Cofilin fluorescence reveals the presence of overlapping cofilin clusters along two-filament bundles. Maximum fluorescence intensity of cofilin measured over 1 µm stretches on two-filament bundles compared with the intensity of cofilin clusters on single actin filaments (N = 3 experiments, with n = 23 (blue), 8 (green), 8 (orange) spots analyzed on two-filament bundles, and n = 35, 5, 18 cofilin clusters on single filaments, respectively). Large symbols represent averages over individual measures from independent experiments.