CAMK4 and autosomal dominant polycystic kidney disease: To determine whether pharmacologic inhibition of CaMK4 reduces mTOR-mediated proliferation of ADPKD cells, we tested KN-93, a cell-permeable inhibitor that antagonizes the binding of Ca2+/CaM to CaMK4 (Koga et al., 2014a; Pellicena and Schulman, 2014; Maeda et al., 2018).