In Mitochondria β-Actin Regulates mtDNA Transcription and Is Required for Mitochondrial Quality Control

Xin Xie, Tomas Venit, Nizar Drou, Piergiorgio Percipalle

Research output: Contribution to journalArticle


In eukaryotic cells, actin regulates both cytoplasmic and nuclear functions. However, whether actin-based structures are present in the mitochondria and are involved in mitochondrial functions has not been investigated. Here, using wild-type β-actin +/+ and knockout (KO)β-actin −/− mouse embryonic fibroblasts we show evidence for the defect in maintaining mitochondrial membrane potential (MMP)in β-actin-null cells. MMP defects were associated with impaired mitochondrial DNA (mtDNA)transcription and nuclear oxidative phosphorylation (OXPHOS)gene expression. Using super-resolution microscopy we provided direct evidence on the presence of β-actin-containing structures inside mitochondria. Large aggregates of TFAM-stained nucleoids were observed in bulb-shaped mitochondria in KO cells, suggesting defects in mitochondrial nucleoid segregation without β-actin. The observation that mitochondria-targeted β-actin rescued mtDNA transcription and MMP suggests an indispensable functional role of a mitochondrial β-actin pool necessary for mitochondrial quality control.

Original languageEnglish (US)
Pages (from-to)226-237
Number of pages12
StatePublished - May 25 2018



  • Cell Biology
  • Functional Aspects of Cell Biology
  • Molecular Biology

ASJC Scopus subject areas

  • General

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