Calcium Induces Mitochondrial Oxidative Stress Because of its Binding to Adenine Nucleotide Translocase

Several studies have demonstrated that the mitochondrial membrane switches from selective to non-selective permeability because of its improved matrix Ca²⁺ accumulation and oxidative stress. This process, known as permeability transition, evokes severe dysfunction in mitochondria through the opening of a non-specific pore, whose chemical nature is still under discussion. There are some proposals regarding the components of the pore structure, e.g., the adenine nucleotide translocase and dimers of the F1 Fo-ATP synthase. Our results reveal that Ca²⁺ induces oxidative stress, which not only increases lipid peroxidation and ROS generation but also brings about both the collapse of the transmembrane potential and the membrane release of cytochrome c. Additionally, it is shown that Ca²⁺ increases the binding of the probe eosin-5-maleimide to adenine nucleotide translocase. Interestingly, these effects are diminished after the addition of ADP. It is suggested that pore opening is caused by the binding of Ca²⁺ to the adenine nucleotide translocase.