Video 3.
Visualization of WASP and Arp2/3 in cell spreading. Wild-type AX3 cells and SCAR-null cells were transfected with both GFP-WASP (green) and the Arp2/3 complex marker mRFP-ArpC4 (red). Cells were incubated overnight in low fluorescent medium to reduce autofluorescence. Cells were then resuspended and transferred onto a fresh glass-bottom dish. Time-lapse images were captured while the cells were still dropping out of suspension and adhering and spreading on the glass substratum at one frame per 2 s (f/s) on a microscope (Eclipse TE2000-U) that was fitted with a custom TIRF condenser. A bright-field image of the cell is overlaid in blue.