Glutamate helps unmask the differences in driving forces for phase separation versus clustering of FET family proteins in sub-saturated solutions.

Autor: Kar M; Max Planck Institute of Cell Biology and Genetics, 01307, Dresden, Germany., Vogel LT; Department of Molecular Physical Chemistry, Heinrich Heine University, 40225, Düsseldorf, Germany., Chauhan G; Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130, USA., Ausserwöger H; Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW, Cambridge, UK., Welsh TJ; Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW, Cambridge, UK., Kamath AR; Max Planck Institute of Cell Biology and Genetics, 01307, Dresden, Germany., Knowles TPJ; Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW, Cambridge, UK., Hyman AA; Max Planck Institute of Cell Biology and Genetics, 01307, Dresden, Germany., Seidel CAM; Department of Molecular Physical Chemistry, Heinrich Heine University, 40225, Düsseldorf, Germany., Pappu RV; Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130, USA.
Jazyk: angličtina
Zdroj: Research square [Res Sq] 2023 Sep 18. Date of Electronic Publication: 2023 Sep 18.
DOI: 10.21203/rs.3.rs-3252197/v1
Abstrakt: Multivalent proteins undergo coupled segregative and associative phase transitions. Phase separation, a segregative transition, is driven by macromolecular solubility, and this leads to coexisting phases above system-specific saturation concentrations. Percolation is a continuous transition that is driven by multivalent associations among cohesive motifs. Contributions from percolation are highlighted by the formation of heterogeneous distributions of clusters in sub-saturated solutions, as was recently reported for Fused in sarcoma (FUS) and FET family proteins. Here, we show that clustering and phase separation are defined by a separation of length- and energy-scales. This is unmasked when glutamate is the primary solution anion. Glutamate is preferentially excluded from protein sites, and this enhances molecular associations. Differences between glutamate and chloride are manifest at ultra-low protein concentrations. These differences are amplified as concentrations increase, and they saturate as the micron-scale is approached. Therefore, condensate formation in supersaturated solutions and clustering in sub-saturated are governed by distinct energy and length scales. Glutamate, unlike chloride, is the dominant intracellular anion, and the separation of scales, which is masked in chloride, is unmasked in glutamate. Our work highlights how components of cellular milieus and sequence-encoded interactions contribute to amplifying distinct contributions from associative versus segregative phase transitions.
Databáze: MEDLINE