Fig. 3. Ext/R4 localizes with the Golgi marker GM130 in a BFA-sensitive juxtanuclear region, whereas R4wt localizes to a BFA-resistant juxtanuclear compartment. COS-1 cells transfected with Ext/R4 (first and second rows) or R4wt (third and fourth rows) were fixed after pretreatment with 2 µg ml^–1 BFA for 3 hours (second and fourth rows) or without BFA (first and third rows). The cells were double labeled with anti-FGFR4 antibodies and secondary FITC-conjugated antibodies (first column) and with anti-GM130 antibodies and rhodamine-conjugated secondary antibodies (second column), and analysed by confocal microscopy. Yellow color in the merged images (third column) indicates co-localization. Scale bar, 10 µm.