Extended Data Fig. 8: Local perturbation of the actin cortex using photoactivatable cytochalasin D increases cell area.
From: Active superelasticity in three-dimensional epithelia of controlled shape
a, Time evolution of the normalized cell area in response to local photoactivation of cytochalasin D (black line, activation at t = 0 min, n = 5 domes; see Methods). The blue line shows the time evolution of control cells (same illumination protocol but no photoactivatable cytochalasin D in the medium, n = 8 domes). The area was normalized to the first time point. Solid lines and shaded areas indicate mean ± s.d. At t = 21 min, normalized cell areas were significantly different (*P = 0.0159, two-tailed Mann–Whitney test). b, Normalized cell area 21 min after photoactivation in three experimental conditions: photoactivated cells (black circles, n = 19 cells from 5 domes), cells subjected to the same illumination protocol but without photoactivatable cytochalasin D in the medium (blue squares, n = 19 cells from 8 domes) and cells with photoactivatable cytochalasin D in the medium but without illumination (red triangles, n = 24 cells from 9 domes). Data include the immediate neighbours of the targeted cells because cytochalasin D quickly diffused after activation. ****P < 0.0001, NS, not significant (P = 0.4130), two-tailed Mann–Whitney test. Data are shown as mean ± s.d. c, Representative photoactivation experiments showing the apex of one dome before (−12 min) and after (6 min and 21 min) photoactivation of the cell marked with a yellow dashed rectangle (n = 5). Top panels show the fluorescently labelled membrane and bottom panels show the SiR–actin channel. Note the increase in cell area and granulation in the SiR–actin channel (white arrowheads), which indicates disruption of the actin cortex. Scale bar, 15 μm. d, Control experiment in which one cell at the apex of the dome (yellow dashed line) was subjected to the illumination protocol of c without photoactivatable cytochalasin D in the medium (n = 8). Top panels show the fluorescently labelled membrane and bottom panels show the SiR–actin channel. Scale bar, 15 μm. See also Supplementary Video 9.
