Movie S3.

Elongation and Xac2-induced filament severing of buckled F-actin (Fig. 1C). Buckled F-actin grows from immobilized mDia1 before and after reducing the actin concentration to 0.1 μM. Buckled F-actin bends by continuing filament elongation from immobilized mDia1 after the pointed end side is trapped. Scale bar is 5 μm.