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Figure S3. Still images of cells treated with Nap1 or WAVE1 siRNA in low density cultures. Cells were transfected with control, Nap1, or WAVE1 siRNA. These cells were plated at low densities and observed with a time-lapse microscope. Although typical lamellipodia (closed arrowheads) are seen along the peripheries of control RNAi-treated cells, these structures poorly develop (open arrowheads) in Nap1 and WAVE1 siRNA–treated cells. Nap1-depleted cells often exhibit elongated protrusions (arrows). Bar, 50 µm.