Regensburg 2022 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 8: Focus Session: Phase Separation in Biochemical Systems
BP 8.12: Vortrag
Dienstag, 6. September 2022, 12:45–13:00, H15
Interface resistance can govern transport of molecules across phase boundaries — •Lars Hubatsch1,2, Anatol Fritsch1,2, Tyler Harmon3, Frank Jülicher2,4, Christoph Weber5, and Anthony Hyman1,2 — 1Max Planck Institute of Molecular Cell Biology and Genetics — 2Center for Systems Biology Dresden — 3Leibniz Institute for Polymer Research — 4Max Planck Institute for the Physics of Complex Systems — 5University of Augsburg
Cells can achieve compartmentalization of biochemical processes via organelles by the selective admission of biomolecules. Organelles are enclosed by a membrane or, in the case of biomolecular condensates, by the condensate-bulk interface. While transport across membranes has been studied for decades, it is less clear how biomolecular condensates regulate transport across their interface. Using a combination of live-imaging and theory, we show that the flux of molecules across the condensate-bulk interface exhibits transients that cannot be explained by local equilibrium between the coexisting phases, a phenomenon also referred to as interface resistance. It is unclear whether this interface resistance stems from molecules adsorbing to the interface or from a kinetic barrier reflecting molecules at the interface. Using single-particle imaging of PGL-3 droplets, we observe no accumulation of molecules at the interface. This observation suggests that molecules are reflected rather than adsorbed at the interface. We quantify the strength of interface resistance by accounting for molecule dynamics outside, inside, and at the droplet interface and thus provide a framework to characterize molecular fluxes across condensate-bulk interfaces.