Inhibition of Bax channel-forming activity by Bcl-2

Science. 1997 Jul 18;277(5324):370-2. doi: 10.1126/science.277.5324.370.


Proteins of the Bcl-2 family are intracellular membrane-associated proteins that regulate programmed cell death (apoptosis) either positively or negatively by as yet unknown mechanisms. Bax, a pro-apoptotic member of the Bcl-2 family, was shown to form channels in lipid membranes. Bax triggered the release of liposome-encapsulated carboxyfluorescein at both neutral and acidic pH. At physiological pH, release could be blocked by Bcl-2. Bcl-2, in contrast, triggered carboxyfluorescein release at acidic pH only. In planar lipid bilayers, Bax formed pH- and voltage-dependent ion-conducting channels. Thus, the pro-apoptotic effects of Bax may be elicited through an intrinsic pore-forming activity that can be antagonized by Bcl-2.

MeSH terms

  • Animals
  • Apoptosis
  • Cell Membrane Permeability
  • Cells, Cultured
  • Erythrocytes / cytology
  • Fluoresceins / metabolism
  • Hemolysis
  • Humans
  • Hydrogen-Ion Concentration
  • Ion Channels / physiology*
  • Lipid Bilayers
  • Liposomes
  • Membrane Potentials
  • Neurons / cytology
  • Patch-Clamp Techniques
  • Proto-Oncogene Proteins / pharmacology
  • Proto-Oncogene Proteins / physiology*
  • Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors
  • Proto-Oncogene Proteins c-bcl-2 / pharmacology
  • Proto-Oncogene Proteins c-bcl-2 / physiology*
  • Sheep
  • Sympathetic Nervous System / cytology
  • bcl-2-Associated X Protein


  • BAX protein, human
  • Fluoresceins
  • Ion Channels
  • Lipid Bilayers
  • Liposomes
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • bcl-2-Associated X Protein
  • 6-carboxyfluorescein