Movie S6.

Liquid bundles spontaneously contract, as visualized with TMR-actin. At t = 0 s, filamin cross-links (10 mol %) quickly bundle F-actin (2.64 μM and 0.25 mol % capping protein) into small bundles which coalesce into long, isolated bundles that shorten over time. The fluorescence intensity is normalized for each frame individually for the clarity of presentation. Time is indicated in min:s.