Fig. 3: A geometry effect induces the asymmetric accumulation of MinE.

a, Schematic (top) and experimental (bottom; MinD fluorescence is shown in magenta, MinE fluorescence is shown in green and SLB is indicated in grey) illustration of asymmetric MinE accumulation around the liposome–SLB contact edges. Liposomes were added to the preformed Min patterns on the SLBs (left), and then nearby SLB-associated MinE accumulated to the liposome–SLB contact edges (centre; pattern dynamics are indicated by the green arrow). Because of the preformed patterns, MinE adopted an asymmetric distribution on the liposome membrane, and the liposomes were asymmetrically deformed (right). Shortly before the liposome settles (t = 0 s), the shape appears distorted due to the high liposome velocity (compared with the image acquisition speed). The Min protein pattern was transiently affected because of the addition of liposome solution containing sucrose (Methods). The side views were obtained by slicing 3D images from the positions shown with the white dashed lines in the top-down images. The buffer contained 25 mM Tris (pH 7.5) and 100 mM KCl. Scale bar, 5 μm. b, Schematic of a narrow bulk volume close to the contact edges confined by the SLB and liposome lipid bilayers. The net protein concentration fluxes and protein (un-)binding are indicated by the magenta and black arrows, respectively. The high membrane-to-bulk ratio alters the reactive equilibria⁴² and reduces the MinD attachment rates per membrane area^29,43. Slowly diffusing MinE can accumulate in this region on the membrane, whereas the MinD concentration is reduced. c, Symmetric MinE accumulation around a symmetrically deformed liposome (marked with a square) in a 3D simulation (top-down view) (top). A 3D image of the area marked in the top panel (bottom). The liposome shape is indicated as a grey hatched surface (Methods). d, Asymmetric MinE accumulation at the more flattened side of asymmetrically deformed liposomes.