Fig. 2
Switch-like regulation of YAP in expanding epithelial layers loosening cell–cell adhesion. a Cells on flat substrata and NRA analyzed by immunoblotting using YAP and phosphorylated YAP antibodies. b Cell migration speed of individual YAPKD and YAPOE cells in cell sheets as a function of the distance from the sheet edge on NRA (each number of independently analyzed cells, n, is indicated, * = statistical significance of speed of control vs. YAPKD cells on NRA (green) and of control vs. YAPOE cells on NRA (purple), *P < 0.05, **P < 5 × 10−4, and ***P < 5 × 10−6). c Immunofluorescence staining for YAP and active β-catenin in epithelial cell sheets on flat substrata and NRA. Translocation of YAP and active β-catenin into nuclei observed in marginal zones and FLPs of sheets expanding on NRA (brown boxes) and mostly cytoplasmic YAP and active β-catenin localization in submarginal cells on NRA (red boxes) and on flat substrata. The samples were analyzed after 8 h from the initiation of sheet expansion. d Fractions of nuclei displaying different intensities of YAP and active β-catenin staining as a function of the distance from the sheet edge determined at 8 h after initiation of sheet expansion (the edge is coincident with the concave regions at the bases of FLPs in panel c). e Velocity correlation length in y-direction, parallel to the direction of epithelial expansion for the control and YAPKD cells on flat substrata and NRA (each number of independently analyzed cells, n, is indicated, * = statistical significance of correlation length, *P < 0.05, **P < 0.01, and n.s = no significance). f Cell migration speed of individual cells in cell sheets as a function of the distance from the sheet edge on flat substrata and NRA, in the presence of an E-cadherin functional blocking antibody. Dashed line with a square marker indicates the average cell migration speed of isolated control cells and solid line with a circle marker corresponds to that of isolated YAPKD cells (each number of independently analyzed cells, n, is indicated, # = statistical significance of speed values in the marginal region vs. the most submarginal region of YAPKD cells with drugs, ###P < 5 × 10−6. * = statistical significance of control vs. YAPKD cells with drugs (green) and of YAPKD cells with vs. without drugs (black), *P < 0.05, **P < 5 × 10−4, and ***P < 5 × 10−6). g Control, YAPKD, and YAPOE cells were immunoblotted using active β-catenin and E-cadherin antibodies. All error bars are S.E.M and statistical significance was determined by two-sided Student’s t-test
