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Inhibiting the mitochondrial fission machinery does not prevent Bax/Bak-dependent apoptosis

Philippe A Parone1, Dominic I James, Sandrine Da Cruz

  • 1Department of Cell Biology, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland.

Molecular and Cellular Biology
|October 4, 2006
PubMed

Insights

Mitochondrial fission, regulated by proteins like Drp1, is not essential for cell death in Bax/Bak-mediated apoptosis. Inhibiting fission prevents mitochondrial fragmentation but does not block cell death, indicating fission is dispensable.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Apoptosis involves mitochondrial network fragmentation.
  • Mitochondrial fission proteins like Drp1 and hFis1 regulate these changes.
  • The exact role of mitochondrial fission in apoptosis is unclear.

Purpose of the Study:

  • To investigate the role of mitochondrial fission in Bax/Bak-mediated apoptosis.
  • To determine if inhibiting mitochondrial fission affects cytochrome c and Smac/DIABLO release.
  • To assess if preventing mitochondrial fragmentation impacts cell death.

Main Methods:

  • Down-regulation of Drp1 or hFis1 to inhibit mitochondrial fission machinery.
  • Analysis of mitochondrial network fragmentation.
  • Measurement of cytochrome c and Smac/DIABLO release.
  • Assessment of cell death induced by Bax/Bak-dependent stimuli.

Main Results:

  • Inhibiting Drp1 or hFis1 prevented mitochondrial fragmentation.
  • Partial inhibition of cytochrome c release was observed.
  • Efflux of Smac/DIABLO was not blocked.
  • Preventing mitochondrial fragmentation did not inhibit Bax/Bak-dependent cell death.

Conclusions:

  • Mitochondrial fission is a dispensable event in Bax/Bak-dependent apoptosis.
  • The fragmentation of mitochondria is not required for cell death signaling in this pathway.

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