Fig. 4. Caveolin-3 binds to TRPC1 and regulates its plasma membrane localisation. (A) C2 cells were transfected with either TRPC1-CFP, caveolin-3–YFP or the combination of both plasmids. Caveolin-3–YFP targeted to the plasma membrane when transfected either alone or with TRPC1. However, when TRPC1-CFP was transfected alone, it did not target to the plasma membrane and rather showed a diffuse cytoplasmic distribution. TRPC1 was only able to target to the membrane when co-transfected with caveolin-3–YFP (arrows). (B) TRPC1 binds to caveolin-3 (FRET – photobleaching of acceptor). TRPC1-CFP and caveolin-3–YFP were co-transfected into C2 myoblasts. A selected region of caveolin-3–YFP was chosen and photobleached using the 514 nm laser line (100% power). CFP fluorescence increased 21% (FRET efficiency) upon YFP photobleaching. Scale bars: A, 10 µm; B, 5 µm.