10):735-749. doi: 10.1007/s13238-017-0448-9. Epub 2017 Jul 20.


Mammalian mitochondrial genome encodes a small set of tRNAs, rRNAs, and mRNAs. The RNA synthesis process has been well characterized. How the RNAs are degraded, however, is poorly understood. It was long assumed that the degradation happens in the matrix where transcription and translation machineries reside. Here we show that contrary to the assumption, mammalian mitochondrial RNA degradation occurs in the mitochondrial intermembrane space (IMS) and the IMS-localized RNASET2 is the enzyme that degrades the RNAs. This provides a new paradigm for understanding mitochondrial RNA metabolism and transport.

Keywords: RNA degradation; RNA trafficking; RNASET2; RNase T2; decay; inner membrane; intermembrane space; mitochondria; mtRNA; ribonuclease; transport.

MeSH terms

  • Cell Line
  • Humans
  • Mitochondrial Membranes / metabolism*
  • Protein Transport
  • RNA / biosynthesis
  • RNA / chemistry*
  • RNA / metabolism*
  • RNA Stability*
  • RNA, Mitochondrial
  • Ribonucleases / metabolism*
  • Tumor Suppressor Proteins / metabolism*


  • RNA, Mitochondrial
  • Tumor Suppressor Proteins
  • RNA
  • Ribonucleases
  • RNASET2 protein, human