A putative tension release signal for VL. (a) Example of asymmetric viscoelastic recoil/relaxation in discrete regions (shaded blue) of MVEC after probe wounding of MVEC. Adjacent untouched filaments undergo visible extension (red shaded areas). Robust VL and VW recovery responses predominantly formed in the relaxed areas (cyan arrows; arrowheads show individual VL). Dashed green and blue lines indicate the original and current position, respectively, of an intercellular junction adjacent to the transcellular micro-wound. At 120 s after wounding significant retraction of the intact junction toward the untouched neighbor is evident. At 210 and 330 s, strong localized VL responses are evident from the neighbor precisely where the initial relaxation occurred (yellow arrow). See Video 6. (b) Zones of viscoelastic recoil (blue shading and curved arrows) in actin networks form nodes of VL initiation on intact filaments. Actin-GFP was imaged in an untouched MVEC immediately before and at indicated times after mechanical micro-wounding of a neighbor cell. Panels on right are zoomed views of the boxed region. Overlay (far right) of the initial (red) and current (green) time points highlights the viscoelastic recoil and shortening of filaments upon broken adhesion with the neighbor. The retracted filaments (blue lines at 0 s) rapidly accumulated actin nodes (cyan arrow) and transitioned to VL that propagated into the micro-wound. Adjacent, nearly orthogonally oriented filaments (dashed magenta lines at 0 s) did not undergo appreciable recoil/retraction or form nodes or VL (left, asterisk). See Video 7. Bars, 5 µm.