Direct molecular interaction of caveolin-3 with KCa1.1 channel in living HEK293 cell expression system

► Caveolin-3 (cav3) directly interacts with large conductance Ca2+ activated K+ (BKCa) channel. ► Single molecular images were obtained by total internal reflection fluorescent (TIRF) microscopy. ► Direct molecular interaction was detected as fluorescent resonance energy transfer (FRET). ► Cav3 binds to a specific C terminus domain of BKCa channel. ► The interaction with cav3 regulates BKCa channel trafficking to cell surface and their accumulation to caveola.