98%
921
2 minutes
20
Liquid-liquid phase separation (LLPS) of putative assembly scaffolds has been proposed to drive the biogenesis of membraneless compartments. LLPS scaffolds are usually identified through in vitro LLPS assays with single macromolecules (homotypic), but the predictive value of these assays remains poorly characterized. Here, we apply a strategy to evaluate the robustness of homotypic LLPS assays. When applied to the chromosomal passenger complex (CPC), which undergoes LLPS in vitro and localizes to centromeres to promote chromosome biorientation, LLPS propensity in vitro emerged as an unreliable predictor of subcellular localization. In vitro CPC LLPS in aqueous buffers was enhanced by commonly used crowding agents. Conversely, diluted cytomimetic media dissolved condensates of the CPC and of several other proteins. We also show that centromeres do not seem to nucleate LLPS, nor do they promote local, spatially restrained LLPS of the CPC. Our strategy can be adapted to purported LLPS scaffolds of other membraneless compartments.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.molcel.2024.03.022 | DOI Listing |
Proc Natl Acad Sci U S A
September 2025
State Key Laboratory of Green Biomanufacturing, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
High-mobility group box protein 1 (HMGB1) is a chromatin-associated nonhistone protein widely distributed in the nucleus of eukaryotic cells. It is transported extracellularly as a proinflammatory mediator or late warning protein to induce immune and inflammatory reactions upon stimuli such as microbial infection. Here, we have found that HMGB1 directly interacts with bacterial DNA analogue CpG-A in the extracellular environment to undergo liquid-liquid phase separation (LLPS) via its positively charged DNA-binding domain.
View Article and Find Full Text PDFInt J Biol Macromol
September 2025
National Demonstration Center for Experimental Fisheries Science Education (Shanghai Ocean University), Shanghai, 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education, Shanghai, 201306, China; International Resea
Phase separation has been discovered as a new form of regulation in innate immunity. Here, we found that IL6Ra in teleost fish has a unique intrinsic disordered region (IDR) in its amino acid sequence, distinguishing it from the IL6Ra of higher vertebrates. This unique feature endows IL6Ra with the ability to undergo liquid-liquid phase separation, enabling the organism to swiftly initiate an immune response at the early stages of viral infection.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Department of Chemical and Biomolecular Engineering, Department of Chemistry, Department of Materials Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign,Urbana, Illinois 61801, United States.
Spontaneous chiral symmetry breaking remains a fascination in chemistry, biology, materials science, and even astronomy. Chiral symmetry breaking usually requires intrinsic molecular chirality or extrinsic chiral sources but remains rare in nonchiral systems. Here, we reveal a ubiquitous, entropy-driven chiral symmetry breaking mechanism observed in 22 out of 35 conjugated polymers in the absence of any chiral source─a phenomenon overlooked for decades.
View Article and Find Full Text PDFJ Phys Chem B
September 2025
Hefei National Research Center for Physical Sciences at the Microscale and Key Laboratory of Precision and Intelligent Chemistry, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Multivalent protein-protein interactions play essential roles in mediating liquid-liquid phase separation (LLPS) that drives biomolecular condensate formation. Here, we systematically investigate how the spatial distribution and relative size of protein binding domains (PBDs) would influence LLPS in a mixture of spherical proteins and RNA single strands by using a patchy-particle polymer model, wherein each protein contains a fixed number of PBDs on the surface distributed closely or sparsely. Intriguingly, we find that LLPS behavior exhibits a nontrivial dependence on the cooperative interplay between PBD distribution and protein size: while sparsely distributed PBDs are more favorable to LLPS for small proteins, closely packed PBDs facilitate LLPS for larger counterparts.
View Article and Find Full Text PDFBiophys Chem
September 2025
Department of Biophysics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
A comprehensive understanding of the molecular mechanism underlying the Liquid-Liquid Phase Separation (LLPS) pathway of LCD-TDP43 remains a challenge in the context of its neuropathogenesis. The primary driving force behind the TDP-43 LLPS is the interplay of hydrophobic interactions reinforced by aromatic residues. This study presents a novel, convenient, sensitive, and probe-free approach using excitation-emission matrix (EEM) fluorescence to monitor the microenvironment of aromatic residues and π-π stacking interactions during different stages of the LLPS pathway.
View Article and Find Full Text PDF