Fig. 3.
The stall force of a single retracting filopodium differs for beads coated with Shigella-membranes and carboxylated beads. (A,B) Plots of the displacement of Shigella-membrane-coated beads (A), or of the force applied by the OTs on beads (B) versus time. Trap stiffness: 24 pN/µm (blue) or 60 pN/µm (red). White dashed lines: stall force position. (C) Stall forces associated with filopodial retraction, recorded at kx ranging between 24 and 80 pN/µm, were determined for beads functionalized with Shigella membranes (red; 14 determinations, 12 independent experiments), carboxyl groups (green; 12 determinations, 10 independent experiments) or Invasin at saturation (black; 20 determinations, 13 independent experiments). Horizontal lines represents the mean stall force. **P<0.001.