The isoprene tail is synthesized from farnesyl pirophosphate by PDSS1/PDSS2 and condensed to the 4HB ring by COQ2. The ring in processed in CoQ by COQ3-7. ADCK3/CABC1 (COQ8) regulates CoQ biosynthesis through phosphorylation of COQ3, COQ5 and COQ7. 