FIGURE 8.

Immunoblockade of EGFR ectodomain inhibits EGFR activation. A431 cells were exposed to EGF (10 ng/ml or 1.67 nm, 10 min), TSP1 (30 μg/ml or 214 nm, 0.5 h), E123 (3.8 μg/ml or 214 nm, 1 h), or media alone, each in the presence or absence of the EGFR ectodomain-blocking antibody GR13L or a species- and isotype-matched antibody control B7-1. The cells were lysed, and the lysates were processed for phospho-EGFR (Tyr-1068) immunoblotting. The blots were stripped and reprobed for β-tubulin to indicate protein loading and transfer. IB, immunoblot; IB^*, immunoblot after stripping. This blot is representative of >2 independent experiments.