Bcl-xL regulates the membrane potential and volume homeostasis of mitochondria

Cell. 1997 Nov 28;91(5):627-37. doi: 10.1016/s0092-8674(00)80450-x.


Mitochondrial physiology is disrupted in either apoptosis or necrosis. Here, we report that a wide variety of apoptotic and necrotic stimuli induce progressive mitochondrial swelling and outer mitochondrial membrane rupture. Discontinuity of the outer mitochondrial membrane results in cytochrome c redistribution from the intermembrane space to the cytosol followed by subsequent inner mitochondrial membrane depolarization. The mitochondrial membrane protein Bcl-xL can inhibit these changes in cells treated with apoptotic stimuli. In addition, Bcl-xL-expressing cells adapt to growth factor withdrawal or staurosporine treatment by maintaining a decreased mitochondrial membrane potential. Bcl-xL expression also prevents mitochondrial swelling in response to agents that inhibit oxidative phosphorylation. These data suggest that Bcl-xL promotes cell survival by regulating the electrical and osmotic homeostasis of mitochondria.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Antimycin A / pharmacology
  • Apoptosis / physiology*
  • B-Lymphocytes / chemistry
  • B-Lymphocytes / cytology
  • B-Lymphocytes / ultrastructure
  • Cytochrome c Group / metabolism
  • Flow Cytometry
  • Gene Expression / physiology
  • Homeostasis / physiology*
  • Humans
  • Intracellular Membranes / metabolism
  • Intracellular Membranes / pathology
  • Jurkat Cells / chemistry
  • Jurkat Cells / cytology
  • Jurkat Cells / ultrastructure
  • Membrane Potentials / physiology
  • Microscopy, Electron
  • Mitochondria / pathology
  • Mitochondria / physiology*
  • Mitochondria / ultrastructure
  • Mitochondrial Swelling
  • Oxidative Phosphorylation / drug effects
  • Proto-Oncogene Proteins c-bcl-2 / genetics*
  • Transfection
  • bcl-X Protein


  • Anti-Bacterial Agents
  • BCL2L1 protein, human
  • Cytochrome c Group
  • Proto-Oncogene Proteins c-bcl-2
  • bcl-X Protein
  • Antimycin A