Abstract:
Condensate droplets are formed in aqueous solutions of macromolecules that undergo phase separation into two liquid phases. A well-studied example are solutions of the two polymers PEG and dextran which have been used for a long time in biochemical analysis and biotechnology. More recently, phase separation has also been observed in living cells where it leads to membrane-less or droplet-like organelles. In the latter case, the condensate droplets are enriched in certain types of proteins. Generic features of condensate droplets can be studied in simple binary mixtures, using molecular dynamics simulations. In this review, I address the interactions of condensate droplets with biomimetic and biological membranes. When a condensate droplet adheres to such a membrane, the membrane forms a contact line with the droplet and acquires a very high curvature close to this line. The contact angles along the contact line can be observed via light microscopy, lead to a classification of the possible adhesion morphologies, and determine the affinity contrast between the two coexisting liquid phases and the membrane. The remodeling processes generated by condensate droplets include wetting transitions, formation of membrane nanotubes as well as complete engulfment and endocytosis of the droplets by the membranes.
摘要:
在经历相分离成两个液相的大分子的水溶液中形成冷凝液滴。一个充分研究的例子是两种聚合物PEG和葡聚糖的溶液,它们已经在生化分析和生物技术中使用了很长时间。最近,在活细胞中也观察到相分离,它导致无膜或液滴样细胞器。在后一种情况下,冷凝液滴富含某些类型的蛋白质。可以在简单的二元混合物中研究冷凝液滴的一般特征,使用分子动力学模拟。在这次审查中,我讨论了冷凝液滴与仿生和生物膜的相互作用。当冷凝液滴附着在这种膜上时,膜与液滴形成接触线并获得接近该线的非常高的曲率。沿接触线的接触角可以通过光学显微镜观察,导致可能的粘附形态的分类,并确定两个共存液相与膜之间的亲和力对比度。冷凝液滴产生的重塑过程包括润湿转变,膜纳米管的形成以及膜对液滴的完全吞噬和内吞作用。