Plasticity of cell migration resulting from mechanochemical coupling*

Eukaryotic cells can migrate using different modes, ranging from amoeboid-like, during which actin filled protrusions come and go, to keratocyte-like, characterized by a stable actin wave at the front of the cell and persistent motion. How cells can switch between these modes is not well understood but waves of signaling events that lead to actin waves propagation are thought to play an important role in these transitions. Our experiments, performed with Dictyostelium discoideum, show that systematically reducing the protrusion force of the actin network using a drug, latrunculin B, leads to different migration modes including amoeboid-like and keratocyte-like. We find that a sufficient decrease of the protrusion force can destabilize keratocyte-like cells, resulting in cells that employ amoeboid-like migration. We then present a simple two-component biochemical reaction-diffusion model based on relaxation oscillators and couple this to a model for the mechanics of cell deformations. Predictions of the model are in good agreement with the experiments. Our results indicate the importance of coupling signaling events to cell mechanics and morphology and may be applicable in a wide variety of cell motility systems.