Fig. 6. Inhibition of ERK1/2 activation reduces lamellipodial stability. (A) WT BMMs in growth medium were pretreated with 1 µg/ml U0126 for 1 hour and plated on to glass-bottomed tissue culture dishes. Time-lapse microscopy was used to monitor cell spreading. Frames from the indicated time points are shown. Arrows indicate lamellipodia. Scale bar: 20 µm. (B) Quantification of the number of lamellipodia per cell observed in the time-lapse movie frames specified. Data are the mean ± s.e.m. of three separate experiments. (C) Representative kymograph of a lamellipodium in a U0126-treated cell. The membrane edge is highlighted (white line).