Fig. 2.

Uniaxial load causes a rapid switch to bleb-driven migration. (A) Rapid induction of blebbing by uniaxial loading of migrating cells. Frames from a movie timed with respect to the start of loading (t = 0); blebs are indicated by an asterisk (*). (Scale bar: 10 μm.) (B) Time course of bleb induction by load. At the Top is shown a typical loading regime with a small up-tick as the plunger first touches the agarose followed by a 15-s ramping of load to 400 Pa. At the Bottom is shown the bleb frequency, with blebs binned into 1-s intervals and scored at the time they first appear (typically, they are fully expanded in one frame of the movie). Aggregation-competent Ax2 cells expressing the F-actin reporter ABD120-GFP were filmed at 2 frames per s under a 0.5% agarose overlay (n = 17 cells).