Figure 4.

Incorporation of Cy3-actin into ruffling lamellipodia induced by activation of Rac. Serum-starved confluent quiescent Swiss 3T3 cells were microinjected with Cy3-actin and constitutively active Rac protein (a, a′, b, and b′) or treated with PDGF (c, c′, d, and d′). At 5 min (a, a′, c, and c′) or 20 min (b, b′, d, and d′) cells were fixed and costained with fluorescein phaloidin to visualize total F-actin. (a–d) Cy3-actin; (a′–d′) fluorescein phalloidin costain of total F-actin. Bar, 5 μm.