Phase separation—the process of converting a solution into its constituent liquids—may explain how living cells keep the molecules within them apart. When a group of protein or RNA molecules gather together in a high enough concentration, physical forces can attract them to one another, causing them to phase-separate, forming droplets within the cell. The process has been observed in bacteria, fungi, plants, and animals (via Nature).
“It’s one of these in-hindsight, intuitive ideas. The second you hear it, it just makes a lot of sense,” Shana Elbaum-Garfinkle, a biophysicist at the City University of New York Advanced Science Research Center, tells Nature. “It’s a new paradigm that’s really transforming our understanding of cell biology as a whole.”
T. Nott et al., “Phase transition of a disordered nuage protein generates environmentally responsive membraneless organelles,” Molecular Cell, doi:10.1016/j.molcel.2015.01.013, 2015.