Fig. 6. Treatment of cells with FAK siRNAs results in a loss of directional movement. REF52 cells were treated with either luciferase siRNA (A) or FAK siRNA (B). A confluent culture of REF52 cells was wounded using a pipette tip, and cell migration into the wound was monitored by time-lapse microscopy. Images correspond to photographs taken at the indicated times following the scraping of the monolayer. In A, the cells develop broad lamellipodia (arrows) as they move into the wound. In B, cell `a' has migrated into the wound yet did not release its trailing edge, and cell `b' eventually has become elongated as it develops two leading edges, one moving toward the wound and the other away from it. Both cells lack broad lamellipodia. See Movies 1 and 2 in supplementary material.