Stochastic Model of Integrin-Mediated Signaling and Adhesion Dynamics at the Leading Edges of Migrating Cells
Figure 7
Effects of myosin IIA knockdown or overexpression assessed by protrusion velocity mapping.
CHO.K1 cells expressing fluorescently labeled paxillin were filmed using TIRF microscopy as they migrated on the indicated densities of fibronectin ([FN], expressed as the coating concentration in µg/ml). Myosin IIA levels were knocked down by RNA interference or increased by overexpression as indicated. a. For each condition, the velocity of protrusion is mapped for a representative cell as a function of time and position around the cell periphery. A gray area indicates a region of the cell periphery where protrusion velocity could not be determined. b. A protrusion event is marked as a contiguous region in space and time with protrusion velocity exceeding 1 nm/s and containing at least one instance where the protrusion velocity exceeded 5 nm/s (Supplemental Fig. S4). The total area of such protrusions on the velocity map (in units of length*time), normalized by the duration of the experiment, is plotted for normal and myosin IIA knockdown conditions from a.