Fig. 3. Inhibition of internalization of EGF-coated microspheres in the presence of the EGFR-specific tyrosine kinase inhibitor PD153035. (A) Stereo-images of GFP fluorescence of E-CHO cells 5 minutes after contact with EGF-coated microspheres. In contrast to Fig. 1, the apical face of the cells is oriented towards the observer. (B) Examples of plasma membrane morphology of E-CHO cells in contact with EGF-coated microspheres after 5 minutes incubation with the microspheres. The locations of the enlarged regions of interest 1-3 are boxed in the overview, showing one confocal slice. A set of three orthogonal sections is given in each case; the positions of the sections are indicated. The sampling frequency along the optical axis was 0.3 µm. The fluorescence stacks were deconvoluted as described in Materials and Methods.