The mechanism of dynamic steady states in lamellipodia
Fig 3
Intermediate actin depolymerization rate led to a continuous flow with uniform network morphology.
(A, B) Snapshots of branched networks taken at ~150 s with a lower (0 s-1) or higher (10 s-1) value for actin depolymerization rate (k-,A) relative to that of the reference condition, 6 s-1. Network contraction without actin depolymerization led to loss of connection between the network and the leading edge, whereas too fast actin depolymerization resulted in loss of connection between the network and the motors. (C, D) Kymographs of actin density as a function of y position and time with different k-,A. (E) Heterogeneity of the network quantified as a coefficient of variation in actin density in the y direction. A lower value is indicative of a more homogeneous network. The network without actin depolymerization (k-,A = 0 s-1) showed very high heterogeneity which is attributed to the severe network accumulation shown in (A). (F) Retrograde flow speed for different values of k-,A. With intermediate values of k-,A, the network was more homogenous, and the flow speed was comparable with experimental observations.