The voltage-dependent anion channel is the target for a new class of inhibitors of the mitochondrial permeability transition pore.
The relevance of the mitochondrial permeability transition pore (PTP) in Ca2+ homeostasis and cell death has gained wide attention. Yet, despite detailed functional characterization, the structure of this channel remains elusive. Here we report on a new class of inhibitors of the PTP and on the identification of their molecular target. The most potent among the compounds prepared, Ro 68-3400, inhibited PTP with a potency comparable to that of cyclosporin A. Since Ro 68-3400 has a reactive moiety capable of covalent modification of proteins, [3H]Ro 68-3400 was used as an affinity label for the identification of its protein target. In intact mitochondria isolated from rodent brain and liver and in SH-SY5Y human neuroblastoma cells, [3H]Ro 68-3400 predominantly labeled a protein of approximately 32 kDa. This protein was identified as the isoform 1 of the voltage-dependent anion channel (VDAC). Both functional and affinity labeling experiments indicated that VDAC might correspond to the site for the PTP inhibitor ubiquinone0, whereas other known PTP modulators acted at distinct sites. While Ro 68-3400 represents a new useful tool for the study of the structure and function of VDAC and the PTP, the results obtained provide direct evidence that VDAC1 is a component of this mitochondrial pore.
Cesura
Andrea M
AM
Pharmaceutical Division, Drug Discovery Department, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland. andrea.cesura@serono.com
Pinard
Emmanuel
E
Schubenel
Robert
R
Goetschy
Valerie
V
Friedlein
Arno
A
Langen
Hanno
H
Polcic
Peter
P
Forte
Michael A
MA
Bernardi
Paolo
P
Kemp
John A
JA
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D016572:Cyclosporine / Q000494:pharmacology; D003986:Dibenzocycloheptenes / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D007166:Immunosuppressive Agents / Q000494:pharmacology; D007473:Ion Channels / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D051379:Mice; D008930:Mitochondria, Liver / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D008956:Models, Chemical; D010101:Oxygen Consumption; D018272:Porins / Q000378:metabolism / Q000502:physiology*; D020033:Protein Isoforms; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013141:Spiro Compounds / Q000494:pharmacology; D013997:Time Factors; D050995:Voltage-Dependent Anion Channel 1; D050994:Voltage-Dependent Anion Channels
D003986:Dibenzocycloheptenes; D007166:Immunosuppressive Agents; D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D018272:Porins; D020033:Protein Isoforms; C480229:Ro 68-3400; D013141:Spiro Compounds; C494762:VDAC1 protein, human; C494763:Vdac1 protein, mouse; C494764:Vdac1 protein, rat; D050994:Voltage-Dependent Anion Channels; D016572:Cyclosporine; D050995:Voltage-Dependent Anion Channel 1; D002118:Calcium