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The FASTK family proteins fine-tune mitochondrial RNA processing

Akira Ohkubo1, Lindsey Van Haute2, Danielle L Rudler3,4,5

  • 1Department of Cell Biology, University of Geneva, Geneva, Switzerland.

Plos Genetics
|November 8, 2021
PubMed

Insights

The FASTK protein family is essential for processing mitochondrial RNA, particularly non-canonical junctions. Loss of FASTKD4 and FASTKD5 disrupts mitochondrial translation and oxidative phosphorylation.

Area of Science:

  • Mitochondrial biology
  • RNA processing
  • Gene expression

Background:

  • Mitochondrial RNA processing is vital for oxidative phosphorylation.
  • The tRNA punctuation model explains most RNA processing, but non-canonical junctions remain unclear.
  • FASTK family proteins are implicated in RNA processing.

Purpose of the Study:

  • Investigate the role of FASTK family proteins in human mitochondrial RNA processing.
  • Identify the specific FASTK members involved in non-canonical junction resolution.
  • Determine the impact of FASTK loss on mitochondrial function.

Main Methods:

  • Generated human cell lines with single and combined knockouts of FASTK family members.
  • Performed comprehensive mitochondrial transcriptome analyses.
  • Assessed mitochondrial translation and oxidative phosphorylation.

Main Results:

  • Loss of FASTKD4 and FASTKD5, especially combined, caused significant defects in RNA processing.
  • Identified processing defects at both canonical and non-canonical RNA junctions.
  • Observed increased antisense transcripts and severe impairment of mitochondrial translation and oxidative phosphorylation upon FASTKD5 loss.

Conclusions:

  • FASTK protein family members are critical regulators of mitochondrial RNA processing, including non-canonical junctions.
  • FASTKD5 plays a particularly crucial role in maintaining mitochondrial translation and oxidative phosphorylation.
  • This study elucidates the function of FASTK proteins in resolving complex mitochondrial RNA processing pathways.

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