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Physics Colloquium: Sarah L. Keller
March 20 | 4:00 pm - 5:00 pm
Title: Phase-separating membranes in hungry yeast are tiny, living thermostats
Abstract: Liquid-liquid phase separation in biological membranes is usually described as occurring on sub-micron length scales. A stunning counterexample occurs in S. cerevisiae – the same yeast used to brew beer and make bread. When these yeast sense that they have run out of glucose to eat, coexisting liquid phases appear within the lipid membrane that surrounds one of their organelles. This phase separation is functionally important, enabling yeast survival during periods of stress. This talk will review recent results showing: (1) This miscibility transition is reversible as would be expected from equilibrium thermodynamics, even though it occurs in a living system. (2) Yeast actively regulate this phase transition to hold the membrane transition ~15C above the yeast growth temperature. (3) In cases when domains appear as stripes, there is no current theory that explains all material properties and physical observables of the system. No previous knowledge of biology is needed for this seminar.
Host: Mary Elting