Western blot analysis with antibodies against p-ERK and total ERK suggested that H2-GMZ-mediated inhibition of cell proliferation occurs at least in part through inhibition of the MEK–ERK pathway (Fig. 2D), which is consistent with previous work that showed that cAMP-driven ERK activation stimulates ADPKD cell proliferation (13, 14, 19, 71). The gene discussed is MAPK1; the disease is autosomal dominant polycystic kidney disease.