Extended Data Fig. 10: Traction force distributions are asymmetric and require myosin-2.
From: Self-generated gradients steer collective migration on viscoelastic collagen networks
a. Integrated 2D tractions from clusters on PAA + thin collagen network or monomeric collagen, n=54, 69 clusters, N=3, 3 independent experiments. ***p < 0.001 for Welch’s t-test. b. Integrated traction force vs. cluster area on PAA + collagen network or monomeric collagen. Solid lines: power-law fits. c. 3D displacements of a cluster on PAA gel + thin collagen network with blebbistatin. Black arrows: xy displacements. Color scale: z displacements. d. Mean radial traction linescans from c. e. Summed displacements before/after blebbistatin treatment, n=11 clusters, N=1 independent experiment. ***p < 0.001 for Welch’s t-test. f. Micrographs of clusters following blebbistatin treatment. Scale Bar: 100μm. HH:MM. g. Micrographs of mCherry-LifeAct A431 cells. Red arrow: migration direction. Lower Panel: PIV vectors of actin flows in the cortical region. Scale bar: 20μm. Scale vector: 0.05μm/min. MM:SS. See also Supplementary Video 22. h. Mean actin flow speeds with respect to migration direction for n=10 clusters, N=3 independent experiments. ***p < 0.001 for Welch’s t-test. i. Radial histogram of summed PIV vector angle with respect to the migration direction (red arrow). P-value: Rayleigh test of uniformity. j. Plot of traction peak asymmetry (Front/Back). Solid circles: all binned data (mean ± SEM). Line: linear fit (raw data). Data represents n=54, 104 clusters/single cells, N=3, 3 independent experiments. k,l. Traction force magnitudes (total (k) or projected along migration axis (l)) for the cluster in Fig. 6a. Lower panels: Unfolded radial linescans with respect to the cluster front. Scale bars: 20μm. m,n. Linescans of tractions along migration axis (absolute values in n). Dots: raw values. Lines: smoothed data.
