Principal Investigator Adam Martin
Adherens junctions (AJs), which contain the transmembrane adhesion molecule E-cadherin, link neighboring cells to each other and the cell surface to the actin cortex. We found that sensitizing AJs to stress (i.e. by reducing AJ levels with E-cadherin RNAi) results in tissue-wide tears across the mesoderm that result from actomyosin generated tension. This epithelial tearing phenotype can be used to investigate how pulsed contraction and stabilization transmit tension across the tissue. Pulsed actomyosin contractions alone are insufficient to generate tissue-wide tension. Epithelial tension requires the ratchet-like stabilization of cell shape, which results from a supracellular meshwork of actomyosin fibers that are connected across the tissue. Thus, while pulsatile actomyosin contractions cause dramatic cell shape changes, stabilizing actomyosin fibers generate global tension across the system. Importantly, the tension that is produced by apical constriction causes cells to constrict anisotropically, demonstrating that these cells “feel” and “respond” to forces transmitted between them. We are further investigating how forces are transmitted across the tissue and how these forces influence cell behavior.