Fig. 5. The ErbB receptor homo- and heterodimers formed in ER. NIH3T3 cells co-expressing the BiFC constructs indicated were serum-starved, and then treated with (+) or without (–) 10 µg/ml BFA for 8 hours at 37°C. The cells were fixed with methanol-acetone and immunostained with anti-calnexin antibody, followed by incubation with Cy3-conjugated secondary antibody. Nuclei were also stained with Hoechst 33342. The cells were observed by confocal microscopy for calnexin (red), Venus (green) or Hoechst 33342 (cyan) fluorescence. Bars, 10 µm.