The diagram shows the production of CoQ within mitochondria, where it transfers electrons to support respiratory energy production in the inner mitochondrial membrane. CoQ is also moved to extra-mitochondrial membranes to scavenge lipid radicals in an FSP1- and NAD(P)H-dependent manner. The mevalonate pathway produces the isoprenoid precursors of CoQ, and the SREBP-SCAP axis functions as the main transcriptional regulator of this pathway. Mitochondrial and cytoplasmic STARD7 isoforms are responsible for CoQ trafficking, and these isoforms are regulated after translation by the mitochondrial proteases PARL and TIM23. The diagram includes labels for various components such as CoQ10(H), ubiquinone; CoQH2, ubiquinol; PLOO, phospholipid peroxyl radical; COP 2, Coat protein complex 2; S1P, site-1 protease; and S2P, site-2 protease.
Dual roles of CoQ and the regulation of its biosynthesis and distribution. CoQ is produced within mitochondria, where it transfers electrons to support respiratory energy production in the inner mitochondrial membrane. Conversely, CoQ is moved to extramitochondrial membranes to scavenge lipid radicals in an FSP1- and NAD(P)H-dependent manner. The mevalonate pathway produces the isoprenoid precursors of CoQ, and the SREBP-SCAP axis functions as the main transcriptional regulator of this pathway. Mitochondrial and cytoplasmic STARD7 isoforms are responsible for CoQ trafficking, and these isoforms are regulated after translation by the mitochondrial proteases PARL and TIM23. CoQ10 is shown as the primary form of CoQ in humans. CoQ10(H), ubiquinone; CoQH2, ubiquinol; PLOO, phospholipid peroxyl radical; COP II, coat protein complex II; S1P, site-1 protease; S2P, site-2 protease.