Figure 3

Without dynacortin, chemotaxing cells send out pseudopods in more diverse directions. A. Four snapshots from an Ax2 control cell moving towards a needle. The images come from the enclosed video (though the images are rotated to make it easier to fit). They show the cell outline (white), the skeleton (green) and the tips (extensions in red, retractions in blue) in each image. B. The tip angles (relative to the gradient) as a function of time for three representative Ax2 control cells (blue, green and red denote individual cells). Extending and retracting tips are marked with circles and triangles, respectively. Note that leading tips cluster near the 0° angle. C. The extending (red bars) and retracting (blue bars) tip angle distribution for all Ax2 control cells considered (27 cells, 1 606 frames). The black line is a Gaussian curve fit of the extending tips. The mean is at 1.2°, with standard deviation 30.6°. D. Four frames from a video of a chemotaxing Ax2:dynhp cell. E. The tip angles (relative to the gradient) as a function of time for three Ax2:dynhp cells. F. The tip angle distribution (as in C) for all Ax2:dynhp cells (10 cells, 921 frames). The Gaussian fit (black line) yields a mean ± SD of -8.0° ± 65.9° at the front relative to the chemoattractant gradient. G,H. The tip angle distributions for Ax3 control (G) (-2.7° ± 52.8°, n = 29 cells, 2 455 frames) and Ax3:dynhp (H) (-5.5° ± 74.6°, n = 13 cells, 1 100 frames).