RT Journal Article
SR Electronic
T1 Non-specific adhesive forces between filaments and membraneless organelles
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.07.22.453380
DO 10.1101/2021.07.22.453380
A1 Thomas J. Böddeker
A1 Kathryn A. Rosowski
A1 Doris Berchtold
A1 Leonidas Emmanouilidis
A1 Yaning Han
A1 Frédéric H. T. Allain
A1 Robert W. Style
A1 Lucas Pelkmans
A1 Eric R. Dufresne
YR 2021
UL http://biorxiv.org/content/early/2021/07/23/2021.07.22.453380.abstract
AB Membraneless organelles are liquid-like domains that form inside living cells by phase-separation. While standard physical models of their formation assume their surroundings to be a simple liquid, the cytoplasm is an active viscoelastic environment. To investigate potential coupling of phase separation with the cytoskeleton, we quantify structural correlations of stress granules and microtubules in a human-derived epithelial cell line. We find that microtubule networks are significantly perturbed in the vicinity of stress granules, and that large stress granules conform to the local pore-structure of the microtubule network. When microtubules are depolymerized by nocodazole, tubulin enrichment is localized near the surface of stress granules. We interpret these data using a thermodynamic model of partitioning of particles to the surface and bulk of droplets. This analysis shows that proteins generically have a non-specific affinity for droplet interfaces, which becomes most apparent when they weakly partition to the bulk of droplets and have a large molecular weight. In this framework, our data is consistent with a weak (≲ kbT) affinity of tubulin sub-units for stress granule interfaces. As microtubules polymerize their affinity for interfaces increases, providing sufficient adhesion to deform droplets and/or the network. We validate this basic physical phenomena in vitro through the interaction of a simple protein-RNA condensate with tubulin and microtubules.Competing Interest StatementThe authors have declared no competing interest.