MAP2K7 and autosomal dominant polycystic kidney disease: As ADPKD cells can be rescued by increasing intracellular Ca2+ levels [24] and cAMP-dependent activation of the B-Raf/MEK/ERK pathway is thought to be the key event underlying the aberrant cell proliferation in PKD [48], the PAC+ATRA-induced intracellular Ca2+ restoration and subsequent ERK inhibition can be considered the potential therapeutic mechanism for ADPKD.