Lipid-binding protein involved in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration (PubMed:25339443). Binds a phospholipid of at least 10 carbons in each acyl group. May be required to present its bound-lipid to COQ7 (By similarity). Cofactor biosynthesis; ubiquinone biosynthesis. Homodimer. Interacts with COQ7. Structurally similar to the bacterial FadR protein (fatty acid metabolism regulator protein). Encephalomyopathy due to a widespread coenzyme Q deficiency and accumulation of demethoxyubiquinone. Lethality between 3 and 6 months of age, due to neuronal death and demyelinization with severe vacuolization and astrogliosis in the brain. Belongs to the COQ9 family.