title: Properties of the permeability transition pore in mitochondria devoid of Cyclophilin D.
abstract: We have studied the properties of the permeability transition pore (PTP) in mitochondria from the liver of mice where the Ppif gene encoding for mitochondrial Cyclophilin D (CyP-D) had been inactivated. Mitochondria from Ppif-/- mice had no CyP-D and displayed a striking desensitization of the PTP to Ca2+, in that pore opening required about twice the Ca2+ load necessary to open the pore in strain-matched, wild-type mitochondria. Mitochondria lacking CyP-D were insensitive to Cyclosporin A (CsA), which increased the Ca2+ retention capacity only in mitochondria from wild-type mice. The PTP response to ubiquinone 0, depolarization, pH, adenine nucleotides, and thiol oxidants was similar in mitochondria from wild-type and Ppif-/- mice. These experiments demonstrate that (i) the PTP can form and open in the absence of CyP-D, (ii) that CyP-D represents the target for PTP inhibition by CsA, and (iii) that CyP-D modulates the sensitivity of the PTP to Ca2+ but not its regulation by the proton electrochemical gradient, adenine nucleotides, and oxidative stress. These results have major implications for our current understanding of the PTP and its modulation in vitro and in vivo.
authors.affiliation: Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Institute of Neuroscience, University of Padova, Viale Giuseppe Colombo 3, I-35121 Padova, Italy.
authors.forename: Emy
authors.initials: E
authors.lastname: Basso
authors.forename: Lisa
authors.initials: L
authors.lastname: Fante
authors.forename: Jonathan
authors.initials: J
authors.lastname: Fowlkes
authors.forename: Valeria
authors.initials: V
authors.lastname: Petronilli
authors.forename: Michael A
authors.initials: MA
authors.lastname: Forte
authors.forename: Paolo
authors.initials: P
authors.lastname: Bernardi
mesh_terms: D000483:Alleles; D000818:Animals; D016227:Benzoquinones / Q000378:metabolism; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins / Q000235:genetics* / Q000502:physiology*; D016572:Cyclosporine / Q000494:pharmacology; D003958:Diamide / Q000737:chemistry; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008928:Mitochondria / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry; D008957:Models, Genetic; D018384:Oxidative Stress; D010100:Oxygen / Q000737:chemistry; D010101:Oxygen Consumption; D010539:Permeability; D011522:Protons
chemical_list: D016227:Benzoquinones; D000081406:Peptidyl-Prolyl Isomerase F; D024101:Mitochondrial Proteins; C000631446:PPIF protein, mouse; D011522:Protons; D003958:Diamide; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; C109863:ubiquinone-O; D016572:Cyclosporine; D021983:Cyclophilins; D010100:Oxygen; D002118:Calcium