Adherens junction mechanics
Adherens junctions, located just basal to the tight junction, mediate cell-cell adhesion and are well known for transmitting mechanically forces across epithelial cells into tissues.  Adherens junctions are functionally important for epithelial homeostasis and morphogenesis.  In addition to resisting mechanical forces from neighboring cells, the contractile actomyosin network associated with adherens junctions can also transmit tension across cell-cell junctions to neighboring cells, actively shaping tissues during development. For example, contraction of actomyosin coupled to adherens junctions promotes apical constriction of individual cells, which collectively leads to tissue folding \cite{Coravos2016,Takeichi2014}, and promotes intercalation, during which cells remodel their cell-cell contacts through neighbor exchange \cite{Lecuit2015}, more on this in the following sections.  Each of these functional roles of adherens junctions is dependent on regulated linkage of the core molecular components of adherens junctions to the actomyosin cytoskeleton.  
The core AJ components include the transmembrane proteins (E-cadherin and Nectins) and cytoplasmic plaque proteins (β-catenin, α-catenin, p120-catenin, Vinculin, Afadin, etc.) \cite{Quiros_2014,Ratheesh2012} (Fig qq). E-cadherin forms both small spot-like clusters along the lateral membrane as well as an apical belt-like structure, the zonula adherens, which is located just basal to the tight junction.  F-actin plays an important role in corralling the small E-cadherin clusters \cite{Wu2015}, and actomyosin drives their coalescence and stabilization at the apical zonula adherens \cite{Ratheesh2012}. The linkage of E-cadherin to F-actin is achieved via catenin proteins. β-catenin binds to the cytoplasmic tail of E-cadherin, and α-catenin binds to β-catenin. Although α-catenin can bind F-actin, there were controversies about whether α-catenin can simultaneously bind to both the cadherin/catenin complex and F-actin \cite{Yamada2005}. Recent work demonstrated that α-catenin can indeed bind both, but only under actomyosin-generated force \cite{Buckley2014,Nelson2016}. This work showed that under tension, the cadherin/catenin complex forms a stable bond with F-actin \cite{Buckley2014}. Furthermore, actomyosin-mediated tension promotes a conformational change in α-catenin, which reveals a binding site for Vinculin \cite{Yonemura2010}. Vinculin is is then only recruited to cell-cell junctions under mechanical tension to function in reinforcing cell adhesion and the linkage to F-actin in the face of mechanical force \cite{le2010,Yonemura2010}.