Fig. 9. EGFR internalization is blocked by NSH3m-YFP at the step of membrane fission. EGF-stimulated COS-7 cells co-expressing NSH3m-YFP and EGFR-CFP were fixed then either permeabilized (A,B) or left unpermeabilized (C,D). Cells were immunostained with an antibody against the extracellular domain of EGFR, followed by a TRITC-conjugated secondary antibody (B,D). Bar, 5 µm. (E) EGFR internalization in COS-7 cells overexpressing the indicated YFP chimeric molecules was measured by determining avidin inaccessibility. Assays were performed as described in Materials and Methods. Data shown are representative of three independent experiments.