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"OptoDroplet" Method Induces On-Demand Protein Phase Transitions

In a paper recently published in the highly-regarded research journal Cell, a Princeton team demonstrated the use of a new method, termed “OptoDroplet”, to induce both reversible and irreversible protein phase transitions within cells.  The research team, led by Clifford Brangwynne, Assistant Professor of Chemical and Biological Engineering (CBE), also included Jared Toettcher, Assistant Professor of Molecular Biology and Associated Faculty in CBE.  OptoDroplet works by fusing a light-sensitive protein tag to the protein components thought to drive phase transitions in living cells.  Shining light on the modified proteins induces the tags to associate and the proteins to condense into submicron-scale droplets within the cell.  Turning the light off causes the droplets to dissolve, and at moderate light intensities, the process is fully reversible even after many cycles.  At higher light intensities, the protein aggregation is irreversible, forming gel structures reminiscent of those found in Alzheimer’s and amyotrophic lateral sclerosis (ALS) patients.  For more information and a video showing the optoDroplet technique in action in a living cell, see the story on the Princeton University homepage.  Those with journal access can access the full Cell article, “Spatiotemporal Control of Intracellular Phase Transitions Using Light-Activated optoDroplets”.