Fig. 5.

EGFR activity is required for HGF-induced phosphorylation of Met receptors and activation of Erk5. MDA-MB-231 breast cancer cells were pretreated with AG1478 (EGFR tyrosine kinase inhibitor) for 30 min prior to HGF stimulation for 15 min. Cells were harvested and Western blotted with antibodies against phospho-Met receptor, total Met receptor, and total Erk5. The up-shifted higher migrating band in the total Erk5 blot represents phosphorylated (i.e., on multiple sites) and activated Erk5