A PIP 2 substitute mediates voltage sensor-pore coupling in KCNQ activation

KCNQ family K + channels (KCNQ1-5) in the heart, nerve, epithelium and ear require phosphatidylinositol 4,5-bisphosphate (PIP 2 ) for voltage dependent activation. While membrane lipids are known to regulate voltage sensor domain (VSD) activation and pore opening in voltage dependent gating, PIP 2 was found to interact with KCNQ1 and mediate VSD-pore coupling. Here, we show that a compound CP1, identified in silico based on the structures of both KCNQ1 and PIP 2 , can substitute for PIP 2 to mediate VSD-pore coupling. Both PIP 2 and CP1 interact with residues amongst a cluster of amino acids critical for VSD-pore coupling. CP1 alters KCNQ channel function due to different interactions with KCNQ compared with PIP 2 . We also found that CP1 returned drug-induced action potential prolongation in ventricular myocytes to normal durations. These results reveal the structural basis of PIP 2 regulation of KCNQ channels and indicate a potential approach for the development of anti-arrhythmic therapy.