Pulsatile contractility of actomyosin networks organizes the cellular cortex at lateral cadherin junctions.

The physical properties of cells reflect how the structure and dynamics of the actomyosin cortex are coupled to the plasma membrane. In epithelia, adhesive E-cadherin clusters associate with the cell cortex to assemble the junctional actomyosin that participates in epithelial morphogenesis. E-cadherin is present not only at the apical zonula adherens (ZA), but also distributed throughout the lateral adherens junction (LAJ) below the ZA. However, the organizational dynamics of the actomyosin network at the LAJs remains elusive. To address this, we used quantitative real-time imaging to characterize the dynamics of actomyosin contractility at lateral cadherin contacts. Here, we report that contractility is coordinated into smaller actomyosin rings that link cadherin clusters together within the larger cortical network at the lateral junctions. We conclude that Myosin II activity determines the contractility of actomyosin cables between cadherin clusters to propagate pulsatility across lateral cell-cell contacts.