Fig. 7. Inhibition of LPA-stimulated phagocytosis of soft particles by dominant negative Rac1. (a) Macrophages microinjected with N17Rac1 or buffer were fed with opsonized hard or soft beads, with or without the additional incubation with LPA. The phagocytic index for each condition was determined with a total of 70-100 cells in three independent experiments. (b) Macrophages microinjected with C3 transferase or buffer were fed with opsonized beads, with or without the additional incubation with LPA. The phagocytic index for each condition was determined with a total of 120-150 cells in three independent experiments. Error bars indicate the standard deviation between experiments. Efficacy of the C3 transferase was confirmed by the induction of cell retraction upon microinjection into serum-starved REF-52 cells. Bar, 10 µm.