Berlin 2024 – scientific programme
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BP: Fachverband Biologische Physik
BP 28: Cytoskeleton
BP 28.6: Talk
Thursday, March 21, 2024, 11:15–11:30, H 2032
The cytoskeleton positions protein condensates — •Thomas J. Böddeker1,2, Roland L. Knorr2, and Eric R. Dufresne1,3 — 1ETH Zürich, Zürich, Switzerland — 2Humboldt-Universität zu Berlin, Berlin, Germany — 3Cornell University, Ithaca, USA
Protein condensates inside human cells are liquid-like droplets composed of protein and RNA. These condensates interact with the heterogeneous, active and dense environment of the cytoplasm, crossed by various cytoskeletal filaments such as microtubules and actin. Capillary interactions with the cytoskeleton lead to stereotypical positioning of such protein droplets inside the cell. Using statistical physics approaches, we identified complementary functions of filamentous actin and microtubules for the positioning of such condensates: protein condensates couple to actin’s native dynamics in the cell through steric interactions leading to directional motion towards the cell center. Microtubules (and their molecular building-blocks), on the other hand, act as Pickering agents and engage in energetically favorable wetting interactions that lead to a robust localization of protein condensates in microtubule-rich regions of the cell. Cytoskeletal filaments, in turn, deform in response to capillary forces, leading to network modulations centered on protein condensates. These mutual interactions are non-specific and ultimately arise from different affinities (contact angles) between condensate and filament, suggesting that similar mechanisms may impact localization of other liquid-like phases within the cell and structure formation within the cytoskeleton.
T.J. Böddeker, et. al. PRX Life, in press
Keywords: Phase separation; Protein condensate; Actin; Microtubules; Wetting