Cortical F-actin stabilization generates apical-lateral patterns of junctional contractility that integrate cells into epithelia.

[wiskott-aldrich syndrome]

E -cadherin cell-cell junctions couple the contractile cortices of epithelial cells together , generating tension within junctions that Â influences tissue organization . Although junctional tension is commonly studied at the apical zonula adherens , we now report that E -cadherin adhesions induce the contractile actomyosin cortex throughout the apical-lateral axis of junctions . However , cells establish distinct regions of contractile activity even within individual contacts , producing high tension at the zonula adherens but substantially lower tension elsewhere . We demonstrate that N-WASP (also known as WASL ) enhances apical junctional tension by Â stabilizing local F-actin networks , which otherwise undergo stress-induced turnover . Further , we find that cells are extruded from monolayers when this pattern of intra-junctional contractility is disturbed , either when N-WASP redistributes into lateral junctions in H-Ras (V 12 )-expressing cells or on mosaic redistribution of active N-WASP itself . We propose that local control of actin filament stability regulates the landscape of intra-junctional contractility to determine whether or not cells integrate into epithelial Â populations .