Figure 5

Overexpression of Met and EGFR is necessary for their activation upon cell adhesion. (a) The expression of Met in A431 cells was reduced to different levels by shRNA. The adhesion-induced activation of Met was analysed by normalization of phospho-Met (p-Met) to its expression level (Met). β-tubulin was used as an internal control. Data (Met and p-Met/Met) are quantified and expressed as percentage relative to the level of the control A431 cells, which is defined as 100%. Values (means ± s.d.) are from three independent experiments. (b) The expression of EGFR in A431 cells was reduced to different levels by shRNA. The adhesion-induced activation of EGFR was analysed by normalization of phospho-EGFR (p-EGFR) to its expression level (EGFR). β-tubulin was used as an internal control. Data (EGFR and p-EGFR/EGFR) are quantified and expressed as percentage relative to the level of the control A431 cells, which is defined as 100%. Values (means ± s.d.) are from three independent experiments. (c) The cells as described in (a) were serum-starved for 24 h and treated with HGF (40 ng/ml) for 10 min. The ligand-induced activation of Met was analysed as described in (a). Data (Met and p-Met/Met) are quantified and expressed as percentage relative to the level of the control A431 cells, which is defined as 100%. Values (means ± s.d.) are from three independent experiments. (d) The cells as described in (b) were serum-starved for 24 h and treated with EGF (100 ng/ml) for 10 min. The ligand-induced activation of EGFR was analysed as described in (b). Data (EGFR and p-EGFR/EGFR) are quantified and expressed as percentage relative to the level of the control A431 cells, which is defined as 100%. Values (means ± s.d.) are from three independent experiments.