PDE4A and cyst: Indeed, MR‐L8 inhibited cyst development evoked by photoactivation of cilia‐bPAC (Figs 4H and I, and EV2E and F) and also by Forskolin (Fig EV2G and H), demonstrating that PDE4 long isoforms predominantly control cyst growth by regulating cAMP signaling in the primary cilium.