FIGURE 2.

Forced dimerization of chiΔEGFR-NLS1 restores activity of ΔEGFR-NLS1. A, biochemical fractionation and Western blot analysis of U87-ΔEGFR and LN428-ΔEGFR cells after AG1478 treatment. Quantitation and statistical analysis of Western blotting are shown in supplemental Fig. S4, C and D. B, immunoprecipitation (IP) followed by Western blot (WB) analysis in U87 stable cells for total phosphotyrosine as well as EGFR-specific phosphoresidues. Quantitation and statistical analysis of Western blotting are shown in supplemental Fig. S4, E–G. C, schematic representation showing the mode of action of chiΔEGFR. D, stable expression of chiΔEGFR and chiΔEGFR in U87 cells. Actin was used as a loading control. E, nuclear and non-nuclear fractions from U87 stable cells after stimulation with either EGF or AP20187 were analyzed by Western blotting for FK506 binding protein (FKBP). Lamin B and tubulin served as markers for nuclear and non-nuclear fractions, respectively. Quantitation and statistical analysis of Western blotting are shown in supplemental Fig. S4H. F, confocal analyses of U87 stable cells stimulated with either EGF or AP20187. Cells were immunostained using pEGFR (Tyr-1068) antibody (green) and EGFR antibody (red). Nuclei were counterstained using Topro3 (blue). CHO, Chinese hamster ovary.