|Dimers of mitochondrial ATP synthase form the permeability transition pore.|
Giorgio V, von Stockum S, Antoniel M, Fabbro A, Fogolari F, Forte M, Glick GD, Petronilli V, Zoratti M, Szabo I, Lippe G, Bernardi P
Proc Natl Acad Sci U S A (2013)
Category: apoptosis, mitochondria, mitochondria-transport ¤ Added: Apr 05, 2013 ¤ Rating: ◊◊
Here we define the molecular nature of the mitochondrial permeability transition pore (PTP), a key effector of cell death. The PTP is regulated by matrix cyclophilin D (CyPD), which also binds the lateral stalk of the FOF1 ATP synthase. We show that CyPD binds the oligomycin sensitivity-conferring protein subunit of the enzyme at the same site as the ATP synthase inhibitor benzodiazepine 423 (Bz-423), that Bz-423 sensitizes the PTP to Ca2+ like CyPD itself, and that decreasing oligomycin sensitivity-conferring protein expression by RNAi increases the sensitivity of the PTP to Ca2+. Purified dimers of the ATP synthase, which did not contain voltage-dependent anion channel or adenine nucleotide translocator, were reconstituted into lipid bilayers. In the presence of Ca2+, addition of Bz-423 triggered opening of a channel with currents that were typical of the mitochondrial megachannel, which is the PTP electrophysiological equivalent. Channel openings were inhibited by the ATP synthase inhibitor AMP-PNP (gamma-imino ATP, a nonhydrolyzable ATP analog) and Mg2+/ADP. These results indicate that the PTP forms from dimers of the ATP synthase.