Skeletal muscle mitoflashes, pH, and the role of uncoupling protein-3.

摘要: Mitochondrial reactive oxygen species (ROS) are important cellular signaling molecules, but can cause oxidative damage if not kept within tolerable limits. An proximal form of ROS in mitochondria is superoxide. Its production thought to occur regulated stochastic bursts, current methods using mitochondrial targeted cpYFP assess superoxide flashes confounded by changes pH. Accordingly, these generally referred as 'mitoflashes'. Here we provide regulatory insights into mitoflashes and pH fluctuations skeletal muscle, the role uncoupling protein-3 (UCP3). Using quantitative confocal microscopy intact muscle fibers, show that mitoflash magnitude significantly correlates with degree inner membrane depolarization ablation UCP3 did affect this correlation. We assessed effects absence on activity found no frequency, amplitude or duration, a slight reduction average size mitoflashes. further investigated regulation (pHlashes, presumably component mitoflash) SypHer (mt-SypHer) fibers. The frequency pHlashes was reduced UCP3, without other flash properties. scavenger, tiron, alter pHlash either WT UCP3KO mice. High resolution respirometry revealed there impaired proton leak Complex I-driven respiration maximal coupled respiration. Total hydrogen peroxide (H2O2) detected Amplex-UltraRed unaffected. Altogether, demonstrate correlation between potential fibers independent for control leak- I coupled-respiration differential tiron also indicate two events, though may be related, identical events.