Measurement of the strength of the cytoskeleton–integrin bond. The small (0.64 μm-diameter) bead in the lower series of snapshots is held in a calibrated optical trap, whose location is shown by the arrows, near the leading edge of a motile lamellipodium. As the bead is pulled backwards at a constant speed of 60 nm/s, the load on the bond increases until the bond ruptures and the bead returns to the trap centre, as shown in the graph of bead displacement versus time.
Reprinted by permission from Macmillan Publishers Ltd: Jiang et al., Nature 424, 334–7, copyright 2003.
Fig. 14.2 — Measurement of the strength of the cytoskeleton-integrin bond