Fig. 5. Effects of constitutively active Rho GTPases on the phagocytosis of soft particles. (a) Microinjection of L61Rac1, but not L63RhoA, stimulates the uptake of soft beads. Protein solutions were microinjected into 230 (L61Rac1), 120 (L63RhoA) or 100 cells (buffer control), before the presentation of opsonized soft beads. (b) Rhodamine phalloidin staining of serum-starved REF cells microinjected with L63RhoA reveals strong staining of stress fibers compared with surrounding uninjected cells, confirming the activity of the injected protein. Error bars indicate the standard deviation between three independent experiments. Bar, 10 µm.