Séminaire IUSTI – 27 nov. 2020 – 11h salle 250

Liquid-liquid phase separation in living cells: like oil in water?

Pierre Ronceray – LGC, Toulouse

Many intracellular bodies in eukaryotic, both in the nucleus and cytoplasm, are now understood to be membrane-less liquid condensates that separate from the cellular environment through a liquid-liquid demixing, often compared to oil in water. In this talk, I will discuss two of the ways in which this phase separation is different from usual binary liquids. First, the molecular interactions that govern protein phase separation are often strong and specific, which lead to unusual properties such as non-monotonic valence effects and sharp composition-dependence of the viscosity – effects that cells could use to dynamically tune the properties of these organelles. Second, the cellular environment surrounding these droplets has complex mechanical properties, which oppose droplet growth and shifts phase boundaries. I predict that this can result in novel, yet-unobserved phases of size-limited “nanodroplets”.