Probing the Cell Peripheral Movements by Optical Trapping Technique Fuminori Takahashi, Yukako Higashino, Hidetake Miyata  Biophysical Journal  Volume 84, Issue 4, Pages 2664-2670 (April 2003) DOI: 10.1016/S0006-3495(03)75072-3 Copyright © 2003 The Biophysical Society Terms and Conditions

Figure 1 The experimental system. For details, see text. Top right, the details of the sample chamber: a 1-μm polystyrene bead held in an optical trap (represented by a pair of shaded triangles) was made to contact with the lamellipodium of a fibroblast with movement of the stage. The figure is not drawn to scale. Biophysical Journal 2003 84, 2664-2670DOI: (10.1016/S0006-3495(03)75072-3) Copyright © 2003 The Biophysical Society Terms and Conditions

Figure 2 (a–c) Representative x-t (cyan) and y-t (magenta) traces of a bead obtained at the trap stiffness of 0.024, 0.056, and 0.090pN/nm, respectively. The bold bar indicates the time period where bead contact procedure was performed. Downward arrowheads indicate the type I movement. In a, upward thin arrow indicates the bead motion in the y direction; black arrowhead and black double arrowhead indicate the forward and rearward movements. In b, the bead movements occurred toward the end of the record. In c, the bold arrow indicates the small random motion of the bead. In d, a representative x-t and y-t traces of an adherent bead. In e–g, the vx-t (cyan) and vy-t (magenta) traces derived from the displacement traces in a–c, respectively. Stars in e indicate the parts that are shown with an expanded time scale in h and i, and those in f show the part shown in m. In h–k, the vx-t curves with an expanded timescale obtained at 0.024pN/nm; l and m, at 0.056pN/nm. Abscissa indicates time in seconds. Biophysical Journal 2003 84, 2664-2670DOI: (10.1016/S0006-3495(03)75072-3) Copyright © 2003 The Biophysical Society Terms and Conditions

Figure 2 (a–c) Representative x-t (cyan) and y-t (magenta) traces of a bead obtained at the trap stiffness of 0.024, 0.056, and 0.090pN/nm, respectively. The bold bar indicates the time period where bead contact procedure was performed. Downward arrowheads indicate the type I movement. In a, upward thin arrow indicates the bead motion in the y direction; black arrowhead and black double arrowhead indicate the forward and rearward movements. In b, the bead movements occurred toward the end of the record. In c, the bold arrow indicates the small random motion of the bead. In d, a representative x-t and y-t traces of an adherent bead. In e–g, the vx-t (cyan) and vy-t (magenta) traces derived from the displacement traces in a–c, respectively. Stars in e indicate the parts that are shown with an expanded time scale in h and i, and those in f show the part shown in m. In h–k, the vx-t curves with an expanded timescale obtained at 0.024pN/nm; l and m, at 0.056pN/nm. Abscissa indicates time in seconds. Biophysical Journal 2003 84, 2664-2670DOI: (10.1016/S0006-3495(03)75072-3) Copyright © 2003 The Biophysical Society Terms and Conditions

Figure 3 (a) Schematic drawing of the method to determine f(vmax+). (b) The experimental vmax+-f(vmax+) plot obtained as shown in a. Filled diamonds, trap stiffness=0.024pN/nm; filled squares, 0.056pN/nm; filled triangles, 0.090pN/nm. Biophysical Journal 2003 84, 2664-2670DOI: (10.1016/S0006-3495(03)75072-3) Copyright © 2003 The Biophysical Society Terms and Conditions

Figure 4 A plot of withdrawal versus protrusive velocities. Results obtained under all conditions are plotted. Diamonds, trap stiffness=0.024pN/nm; filled squares, 0.056pN/nm; filled triangles, data in the presence of 50 nM cytochalasin D; filled circles, in the presence of 200 nM cytochalasin D. In the presence of cytochalasin D, trap stiffness was 0.024pN/nm. Biophysical Journal 2003 84, 2664-2670DOI: (10.1016/S0006-3495(03)75072-3) Copyright © 2003 The Biophysical Society Terms and Conditions