Fig. 5. Colocalization studies of linker-GFP, G2A-GFP and C3S-GFP with caveolin 1. COS-7 cells were transfected with the linker-GFP (upper panels), G2A-GFP (middle panels) or C3S-GFP (lower panels) constructs and analyzed 36 hours post-transfection (A). The GFP fluorescence (left panels) was obtained after excitation at 488 nm, whereas the Cy3 fluorescence (middle panels) was obtained after excitation at 543 nm. The right panels show the merge of both fluorescence signals. Bar, 50 µm. The physical interaction of caveolin-1 with the GFP chimeras was analyzed in pull-down experiments (B). COS-7 cells transfected with the linker-GFP construct, C3S-GFP construct or mock-transfected were lysed and immunoprecipitated with anti-caveolin-1 antibodies (left panel) or with anti-GFP antibodies (right panel) as described in the Materials and Methods. The immunoprecipitated samples were then analyzed (immunodetected, I.D.) with anti-GFP, anti-caveolin-1 or anti-Gq antibodies as outlined in the figure.