Junctional tension is increased in claudin/JAM-A KO cells. (A) Laser ablation of a cell junction of MDCK II cells expressing ZO1-GFP. A modest recoiling of the vertices was observed. (B) Laser ablation of a cell junction of claudin/JAM-A KO cells expressing ZO1-GFP. Rapid recoiling of the vertices was observed. (C) Time course of the vertex displacement after laser ablation. (D) Recoil velocity immediately after the laser ablation. Claudin/JAM-A KO cells showed an increase in the recoil velocity, suggesting that the junctional tension was elevated. (E) Length of the junctions ablated. The data are presented as mean ± SD (n = 20), ***P < 0.0005, compared by t test. Scale bars: 5 μm.