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Mitochondrial outer membrane permeabilization during apoptosis: the innocent bystander scenario

J E Chipuk1, L Bouchier-Hayes, D R Green

  • 1Department of Immunology, St Jude Children's Research Hospital, Memphis, TN 38105, USA.

Cell Death and Differentiation
|May 20, 2006
PubMed

Insights

Mitochondrial outer membrane permeabilization (MOMP), a key step in apoptosis, is dictated by cytosolic signals interacting with the outer mitochondrial membrane (OMM). Mitochondria do not independently decide when to initiate this cell death process.

Area of Science:

  • Cellular Biology
  • Biochemistry
  • Molecular Biology

Background:

  • Mitochondrial outer membrane permeabilization (MOMP) is a critical 'point of no return' in apoptosis.
  • MOMP involves proapoptotic BCL-2 proteins disrupting the outer mitochondrial membrane (OMM) and releasing factors like cytochrome c.

Purpose of the Study:

  • To test the hypothesis that MOMP is primarily dictated by cytosolic-OMM interactions.
  • To investigate the role of the cytosol versus mitochondria in initiating the apoptotic decision.

Main Methods:

  • The study proposes a hypothesis regarding the control of MOMP.
  • The research focuses on the interaction between the cytosol and the outer mitochondrial membrane.

Main Results:

  • The 'decision' to undergo apoptosis originates in the cytosol.
  • Mitochondria do not participate in the 'yes/no' or 'when' of initiating apoptosis.

Conclusions:

  • MOMP is governed by cytosolic signals, not intrinsic mitochondrial timing.
  • The apoptotic cascade's initiation is a cytosolic event, independent of mitochondrial decision-making.

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