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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: Focus Phase Separation in Biological Systems I (joint session BP/CPP)

CPP 9.3: Talk

Tuesday, March 23, 2021, 09:40–10:00, BPc

Quantitative Theory for the Diffusive Dynamics of Liquid Condensates — •Lars Hubatsch^1,2, Louise M Jawerth^1,2, Celina Love², Jonathan Bauermann¹, Stefano Bo¹, T-Y Dora Tang², Anthony A Hyman², and Christoph A Weber^{1, 2} — ¹Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — ²Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany

To unravel the biological functions of membraneless liquid condensates it is crucial to develop a quantitative understanding of the physics underlying their dynamics. Key properties of such condensates are diffusion and exchange of material with their environment. Experimentally, such diffusive dynamics are typically probed through the direct observation of the individual or collective motion of fluorescently labelled molecules. However, to date we lack a physics-based quantitative framework for the dynamics of labeled condensate components. Here, we derive the corresponding theory, building on the physics of phase separation, and quantitatively validate this framework via experiments. We show that using our theory we can precisely determine diffusion coefficients inside liquid condensates via a spatio-temporal analysis of fluorescence recovery after photobleaching (FRAP) experiments. We showcase the accuracy and precision of our approach by considering space and time resolved data of protein condensates and two different coacervate systems. Strikingly, our theory can be used to determine the diffusion coefficient in the dilute phase and the partition coefficient, purely based on fluorescence measurements in the droplet.