Quantifying mechano-chemical coupling between RhoA and the actomyosin cortex in vivo

Spatiotemporal symmetry-breaking transitions in biochemical patterns are essential in triggering morphological changes during the developmental processes. Cell and tissue-scale deformations is achieved through intra-cellular force networks that translate localized biochemical signals into effective mechanical stresses that determine the global shape dynamics. However, the mechanochemical coupling between the biochemical patterns and the resulting stress patterns is not well understood. Here, we quantify the local coupling between membrane-bound Rho-GTP concentration fields and the mechanical deformations of the actomyosin cortex in the starfish oocytes during meiosis. We generate various Rho-GTP dynamic patterns by overexpressing the Rho activator and map the resulting stress patterns via tracking endogenous probe particles embedded in the cell cortex. This method provides a novel approach to probe the local coupling between biochemistry and mechanics.