Fig. 4

Patterned substrates. a Schematic representation of the wrinkled substrates (blue) and lipid bilayer (red). b Relative septin density (green) on SLB deposited on the patterned substrates as a function of the curvature (N = 202). The red and orange curves correspond to the lipid signals as controls (Bodipy-TR-ceramide and fluorescent PI(4,5)P2, respectively). Error bars represent s.d. c Low magnification SEM image of a representative patterned substrate. Scale bar is 10 µm. d, e SEM image of a patterned substrate incubated with a septin bulk solution at 200 nM. Scale bar is 1 µm in d and 300 nm in e. f, g Color-labeled image of the septin orientation with respect to the wrinkle substrate of image d and e, respectively. The inset shows the angular distribution of pixels at the top (purple) (positive curvature) and at the bottom (green) (negative curvature of the substrate). The white arrow points to a convex surface where septins align and bundle parallel to the undulations. h SEM image of a patterned substrate incubated with mutant septin solution at 200 nM. Scale bar is 200 nm. The inset shows the angular distribution of septins. No preferential orientation is found on positive or negative curvature. i Schematic representation of the wavy substrates with septin filaments following the null curvature at the top, positive, (green) and the bottom, negative, curvature (purple) of the wrinkled substrate