Fig. 7.

Feedback actin polymer restoration mechanism involving mDia1. Rho signaling determines the ratio between the closed (left) and the opened (right) form of mDia1. An increase in free G-actin efficiently converts “opened” mDia1 to the fully-active actin nucleating state, leading to fast long-range actin filament assembly in cells. With this property, mDia1 responds to acute disruption of F-actin structures evoked by physical stress or by extracellular stimuli-induced active actin remodeling, and rapidly restores cellular actin polymers by their fast actin elongation ability.