The mechanism of dynamic steady states in lamellipodia
Fig 6
Focal adhesions (FAs) hinder the actin retrograde flow by exerting frictional forces.
(A, B) Snapshots of the branched network taken at ~150 s with smaller (0) or larger (0.5) size of the FA region (AFA) relative to that of the reference condition, 0.35. (C, D) Kymographs of actin concentration depending on time and y position with AFA. Without the FA region, the accumulation of F-actins into a bundle was noticeable, whereas large FA region led to discontinuity between the network and the motors. (E) Heterogeneity of the network quantified as a coefficient of variation in actin density in the y direction. (F) Actin retrograde flow speed depending on AFA. The flow speed tended to be smaller with larger FA region due to higher frictional forces. (G) Total force acting on the substrate by the network with different AFA. At AFA ≤ 0.35, the total substrate force was proportional to AFA due to the formation of more links, but the case with AFA = 0.5 showed a lower total force because of the discontinuity between the network and the motors occurring at later times.