FIGURE 7.

Effect of stretching of cell doublets on vinculin and α18 epitope recruitment at Ecad cell-cell contacts. A and B, schematic representation of the stretching experiment. Shown are a top view (A) and side view (B) of the experimental procedure. Cell doublets (green ovals with blue nucleus) were deposited on silicon substrates (blue) micropatterned with polylysine-coated parallel lines (pink lines) and incubated at 37 °C for 20 min. The left and right panels represent the non-stretched and stretched conditions, respectively. The orientation of the force field exerted perpendicular to the cell-cell contact is represented by the red dashed arrow and induced an increase in the original substrate length by 20% (dashed blue line in the right panel indicates the position of the original relaxed border of the substrate). C, z projection of confocal images showing E-cadherin (green), vinculin (red), and α-catenin α18 conformational epitope (cyan) localization on Ecad cell doublets deposited on polylysine-coated silicon substrates and exposed (bottom panel) or not (top panel) to 2 min of stretching before fixation. D, mean ratios between α18 and E-cadherin intensity or vinculin and E-cadherin intensity were measured at the cell contact area of non-stretched (white bars; n = 11) and stretched (black bars; n = 16) doublets. Error bars, S.D. for non-stretched versus stretched doublets. ***, p value < 0.0001 (two-tailed). Scale bar and double arrow in C represent 10 μm and the orientation of the stretch, respectively.