Earlier studies had shown that the formation of biological patterns through self-organizing proteins plays a crucial role in determining cell shape. The researchers investigated this complex network using the oocytes (egg cells) of the starfish Patiria miniata, which undergo a characteristic change in shape during division.
A wide range of variants
This shape change is driven by two enzymes: the small GTPase Rho and its activation enzyme GEF. By incorporating light-controllable molecular switches into GEF enzymes, the researchers managed to optogenetically influence the shape dynamics of the oocytes in a targeted manner. “With these switches, we were able to arbitrarily modulate the protein distribution in the cell through light stimuli, which led to deformations,” says Tom Burkart, lead author of the study. “So we generated a wide range of variants – from local pinching to an impressive deformation into a square cell.”
Subsequently, the scientists developed a theoretical model that describes how the optical stimulus triggers a change in the shape of the cell via chemical and mechanical interactions. They identified two key mechanisms: guided deformations, where the shape changes are locally limited, and unguided deformations, which spread throughout the cell by means of self-organization. “Our results show that living cells are much more versatile than previously assumed,” says Frey. “These findings could have wide-ranging implications for the development of synthetic cells and biomimetic materials and open up new opportunities for synthetic biology and cell-based technologies.”
Publikation: Jinghui Liu, Tom Burkart, Alexander Ziepke, John Reinhard, Yu-Chen Chao, Tzer Han Tan, S. Zachary Swartz, Erwin Frey, Nikta Fakhri: "Light-induced cortical excitability reveals programmable shape dynamics in starfish oocytes". Nature Physics 2025
Contact:
Prof. Dr. Erwin Frey
Ludwig-Maximilians-Universität Munich / Excellence Cluster ORIGINS
email: frey(at)lmu.de
