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. In the kidney, expressed in glomeruli, predominantly in podocyte foot precesses, as well as in proximal tubules and collecting ducts (at protein level). 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.