Figure 5.

Basal EGF-stimulated ERK phosphorylation in NHK is dependent upon ErbB1. Growth factor-deprived NHKs were pretreated for 90 min at 37°C in fresh basal M154 with either the ErbB1 blocking antibody 225 IgG (5 μg/ml), or PBS (control), and then stimulated with 100, 10, or 1 ng/ml EGF for 10 min at 37°C. After lysate preparation and Western blotting, replicate blots were decorated with the antibodies indicated to the right of the autoradiograms. The arrowhead indicates the mobility of ErbB1 (170–180 kDa). The result shown is from a single experiment, and is representative of three independent experiments yielding similar results.