Fig. 2.

Epithelial cell involvement in experimental models of dRTA secondary to vH⁺ATPase dysfunction. ATP6V0A4 knockout (KO) mice present with signs of dysfunction of proximal tubule cells, while ATP6V1B1 KO mice show an indirect involvement of cortical and medullary principal cells secondary to A-IC dysfunction. Finally, genetic ablation of ATP6AP2 shows a critical role of medullary thick ascending limb and principal cells together with A-IC. This latter vH⁺ATPase subunit has not been identified yet in humans as a cause of dRTA.