Despite more than 100 years of study, it is unclear if the movement of proteins inside the cell is best described as a mosh pit or an exquisitely choreographed dance. Recent studies suggest the latter. Local interactions induce molecular condensates such as liquid-liquid phase separations (LLPSs) or non-liquid, functionally significant molecular aggregates, including synaptic densities, nucleoli, and Amyloid fibrils. Molecular condensates trigger intracellular signaling and drive processes ranging from gene expression to cell division. However, the descriptions of condensates tend to be qualitative and correlative. Here, we indicate how single-molecule imaging and analyses can be applied to quantify condensates. We discuss the pros and cons of different techniques for measuring differences between transient molecular behaviors inside and outside condensates. Finally, we offer suggestions for how imaging and analyses from different time and space regimes can be combined to identify molecular behaviors indicative of condensates within the dynamic high-density intracellular environment.

尽管经过了 100 多年的研究，目前尚不清楚细胞内蛋白质的运动是否应该被描述为“狂欢”或“精心编排的舞蹈” 。最近的研究表明是后者。局部相互作用诱导分子凝聚，例如液-液相分离 (LLPS) 或非液体、功能上重要的分子聚集体，包括突触密度、核仁和淀粉样原纤维。分子缩合物触发细胞内信号传导并驱动从基因表达到细胞分裂的过程。然而，凝聚态的描述往往是定性的和相关的。在这里，我们展示了如何应用单分子成像和分析来量化冷凝物。我们讨论了测量冷凝物内部和外部瞬态分子行为之间差异的不同技术的优缺点。最后，我们就如何结合不同时间和空间状态的成像和分析来识别动态高密度细胞内环境中凝聚物的分子行为提出了建议。