Induction of the intrinsic apoptosis pathway in insulin-secreting cells is dependent on oxidative damage of mitochondria but independent of caspase-12 activation

► Caspase-9 is not a target of the ER-specific caspase-12 in insulin-producing cells. ► Activation of caspase-12 is not involved in cytokine-induced beta cell apoptosis. ► Cytokines induce beta cell death by ROS-mediated mitochondrial damage. ► Mitochondrially located catalase prevents ROS-induced damage of mitochondrial structures.