Cell lysis and western blot

For western blotting, the cells were seeded in 8.8 cm² cell culture column prepared by cutting from 50 mL NUNC-tube and attached with silicone grease on fibronectin (10 μg/mL) coated thin Si membrane assembled in Brick Strex L with a 25% strain. In control studies, the cells were seeded on unstretched PDMS membranes. To detect the mechanosensitive proteins prior and after the relaxation, the cells from the control and the compressed membranes, respectively, were lysed as previously described⁶⁵. The entire method to produce the lysates and to run the western blot can be found in Supplementary methods section online. The immunoblotting was done using anti-YAP1 (1:1000, YAP163.7, sc-101199, Santa Cruz Biotechnology), anti-β-actin (1:5000, ab6276, Abcam), anti-YAP1 S127P (1:1000, #13,008, Cell Signaling Technology, Denvers, MA, USA), and anti-β-catenin (1:1000, ab6302, Abcam) primary antibodies for o/n in + 4 °C in tilting followed incubation with a horseradish peroxidase -conjugated goat-anti mouse/rabbit secondary Abs for 1 h in RT (in tilting).