Twist-constraining two-filament bundles lead to its faster fragmentation by cofilin. Survival fractions of unsevered 5-µm long segments from unanchored bundles (twist-unconstrained, n = 20) or anchored bundles (twist-constrained, n = 16) as a function of time, when exposed to 200 nM mCherry-cofilin1 and 200 nM fascin. 95% confidence intervals are shown as shaded surfaces. Log-rank test P value <0.005.