Optical characterization of molecular interaction strength in protein condensates.

IF 3.1 3区 生物学 Q3 CELL BIOLOGY
Molecular Biology of the Cell Pub Date : 2024-12-01 Epub Date: 2024-11-13 DOI:10.1091/mbc.E24-03-0128
Timon Beck, Lize-Mari van der Linden, Wade M Borcherds, Kyoohyun Kim, Raimund Schlüßler, Paul Müller, Titus M Franzmann, Conrad Möckel, Ruchi Goswami, Mark Leaver, Tanja Mittag, Simon Alberti, Jochen Guck
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引用次数: 0

Abstract

Biomolecular condensates have been identified as a ubiquitous means of intracellular organization, exhibiting very diverse material properties. However, techniques to characterize these material properties and their underlying molecular interactions are scarce. Here, we introduce two optical techniques-Brillouin microscopy and quantitative phase imaging (QPI)-to address this scarcity. We establish Brillouin shift and linewidth as measures for average molecular interaction and dissipation strength, respectively, and we used QPI to obtain the protein concentration within the condensates. We monitored the response of condensates formed by fused in sarcoma (FUS) and by the low-complexity domain of hnRNPA1 (A1-LCD) to altering temperature and ion concentration. Conditions favoring phase separation increased Brillouin shift, linewidth, and protein concentration. In comparison to solidification by chemical cross-linking, the ion-dependent aging of FUS condensates had a small effect on the molecular interaction strength inside. Finally, we investigated how sequence variations of A1-LCD, that change the driving force for phase separation, alter the physical properties of the respective condensates. Our results provide a new experimental perspective on the material properties of protein condensates. Robust and quantitative experimental approaches such as the presented ones will be crucial for understanding how the physical properties of biological condensates determine their function and dysfunction.

蛋白质凝聚体中分子相互作用强度的光学表征。
生物分子凝聚物已被确定为一种无处不在的细胞内组织方式,表现出多种多样的物质特性。然而,表征这些材料特性及其潜在分子相互作用的技术却十分匮乏。在这里,我们引入了两种光学技术--布里渊显微镜和定量相位成像(QPI)--来解决这一稀缺问题。我们将布里渊位移和线宽分别作为衡量平均分子相互作用和耗散强度的指标,并使用 QPI 来获得凝聚物内部的蛋白质浓度。我们监测了 FUS 和 hnRNPA1 的低复杂度结构域(A1-LCD)形成的凝聚体对改变温度和离子浓度的反应。有利于相分离的条件增加了布里渊位移、线宽和蛋白质浓度。与化学交联固化相比,FUS 凝聚物的离子依赖性老化对内部分子相互作用强度的影响较小。最后,我们研究了改变相分离驱动力的 A1-LCD 序列变化如何改变各自冷凝物的物理性质。我们的研究结果为蛋白质凝聚物的物理性质提供了一个新的实验视角。稳健的定量实验方法(如本文介绍的方法)对于理解生物凝聚物的物理性质如何决定其功能和功能障碍至关重要。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Molecular Biology of the Cell
Molecular Biology of the Cell 生物-细胞生物学
CiteScore
6.00
自引率
6.10%
发文量
402
审稿时长
2 months
期刊介绍: MBoC publishes research articles that present conceptual advances of broad interest and significance within all areas of cell, molecular, and developmental biology. We welcome manuscripts that describe advances with applications across topics including but not limited to: cell growth and division; nuclear and cytoskeletal processes; membrane trafficking and autophagy; organelle biology; quantitative cell biology; physical cell biology and mechanobiology; cell signaling; stem cell biology and development; cancer biology; cellular immunology and microbial pathogenesis; cellular neurobiology; prokaryotic cell biology; and cell biology of disease.
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