RhoG is necessary for the formation of lamellipodia and invadopodia. A) Fluorescence micrographs illustrating the effects of knockdown of RhoG and Rac1 on the formation of lamellipodia and ruffles. SNB19 glioblastoma cells were transfected with siRNAs directed against luciferase (control, 20 nM), RhoG-2 (10 nM) or Rac1 (20 nM). Two days after transfection, cells were plated on laminin-coated coverslips and serum starved overnight. Subsequently, cells were incubated with DMEM (untreated) or stimulated 4 min with DMEM containing 25 ng/ml HGF and processed as described in Materials and Methods. Scale bar represents 10 μm. Lamellipodia are indicated by an arrowhead. Ruffles are indicated by arrows. B) Quantification of lamellipodia and ruffle formation. Presented are mean values (+/− SEM) for approximately 35 cells per condition. The results shown are representative of two independent experiments. C) RhoG is necessary for invadopodia formation. SNB19 cells were transfected with siRNA (20 nM) directed against luciferase (control), RhoG-2 or Rac1-1. Forty eight hours after transfection, cells were split to a new dish for another 24 hours prior to plating on FITC-gelatin coated coverslips for 16 to 18 hours. Invadopodia formation was determined as described in Materials and Methods. For each condition, 16 (60x) fields were quantified, comprising a total of approximately 30 cells. The results shown represent the means +/− SEM of 5 independent experiments (*p < 0.05 and **p < 0.0005, two-tailed t test).