Src Kinase Slows Collective Rotation of Confined Epithelial Cell Monolayers

Collective cell migration is key during development, wound healing and metastasis and relies on coordinated cell behaviors at the group level. Src kinase is a signalling enzyme regulating many cellular processes including adhesion and motility and its deregulated activation has been associated to aggressiveness of different cancers. Here, we take advantage of optogenetics to precisely control Src activation in time to study the effect of its over activation on collective rotation of confined monolayers. We show that Src activation slows down collective rotation of epithelial cells confined into circular adhesive patches. We interpret velocity, force and stress data during period of non-activation and period of activation of Src thanks to an hydrodynamic description of the cell assembly as a polar active fluid. Src activation leads to a 2-fold decrease in the ratio of polar angle to friction, which could result from increased adhesive bonds at the cell-substrate interface. Our work reveals the importance of fine-tuning the level of Src activity for coordinated collective behaviors.