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Transient assembly of F-actin on the outer mitochondrial membrane contributes to mitochondrial fission

Sunan Li1, Shan Xu1, Brian A Roelofs1

  • 1Center for Biomedical Engineering and Technology, Department of Biochemistry and Molecular Biology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201 Center for Biomedical Engineering and Technology, Department of Biochemistry and Molecular Biology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201.

The Journal of Cell Biology
|December 31, 2014
PubMed

Insights

Actin dynamics on mitochondria are crucial for mitochondrial fission. This study reveals actin assembly and disassembly on mitochondria depend on Drp1 activity, impacting mitochondrial division.

Area of Science:

  • Cell Biology
  • Mitochondrial Dynamics

Background:

  • Actin's role in membrane remodeling is established.
  • Actin's involvement in mitochondrial fission is a recent discovery with unknown mechanisms.

Purpose of the Study:

  • To elucidate the mechanisms of actin's participation in mitochondrial fission.
  • To investigate the dynamic assembly and disassembly of F-actin on mitochondria during fission.

Main Methods:

  • Induction of mitochondrial fission.
  • Drp1 knockout and inhibition.
  • Analysis of actin and actin regulatory factors (cortactin, cofilin, Arp2/3) on mitochondria.
  • Down-regulation of actin regulatory proteins.
  • Assessment of mitochondrial morphology and Drp1 localization.

Main Results:

  • Transient de novo F-actin assembly occurs on mitochondria during fission.
  • Impairing Drp1 activity prolonged F-actin accumulation and led to abnormal accumulation of actin regulatory factors.
  • Disassembly of mitochondrial F-actin depends on Drp1 activity.
  • Down-regulation of actin regulatory proteins caused mitochondrial elongation and Drp1 accumulation.
  • Cortactin depletion inhibited mitochondrial fragmentation.

Conclusions:

  • Dynamic assembly and disassembly of mitochondrial F-actin are integral to Drp1-mediated mitochondrial fission.
  • Actin regulatory proteins play a role in regulating mitochondrial fission and dynamics.

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