Figure 1.
Redistribution of Forces during CIL
(A) Membrane GFP-labeled NC cells undergoing CIL. Red indicates the protrusion extension (Figure S1E).
(B) Dynamic behaviors of the protrusions toward the contact (green), away from the contact (red), and the length of the cell-cell contact (blue). Beige bar indicates the time when cells collided. Gray bar indicates the time when cells separated. Yellow bar indicates when laser ablation was carried out.
(C, F, H, and J) TFM showing substrate displacement vectors. Cells labeled with membrane RFP are outlined in gray.
(D and G) Average traction at leading edge/free edge (D) and trailing edge/contact (G). n = 17 for single cells and n = 27 for cells in contact. n.s., not significant.
(E) Imbalance of traction at front and rear of a single cell (Pa); orange block indicates when the cell starts to migrate.
(I and K) Traction at contact pointing away from the contact over time in colliding/separating cells. 0 min = first frame of contact for (I), and last frame before separation for (K). Tension across the contact is shown in red.
(L–P) Schematic of cells and frames from movies as indicated. Cells were injected to express membrane RFP (red) and either p120-catenin-GFP to label CCAs (green in L and M) or GFP- FAK to label cell-matrix adhesions (green in N). Bottom row: zoom of cell-cell contact. Ablation area marked with a cyan box. To maintain the same orientation and scale, images in N–P were rotated, zoomed, and the background was filled with black.
(Q) Median value of the length of the cell-cell contact relative to length at the start of laser ablation (0 min). Yellow area shows time of laser ablation. n = 10 for no ablation, CCA ablation, and CMA ablation; n = 8 for cytosol ablation; n = 3 for free membrane ablation.
(R) Percentage of cells that separate within 3 min after ablation.
Scale bars, 20 μm. Line graphs show medians. Bar graphs show means, errors ± SEM. ∗∗∗p ≤ 0.001, ∗∗p ≤ 0.01. (D and G) Mann-Whitney test, (K) Kruskal-Wallis test. See also Figure S1.