Liquid-liquid phase separation has emerged as an important means of intracellular RNA compartmentalization. Some membraneless organelles host two or more compartments serving different putative biochemical roles. The mechanisms for, and functional consequences of, this subcompartmentalization are not yet well understood. Here we show that adjacent phases of decapeptide-based multiphase model membraneless organelles differ markedly in their interactions with RNA. Single- and double-stranded RNAs preferentially accumulate in different phases within the same droplet, and one phase is more destabilizing for RNA duplexes than the other. Single-phase peptide droplets did not capture this behaviour. Phase coexistence introduces new thermodynamic equilibria that alter RNA duplex stability and RNA sorting by hybridization state. These effects require neither biospecific RNA-binding sites nor full-length proteins. As such, they are more general and point to primitive versions of mechanisms operating in extant biology that could aid understanding and enable the design of functional artificial membraneless organelles.
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http://dx.doi.org/10.1038/s41557-022-00980-7 | DOI Listing |
J Am Chem Soc
January 2025
Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China.
Biomolecular condensation lays the foundation of forming biologically important membraneless organelles, but abnormal condensation processes are often associated with human diseases. Ribonucleic acid (RNA) plays a critical role in the formation of biomolecular condensates by mediating the phase transition through its interactions with proteins and other RNAs. However, the physicochemical principles governing RNA phase transitions, especially for short RNAs, remain inadequately understood.
View Article and Find Full Text PDFBiomacromolecules
January 2025
Instituto de Química de los Materiales, Ambiente y Energía, CONICET, Universidad de Buenos Aires, Intendente Güiraldes 2160, CABA (Buenos Aires) 1428, Argentina.
The study of the phase behavior of polyelectrolyte complex coacervates has attracted significant attention in recent years due to their potential use as membrane-less organelles, microreactors, and drug delivery platforms. In this work, we investigate the mechanism of protein loading in chain-length asymmetric complex coacervates composed of a polyelectrolyte and an oppositely charged multivalent ion. Unlike the symmetric case (polycation + polyanion), we show that protein loading is highly selective based on the protein's net charge: only proteins with charges opposite to the polyelectrolyte can be loaded.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
School of Physics, Zhejiang University, Hangzhou, 310058, PR China.
The self-assembly of intrinsically disordered proteins (IDPs) into condensed phases and the formation of membrane-less organelles (MLOs) can be considered as the phenomenon of collective behavior. The conformational dynamics of IDPs are essential for their interactions and the formation of a condensed phase. From a physical perspective, collective behavior and the emergence of phase are associated with long-range correlations.
View Article and Find Full Text PDFPLoS Comput Biol
January 2025
Department of Physical-Chemistry, Complutense University of Madrid, Madrid, Spain.
Intracellular liquid-liquid phase separation (LLPS) of proteins and nucleic acids is a fundamental mechanism by which cells compartmentalize their components and perform essential biological functions. Molecular simulations play a crucial role in providing microscopic insights into the physicochemical processes driving this phenomenon. In this study, we systematically compare six state-of-the-art sequence-dependent residue-resolution models to evaluate their performance in reproducing the phase behaviour and material properties of condensates formed by seven variants of the low-complexity domain (LCD) of the hnRNPA1 protein (A1-LCD)-a protein implicated in the pathological liquid-to-solid transition of stress granules.
View Article and Find Full Text PDFCell Rep
January 2025
Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan; Sustainable Chemical Science and Technology, Taiwan International Graduate Program, Academia Sinica, Taipei 115, Taiwan; Department of Applied Chemistry, National Chiayi University, Chiayi City 600, Taiwan; Neuroscience Program of Academia Sinica, Academia Sinica, Taipei 115, Taiwan. Electronic address:
The toxicity of C9ORF72-encoded polyproline-arginine (poly-PR) dipeptide is associated with its ability to disrupt the liquid-liquid phase separation of intrinsically disordered proteins participating in the formation of membraneless organelles, such as the nucleolus and paraspeckles. Amyotrophic lateral sclerosis (ALS)-related TAR DNA-binding protein 43 (TDP-43) also undergoes phase separation to form nuclear condensates (NCs) in response to stress. However, whether poly-PR alters the nuclear condensation of TDP-43 in ALS remains unclear.
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