Atypical kinase involved in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration. Its substrate specificity is unclear: does not show any protein kinase activity. Probably acts as a small molecule kinase, possibly a lipid kinase that phosphorylates a prenyl lipid in the ubiquinone biosynthesis pathway. Required for podocyte migration. Homodimer; homodimerizes via its transmembrane region. Interacts with COQ6 and COQ7. Interacts with the multi-subunit COQ enzyme complex, composed of at least COQ3, COQ4, COQ5, COQ6, COQ7 and COQ9. Adopts an atypical protein kinase-like fold: while it adopts a core fold similar to that of well-characterized protein kinase-like domains. The KxGQ motif completely occludes the typical substrate binding pocket. Nucleotide-binding opens the substrate binding pocket and flips the active site from inside the hydrophobic core into a catalytically competent, solvent-exposed posture. Belongs to the protein kinase superfamily. ADCK protein kinase family.