Atypical kinase involved in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration (PubMed:24270420, PubMed:36302899, PubMed:38425362). Its substrate specificity is still unclear: may act as a protein kinase that mediates phosphorylation of COQ3 (PubMed:38425362). According to other reports, acts as a small molecule kinase, possibly a lipid kinase that phosphorylates a prenyl lipid in the ubiquinone biosynthesis pathway, as suggested by its ability to bind coenzyme Q lipid intermediates (By similarity). However, the small molecule kinase activity was not confirmed by another publication (PubMed:38425362). Required for podocyte migration (PubMed:24270420). {ECO:0000250|UniProtKB:Q8NI60, ECO:0000269|PubMed:24270420, ECO:0000269|PubMed:36302899, ECO:0000269|PubMed:38425362}. This is the function of COQ8B (coenzyme Q8B, Ensembl gene identifier ENSG00000123815).