ABC1

The ABC1 group, also known as the ADCK or COQ8 family, contains atypical protein kinases whose catalytic domains resemble prokaryotic kinases more than the canonical human eukaryotic protein kinase fold. Mammalian members include ADCK1, ADCK2, and the coenzyme Q-binding proteins COQ8A/ADCK3 and COQ8B/ADCK4, all localized to mitochondria. COQ8A and COQ8B function within the CoQ (ubiquinone) biosynthesis complex, stabilizing and phosphorylating partners of the synthome rather than propagating classical signaling cascades, and loss-of-function mutations in COQ8A cause cerebellar ataxia while COQ8B mutations cause steroid-resistant nephrotic syndrome, both forms of primary CoQ10 deficiency that respond to CoQ supplementation. Recombinant ABC1-family proteins support studies of mitochondrial bioenergetics, atypical kinase catalysis, and CoQ-deficiency disease modeling.