The Complexity of Making Ubiquinone

Ubiquinone (UQ, coenzyme Q) is an essential electron transfer lipid in the mitochondrial respiratorychain. It is a main source of mitochondrial reactive oxygen species (ROS) but also has antioxidant properties. This mix of characteristics is why ubiquinone supplementation is considereda potential therapy for many diseases involving mitochondrial dysfunction. Mutations in the ubiquinone biosynthetic pathway are increasingly being identified in patients. Furthermore, secondary ubiquinone deficiency is a common finding associated with mitochondrial disorders and might exacerbate these conditions. Recent developments have suggested that ubiquinone biosynthesis occurs in discrete domains of the mitochondrial inner membrane close to ER-mitochondria contact sites. This spatial requirement for ubiquinone biosynthesis could be the link between secondary ubiquinone deficiency and mitochondrial dysfunction, which commonly results in loss of mitochondrial structural integrity.