Lipid-binding protein involved in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration. Binds a phospholipid of at least 10 carbons in each acyl group. May be required to present its bound-lipid to COQ7. Cofactor biosynthesis; ubiquinone biosynthesis. Homodimer. Interacts with COQ7. Structurally similar to the bacterial FadR protein (fatty acid metabolism regulator protein). The disease is caused by variants affecting the gene represented in this entry. Belongs to the COQ9 family.