Rng2Ns bundles F-actin. (A–D) Fluorescence micrographs of actin bundles. G-actin (2 μM) was polymerized alone (D), or with 0.6 μM Rng2Ns (A), Fim1 (B), or 1.8 μM Rng2CHD (C) for 10 min (A) or 50 min (B, C), and then stained with rhodamine–phalloidin. Asterisks indicate the centres of the radial arrays of actin bundles. Arrowheads indicate points where the bundles were loosened. (E–H) Electron micrographs of actin bundles. (I) Width distribution of Rng2Ns/actin (black bars) and Fim1/actin (white bars) bundles. The means±s.d. are depicted in the graph. The widths of the bundles were measured at more than 170 points for each condition. (J) Rng2Ns/actin bundles splitting. (K) Rng2Ns/actin bundles twisting (a) and simultaneously splitting (b). Bars: 10 μm (A–D) or 200 nm (E–H, J, and K).