Bcl-xL regulates metabolic efficiency of neurons through interaction with the mitochondrial F1FO ATP synthase

Abstract

Anti-apoptotic BCL-2 family proteins such as Bcl-xL protect cells from death by sequestering apoptotic molecules, but also contribute to normal neuronal function. We find in hippocampal neurons that Bcl-xL enhances the efficiency of energy metabolism. Our evidence suggests that Bcl-xL interacts directly with the beta subunit of the F1FO ATP synthase, decreasing an ion leak within the F1FO ATPase complex and thereby increasing net transport of H+ by F1FO during F1FO ATPase activity. By patch clamping submitochondrial vesicles enriched in F1FO ATP synthase complexes, we find that, in the presence of ATP, pharmacological or genetic inhibition of Bcl-xL increases the membrane leak conductance. In addition, recombinant Bcl-xL protein directly increases ATPase activity of purified synthase complexes, while inhibition of endogenous Bcl-xL decreases F1FO enzymatic activity. Our findings suggest that increased mitochondrial efficiency contributes to the enhanced synaptic efficacy found in Bcl-xL expressing neurons.