The solubility product extends the buffering concept to heterotypic biomolecular condensates

eLife

Michael L Blinov¹  Leslie M Loew¹  Aniruddha Chattaraj¹ 

[1] R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, United States;

关键词: LLPS;    biomolecular condensate;    solubility product;    rule based modeling;    None;   

DOI  :  10.7554/eLife.67176

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Biomolecular condensates are formed by liquid-liquid phase separation (LLPS) of multivalent molecules. LLPS from a single ("homotypic") constituent is governed by buffering: above a threshold, free monomer concentration is clamped, with all added molecules entering the condensed phase. However, both experiment and theory demonstrate that buffering fails for the concentration dependence of multicomponent ("heterotypic") LLPS. Using network-free stochastic modeling, we demonstrate that LLPS can be described by the solubility product constant (Ksp): the product of free monomer concentrations, accounting for the ideal stoichiometries governed by the valencies, displays a threshold above which additional monomers are funneled into large clusters; this reduces to simple buffering for homotypic systems. The Ksp regulates the composition of the dilute phase for a wide range of valencies and stoichiometries. The role of Ksp is further supported by coarse-grained spatial particle simulations. Thus, the solubility product offers a general formulation for the concentration dependence of LLPS.

【 授权许可】

CC BY