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The Cell-based L-Glutathione Protection Assays to Study Endocytosis and Recycling of Plasma Membrane Proteins
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Glutathione binding to the Bcl-2 homology-3 domain groove: a molecular basis for Bcl-2 antioxidant function at

Angela K Zimmermann1, F Alexandra Loucks, Emily K Schroeder

  • 1Eleanor Roosevelt Institute, Department of Biological Sciences, University of Denver, Denver, Colorado 80208, USA.

The Journal of Biological Chemistry
|August 11, 2007
PubMed

Insights

The Bcl-2 protein’s antioxidant function involves regulating mitochondrial glutathione (GSH). BH3 mimetics disrupt this interaction, causing cell death, suggesting Bcl-2 directly binds GSH via its BH3 groove.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Neuroscience

Background:

  • Bcl-2 protein inhibits apoptosis and mitochondrial oxidative stress.
  • The antioxidant mechanism of Bcl-2 is not fully understood.
  • Pro-apoptotic proteins induce a pro-oxidant state at mitochondria.

Purpose of the Study:

  • To investigate the mechanism of Bcl-2's antioxidant function.
  • To test the hypothesis that Bcl-2's antioxidant activity is antagonized by BH3-only proteins.
  • To explore the interaction between Bcl-2, glutathione (GSH), and mitochondrial function.

Main Methods:

  • Utilized BH3 mimetics targeting Bcl-2's BH3 groove.
  • Assessed mitochondrial dysfunction and apoptosis in cerebellar granule neurons.
  • Measured mitochondrial GSH displacement and transport.
  • Investigated in vitro interaction between Bcl-2, GSH, and BH3-only protein Bim.

Main Results:

  • BH3 mimetics induced GSH-sensitive mitochondrial dysfunction and apoptosis.
  • BH3 mimetics displaced mitochondrial GSH and inhibited GSH transport.
  • BH3 mimetics and Bim inhibited the interaction between Bcl-2 and GSH in vitro.
  • Bcl-2 appears to directly interact with GSH via the BH3 groove.

Conclusions:

  • Bcl-2 regulates a critical pool of mitochondrial glutathione (GSH).
  • This regulation is likely mediated by direct GSH binding to Bcl-2's BH3 groove.
  • This novel GSH-binding property is central to Bcl-2's antioxidant role in mitochondria.

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