Migration of PIP 2 lipids on voltage-gated potassium channel surface influences channel deactivation

Abstract

Published studies of lipid-protein interactions have mainly focused on lipid binding to an individual site of the protein. Here, we show that a lipid can migrate between different binding sites in a protein and this migration modulates protein function. Voltage-gated potassium (Kv) channels have several potential binding sites for phosphatidylinositol-4,5-bisphosphate (PIP 2). Our molecular dynamics (MD) simulations on the KCNQ2 channel reveal that PIP 2 preferentially binds to the S4-S5 linker when the channel is in the open state while maintains a certain probability of migrating to the S2-S3 linker. Guided by the MD results, electrophysiological experiments using KCNQ2, KCNQ1, and hERG channels show that the migration of PIP 2 toward the S2-S3 linker controls the deactivation rate of the channel. The data suggest that PIP 2 can migrate between different binding sites in Kv channels with significant impacts on channel deactivation, casting new insights into the dynamics and physiological functions of lipid-protein interactions.