Fig. 2: In vitro reconstitution of lumenal F-actin and cofilin-bound F-actin.

a Representative slice from a tomogram showing organisation of microtubules and actin filaments that have been polymerised together (Scale bar = 100 nm). Expanded box highlights the canonical ‘beads-on-a-string’ F-actin morphology and long crossover spacing (blue line is 37 nm). b Representative slice from a tomogram showing the typical organisation of microtubules and actin filaments that have been polymerised together in the presence of cofilin (Scale bar = 100 nm). Expanded box highlights the distinctive smooth appearance of the cofilin-bound actin filaments and short-crossover spacing (magenta line is 27 nm). c Representative slice from a tomogram showing a canonical actin filament within a microtubule, boxed and expanded below. Scale bar on main panel is 100 nm, and 25 nm on the zoom panel. d Representative slice from a tomogram showing a cofilin-bound actin filament within a microtubule, boxed and expanded in below. Scale bar on main panel is 100 nm, and 25 nm on the zoom panel. e Examples of actin filaments at microtubule ends or breaks in the lattice (Scale bar = 25 nm) (f) Examples of cofilin-bound actin-filaments at microtubule ends or breaks in the lattice (Scale bar = 25 nm). Examples shown in this figure are representative of 3 independent polymerisation and freezing sessions.