Figure 5.

VavΔDH does not act by sequestering endogenous Rac protein or inhibiting Rac-induced actin polymerization. Quiescent serum-starved S3T3 fibroblasts were microinjected with biotin dextran (A and B), or cDNAs encoding HA-tagged Tiam1 and either empty vector (C and D), myc-tagged VavΔDH (E–G), or myc-tagged N17Rac (H–J). Cells were stained for F-actin (B, D, F, and I), HA-tagged constructs (C, E, and H), and myc-tagged constructs (G and J). Representative images from three independent experiments are shown. (K) Quantitation of cells showing a ruffling phenotype after expression of the indicated constructs. Data shown are the mean ± SEM of at least three independent experiments. Bar, 10 μm.