Fig. 7. BFA treatment inhibits the caveolae-mediated endocytosis of CTX to the Golgi apparatus but not of AMF to the smooth ER. NIH-3T3 cells were pretreated with 10 µg/ml BFA for 30 minutes at 37°C and then incubated in the presence of BFA with 5 µg/ml FITC-CTX for 30 minutes at 37°C (A-F) or with 50 µg/ml AMF-FITC for 60 minutes at 37°C (G-I). Cells incubated with FITC-CTX were labeled with either anti-GM130 (B) or anti-TfR (E) antibodies and merged confocal images present FITC-CTX in green and GM130 (C) or TfR (F) in red and colocalization in yellow. Internalized AMF-FITC was revealed with rabbit anti-FITC (G) and AMF-R tubules with anti-AMF-R mAb (H) followed by the appropriate secondary antibodies. The merged confocal image (I) presents the AMF in green and AMF-R in red and colocalization in yellow. In the presence of BFA, CTX is delivered to the endosomes but not to Golgi fragments, whereas AMF is still delivered to AMF-R-labeled smooth ER (arrows). Bar, 8 µm.