Fig. 5. HEp2 cells were electroporated with RhoB-G14V cDNA and incubated overnight in medium containing 10% serum before incubation with serum-free medium for 1 hour. Cells were then stimulated with EGF in the presence of anti-EGF receptor-gold (10 nm) for 45 minutes (a) or 90 minutes (b and c). RhoB-G14V-expressing cells were identified by immuno-labelling with anti-myc antibody (5 nm gold). The majority of anti-EGF-receptor gold in RhoB-G14V-expressing cells is found in MVBs, even after 90 minutes of EGF stimulation. RhoB-G14V is found on EGF-receptor-containing MVBs as well as on small vesicles and/or tubules in the vicinity of MVBs. Scale bar, 100 nm.