Fig. 9. Cell migration speed is a function of ligand release rate and ERK phosphorylation. ERK phosphorylation was measured from triplicate lysates using a BioPlex assay (see supplementary material Fig. S5 for ERK data alone). The parental cells were lysed after a 2-hour incubation with serum-free media (SFM) or exogenous EGF (0.2 and 2.0 nM). ECT cells were lysed after a 2-hour incubation in fresh serum-free media. In addition, TCT cells were lysed after a 2-hour incubation in serum-free media or increasing concentrations of batimastat (0.12, 0.33, 0.86 and 10.00 µM Bat). (A) Cell migration speed (shown in Fig. 7, error represents s.e.m., and n >200 cells) is plotted as a function of ERK phosphorylation (error represents standard deviation from triplicate lysates). (B) Parental and TCT cells were pre-incubated with multiple concentrations of the MEK inhibitor PD98059 (0.04, 0.20, 1.00, 5.00 and 25.00 µM PD) for 30 minutes. Parental cells were then stimulated with 2 nM of EGF under the same PD conditions. Cell migration speed is shown as a function of ERK1/2 phosphorylation measured at 2 hours after exogenous stimulation (see supplementary material Fig. S6 for ERK and migration data separately).