BCL-2 improves oxidative phosphorylation and modulates adenine nucleotide translocation in mitochondria of cells harboring mutant mtDNA.

Members of the BCL-2-related antiapoptotic family of proteins have been shown previously to regulate ATP/ADP exchange across the mitochondrial membranes and to prevent the loss of coupled mitochondrial respiration during apoptosis. We have found that BCL-2/BCL-x(L) can also improve mitochondrial oxidative phosphorylation in cells harboring pathogenic mutations in mitochondrial tRNA genes. The effect of BCL-2 overexpression in mutated cells was independent from apoptosis and was presumably associated with a modulation of adenine nucleotide exchange between mitochondria and cytosol. These results suggest that BCL-2 can regulate respiratory functions in response to mitochondrial distress by regulating the levels of adenine nucleotides.