Figure 7.

GC-A is required for PDGF-induced lamellipodium formation. A, PDGF (20 ng/ml for 30 min) induced the formation of lamellipodia (indicated by arrowheads) in control siRNA-treated cells at the edge of the wound. GC-A siRNA treatment blocked PDGF-induced lamellipodium formation. Data are representative of three to four similar experiments. B, Quantification of the data from experiments in A. C, GC-A RNAi treatment inhibited the formation of lamellipodia induced by HA-tagged constitutively active Rac1 [Rac1(G12V)]. Infected cells were identified with anti-HA antibody immuno-staining (inserts). Data are representative of three to four similar experiments. D, Quantification of the data from experiments in C. E, While PDGF induced persistent lamellipodia (indicated by arrowheads), ANP (10 μM) induced transient formation of lamellipodia (at 10 min). F, Cells were fixed after treated with or without PDGF (20 ng/ml for 2 hours) after wounding and stained with anti-tubulin antibodies (Red), anti-pericentrin antibodies (to visualize MTOC)(Green), and Hoechst (to visualize the nucleus)(Blue). Left panels: low magnification. Right panels: high magnification. The large arrow indicates the direction of the wound. G, The percentage of cells at the wound edge with their MTOC facing the wound was measured. A minimum of 100 cells were scored. H, Schematic diagram of the activation of membrane-bound GCs by intracellular signals. Error bars show mean ± s.d., **, P < 0.001 (Student’s t-test).