FIGURE 4.

Decomposition of traction forces shown in Fig. 3 (A and B) into their t₁,t₂ (in-plane) and t₃ (out-of-plane) traction components in two dimensions (A) and 2.5D (B). All of the contour maps and color bars represent tractions in Pa. Positive and negative t₃ traction are defined using the local, positive outward normal vector for each upper and lower gel as illustrated in Fig. 2B. Comparison of the two-dimensional and 2.5D traction profiles reveals similar spatiotemporal patterns with significant traction generation in the uropod of the cell. Traction profiles in 2.5D show a significant contribution from the central, nuclear region of the neutrophil against the top surface.