Figure 8.

Model of the role of stress fibers to determine the fan shape of keratocytes. (A and B) Summary of the results in this study. Wide keratocyte showed small ARF rate gradient and exerted large traction forces at both ends of the stress fibers (A). Round keratocyte showed large ARF rate gradient and exerted small traction forces at both ends of the stress fibers (B). (C and D) Hypothesis of the relationship between traction forces and ARF rate gradient. Schematical illustrations (C) and (D) indicate the side views of the rectangles in (A) and (B), respectively. Large contractile forces, detected as large traction forces, enhance the tension of forward F-actin. The tension accelerates the maturation of the focal adhesions via molecular clutches. This reduces the ARF rate (C). Whereas, small traction forces cause the detachment of F-actin from the focal adhesions. This enhances the ARF rate (D). To see this figure in color, go online.