The properties of the mitochondrial megachannel in mitoplasts from human colon carcinoma cells are not influenced by Bax.
This paper explores the relationship between Bax and the mitochondrial permeability transition pore (PTP). Isolated human colon tumor (HCT116) Bax- mitochondria exposed to recombinant Bax exhibited a slow, cyclosporin A-sensitive swelling, but only at [Bax]>200 nM. The amount of Bax incorporated was much higher than that found in organelles isolated from HCT116 Bax+ staurosporine- or etoposide-treated apoptotic cells, casting doubts on the significance of the putative PT induction for apoptosis. Bax did not influence the electrophysiological properties of an approximately 1 nS channel ascribed to the Ca2+-dependent mitochondrial permeability transition pore. These observations indicate that the PTP is independent of Bax.
Campello
Silvia
S
CNR Institute of Neuroscience, Biomembranes Section, Department of Biomedical Sciences, University of Padova, Viale Giuseppe Colombo 3, 35121 Padova, Italy.
De Marchi
Umberto
U
Szabò
Ildikò
I
Tombola
Francesco
F
Martinou
Jean-Claude
JC
Zoratti
Mario
M
D002118:Calcium / Q000494:pharmacology; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism*; D002413:Cations, Divalent / Q000494:pharmacology; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000502:physiology*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D008933:Mitochondrial Swelling; D009154:Mutation; D018408:Patch-Clamp Techniques; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D002413:Cations, Divalent; D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D002118:Calcium