Fig. 1: Patterned light-activation induces cell division-like membrane deformation.
a Schematic of a liposome encapsulating actomyosin. His-tagged proteins were tethered to the membrane via DOGS-NiNTA lipids embedded in the lipid bilayer. Linear F-actin was nucleated by His-mDia1 and tethered to the membrane via His-α-actinin. b Confocal slices of the actin fluorescence image in the midplane and at the bottom surface of the liposome. Similar F-actin organization was consistently obtained in more than 10 independent repeats (e.g., Fig. 4b, Fig. 5a). c Schematic of the patterned light-activation of myosin. (i) Myosin is inhibited during liposome preparation. (ii) Dissociating the actin cortex at the poles by high-power laser (405 nm) to allow membrane expansion during (iii) light-activation by 488 nm laser along the equatorial plane. d Time-lapse images showing the midplane of a light-activated liposome exhibiting cell division-like deformation. e Side view (y–z plane) and furrow (x–z plane) of a three-dimensional reconstruction of the deformed liposome. f PIV of the contracting actomyosin network (left). Yellow arrows show the total displacement, u, over 5 min with vector magnitudes normalized by the maximum. The colormap represents local strain fields (right). g Mean actin flow speed within the liposome over time (n = 5 liposomes and N = 2 independent experiments in 0 nM; n = 5 and N = 2 in 35 nM; n = 5 and N = 3 in 70 nM; n = 4 and N = 2 in 140 nM; n = 5 and N = 2 in 280 nM). h Contour shape of the liposome membrane over time. Time is color-coded. i Aspect ratio \({\alpha }_{{{{\rm{shape}}}}}\) of the liposome estimated from ellipse fitting to the contour shape. j Aspect ratio over time (n = 13 liposomes and N = 3 independent experiments in 0 nM; n = 20 and N = 2 in 35 nM; n = 39 and N = 4 in 70 nM; n = 28 and N = 6 in 140 nM; n = 15 and N = 2 in 280 nM). k and l Boxplots showing the time at maximum aspect ratio (k) and maximum aspect ratio (j) (n = 13 liposomes and N = 3 independent experiments in 0 nM; n = 20 and N = 2 in 35 nM; n = 39 and N = 4 in 70 nM; n = 28 and N = 6 in 140 nM; n = 15 and N = 2 in 280 nM). Data are presented as mean ± SD (g, j) or boxplots where the interquartile range (IQR) is between Q1 (25th percentile) and Q3 (75th percentile), the center line indicates the median, whiskers are extended to Q3 + 1.5 × IQR and Q1 − 1.5 × IQR (k, l); *p < 0.05; **p < 0.01; ***p < 0.001 in a two-sided Wilcoxon rank sum test. n.s., not significant. Scale bars, 10 μm. Source data are provided as a Source Data file.
