Figure 10.

The fibroblast lamellum pulls rearward and the tail pulls forward. These images were focused on the substratum to show crinkles located underneath the cell body and wrinkles extending out from the cell; the outline of the cell is taken from images acquired 15 s later at a higher focal plane. Note that the time is in minutes. Forces estimated for wrinkles 1–4 at time 0 were 265, 500, 480, and 800 nN, respectively. The substratum was compressed by the cell when it formed a tail and contracted, as shown by two substratum markers in front of and behind the cell (arrowheads connected by a double-arrow line; separation quantitated in graph inset [24 min]). A second marker located farther in front of the cell was also pulled rearward between 12.5 and 19 min. Contraction of this cell and others outside of the field of view caused large shifts in the substratum, and individual marker trajectories reflect all of these movements. To better visualize the relative displacements of markers, the images at 0 and 19 min were shifted so that a reference marker behind the cell (circled) was positioned at the same location in the image. The reference marker had moved out of the field of view in the last image shown (24 min), and no correction was applied; hence, the displacement of all features in the image contains a large upward-right component. Bar, 20 μm.