FIGURE 4.

The association of DOCK1 with PA is required for dorsal ruffle formation. A, following expression of WT or mutant DOCK1-GFP (D1–3A or D1–9A) in D1^d/d MEFs, cells were stimulated with PDGF for 7 min. Formation of dorsal ruffles was defined by staining cells with phalloidin. Scale bar, 50 μm. B, quantification of data from A. The data are expressed as percentages of cells with dorsal ruffles (means ± S.E.) and are from three separate experiments. For each category, more than 200 cells were analyzed. **, p < 0.01. C, following expression of WT or mutant DOCK1-GFP (D1–3A or D1–9A) in HEK293T cells, cell extracts were subjected to Rac activation assay. D, following expression of WT or mutant DOCK1-GFP (ΔDHR-2, V1534A, or ΔC113) in D1^d/d MEFs, cells were stimulated with PDGF for 7 min. Formation of dorsal ruffles was defined by staining cells with phalloidin. Scale bar, 50 μm. E, quantification of data from D. The data are expressed as percentages of cells with dorsal ruffles (means ± S.E.) and are from four separate experiments. For each category, more than 200 cells were analyzed. Statistical analysis was performed by using analysis of variance followed by Bonferroni correction. **, p < 0.01. F, low magnification images of D1^d/d MEFs stimulated with PDGF after expression of WT or mutant DOCK1. Formation of peripheral (arrowheads) and dorsal ruffles (arrows) was defined by staining cells with phalloidin. Scale bar, 100 μm.