Fig. 5.

ACR directly inhibits EGFR activation by modification of C797. A and B: HBE1 cells were exposed to ACR (30 min) and stimulated with EGF (100 ng/ml) for 10 min for analysis of activation of EGFR, STAT3, and ERK 1/2 by Western blot as in Fig. 4. Representative blots (A) and densitometry data from 2 independent experiments (B) are shown. *P < 0.05 compared with untreated control; #P < 0.05 compared with control EGF treatment. C: effect of ACR treatment (30 min) of recombinant EGFR kinase domain on tyrosine kinase activity. D: kinase activity analysis of wild-type and C797S variant form of EGFR. The kinase activity of wild-type enzyme was significantly reduced due to the effect of ACR while C797S variant's activity remained unchanged. *P < 0.05.