Real-Time Quantitative Measurement of Myosin and Strain Dependent Recruitment of E-Cad in Spot Adherens Junctions

Abstract

The response of adherens junction to mechanical stress is a key process in cell-cell contact reorganization that remains poorly understood partly owing to the lack of appropriate measurement techniques. In this paper, we present an innovative micro-well based approach to image at high resolution the horizontal adherens junction of a suspended vertical cell doublet during contact elongation and under mechanical constrain. We find that the E-cadherins cluster in submicron sized puncta at the edge the actin depleted contact area. They form an almost periodic ring-like structure that displays spatially organized fluctuations of E-cad recruitment levels. We demonstrate by real time imaging that these fluctuations correlate with the local contact deformations induced by local myosin contractility gradients. Finally we establish a unified relationship between the local strain and the changes in E-cad recruitment levels induced by global contractility changes, local gradients and external mechanical stimuli. We hence provide the first quantitative real time measurement of the response of an adherens junction to mechanical strain. We propose the existence of an adaptive pathway with a fast and strong response for weak mechanical stimuli.View Large Image | View Hi-Res Image | Download PowerPoint Slide