Redox Regulation of Mitochondrial ATP Synthase

Abstract

Rationale: Cardiac resynchronization therapy (CRT) is an effective clinical treatment for heart failure patients with conduction delay, impaired contraction, and energetics. Our recent studies have revealed that mitochondrial posttranslational modifications (PTM) may contribute to its benefits, motivating the present study of the oxidative regulation of mitochondrial ATP synthase. Objectives: We tested whether CRT alteration of ATP synthase function is linked to cysteine (Cys) oxidative PTM (Ox-PTM) of specific ATP synthase subunits. Methods and Results: Canine left ventricular myocardium was collected under conditions to preserve Ox-PTM from control, dyssynchronous heart failure (DHF), or hearts that had undergone CRT. In-gel ATPase activity showed that CRT increased ATPase activity by ≈2-fold (PPPP<0.05). All modifications occurred at ATP synthase α subunit Cys294 and Cys to Ser mutation indicated that this residue is critical for ATP synthase function. Conclusions: A selective Cys in ATP synthase α subunit is targeted by multiple Ox-PTM suggesting that this Cys residue may act as a redox sensor modulating ATP synthase function.