Movie 5

MDA-MB-231 cell labeled with (red) CellMask and embedded in (green) fluorescently labeled collagen I imaged shortly after completion of collagen gelation (t = 36 min after collagen embedding). The cell shows initial attachment to and pulling of a collagen fiber by a single bleb (white arrows). Images were taken every 10 seconds. Length of movie is 560 seconds. Movie is played back at 7 frames/s. Frames from this movie are also shown in Fig. 7A in the main text. Scale bar = 10 μm.