Hold on tightly, let go lightly: myosin functions at adherens junctions

Abstract

Adherens junctions, the sites of cadherin-dependent cell-cell adhesion, are also important for dynamic tension sensing, force transduction and signalling. Different myosin motors contribute to adherens junction assembly and versatility in distinct ways.

Figure 1

Adherens junctions may be functionally analogous to the kinetochore–sister chromatid complex. Both the kinetochore–sister chromatid complex (a) and the adherens junction (b) mediate attachment while simultaneously sensing and reacting to changes in tension exerted from opposing directions. In the AJ, the attachment is between cells and the tension changes are exerted primarily by the F-actin cytoskeleton, whereas in the kinetochore–sister chromatid complex the attachment is between sister chromatids and tension changes are exerted primarily by the microtubule cytoskeleton. Accordingly, AJs are equipped with proteins that link the cells (cadherins), tether the cadherins to F-actin (vinculin and α-actinin), sense and respond to tension (α-catenin), and impart force (myosins). The kinetochore–sister chromatid complex is respectively equipped with securins, the KMN network, and various microtubule-associated proteins and motors. Finally, both structures contain proteins that regulate the assembly and disassembly of their associated polymer system.