Targeting the Protein–Membrane Interface Enables Design of Long-Acting CFTR Potentiators

Many therapeutically relevant membrane proteins possess druggable sites at the lipid-protein interface, but principles guiding ligand design for these sites are not well-defined. CFTR potentiators, a clinically validated drug class for cystic fibrosis, offer a compelling model for exploring membrane-targeted design principles, as their efficacy depends on sustained intramembrane binding to prolong channel opening and chloride conductance. Here, we systematically modified the lipophilic substituent of the CFTR potentiator ABBV-974 and identified an analog that confers markedly increased functional residence time, as measured by delayed current decay after compound washout in patch-clamp assays. Kinetic analysis incorporating the physicochemical properties of the lipophilic substituents suggests that this increased kinetic stability may arise from an increased residence time in the cell membrane, consistent with qualitative results of molecular dynamics simulations. These results establish a structure-function link between membrane-facing ligand modifications and functional target engagement and potentially offer generalizable strategies for designing probe molecules and drugs that stably engage lipid-exposed binding sites on membrane proteins.