Light-induced cortical excitability reveals programmable shape dynamics in starfish oocytes

Chemomechanical waves on active deformable surfaces are a key component for many vital cellular functions. In particular, these waves play a key role for force generation and long-range signal transmission in cells that dynamically change shape, as encountered during morphogenesis or cell division. Under wild-type conditions, the generation and propagation of these waves is usually tightly controlled by spatial and temporal cell-cycle-dependent cues. Here, we develop an optogenetic method to qualitatively explore the mechanism responsible for coordinating surface contraction waves that are generic to sea star oocytes during meiotic cell division. Using spatiotemporally-patterned light stimuli as a control input, we create chemomechanical excitations in oocytes that are decoupled from meiotic cues and drive diverse shape deformations ranging from local pinching to surface contraction waves and to cell lysis. We develop a quantitative model that entails the hierarchy of chemical and mechanical dynamics, which allows to relate the variety of mechanical responses to optogenetic control input. Our results pave the way towards high-precision real-time control over dynamical deformations in living organisms and programmable active materials. On a broader perspective, our results demonstrate how the versatility of intracellular protein dynamics can give rise to a broad range of mechanical phenomenologies that are important for the design of synthetic cells and life-like cellular functions.