Dyn2-GFP localizes to the bulb and not the neck of caveolae. (A) SIM image of a Dyn2-GFP-Cav1-mCh cell transiently expressing ΔNΔEH EHD2-BFP. Yellow arrows highlight Dyn2-GFP localization to Cav1-mCh at the tip of membrane tubes. Insets show magnification of the indicated area. Scale bar, 2 or 0.4 μm for magnification. The experiment was repeated three times. (B) Quantification of the fluorescent area of ΔNΔEH EHD2-BFP–positive tubes or Cav1-mCh–positive spots that were overlapping with Dyn2 fluorescence. Data are shown as scatter dot plot, mean ± SEM from three cells. Significance was assessed using t test, ****P ≤ 0.0001. (C) Apparent FRET efficiency between GFP and mCh fluorophores in GFP-EHD2-Cav1-mCh cells, Dyn2-GFP-Cav1-mCh cells, or Cav1-mCh transiently expressing Cavin1-GFP. ROIs of structures positive for only GFP (green) or GFP and Cav1 (orange) were used to calculate the apparent FRET efficiency. Significance was assessed using t test, ****P ≤ 0.0001.