%0 Journal Article
%T Branched actin networks push against each other at adherens junctions to maintain cell每cell adhesion
%A Efimova
%A Nadia
%A Nadia Efimova
%A Svitkina
%A Tatyana M.
%A Tatyana M. Svitkina
%J JCB | The Journal of Cell Biology
%D 2018
%R 10.1083/jcb.201708103
%X Adherens junctions (AJs) are mechanosensitive cadherin-based intercellular adhesions that interact with the actin cytoskeleton and carry most of the mechanical load at cell每cell junctions. Both Arp2/3 complex每dependent actin polymerization generating pushing force and nonmuscle myosin II (NMII)-dependent contraction producing pulling force are necessary for AJ morphogenesis. Which actin system directly interacts with AJs is unknown. Using platinum replica electron microscopy of endothelial cells, we show that vascular endothelial (VE)-cadherin colocalizes with Arp2/3 complex每positive actin networks at different AJ types and is positioned at the interface between two oppositely oriented branched networks from adjacent cells. In contrast, actin每NMII bundles are located more distally from the VE-cadherin每rich zone. After Arp2/3 complex inhibition, linear AJs split, leaving gaps between cells with detergent-insoluble VE-cadherin transiently associated with the gap edges. After NMII inhibition, VE-cadherin is lost from gap edges. We propose that the actin cytoskeleton at AJs acts as a dynamic push每pull system, wherein pushing forces maintain extracellular VE-cadherin transinteraction and pulling forces stabilize intracellular adhesion complexes.
%U http://jcb.rupress.org/content/217/5/1827