Kelley Fleurie M, Ani Anas, Pinlac Emily G, Linders Bridget, Favetta Bruna, Barai Mayur, Ma Yuchen, Singh Arjun, Dignon Gregory L, Gu Yuwei, Schuster Benjamin S
Department of Chemical and Biochemical Engineering, Rutgers, the State University of New Jersey, Piscataway, NJ 08854.
Department of Chemistry and Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854.
bioRxiv. 2024 Jul 16:2024.07.11.603072. doi: 10.1101/2024.07.11.603072.
Biomolecular condensates arising from liquid-liquid phase separation contribute to diverse cellular processes, such as gene expression. Partitioning of client molecules into condensates is critical to regulating the composition and function of condensates. Previous studies suggest that client size limits partitioning, with dextrans >5 nm excluded from condensates. Here, we asked whether larger particles, such as macromolecular complexes, can partition into condensates based on particle-condensate interactions. We sought to discover the biophysical principles that govern particle inclusion in or exclusion from condensates using polymer nanoparticles with tailored surface chemistries as models of macromolecular complexes. Particles coated with polyethylene glycol (PEG) did not partition into condensates. We next leveraged the PEGylated particles as an inert platform to which we conjugated specific adhesive moieties. Particles functionalized with biotin partitioned into condensates containing streptavidin, driven by high-affinity biotin-streptavidin binding. Oligonucleotide-decorated particles exhibited varying degrees of partitioning into condensates, depending on condensate composition. Partitioning of oligonucleotide-coated particles was tuned by altering salt concentration, oligonucleotide length, and oligonucleotide surface density. Remarkably, beads with distinct surface chemistries partitioned orthogonally into immiscible condensates. Based on our experiments, we conclude that arbitrarily large particles can controllably partition into biomolecular condensates given sufficiently strong condensate-particle interactions, a conclusion also supported by our coarse-grained molecular dynamics simulations and theory. These findings may provide insights into how various cellular processes are achieved based on partitioning of large clients into biomolecular condensates, as well as offer design principles for the development of drug delivery systems that selectively target disease-related biomolecular condensates.
由液-液相分离产生的生物分子凝聚物参与多种细胞过程，如基因表达。客体分子分配到凝聚物中对于调节凝聚物的组成和功能至关重要。先前的研究表明，客体大小限制分配，大于5纳米的葡聚糖被排除在凝聚物之外。在此，我们探讨了诸如大分子复合物等较大颗粒是否能基于颗粒-凝聚物相互作用分配到凝聚物中。我们试图利用具有定制表面化学性质的聚合物纳米颗粒作为大分子复合物的模型，来发现控制颗粒进入或排除凝聚物的生物物理原理。涂有聚乙二醇（PEG）的颗粒不会分配到凝聚物中。接下来，我们利用聚乙二醇化颗粒作为惰性平台，并在其上偶联特定的粘附基团。用生物素功能化的颗粒在高亲和力的生物素-链霉亲和素结合驱动下，分配到含有链霉亲和素的凝聚物中。寡核苷酸修饰的颗粒根据凝聚物组成表现出不同程度的分配到凝聚物中。通过改变盐浓度、寡核苷酸长度和寡核苷酸表面密度来调节寡核苷酸包被颗粒的分配。值得注意的是，具有不同表面化学性质的珠子正交分配到互不相溶的凝聚物中。基于我们的实验，我们得出结论，给定足够强的凝聚物-颗粒相互作用，任意大的颗粒都可以可控地分配到生物分子凝聚物中，我们的粗粒度分子动力学模拟和理论也支持这一结论。这些发现可能为基于大客体分配到生物分子凝聚物来实现各种细胞过程提供见解，也为开发选择性靶向疾病相关生物分子凝聚物的药物递送系统提供设计原则。
