Mitochondria are excitable organelles capable of generating and conveying electrical and calcium signals.
We report Ca2(+)-induced release of Ca2+ from mitochondria (mCICR) dependent on transitory opening of the permeability transition pore (PTP) operating in a low conductance mode. The Ca2+ fluxes taking place during mCICR are a direct consequence of the mitochondrial depolarization spike (mDPS) caused by PTP opening. Both mDPS and mCICR can propagate from one mitochondrion to another in vitro, generating traveling depolarization and Ca2+ waves. Mitochondria thus appear to be excitable organelles capable of generating and conveying electrical and Ca2+ signals. In living cells, mDPS/mCICR is triggered during IP3-induced Ca2+ mobilization and results in the amplification of the Ca2+ signals primarily emitted from the endoplasmic reticulum.
Ichas
F
F
Department of Medical Biochemistry and Molecular Biology, Integrated Biological Systems Study Group, Victor Segalen-Bordeaux 2 University, France.
Jouaville
L S
LS
Mazat
J P
JP
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D002286:Carcinoma, Ehrlich Tumor; D004553:Electric Conductivity; D004594:Electrophysiology; D004721:Endoplasmic Reticulum / Q000502:physiology; D015544:Inositol 1,4,5-Trisphosphate / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D008928:Mitochondria / Q000737:chemistry / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure
D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium