FIGURE A4.
Predictions of force versus time for retraction of a PMN from the BFP at fixed speeds (2 μm/s, 4.5 μm/s, 10 μm/s), corresponding to the lowest three loading rates of data in Fig. 7 B, i.e., 〈rf〉 ∼ 240 pN/s, 650 pN/s, and 1480 pN/s. The BFP force constant was kf = 0.5 pN/nm. A slow cell-body response described by, kD ∼ 0.04–0.05 pN/nm and tD ∼ 1.2–1.4 s, was needed to match the loading rates measured in the experiments up to the point of membrane separation (stars), accounting for the weak dependence on pulling speed seen in Fig. 5 A.