Biophysical Society Thematic Meeting | Singapore

Mechanobiology of Disease

Poster Abstracts

42-POS Board 42 The Mechanotransduction Role of Cell-Cell Junction in Cell Extrusion Context – An Alpha-Catenin Study Anh Phuong Le 1,2 , Benoit Ladoux 1,3 , Rene-Marc Mege 1,3 , Chwee Teck Lim 1,2 . 1 Mechanobiology Institute, Singapore, 2 National University of Singapore, Singapore, 3 Université Paris Diderot, Paris, France. The active role of cell-cell junction (CCJ) during epithelia extrusion has not been extensively discusses in the literature despite a plethora of research on its role in maintaining epithelial integrity. At CCJ, alpha-Catenin (a-Cat) plays a key role as a mechanotransducer at adherent junctions of epithelial cells. In the cadherin adherent complex, a-Cat can interact with F-Actin or via vinculin in a mechano-reponsive manner. Such tension-dependent vinculin recruitment process involves biphasic transition of a-Cat structure from the weak-binding state to the stabilized-binding state to F-actin, and hence, stabilizes the adherent junction. Here we show that by changing CCJ strength via manipulating different forms of a-Cat mutants, the extrusion rate, global dynamics and local traction changes were observed in MDCK monolayer. We transfected two forms of a-Cat mutants into MDCK cells with a-Cat knock-down background and observed the cell extrusion from the confluent monolayer for 24-48 hours. The extrusion rate was decreased and the duration was prolonged in the mutant that binds to vinculin constitutively and vice versa, there was increased rate and duration for the mutant with deficiency of vinculin- binding domain compared to both WT and MDCK with a-Cat knock-down with rescued WT a- cat. Moreover, re-localization of traction force tissue exerted on the substrate was observed with a-Cat mutants, implying different mechanism surrounding extrusion site with different CCJ strength. Instant drop of traction followed by recovery from neighboring cells with weakened CCJ suggests a lamellipodia-forming mechanism to help extrude the cells and close the gaps. Overall, our experimental results demonstrate that cell-cell adhesion via the stabilization of cadherin-catenin-vinculin complex regulates epithelial homeostasis.

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