Figure 5

Effects of VPA on individual cell motility by modulation of signal transduction upstream of Erk1/2. (a) Micrographs of L929 cells stably expressing or not expressing constitutively active Ras (caRas) and grown in the absence or presence of VPA (3 mM, 48 h). (b) Representative immunoblot showing the degree of Erk1/2 phosphorylation in cells grown in the presence or absence of VPA (3 mM, 48 h). (c) Bar graph showing the mean-cell speed of cells grown in the presence or absence of VPA (3 mM, 48 h). (d) Bar graph showing the mean-cell speed of L929 cells transiently expressing or not expressing constitutively active MEK2 (caMEK2). Cells grown in the presence or absence of VPA (3 mM, 4 h) were recorded 48 h after transfection. Data presented in c and d are from cells recorded for 50 min at 10 min intervals. Results were normalized to the corresponding controls from four individual experiments. (e) Representative immunoblot showing the expression of Ras in BT4Cn cells transiently expressing or not expressing dominant-negative Ras (dnRas). Lysates were prepared 48 h after transfection. (f) Bar graph showing the mean-cell speed of BT4Cn cells grown in the presence or absence of VPA (3 mM, 4 or 24 h) and recorded for 20 min at 2 min intervals (48 h after transfection). Results were normalized to the corresponding controls from 6 individual experiments. (g) Representative immunoblot showing the degree of Erk1/2 phosphorylation in BT4Cn cells grown in the presence or absence of VPA (3 mM, 48 h) and treated or untreated with 25 μM PD98059 for 1 h. (h) Bar graph showing the mean-cell speed of BT4Cn cells grown in the presence or absence of VPA (3 mM, 48 h) and treated or untreated with 25 μM PD98059 for 1 h. Recordings were performed for 20 min at 5 min intervals. Results were normalized to the corresponding controls from eight individual experiments.