Fig. 1. Adhesion of differentiated myofibroblasts is stronger than that of proto-myofibroblasts. Adhesion forces are measured with AFM between cadherin dimer-coated cantilevers and similarly coated substrates (A-C), between cadherin dimer-coated cantilevers and myofibroblasts (D,E), and between myofibroblasts grown on cantilevers and myofibroblasts grown in monolayers (G-I). In all conditions, cantilever approach-retraction velocities were set to 0.1 µm/second, loading force to 3 nN and contact time to 2 seconds. (B,E,H) Typical force-distance curves under different conditions are displayed for each configuration; arrows indicate positions where bond rupture occurs in a `jump'. Red profiles indicate typical interaction between OB-cadherins or differentiated myofibroblasts in the different set-ups, green lines represent controls in the absence of extracellular Ca²⁺ (EGTA) and pink lines show controls performed with IgG-coated cantilevers (B,E) or contacts formed in the presence of OB-cadherin-blocking peptides (H). (C,F,I) Rupture forces displayed as histograms (n5000 in each condition), normalized for the total number of rupture events in every configuration and fitted with Gaussian curves. Results obtained with proto-myofibroblasts and N-cadherin are displayed in blue, whereas results with differentiated myofibroblasts and OB-cadherin rupture forces are indicated in red. Note the different scale in H, which allows for the significantly higher bond strength in the cell-cell set-up compared with set-ups in B and E. Cadherin specificity of interactions was controlled by coating cantilevers with human IgG (C,F, pink), by using EGTA (green) and by applying anti-cadherin peptides (I, dashed lines).