The mechanism of dynamic steady states in lamellipodia
Fig 5
An increase in motor density makes the retrograde flow faster by enhancing contractile forces.
(A, B) Snapshots of the branched network taken at ~150 s with a lower (0.001) or higher (0.04) value of motor density (RM) relative to that of the reference condition, 0.004. (C, D) Kymographs of actin density as a function of y position and time with different values of RM. The case with insufficient motors did not show a noticeable flow because it could not overcome frictional forces from FAs. As RM increased, more F-actins were accumulated as a bundle near the -y boundary. (E) Heterogeneity of the network quantified as a coefficient of variation in actin density in the y direction. The network was most homogeneous with intermediate values of RM. (F) Actin retrograde flow speed depending on RM. With higher RM, the flow tended to be faster. (G) Total force acting on the entire substrate via elastic links with different RM. The total force showed a clear plateau at high RM.