Mapping the distribution of tension across paxillin upon shear stress with FRET-based biosensor

Abstract

Paxillin communicates with multiple signalling molecules in focal adhesions (FAs) and participates in the intracellular force transmission upon shear stress. Thus, paxillin is likely to contribute to establishing the shear stress induced-cell polarity. However, it is still unclear whether the tension across FAs proteins can direct the polarity establishments by providing spatial features, due to a lack of efficient manners. This work proposes a visualization approach containing a DNA-encoded biosensor and fluorescent image processing algorithm to collect the spatiotemporal features of tension across paxillin. The results indicate that the tension across paxillin shows polarity between the upstream and downstream zones of the cell along the direction of shear stress, which was mediated by the membrane fluidity and integrity of the cytoskeleton. It demonstrates that the spatial information from the upper surface of cells upon shear stress can be transmitted to the interior of FAs on the basal layer by the architecture consisting of plasma membrane and cytoskeleton. Paxillin is a potential participant in activating cell polarity by providing a spatial mechanical guide to related signaling molecules upon shear stress.Graphical