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Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c
07:42

Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c

Published on: June 29, 2011

GSH extrusion and and the mitochondrial pathway of apoptotic signalling

S Coppola1, L Ghibelli

  • 1Dipartimento di Biologia, Università di Tor Vergata, Roma, Italy.

Biochemical Society Transactions
|May 18, 2000
PubMed

Insights

Physiological and damaging agents trigger distinct apoptotic signaling pathways. Redox imbalance is crucial for damage-induced apoptosis, involving glutathione depletion and mitochondrial changes.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Molecular Biology

Background:

  • Apoptosis, or programmed cell death, is essential for development and tissue homeostasis.
  • Previously, contradictory findings complicated the understanding of apoptotic signaling pathways.
  • The roles of oxidative stress and redox imbalance in apoptosis were unclear.

Purpose of the Study:

  • To elucidate the distinct molecular mechanisms of physiological and damage-induced apoptosis.
  • To clarify the role of oxidative stress and redox imbalance in different apoptotic pathways.
  • To propose a model for damage-induced apoptotic signaling.

Main Methods:

  • Investigated apoptotic signaling pathways activated by physiological and damaging agents.
  • Analyzed protein-protein interactions and mitochondrial alterations.
  • Examined the role of glutathione depletion and cytochrome c release.

Main Results:

  • Identified two distinct apoptotic signaling pathways: one mediated by protein-protein interactions (physiological) and another by mitochondrial alterations (damage-induced).
  • Both pathways converge on caspase 3 activation.
  • Oxidative alterations are not required for the physiological pathway but are essential for the damage-induced mitochondrial pathway, with glutathione depletion being a key event.

Conclusions:

  • Distinct biochemical routes govern physiological and damage-induced apoptosis.
  • Redox imbalance, specifically glutathione efflux, is a critical component of the damage-induced mitochondrial apoptotic pathway.
  • This understanding reconciles previous contradictory findings regarding apoptosis signaling.

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