1
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Chadha Y, Khurana A, Schmoller KM. Eukaryotic cell size regulation and its implications for cellular function and dysfunction. Physiol Rev 2024; 104:1679-1717. [PMID: 38900644 DOI: 10.1152/physrev.00046.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 05/24/2024] [Accepted: 06/19/2024] [Indexed: 06/22/2024] Open
Abstract
Depending on cell type, environmental inputs, and disease, the cells in the human body can have widely different sizes. In recent years, it has become clear that cell size is a major regulator of cell function. However, we are only beginning to understand how the optimization of cell function determines a given cell's optimal size. Here, we review currently known size control strategies of eukaryotic cells and the intricate link of cell size to intracellular biomolecular scaling, organelle homeostasis, and cell cycle progression. We detail the cell size-dependent regulation of early development and the impact of cell size on cell differentiation. Given the importance of cell size for normal cellular physiology, cell size control must account for changing environmental conditions. We describe how cells sense environmental stimuli, such as nutrient availability, and accordingly adapt their size by regulating cell growth and cell cycle progression. Moreover, we discuss the correlation of pathological states with misregulation of cell size and how for a long time this was considered a downstream consequence of cellular dysfunction. We review newer studies that reveal a reversed causality, with misregulated cell size leading to pathophysiological phenotypes such as senescence and aging. In summary, we highlight the important roles of cell size in cellular function and dysfunction, which could have major implications for both diagnostics and treatment in the clinic.
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Affiliation(s)
- Yagya Chadha
- Institute of Functional Epigenetics, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, Germany
| | - Arohi Khurana
- Institute of Functional Epigenetics, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, Germany
| | - Kurt M Schmoller
- Institute of Functional Epigenetics, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, Germany
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2
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Yang S, Potoyan DA. Microscopic Origins of Flow Activation Energy in Biomolecular Condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.24.614801. [PMID: 39386700 PMCID: PMC11463594 DOI: 10.1101/2024.09.24.614801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
Material properties of biomolecular condensates dictate their form and function, influencing the diffusion of regulatory molecules and the dynamics of biochemical reactions. The increasing quality and quantity of microrheology experiments on biomolecular condensates necessitate a deeper understanding of the molecular grammar that encodes their material properties. Recent reports have identified a characteristic timescale related to network relaxation dynamics in condensates, which governs their temperature-dependent viscoelastic properties. This timescale is intimately connected to an activated process involving the dissociation of sticker regions, with the energetic barrier referred to as flow activation energy. The microscopic origin of activation energy is a complex function of sequence patterns, component stoichiometry, and external conditions. This study elucidates the microscopic origins of flow activation energy in single and multicomponent condensates composed of model peptide sequences with varying sticker and spacer motifs, with RNA as a secondary component. We dissected the effects of condensate density, RNA stoichiometry, and peptide sequence patterning using extensive sequence-resolved coarse-grained simulations. We found that flow activation energy is closely linked to the lifetime of sticker-sticker pairs under certain conditions, though the presence of multiple competing stickers further complicates this relationship. The insights gained in this study should help establish predictive multiscale models for the material properties and serve as a valuable guide for the programmable design of condensates.
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3
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Morimitsu Y, Browne CA, Liu Z, Severino PG, Gopinadhan M, Sirota EB, Altintas O, Edmond KV, Osuji CO. Spontaneous assembly of condensate networks during the demixing of structured fluids. Proc Natl Acad Sci U S A 2024; 121:e2407914121. [PMID: 39269770 PMCID: PMC11441503 DOI: 10.1073/pnas.2407914121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Accepted: 07/16/2024] [Indexed: 09/15/2024] Open
Abstract
Liquid-liquid phase separation, whereby two liquids spontaneously demix, is ubiquitous in industrial, environmental, and biological processes. While isotropic fluids are known to condense into spherical droplets in the binodal region, these dynamics are poorly understood for structured fluids. Here, we report the unique observation of condensate networks, which spontaneously assemble during the demixing of a mesogen from a solvent. Condensing mesogens form rapidly elongating filaments, rather than spheres, to relieve distortion of an internal smectic mesophase. As filaments densify, they collapse into bulged discs, lowering the elastic free energy. Additional distortion is relieved by retraction of filaments into the discs, which are straightened under tension to form a ramified network. Understanding and controlling these dynamics may provide different avenues to direct pattern formation or template materials.
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Affiliation(s)
- Yuma Morimitsu
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA19104
| | - Christopher A. Browne
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA19104
| | - Zhe Liu
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA19104
| | - Paul G. Severino
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA19104
| | - Manesh Gopinadhan
- Research Division, ExxonMobil Technology and Engineering Company, Annandale, NJ08801
| | - Eric B. Sirota
- Research Division, ExxonMobil Technology and Engineering Company, Annandale, NJ08801
| | - Ozcan Altintas
- Research Division, ExxonMobil Technology and Engineering Company, Annandale, NJ08801
| | - Kazem V. Edmond
- Research Division, ExxonMobil Technology and Engineering Company, Annandale, NJ08801
| | - Chinedum O. Osuji
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA19104
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4
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Sternke‐Hoffmann R, Sun X, Menzel A, Pinto MDS, Venclovaite U, Wördehoff M, Hoyer W, Zheng W, Luo J. Phase Separation and Aggregation of α-Synuclein Diverge at Different Salt Conditions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2308279. [PMID: 38973194 PMCID: PMC11425899 DOI: 10.1002/advs.202308279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 05/27/2024] [Indexed: 07/09/2024]
Abstract
The coacervation of alpha-synuclein (αSyn) into cytotoxic oligomers and amyloid fibrils are considered pathological hallmarks of Parkinson's disease. While aggregation is central to amyloid diseases, liquid-liquid phase separation (LLPS) and its interplay with aggregation have gained increasing interest. Previous work shows that factors promoting or inhibiting aggregation have similar effects on LLPS. This study provides a detailed scanning of a wide range of parameters, including protein, salt and crowding concentrations at multiple pH values, revealing different salt dependencies of aggregation and LLPS. The influence of salt on aggregation under crowding conditions follows a non-monotonic pattern, showing increased effects at medium salt concentrations. This behavior can be elucidated through a combination of electrostatic screening and salting-out effects on the intramolecular interactions between the N-terminal and C-terminal regions of αSyn. By contrast, this study finds a monotonic salt dependence of LLPS due to intermolecular interactions. Furthermore, it observes time evolution of the two distinct assembly states, with macroscopic fibrillar-like bundles initially forming at medium salt concentration but subsequently converting into droplets after prolonged incubation. The droplet state is therefore capable of inhibiting aggregation or even dissolving aggregates through heterotypic interactions, thus preventing αSyn from its dynamically arrested state.
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Affiliation(s)
| | - Xun Sun
- Center for Life SciencesPaul Scherrer InstituteForschungsstrasse 111Villigen5232Switzerland
| | - Andreas Menzel
- Center for Photon SciencePaul Scherrer InstituteForschungsstrasse 111Villigen5232Switzerland
| | | | - Urte Venclovaite
- Center for Life SciencesPaul Scherrer InstituteForschungsstrasse 111Villigen5232Switzerland
| | - Michael Wördehoff
- Institut für Physikalische BiologieHeinrich‐Heine University Düsseldorf40225DüsseldorfGermany
| | - Wolfgang Hoyer
- Institut für Physikalische BiologieHeinrich‐Heine University Düsseldorf40225DüsseldorfGermany
| | - Wenwei Zheng
- College of Integrative Sciences and ArtsArizona State UniversityMesaAZ85212USA
| | - Jinghui Luo
- Center for Life SciencesPaul Scherrer InstituteForschungsstrasse 111Villigen5232Switzerland
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5
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O'Neill NS, Alvarez NJ, Schweitzer-Stenner R. Tuning the thermostability of GHG gels by salts at different positions on the Hofmeister scale. Sci Rep 2024; 14:14742. [PMID: 38926473 PMCID: PMC11208536 DOI: 10.1038/s41598-024-65145-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
The influence of Hofmeister cations (NH4+, Na+, Mg2+) and anions (H2PO4-, CH3COO-, Cl-, NO3-) on the thermostability of a GHG hydrogel was investigated. The combined results of UV circular dichroism (UVCD) and Small Amplitude Oscillatory Shear Rheology experiments reveal that the addition of salt reduces the stability of the gel phase and the underlying fibrils. In line with the cationic Hofmeister hierarchy, the chaotropic Mg2+ ions caused the greatest thermal destabilization of the gel phase with the gel → sol transition temperature Tgs value lowered by 10 °C. In the absence of salt, the gel → sol transition probed by the storage modulus and microscopy is biphasic. In the presence of salt, it becomes monophasic. Contrary to expectations the presence of Hofmeister anions leads to a nearly identical reduction of the gel → sol transition temperatures. However, UVCD spectra suggest that they affect the ππ-stacking between imidazole groups to a different extent. We relate the absence of ion specificity regarding the solubility of fibrils (probed by UVCD) to the observed enthalpy-entropy compensation of the dissolution process. Our results combined show how CD spectroscopy and rheology combined yields a more nuanced picture of the processes underlying the gel → sol transition.
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Affiliation(s)
- Nichole S O'Neill
- Department of Chemistry, Drexel University, Philadelphia, PA, 19104, USA
| | - Nicolas J Alvarez
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA, 19104, USA.
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6
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Chen F, Li X, Guo W, Wang Y, Guo M, Shum HC. Size Scaling of Condensates in Multicomponent Phase Separation. J Am Chem Soc 2024; 146:16000-16009. [PMID: 38809420 DOI: 10.1021/jacs.4c02906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Constant proportionalities between cells and their intracellular organelles have been widely observed in various types of cells, known as intracellular size scaling. However, the mechanism underlying the size scaling and its modulation by environmental factors in multicomponent systems remain poorly understood. Here, we study the size scaling of membrane-less condensates using microdroplet-encapsulated minimalistic condensates formed by droplet microfluidics and mean-field theory. We demonstrate that the size scaling of condensates is an inherent characteristic of liquid-liquid phase separation. This concept is supported by experiments showing the occurrence of size scaling phenomena in various condensate systems and a generic lever rule acquired from mean-field theory. Moreover, it is found that the condensate-to-microdroplet scaling ratio can be affected by the solute and salt concentrations, with good agreement between experiments and predictions by theory. Notably, we identify a noise buffering mechanism whereby condensates composed of large macromolecules effectively maintain constant volumes and counteract concentration fluctuations of small molecules. This mechanism is achieved through the dynamic rearrangement of small molecules in and out of membrane-free interfaces. Our work provides crucial insights into understanding mechanistic principles that govern the size of cells and intracellular organelles as well as associated biological functions.
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Affiliation(s)
- Feipeng Chen
- Department of Mechanical Engineering, the University of Hong Kong, Pokfulam Road, Hong Kong (SAR) 999077, China
| | - Xiufeng Li
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong (SAR) 999077, China
- College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Wei Guo
- Department of Mechanical Engineering, the University of Hong Kong, Pokfulam Road, Hong Kong (SAR) 999077, China
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong (SAR) 999077, China
| | - Yuchao Wang
- Department of Mechanical Engineering, the University of Hong Kong, Pokfulam Road, Hong Kong (SAR) 999077, China
| | - Ming Guo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Ho Cheung Shum
- Department of Mechanical Engineering, the University of Hong Kong, Pokfulam Road, Hong Kong (SAR) 999077, China
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong (SAR) 999077, China
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7
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Boyer NP, Sharma R, Wiesner T, Delamare A, Pelletier F, Leterrier C, Roy S. Spectrin condensates provide a nidus for assembling the periodic axonal structure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.05.597638. [PMID: 38895400 PMCID: PMC11185721 DOI: 10.1101/2024.06.05.597638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Coordinated assembly of individual components into higher-order structures is a defining theme in biology, but underlying principles are not well-understood. In neurons, α/β spectrins, adducin, and actinfilaments assemble into a lattice wrapping underneath the axonal plasma membrane, but mechanistic events leading to this periodic axonal structure (PAS) are unclear. Visualizing PAS components in axons as they develop, we found focal patches in distal axons containing spectrins and adducin (but sparse actin filaments) with biophysical properties reminiscent of biomolecular condensation. Overexpressing spectrin-repeats - constituents of α/β-spectrins - in heterologous cells triggered condensate formation, and preventing association of βII-spectrin with actin-filaments/membranes also facilitated condensation. Finally, overexpressing condensate-triggering spectrin repeats in neurons before PAS establishment disrupted the lattice, presumably by competing with innate assembly, supporting a functional role for biomolecular condensation. We propose a condensation-assembly model where PAS components form focal phase-separated condensates that eventually unfurl into a stable lattice-structure by associating with subplasmalemmal actin. By providing local 'depots' of assembly parts, biomolecular condensation may play a wider role in the construction of intricate cytoskeletal structures.
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8
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Ashraf HN, Uversky VN. Intrinsic Disorder in the Host Proteins Entrapped in Rabies Virus Particles. Viruses 2024; 16:916. [PMID: 38932209 PMCID: PMC11209445 DOI: 10.3390/v16060916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/23/2024] [Accepted: 05/28/2024] [Indexed: 06/28/2024] Open
Abstract
A proteomics analysis of purified rabies virus (RABV) revealed 47 entrapped host proteins within the viral particles. Out of these, 11 proteins were highly disordered. Our study was particularly focused on five of the RABV-entrapped mouse proteins with the highest levels of disorder: Neuromodulin, Chmp4b, DnaJB6, Vps37B, and Wasl. We extensively utilized bioinformatics tools, such as FuzDrop, D2P2, UniProt, RIDAO, STRING, AlphaFold, and ELM, for a comprehensive analysis of the intrinsic disorder propensity of these proteins. Our analysis suggested that these disordered host proteins might play a significant role in facilitating the rabies virus pathogenicity, immune system evasion, and the development of antiviral drug resistance. Our study highlighted the complex interaction of the virus with its host, with a focus on how the intrinsic disorder can play a crucial role in virus pathogenic processes, and suggested that these intrinsically disordered proteins (IDPs) and disorder-related host interactions can also be a potential target for therapeutic strategies.
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Affiliation(s)
- Hafiza Nimra Ashraf
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA;
| | - Vladimir N. Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA;
- USF Health Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
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9
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Islam M, Shen F, Regmi D, Petersen K, Karim MRU, Du D. Tau liquid-liquid phase separation: At the crossroads of tau physiology and tauopathy. J Cell Physiol 2024; 239:e30853. [PMID: 35980344 PMCID: PMC9938090 DOI: 10.1002/jcp.30853] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/12/2022] [Accepted: 07/22/2022] [Indexed: 12/14/2022]
Abstract
Abnormal deposition of tau in neurons is a hallmark of Alzheimer's disease and several other neurodegenerative disorders. In the past decades, extensive efforts have been made to explore the mechanistic pathways underlying the development of tauopathies. Recently, the discovery of tau droplet formation by liquid-liquid phase separation (LLPS) has received a great deal of attention. It has been reported that tau condensates have a biological role in promoting and stabilizing microtubule (MT) assembly. Furthermore, it has been hypothesized that the transition of phase-separated tau droplets to a gel-like state and then to fibrils is associated with the pathology of neurodegenerative diseases. In this review, we outline LLPS, the structural disorder that facilitates tau droplet formation, the effects of posttranslational modification of tau on condensate formation, the physiological function of tau droplets, the pathways from droplet to toxic fibrils, and the therapeutic strategies for tauopathies that might evolve from toxic droplets. We expect a deeper understanding of tau LLPS will provide additional insights into tau physiology and tauopathies.
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Affiliation(s)
- Majedul Islam
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Fengyun Shen
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Deepika Regmi
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Katherine Petersen
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Md Raza Ul Karim
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Deguo Du
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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10
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Juković M, Ratkaj I, Kalafatovic D, Bradshaw NJ. Amyloids, amorphous aggregates and assemblies of peptides - Assessing aggregation. Biophys Chem 2024; 308:107202. [PMID: 38382283 DOI: 10.1016/j.bpc.2024.107202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/31/2024] [Accepted: 02/14/2024] [Indexed: 02/23/2024]
Abstract
Amyloid and amorphous aggregates represent the two major categories of aggregates associated with diseases, and although exhibiting distinct features, researchers often treat them as equivalent, which demonstrates the need for more thorough characterization. Here, we compare amyloid and amorphous aggregates based on their biochemical properties, kinetics, and morphological features. To further decipher this issue, we propose the use of peptide self-assemblies as minimalistic models for understanding the aggregation process. Peptide building blocks are significantly smaller than proteins that participate in aggregation, however, they make a plausible means to bridge the gap in discerning the aggregation process at the more complex, protein level. Additionally, we explore the potential use of peptide-inspired models to research the liquid-liquid phase separation as a feasible mechanism preceding amyloid formation. Connecting these concepts can help clarify our understanding of aggregation-related disorders and potentially provide novel drug targets to impede and reverse these serious illnesses.
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Affiliation(s)
- Maja Juković
- Faculty of Biotechnology and Drug Development, University of Rijeka, 51000 Rijeka, Croatia
| | - Ivana Ratkaj
- Faculty of Biotechnology and Drug Development, University of Rijeka, 51000 Rijeka, Croatia
| | - Daniela Kalafatovic
- Faculty of Biotechnology and Drug Development, University of Rijeka, 51000 Rijeka, Croatia.
| | - Nicholas J Bradshaw
- Faculty of Biotechnology and Drug Development, University of Rijeka, 51000 Rijeka, Croatia.
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11
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Zacco E, Broglia L, Kurihara M, Monti M, Gustincich S, Pastore A, Plath K, Nagakawa S, Cerase A, Sanchez de Groot N, Tartaglia GG. RNA: The Unsuspected Conductor in the Orchestra of Macromolecular Crowding. Chem Rev 2024; 124:4734-4777. [PMID: 38579177 PMCID: PMC11046439 DOI: 10.1021/acs.chemrev.3c00575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 04/07/2024]
Abstract
This comprehensive Review delves into the chemical principles governing RNA-mediated crowding events, commonly referred to as granules or biological condensates. We explore the pivotal role played by RNA sequence, structure, and chemical modifications in these processes, uncovering their correlation with crowding phenomena under physiological conditions. Additionally, we investigate instances where crowding deviates from its intended function, leading to pathological consequences. By deepening our understanding of the delicate balance that governs molecular crowding driven by RNA and its implications for cellular homeostasis, we aim to shed light on this intriguing area of research. Our exploration extends to the methodologies employed to decipher the composition and structural intricacies of RNA granules, offering a comprehensive overview of the techniques used to characterize them, including relevant computational approaches. Through two detailed examples highlighting the significance of noncoding RNAs, NEAT1 and XIST, in the formation of phase-separated assemblies and their influence on the cellular landscape, we emphasize their crucial role in cellular organization and function. By elucidating the chemical underpinnings of RNA-mediated molecular crowding, investigating the role of modifications, structures, and composition of RNA granules, and exploring both physiological and aberrant phase separation phenomena, this Review provides a multifaceted understanding of the intriguing world of RNA-mediated biological condensates.
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Affiliation(s)
- Elsa Zacco
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Laura Broglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Misuzu Kurihara
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Michele Monti
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Stefano Gustincich
- Central
RNA Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Annalisa Pastore
- UK
Dementia Research Institute at the Maurice Wohl Institute of King’s
College London, London SE5 9RT, U.K.
| | - Kathrin Plath
- Department
of Biological Chemistry, David Geffen School
of Medicine at the University of California Los Angeles, Los Angeles, California 90095, United States
| | - Shinichi Nagakawa
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Andrea Cerase
- Blizard
Institute,
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, U.K.
- Unit
of Cell and developmental Biology, Department of Biology, Università di Pisa, 56123 Pisa, Italy
| | - Natalia Sanchez de Groot
- Unitat
de Bioquímica, Departament de Bioquímica i Biologia
Molecular, Universitat Autònoma de
Barcelona, 08193 Barcelona, Spain
| | - Gian Gaetano Tartaglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
- Catalan
Institution for Research and Advanced Studies, ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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12
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Khorsand FR, Uversky VN. Liquid-liquid phase separation as triggering factor of fibril formation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2024; 206:143-182. [PMID: 38811080 DOI: 10.1016/bs.pmbts.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Liquid-liquid phase separation (LLPS) refers to the phenomenon, where a homogeneous solution spontaneously undergoes a transition into two or more immiscible phases. Through transient weak multivalent macromolecular interactions, a homogeneous solution can spontaneously separate into two phases: one rich in biomolecules and the other poor in biomolecules. Phase separation is believed to serve as the physicochemical foundation for the formation of membrane-less organelles (MLOs) and bio-molecular condensates within cells. Moreover, numerous biological processes depend on LLPS, such as transcription, immunological response, chromatin architecture, DNA damage response, stress granule formation, viral infection, etc. Abnormalities in phase separation can lead to diseases, such as cancer, neurodegeneration, and metabolic disorders. LLPS is regulated by various factors, such as concentration of molecules undergoing LLPS, salt concentration, pH, temperature, post-translational modifications, and molecular chaperones. Recent research on LLPS of biomolecules has progressed rapidly and led to the development of databases containing information pertaining to various aspects of the biomolecule separation analysis. However, more comprehensive research is still required to fully comprehend the specific molecular mechanisms and biological effects of LLPS.
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Affiliation(s)
| | - Vladimir N Uversky
- Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Institute for Biological Instrumentation, Pushchino, Moscow, Russia; Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.
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13
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Chin KY, Ishida S, Sasaki Y, Terayama K. Predicting condensate formation of protein and RNA under various environmental conditions. BMC Bioinformatics 2024; 25:143. [PMID: 38566033 PMCID: PMC10988968 DOI: 10.1186/s12859-024-05764-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/26/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Liquid-liquid phase separation (LLPS) by biomolecules plays a central role in various biological phenomena and has garnered significant attention. The behavior of LLPS is strongly influenced by the characteristics of RNAs and environmental factors such as pH and temperature, as well as the properties of proteins. Recently, several databases recording LLPS-related biomolecules have been established, and prediction models of LLPS-related phenomena have been explored using these databases. However, a prediction model that concurrently considers proteins, RNAs, and experimental conditions has not been developed due to the limited information available from individual experiments in public databases. RESULTS To address this challenge, we have constructed a new dataset, RNAPSEC, which serves each experiment as a data point. This dataset was accomplished by manually collecting data from public literature. Utilizing RNAPSEC, we developed two prediction models that consider a protein, RNA, and experimental conditions. The first model can predict the LLPS behavior of a protein and RNA under given experimental conditions. The second model can predict the required conditions for a given protein and RNA to undergo LLPS. CONCLUSIONS RNAPSEC and these prediction models are expected to accelerate our understanding of the roles of proteins, RNAs, and environmental factors in LLPS.
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Affiliation(s)
- Ka Yin Chin
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Shoichi Ishida
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Yukio Sasaki
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Kei Terayama
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
- RIKEN Center for Advanced Intelligence Project, 1-4-1, Nihonbashi, Chuo-ku, Tokyo, 103-0027, Japan.
- MDX Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan.
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14
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Park J, Kim JJ, Ryu JK. Mechanism of phase condensation for chromosome architecture and function. Exp Mol Med 2024; 56:809-819. [PMID: 38658703 PMCID: PMC11059216 DOI: 10.1038/s12276-024-01226-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/23/2024] [Accepted: 02/28/2024] [Indexed: 04/26/2024] Open
Abstract
Chromosomal phase separation is involved in a broad spectrum of chromosome organization and functional processes. Nonetheless, the intricacy of this process has left its molecular mechanism unclear. Here, we introduce the principles governing phase separation and its connections to physiological roles in this context. Our primary focus is contrasting two phase separation mechanisms: self-association-induced phase separation (SIPS) and bridging-induced phase separation (BIPS). We provide a comprehensive discussion of the distinct features characterizing these mechanisms and offer illustrative examples that suggest their broad applicability. With a detailed understanding of these mechanisms, we explore their associations with nucleosomes and chromosomal biological functions. This comprehensive review contributes to the exploration of uncharted territory in the intricate interplay between chromosome architecture and function.
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Affiliation(s)
- Jeongveen Park
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Jeong-Jun Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Je-Kyung Ryu
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea.
- Institute of Applied Physics of Seoul National University, Seoul, 08826, South Korea.
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, South Korea.
- Department of Biological Sciences, Seoul National University, Seoul, 08826, South Korea.
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul, 08826, South Korea.
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15
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Wahiduzzaman, Tindell SJ, Alexander E, Hackney E, Kharel K, Schmidtke R, Arkov AL. Drosophila germ granules are assembled from protein components through different modes of competing interactions with the multi-domain Tudor protein. FEBS Lett 2024; 598:774-786. [PMID: 38499396 DOI: 10.1002/1873-3468.14846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 12/21/2023] [Accepted: 02/14/2024] [Indexed: 03/20/2024]
Abstract
Membraneless organelles are RNA-protein assemblies which have been implicated in post-transcriptional control. Germ cells form membraneless organelles referred to as germ granules, which contain conserved proteins including Tudor domain-containing scaffold polypeptides and their partner proteins that interact with Tudor domains. Here, we show that in Drosophila, different germ granule proteins associate with the multi-domain Tudor protein using different numbers of Tudor domains. Furthermore, these proteins compete for interaction with Tudor in vitro and, surprisingly, partition to distinct and poorly overlapping clusters in germ granules in vivo. This partition results in minimization of the competition. Our data suggest that Tudor forms structurally different configurations with different partner proteins which dictate different biophysical properties and phase separation parameters within the same granule.
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Affiliation(s)
- Wahiduzzaman
- Department of Biological Sciences, Murray State University, KY, USA
| | - Samuel J Tindell
- Department of Biological Sciences, Murray State University, KY, USA
| | - Emma Alexander
- Department of Biological Sciences, Murray State University, KY, USA
| | - Ethan Hackney
- Department of Biological Sciences, Murray State University, KY, USA
| | - Kabita Kharel
- Department of Biological Sciences, Murray State University, KY, USA
| | - Ryan Schmidtke
- Department of Biological Sciences, Murray State University, KY, USA
| | - Alexey L Arkov
- Department of Biological Sciences, Murray State University, KY, USA
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16
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Bryan NW, Ali A, Niedzialkowska E, Mayne L, Stukenberg PT, Black BE. Structural basis for the phase separation of the chromosome passenger complex. eLife 2024; 13:e92709. [PMID: 38456462 PMCID: PMC10977965 DOI: 10.7554/elife.92709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 03/07/2024] [Indexed: 03/09/2024] Open
Abstract
The physical basis of phase separation is thought to consist of the same types of bonds that specify conventional macromolecular interactions yet is unsatisfyingly often referred to as 'fuzzy'. Gaining clarity on the biogenesis of membraneless cellular compartments is one of the most demanding challenges in biology. Here, we focus on the chromosome passenger complex (CPC), that forms a chromatin body that regulates chromosome segregation in mitosis. Within the three regulatory subunits of the CPC implicated in phase separation - a heterotrimer of INCENP, Survivin, and Borealin - we identify the contact regions formed upon droplet formation using hydrogen/deuterium exchange mass spectrometry (HXMS). These contact regions correspond to some of the interfaces seen between individual heterotrimers within the crystal lattice they form. A major contribution comes from specific electrostatic interactions that can be broken and reversed through initial and compensatory mutagenesis, respectively. Our findings reveal structural insight for interactions driving liquid-liquid demixing of the CPC. Moreover, we establish HXMS as an approach to define the structural basis for phase separation.
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Affiliation(s)
- Nikaela W Bryan
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
- Graduate Program in Biochemistry and Molecular Biophysics, University of PennsylvaniaPhiladelphiaUnited States
| | - Aamir Ali
- Department of Biochemistry and Molecular Genetics, University of VirginiaCharlottesvilleUnited States
| | - Ewa Niedzialkowska
- Department of Biochemistry and Molecular Genetics, University of VirginiaCharlottesvilleUnited States
| | - Leland Mayne
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - P Todd Stukenberg
- Department of Biochemistry and Molecular Genetics, University of VirginiaCharlottesvilleUnited States
| | - Ben E Black
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
- Graduate Program in Biochemistry and Molecular Biophysics, University of PennsylvaniaPhiladelphiaUnited States
- Penn Center for Genome Integrity, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
- Epigenetics Institute, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
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17
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Sternke-Hoffmann R, Sun X, Menzel A, Pinto MDS, Venclovaitė U, Wördehoff M, Hoyer W, Zheng W, Luo J. Phase Separation and Aggregation of α-Synuclein Diverge at Different Salt Conditions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.582895. [PMID: 38464093 PMCID: PMC10925286 DOI: 10.1101/2024.03.01.582895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
The coacervation and structural rearrangement of the protein alpha-synuclein (αSyn) into cytotoxic oligomers and amyloid fibrils are considered pathological hallmarks of Parkinson's disease. While aggregation is recognized as the key element of amyloid diseases, liquid-liquid phase separation (LLPS) and its interplay with aggregation have gained increasing interest. Previous work showed that factors promoting or inhibiting amyloid formation have similar effects on phase separation. Here, we provide a detailed scanning of a wide range of parameters including protein, salt and crowding concentrations at multiple pH values, revealing different salt dependencies of aggregation and phase separation. The influence of salt on aggregation under crowded conditions follows a non-monotonic pattern, showing increased effects at medium salt concentrations. This behavior can be elucidated through a combination of electrostatic screening and salting-out effects on the intramolecular interactions between the N-terminal and C-terminal regions of αSyn. By contrast, we find a monotonic salt dependence of phase separation due to the intermolecular interaction. Furthermore, we observe the time evolution of the two distinct assembly states, with macroscopic fibrillar-like bundles initially forming at medium salt concentration but subsequently converting into droplets after prolonged incubation. The droplet state is therefore capable of inhibiting aggregation or even dissolving the aggregates through a variety of heterotypic interactions, thus preventing αSyn from its dynamically arrested state.
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Affiliation(s)
- Rebecca Sternke-Hoffmann
- Department of Biology and Chemistry, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Xun Sun
- Department of Biology and Chemistry, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Andreas Menzel
- Photon Science Division, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Miriam Dos Santos Pinto
- Department of Biology and Chemistry, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Urtė Venclovaitė
- Department of Biology and Chemistry, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Michael Wördehoff
- Institut für Physikalische Biologie, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Wolfgang Hoyer
- Institut für Physikalische Biologie, Heinrich-Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Wenwei Zheng
- College of Integrative Sciences and Arts, Arizona State University, Mesa, AZ, 85212, United States
| | - Jinghui Luo
- Department of Biology and Chemistry, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
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18
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Sato K, Takayama KI, Inoue S. Stress granule-mediated RNA regulatory mechanism in Alzheimer's disease. Geriatr Gerontol Int 2024; 24 Suppl 1:7-14. [PMID: 37726158 DOI: 10.1111/ggi.14663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/20/2023] [Accepted: 08/27/2023] [Indexed: 09/21/2023]
Abstract
Living organisms experience a range of stresses. To cope effectively with these stresses, eukaryotic cells have evolved a sophisticated mechanism involving the formation of stress granules (SGs), which play a crucial role in protecting various types of RNA species under stress, such as mRNAs and long non-coding RNAs (lncRNAs). SGs are non-membranous cytoplasmic ribonucleoprotein (RNP) granules, and the RNAs they contain are translationally stalled. Importantly, SGs have been thought to contribute to the pathophysiology of neurodegenerative diseases, including Alzheimer's disease (AD). SGs also contain multiple RNA-binding proteins (RBPs), several of which have been implicated in AD progression. SGs are transient structures that dissipate after stress relief. However, the chronic stresses associated with aging lead to the persistent formation of SGs and subsequently to solid-like pathological SGs, which could impair cellular RNA metabolism and also act as a nidus for the aberrant aggregation of AD-associated proteins. In this paper, we provide a comprehensive summary of the physical basis of SG-enriched RNAs and SG-resident RBPs. We then review the characteristics of AD-associated gene transcripts and their similarity to the SG-enriched RNAs. Furthermore, we summarize and discuss the functional implications of SGs in neuronal RNA metabolism and the aberrant aggregation of AD-associated proteins mediated by SG-resident RBPs in the context of AD pathogenesis. Geriatr Gerontol Int 2024; 24: 7-14.
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Affiliation(s)
- Kaoru Sato
- Department of Systems Aging Science and Medicine, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan
- Integrated Research Initiative for Living Well with Dementia, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan
| | - Ken-Ichi Takayama
- Department of Systems Aging Science and Medicine, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan
| | - Satoshi Inoue
- Department of Systems Aging Science and Medicine, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo, Japan
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19
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Monterroso B, Margolin W, Boersma AJ, Rivas G, Poolman B, Zorrilla S. Macromolecular Crowding, Phase Separation, and Homeostasis in the Orchestration of Bacterial Cellular Functions. Chem Rev 2024; 124:1899-1949. [PMID: 38331392 PMCID: PMC10906006 DOI: 10.1021/acs.chemrev.3c00622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/01/2023] [Accepted: 01/10/2024] [Indexed: 02/10/2024]
Abstract
Macromolecular crowding affects the activity of proteins and functional macromolecular complexes in all cells, including bacteria. Crowding, together with physicochemical parameters such as pH, ionic strength, and the energy status, influences the structure of the cytoplasm and thereby indirectly macromolecular function. Notably, crowding also promotes the formation of biomolecular condensates by phase separation, initially identified in eukaryotic cells but more recently discovered to play key functions in bacteria. Bacterial cells require a variety of mechanisms to maintain physicochemical homeostasis, in particular in environments with fluctuating conditions, and the formation of biomolecular condensates is emerging as one such mechanism. In this work, we connect physicochemical homeostasis and macromolecular crowding with the formation and function of biomolecular condensates in the bacterial cell and compare the supramolecular structures found in bacteria with those of eukaryotic cells. We focus on the effects of crowding and phase separation on the control of bacterial chromosome replication, segregation, and cell division, and we discuss the contribution of biomolecular condensates to bacterial cell fitness and adaptation to environmental stress.
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Affiliation(s)
- Begoña Monterroso
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
| | - William Margolin
- Department
of Microbiology and Molecular Genetics, McGovern Medical School, UTHealth-Houston, Houston, Texas 77030, United States
| | - Arnold J. Boersma
- Cellular
Protein Chemistry, Bijvoet Centre for Biomolecular Research, Faculty
of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Germán Rivas
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
| | - Bert Poolman
- Department
of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Silvia Zorrilla
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
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20
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Chatterjee S, Ganguly A, Bhattacharyya D. Reprogramming nucleolar size by genetic perturbation of the extranuclear Rab GTPases Ypt6 and Ypt32. FEBS Lett 2024; 598:283-301. [PMID: 37994551 DOI: 10.1002/1873-3468.14776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 11/24/2023]
Abstract
Reprogramming organelle size has been proposed as a potential therapeutic approach. However, there have been few reports of nucleolar size reprogramming. We addressed this question in Saccharomyces cerevisiae by studying mutants having opposite effects on the nucleolar size. Mutations in genes involved in nuclear functions (KAR3, CIN8, and PRP45) led to enlarged nuclei/nucleoli, whereas mutations in secretory pathway family genes, namely the Rab-GTPases YPT6 and YPT32, reduced nucleolar size. When combined with mutations leading to enlarged nuclei/nucleoli, the YPT6 or YPT32 mutants can effectively reprogram the nuclear/nucleolar size almost back to normal. Our results further indicate that null mutation of YPT6 causes secretory stress that indirectly influences nuclear localization of Maf1, the negative regulator of RNA Polymerase III, which might reduce the nucleolar size by inhibiting nucleolar transcript enrichment.
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Affiliation(s)
- Shreosi Chatterjee
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
| | - Abira Ganguly
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
| | - Dibyendu Bhattacharyya
- Department of Cell and Tumor Biology, Advanced Centre for Treatment Research & Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Training School Complex, Mumbai, Maharashtra, India
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
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21
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Gupta MN, Uversky VN. Biological importance of arginine: A comprehensive review of the roles in structure, disorder, and functionality of peptides and proteins. Int J Biol Macromol 2024; 257:128646. [PMID: 38061507 DOI: 10.1016/j.ijbiomac.2023.128646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/02/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024]
Abstract
Arginine shows Jekyll and Hyde behavior in several respects. It participates in protein folding via ionic and H-bonds and cation-pi interactions; the charge and hydrophobicity of its side chain make it a disorder-promoting amino acid. Its methylation in histones; RNA binding proteins; chaperones regulates several cellular processes. The arginine-centric modifications are important in oncogenesis and as biomarkers in several cardiovascular diseases. The cross-links involving arginine in collagen and cornea are involved in pathogenesis of tissues but have also been useful in tissue engineering and wound-dressing materials. Arginine is a part of active site of several enzymes such as GTPases, peroxidases, and sulfotransferases. Its metabolic importance is obvious as it is involved in production of urea, NO, ornithine and citrulline. It can form unusual functional structures such as molecular tweezers in vitro and sprockets which engage DNA chains as part of histones in vivo. It has been used in design of cell-penetrating peptides as drugs. Arginine has been used as an excipient in both solid and injectable drug formulations; its role in suppressing opalescence due to liquid-liquid phase separation is particularly very promising. It has been known as a suppressor of protein aggregation during protein refolding. It has proved its usefulness in protein bioseparation processes like ion-exchange, hydrophobic and affinity chromatographies. Arginine is an amino acid, whose importance in biological sciences and biotechnology continues to grow in diverse ways.
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Affiliation(s)
- Munishwar Nath Gupta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
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22
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Chou HY, Aksimentiev A. RNA regulates cohesiveness and porosity of a biological condensate. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574811. [PMID: 38260307 PMCID: PMC10802450 DOI: 10.1101/2024.01.09.574811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Biological condensates have emerged as key elements of a biological cell function, concentrating disparate biomolecules to accomplish specific biological tasks. RNA was identified as a key ingredient of such condensates, however, its effect on the physical properties of the condensate was found to depend on the condensate's composition while its effect on the microstructure has remained elusive. Here, we characterize the physical properties and the microstructure of a protein-RNA condensate by means of large-scale coarse-grained (CG) molecular dynamics simulations. By developing a custom CG model of RNA compatible with a popular CG model of proteins, we systematically investigate the structural, thermodynamic, and kinetic properties of condensate droplets containing thousands of individual protein and RNA molecules over a range of temperatures. While we find RNA to increase the condensate's cohesiveness, its effect on the condensate's fluidity is more nuanced with longer molecules compacting the condensate and making it less fluid. We show that a biological condensate has a sponge-like morphology of interconnected channels of size that increases with temperature and decreases in the presence of RNA. Our results suggest that longer RNA form a dynamic scaffold within a condensate, regulating not only its fluidity but also permeability to intruder molecules.
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23
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Asakawa K, Handa H, Kawakami K. In Vivo Optogenetic Phase Transition of an Intrinsically Disordered Protein. Methods Mol Biol 2024; 2707:257-264. [PMID: 37668918 DOI: 10.1007/978-1-0716-3401-1_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Proteins containing intrinsically disordered regions (IDRs) control a wide variety of cellular processes by assembly of membrane-less organelles via IDR-mediated liquid-liquid phase separation. Dysregulated IDR-mediated phase transition has been implicated in the pathogenesis of diseases characterized by deposition of abnormal protein aggregates. Here, we describe a method to enhance interactions between the IDRs of the RNA/DNA-binding protein and TAR DNA-binding protein 43 (TDP-43) by light to drive its phase transition in the motor neurons of zebrafish. The optically controlled TDP-43 phase transition in motor neurons, in vivo, provides a unique opportunity to evaluate the impact of dysregulated TDP-43 phase transition on the physiology of motor neurons. This will help to address the etiology of neurodegenerative diseases associated with abnormal TDP-43 phase transition and aggregation, including amyotrophic lateral sclerosis (ALS).
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Affiliation(s)
- Kazuhide Asakawa
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Shizuoka, Japan.
| | - Hiroshi Handa
- Department of Molecular Pharmacology, Center for Future Medical Research, Tokyo Medical University, Tokyo, Japan
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
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24
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Gorsheneva NA, Sopova JV, Azarov VV, Grizel AV, Rubel AA. Biomolecular Condensates: Structure, Functions, Methods of Research. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:S205-S223. [PMID: 38621751 DOI: 10.1134/s0006297924140116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/12/2023] [Accepted: 10/16/2023] [Indexed: 04/17/2024]
Abstract
The term "biomolecular condensates" is used to describe membraneless compartments in eukaryotic cells, accumulating proteins and nucleic acids. Biomolecular condensates are formed as a result of liquid-liquid phase separation (LLPS). Often, they demonstrate properties of liquid-like droplets or gel-like aggregates; however, some of them may appear to have a more complex structure and high-order organization. Membraneless microcompartments are involved in diverse processes both in cytoplasm and in nucleus, among them ribosome biogenesis, regulation of gene expression, cell signaling, and stress response. Condensates properties and structure could be highly dynamic and are affected by various internal and external factors, e.g., concentration and interactions of components, solution temperature, pH, osmolarity, etc. In this review, we discuss variety of biomolecular condensates and their functions in live cells, describe their structure variants, highlight domain and primary sequence organization of the constituent proteins and nucleic acids. Finally, we describe current advances in methods that characterize structure, properties, morphology, and dynamics of biomolecular condensates in vitro and in vivo.
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Affiliation(s)
| | - Julia V Sopova
- St. Petersburg State University, St. Petersburg, 199034, Russia.
| | | | - Anastasia V Grizel
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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25
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Xie P, Xie X, Ye C, Dean KM, Laothamatas I, Taufique SKT, Takahashi J, Yamazaki S, Xu Y, Liu Y. Mammalian circadian clock proteins form dynamic interacting microbodies distinct from phase separation. Proc Natl Acad Sci U S A 2023; 120:e2318274120. [PMID: 38127982 PMCID: PMC10756265 DOI: 10.1073/pnas.2318274120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) underlies diverse biological processes. Because most LLPS studies were performed in vitro using recombinant proteins or in cells that overexpress protein, the physiological relevance of LLPS for endogenous protein is often unclear. PERIOD, the intrinsically disordered domain-rich proteins, are central mammalian circadian clock components and interact with other clock proteins in the core circadian negative feedback loop. Different core clock proteins were previously shown to form large complexes. Circadian clock studies often rely on experiments that overexpress clock proteins. Here, we show that when Per2 transgene was stably expressed in cells, PER2 protein formed nuclear phosphorylation-dependent slow-moving LLPS condensates that recruited other clock proteins. Super-resolution microscopy of endogenous PER2, however, revealed formation of circadian-controlled, rapidly diffusing nuclear microbodies that were resistant to protein concentration changes, hexanediol treatment, and loss of phosphorylation, indicating that they are distinct from the LLPS condensates caused by protein overexpression. Surprisingly, only a small fraction of endogenous PER2 microbodies transiently interact with endogenous BMAL1 and CRY1, a conclusion that was confirmed in cells and in mice tissues, suggesting an enzyme-like mechanism in the circadian negative feedback process. Together, these results demonstrate that the dynamic interactions of core clock proteins are a key feature of mammalian circadian clock mechanism and the importance of examining endogenous proteins in LLPS and circadian clock studies.
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Affiliation(s)
- Pancheng Xie
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX75390
- Cambridge-Su Genomic Resource Center, Soochow University, Suzhou, Jiangsu215123, China
| | - Xiaowen Xie
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Congrong Ye
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Kevin M. Dean
- Lyda Hill Department of Bioinformatics and Cecil H. and Ida Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Isara Laothamatas
- HHMI, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
| | - S. K. Tahajjul Taufique
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
| | - Joseph Takahashi
- HHMI, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
| | - Shin Yamazaki
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
| | - Ying Xu
- Cambridge-Su Genomic Resource Center, Soochow University, Suzhou, Jiangsu215123, China
| | - Yi Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX75390
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26
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Dickinson RB, Lele TP. A new function for nuclear lamins: providing surface tension to the nuclear drop. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2023; 28:100483. [PMID: 38283102 PMCID: PMC10812902 DOI: 10.1016/j.cobme.2023.100483] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
The nuclear lamina, a conserved structure in metazoans, provides mechanical rigidity to the nuclear envelope. A decrease in lamin levels and/or lamin mutations are associated with a host of human diseases. Despite being only about 15 nm thick, perturbation of components of the nuclear lamina dramatically impacts the deformation response of the entire nucleus through mechanisms that are not well understood. Here we discuss evidence for the recently proposed 'nuclear drop' model that explains the role of A-type lamins in nuclear deformation in migrating cells. In this model, the nuclear lamina acts as an inextensible surface, supporting a surface tension when fully unfolded, that balances nuclear interior pressure. Much like a liquid drop surface where the molecularly thin interface governs surface tension and drop shape under external forces, the thin nuclear lamina imparts a surface tension on the nuclear drop to resist nuclear deformation as well as to establish nuclear shape. We discuss implications of the nuclear drop model for the function of this crucially important eukaryotic organelle.
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Affiliation(s)
- Richard B. Dickinson
- Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, FL, 32611, USA
| | - Tanmay P. Lele
- Department of Biomedical Engineering, Texas A&M University, 101 Bizzell St., College Station, TX, 77843, USA
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, 3122 TAMU, College Station, TX, 77843, USA
- Department of Translational Medical Sciences, Texas A&M University, 2121 W Holcombe St., Houston, TX, 77030, USA
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27
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Suganuma T, Workman JL. Chromatin balances cell redox and energy homeostasis. Epigenetics Chromatin 2023; 16:46. [PMID: 38017471 PMCID: PMC10683155 DOI: 10.1186/s13072-023-00520-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/30/2023] [Indexed: 11/30/2023] Open
Abstract
Chromatin plays a central role in the conversion of energy in cells: alteration of chromatin structure to make DNA accessible consumes energy, and compaction of chromatin preserves energy. Alteration of chromatin structure uses energy sources derived from carbon metabolism such as ATP and acetyl-CoA; conversely, chromatin compaction and epigenetic modification feedback to metabolism and energy homeostasis by controlling gene expression and storing metabolites. Coordination of these dual chromatin events must be flexibly modulated in response to environmental changes such as during development and exposure to stress. Aging also alters chromatin structure and the coordination of metabolism, chromatin dynamics, and other cell processes. Noncoding RNAs and other RNA species that associate directly with chromatin or with chromatin modifiers contribute to spatiotemporal control of transcription and energy conversion. The time required for generating the large amounts of RNAs and chromatin modifiers observed in super-enhancers may be critical for regulation of transcription and may be impacted by aging. Here, taking into account these factors, we review alterations of chromatin that are fundamental to cell responses to metabolic changes due to stress and aging to maintain redox and energy homeostasis. We discuss the relationship between spatiotemporal control of energy and chromatin function, as this emerging concept must be considered to understand how cell homeostasis is maintained.
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Affiliation(s)
- Tamaki Suganuma
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO, 64110, USA.
| | - Jerry L Workman
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO, 64110, USA
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28
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Uversky VN. Functional unfoldomics: Roles of intrinsic disorder in protein (multi)functionality. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 138:179-210. [PMID: 38220424 DOI: 10.1016/bs.apcsb.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Intrinsically disordered proteins (IDPs), which are functional proteins without stable tertiary structure, and hybrid proteins containing ordered domains and intrinsically disordered regions (IDRs) constitute prominent parts of all proteomes collectively known as unfoldomes. IDPs/IDRs exist as highly dynamic structural ensembles of rapidly interconverting conformations and are characterized by the exceptional structural heterogeneity, where their different parts are (dis)ordered to different degree, and their overall structure represents a complex mosaic of foldons, inducible foldons, inducible morphing foldons, non-foldons, semifoldons, and even unfoldons. Despite their lack of unique 3D structures, IDPs/IDRs play crucial roles in the control of various biological processes and the regulation of different cellular pathways and are commonly involved in recognition and signaling, indicating that the disorder-based functional repertoire is complementary to the functions of ordered proteins. Furthermore, IDPs/IDRs are frequently multifunctional, and this multifunctionality is defined by their structural flexibility and heterogeneity. Intrinsic disorder phenomenon is at the roots of the structure-function continuum model, where the structure continuum is defined by the presence of differently (dis)ordered regions, and the function continuum arises from the ability of all these differently (dis)ordered parts to have different functions. In their everyday life, IDPs/IDRs utilize a broad spectrum of interaction mechanisms thereby acting as interaction specialists. They are crucial for the biogenesis of numerous proteinaceous membrane-less organelles driven by the liquid-liquid phase separation. This review introduces functional unfoldomics by representing some aspects of the intrinsic disorder-based functionality.
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Affiliation(s)
- Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.
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29
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Xie P, Xie X, Ye C, Dean KM, Laothamatas I, Taufique SKT, Takahashi J, Yamazaki S, Xu Y, Liu Y. Mammalian circadian clock proteins form dynamic interacting microbodies distinct from phase separation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.19.563153. [PMID: 37961341 PMCID: PMC10634710 DOI: 10.1101/2023.10.19.563153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Liquid-liquid phase separation (LLPS) underlies diverse biological processes. Because most LLPS studies were performed in vitro or in cells that overexpress protein, the physiological relevance of LLPS is unclear. PERIOD proteins are central mammalian circadian clock components and interact with other clock proteins in the core circadian negative feedback loop. Different core clock proteins were previously shown to form large complexes. Here we show that when transgene was stably expressed, PER2 formed nuclear phosphorylation-dependent LLPS condensates that recruited other clock proteins. Super-resolution microscopy of endogenous PER2, however, revealed formation of circadian-controlled, rapidly diffusing microbodies that were resistant to protein concentration changes, hexanediol treatment, and loss of phosphorylation, indicating that they are distinct from the LLPS condensates caused by overexpression. Surprisingly, only a small fraction of endogenous PER2 microbodies transiently interact with endogenous BMAL1 and CRY1, a conclusion that was confirmed in cells and in mice tissues, suggesting an enzyme-like mechanism in the circadian negative feedback process. Together, these results demonstrate that the dynamic interactions of core clock proteins is a key feature of mammalian circadian clock mechanism and the importance of examining endogenous proteins in LLPS and circadian studies.
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Affiliation(s)
- Pancheng Xie
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Cambridge-Su Genomic Resource Center, Soochow University; Suzhou, Jiangsu 215123, China
| | - Xiaowen Xie
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Congrong Ye
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kevin M. Dean
- Lyda Hill Department of Bioinformatics and Cecil H. and Ida Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Isara Laothamatas
- Department of Neuroscience and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, 75390-9111, USA
| | - S K Tahajjul Taufique
- Department of Neuroscience and Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, Texas, 75390-9111, USA
| | - Joseph Takahashi
- Department of Neuroscience and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, 75390-9111, USA
| | - Shin Yamazaki
- Department of Neuroscience and Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, Texas, 75390-9111, USA
| | - Ying Xu
- Cambridge-Su Genomic Resource Center, Soochow University; Suzhou, Jiangsu 215123, China
| | - Yi Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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30
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Land R, Fetter R, Liang X, Tzeng CP, Taylor CA, Shen K. Endoplasmic Reticulum Exit Sites scale with somato-dendritic size in neurons. Mol Biol Cell 2023; 34:ar106. [PMID: 37556208 PMCID: PMC10559313 DOI: 10.1091/mbc.e23-03-0090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/10/2023] [Accepted: 08/02/2023] [Indexed: 08/11/2023] Open
Abstract
Nervous systems exhibit dramatic diversity in cell morphology and size. How neurons regulate their biosynthetic and secretory machinery to support such diversity is not well understood. Endoplasmic reticulum exit sites (ERESs) are essential for maintaining secretory flux, and are required for normal dendrite development, but how neurons of different size regulate secretory capacity remains unknown. In Caenorhabditis elegans, we find that the ERES number is strongly correlated with the size of a neuron's dendritic arbor. The elaborately branched sensory neuron, PVD, has especially high ERES numbers. Asymmetric cell division provides PVD with a large initial cell size critical for rapid establishment of PVD's high ERES number before neurite outgrowth, and these ERESs are maintained throughout development. Maintenance of ERES number requires the cell fate transcription factor MEC-3, C. elegans TOR (ceTOR/let-363), and nutrient availability, with mec-3 and ceTOR/let-363 mutant PVDs both displaying reductions in ERES number, soma size, and dendrite size. Notably, mec-3 mutant animals exhibit reduced expression of a ceTOR/let-363 reporter in PVD, and starvation reduces ERES number and somato-dendritic size in a manner genetically redundant with ceTOR/let-363 perturbation. Our data suggest that both asymmetric cell division and nutrient sensing pathways regulate secretory capacities to support elaborate dendritic arbors.
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Affiliation(s)
- Ruben Land
- Department of Biology, Stanford University, Stanford, CA 94305
- Neurosciences IDP, Stanford University, Stanford, CA 94305
| | - Richard Fetter
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Xing Liang
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Christopher P. Tzeng
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Caitlin A. Taylor
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
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31
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Uversky VN. Biological Liquid-Liquid Phase Separation, Biomolecular Condensates, and Membraneless Organelles: Now You See Me, Now You Don't. Int J Mol Sci 2023; 24:13150. [PMID: 37685957 PMCID: PMC10488282 DOI: 10.3390/ijms241713150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
Liquid-liquid phase separation (LLPS, also known as biomolecular condensation) and the related biogenesis of various membraneless organelles (MLOs) and biomolecular condensates (BMCs) are now considered fundamental molecular mechanisms governing the spatiotemporal organization of the intracellular space [...].
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Affiliation(s)
- Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
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32
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Kaddis Maldonado R, Lambert GS, Rice BL, Sudol M, Flanagan JM, Parent LJ. The Rous sarcoma virus Gag Polyprotein Forms Biomolecular Condensates Driven by Intrinsically-disordered Regions. J Mol Biol 2023; 435:168182. [PMID: 37328094 PMCID: PMC10527454 DOI: 10.1016/j.jmb.2023.168182] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 06/18/2023]
Abstract
Biomolecular condensates (BMCs) play important roles incellular structures includingtranscription factories, splicing speckles, and nucleoli. BMCs bring together proteins and other macromolecules, selectively concentrating them so that specific reactions can occur without interference from the surrounding environment. BMCs are often made up of proteins that contain intrinsically disordered regions (IDRs), form phase-separated spherical puncta, form liquid-like droplets that undergo fusion and fission, contain molecules that are mobile, and are disrupted with phase-dissolving drugs such as 1,6-hexanediol. In addition to cellular proteins, many viruses, including influenza A, SARS-CoV-2, and human immunodeficiency virus type 1 (HIV-1) encode proteins that undergo phase separation and rely on BMC formation for replication. In prior studies of the retrovirus Rous sarcoma virus (RSV), we observed that the Gag protein forms discrete spherical puncta in the nucleus, cytoplasm, and at the plasma membrane that co-localize with viral RNA and host factors, raising the possibility that RSV Gag forms BMCs that participate in the intracellular phase of the virion assembly pathway. In our current studies, we found that Gag contains IDRs in the N-terminal (MAp2p10) and C-terminal (NC) regions of the protein and fulfills many criteria of BMCs. Although the role of BMC formation in RSV assembly requires further study, our results suggest the biophysical properties of condensates are required for the formation of Gag complexes in the nucleus and the cohesion of these complexes as they traffic through the nuclear pore, into the cytoplasm, and to the plasma membrane, where the final assembly and release of virus particles occurs.
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Affiliation(s)
- Rebecca Kaddis Maldonado
- Department of Medicine, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA; Department of Microbiology & Immunology, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Gregory S Lambert
- Department of Medicine, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Breanna L Rice
- Department of Medicine, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Malgorzata Sudol
- Department of Medicine, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - John M Flanagan
- Department of Biochemistry & Molecular Biology, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Leslie J Parent
- Department of Medicine, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA; Department of Microbiology & Immunology, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
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33
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Bryan NW, Ali A, Niedzialkowska E, Mayne L, Stukenberg PT, Black BE. Structural Basis for the Phase Separation of the Chromosome Passenger Complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541822. [PMID: 37292983 PMCID: PMC10245869 DOI: 10.1101/2023.05.22.541822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The physical basis of phase separation is thought to consist of the same types of bonds that specify conventional macromolecular interactions yet is unsatisfyingly often referred to as 'fuzzy'. Gaining clarity on the biogenesis of membraneless cellular compartments is one of the most demanding challenges in biology. Here, we focus on the chromosome passenger complex (CPC), that forms a chromatin body that regulates chromosome segregation in mitosis. Within the three regulatory subunits of the CPC implicated in phase separation - a heterotrimer of INCENP, Survivin, and Borealin - we identify the contact regions formed upon droplet formation using hydrogen/deuterium-exchange mass spectrometry (HXMS). These contact regions correspond to some of the interfaces seen between individual heterotrimers within the crystal lattice they form. A major contribution comes from specific electrostatic interactions that can be broken and reversed through initial and compensatory mutagenesis, respectively. Our findings reveal structural insight for interactions driving liquid-liquid demixing of the CPC. Moreover, we establish HXMS as an approach to define the structural basis for phase separation.
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Affiliation(s)
- Nikaela W. Bryan
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104
- Graduate Program in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, 19104
| | - Aamir Ali
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22904
| | - Ewa Niedzialkowska
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22904
| | - Leland Mayne
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104
| | - P. Todd Stukenberg
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22904
| | - Ben E. Black
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104
- Graduate Program in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, 19104
- Penn Center for Genome Integrity, University of Pennsylvania, Philadelphia, PA, 19104
- Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
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34
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Ramm B, Schumacher D, Harms A, Heermann T, Klos P, Müller F, Schwille P, Søgaard-Andersen L. Biomolecular condensate drives polymerization and bundling of the bacterial tubulin FtsZ to regulate cell division. Nat Commun 2023; 14:3825. [PMID: 37380708 PMCID: PMC10307791 DOI: 10.1038/s41467-023-39513-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 06/07/2023] [Indexed: 06/30/2023] Open
Abstract
Cell division is spatiotemporally precisely regulated, but the underlying mechanisms are incompletely understood. In the social bacterium Myxococcus xanthus, the PomX/PomY/PomZ proteins form a single megadalton-sized complex that directly positions and stimulates cytokinetic ring formation by the tubulin homolog FtsZ. Here, we study the structure and mechanism of this complex in vitro and in vivo. We demonstrate that PomY forms liquid-like biomolecular condensates by phase separation, while PomX self-assembles into filaments generating a single large cellular structure. The PomX structure enriches PomY, thereby guaranteeing the formation of precisely one PomY condensate per cell through surface-assisted condensation. In vitro, PomY condensates selectively enrich FtsZ and nucleate GTP-dependent FtsZ polymerization and bundle FtsZ filaments, suggesting a cell division site positioning mechanism in which the single PomY condensate enriches FtsZ to guide FtsZ-ring formation and division. This mechanism shares features with microtubule nucleation by biomolecular condensates in eukaryotes, supporting this mechanism's ancient origin.
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Affiliation(s)
- Beatrice Ramm
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
| | - Dominik Schumacher
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.
| | - Andrea Harms
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Tamara Heermann
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Philipp Klos
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Franziska Müller
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Petra Schwille
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.
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35
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Zhang X, Li H, Ma Y, Zhong D, Hou S. Study liquid-liquid phase separation with optical microscopy: A methodology review. APL Bioeng 2023; 7:021502. [PMID: 37180732 PMCID: PMC10171890 DOI: 10.1063/5.0137008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 04/28/2023] [Indexed: 05/16/2023] Open
Abstract
Intracellular liquid-liquid phase separation (LLPS) is a critical process involving the dynamic association of biomolecules and the formation of non-membrane compartments, playing a vital role in regulating biomolecular interactions and organelle functions. A comprehensive understanding of cellular LLPS mechanisms at the molecular level is crucial, as many diseases are linked to LLPS, and insights gained can inform drug/gene delivery processes and aid in the diagnosis and treatment of associated diseases. Over the past few decades, numerous techniques have been employed to investigate the LLPS process. In this review, we concentrate on optical imaging methods applied to LLPS studies. We begin by introducing LLPS and its molecular mechanism, followed by a review of the optical imaging methods and fluorescent probes employed in LLPS research. Furthermore, we discuss potential future imaging tools applicable to the LLPS studies. This review aims to provide a reference for selecting appropriate optical imaging methods for LLPS investigations.
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Affiliation(s)
| | | | - Yue Ma
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China
| | | | - Shangguo Hou
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China
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36
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Ranganathan S, Dasmeh P, Furniss S, Shakhnovich E. Phosphorylation sites are evolutionary checkpoints against liquid-solid transition in protein condensates. Proc Natl Acad Sci U S A 2023; 120:e2215828120. [PMID: 37155880 PMCID: PMC10193986 DOI: 10.1073/pnas.2215828120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 03/30/2023] [Indexed: 05/10/2023] Open
Abstract
Assemblies of multivalent RNA-binding protein fused in sarcoma (FUS) can exist in the functional liquid-like state as well as less dynamic and potentially toxic amyloid- and hydrogel-like states. How could then cells form liquid-like condensates while avoiding their transformation to amyloids? Here, we show how posttranslational phosphorylation can provide a "handle" that prevents liquid-solid transition of intracellular condensates containing FUS. Using residue-specific coarse-grained simulations, for 85 different mammalian FUS sequences, we show how the number of phosphorylation sites and their spatial arrangement affect intracluster dynamics preventing conversion to amyloids. All atom simulations further confirm that phosphorylation can effectively reduce the β-sheet propensity in amyloid-prone fragments of FUS. A detailed evolutionary analysis shows that mammalian FUS PLDs are enriched in amyloid-prone stretches compared to control neutrally evolved sequences, suggesting that mammalian FUS proteins evolved to self-assemble. However, in stark contrast to proteins that do not phase-separate for their function, mammalian sequences have phosphosites in close proximity to these amyloid-prone regions. These results suggest that evolution uses amyloid-prone sequences in prion-like domains to enhance phase separation of condensate proteins while enriching phosphorylation sites in close proximity to safeguard against liquid-solid transitions.
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Affiliation(s)
- Srivastav Ranganathan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA02138
| | - Pouria Dasmeh
- Center for Human Genetics, Marburg University, Marburg35033, Germany
| | - Seth Furniss
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA02138
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, OxfordOX1 3QZ, United Kingdom
| | - Eugene Shakhnovich
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA02138
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37
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Li M, Li S, Zhang L. Phosphorylation Promotes the Accumulation of PERIOD Protein Foci. RESEARCH (WASHINGTON, D.C.) 2023; 6:0139. [PMID: 37223461 PMCID: PMC10202380 DOI: 10.34133/research.0139] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/17/2023] [Indexed: 05/25/2023]
Abstract
Circadian clock drives the 24-h rhythm in our behavior and physiology. The molecular clock consists of a series of transcriptional/translational feedback loops operated by a number of clock genes. A very recent study reported that the clock protein PERIOD (PER) is organized into discrete foci at the nuclear envelope in fly circadian neurons, which is believed to be important for controlling the subcellular localization of clock genes. Loss of inner nuclear membrane protein lamin B receptor (LBR) leads to disruption of these foci, but how they are regulated is yet unknown. Here, we found that PER foci are likely phase-separated condensates, the formation of which is mediated by intrinsically disordered region in PER. Phosphorylation promotes the accumulation of these foci. Protein phosphatase 2A, which is known to dephosphorylate PER, hampers the accumulation of the foci. On the other hand, the circadian kinase DOUBLETIME (DBT) which phosphorylates PER enhances the accumulation of the foci. LBR likely facilitates PER foci accumulation by destabilizing the catalytic subunit of protein phosphatase 2A, MICROTUBULE STAR (MTS). In conclusion, here, we demonstrate a key role for phosphorylation in promoting the accumulation of PER foci, while LBR modulates this process by impinging on the circadian phosphatase MTS.
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Affiliation(s)
- Mengna Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shujing Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Department of Life Sciences, Bengbu Medical College, Bengbu, Anhui 233030, China
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, Hubei 430022, China
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38
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Hagan MF, Mohajerani F. Self-assembly coupled to liquid-liquid phase separation. PLoS Comput Biol 2023; 19:e1010652. [PMID: 37186597 PMCID: PMC10212142 DOI: 10.1371/journal.pcbi.1010652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 05/25/2023] [Accepted: 04/26/2023] [Indexed: 05/17/2023] Open
Abstract
Liquid condensate droplets with distinct compositions of proteins and nucleic acids are widespread in biological cells. While it is known that such droplets, or compartments, can regulate irreversible protein aggregation, their effect on reversible self-assembly remains largely unexplored. In this article, we use kinetic theory and solution thermodynamics to investigate the effect of liquid-liquid phase separation on the reversible self-assembly of structures with well-defined sizes and architectures. We find that, when assembling subunits preferentially partition into liquid compartments, robustness against kinetic traps and maximum achievable assembly rates can be significantly increased. In particular, both the range of solution conditions leading to productive assembly and the corresponding assembly rates can increase by orders of magnitude. We analyze the rate equation predictions using simple scaling estimates to identify effects of liquid-liquid phase separation as a function of relevant control parameters. These results may elucidate self-assembly processes that underlie normal cellular functions or pathogenesis, and suggest strategies for designing efficient bottom-up assembly for nanomaterials applications.
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Affiliation(s)
- Michael F. Hagan
- Martin A. Fisher School of Physics, Brandeis University, Waltham, Massachusetts, United States of America
| | - Farzaneh Mohajerani
- Martin A. Fisher School of Physics, Brandeis University, Waltham, Massachusetts, United States of America
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39
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Maldonado RK, Rice BL, Lambert GS, Sudol M, Flanagan JM, Parent LJ. The Rous sarcoma virus Gag polyprotein forms biomolecular condensates driven by intrinsically-disordered regions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.07.536043. [PMID: 37066255 PMCID: PMC10104128 DOI: 10.1101/2023.04.07.536043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Biomolecular condensates (BMCs) play important roles in cellular structures including transcription factories, splicing speckles, and nucleoli. BMCs bring together proteins and other macromolecules, selectively concentrating them so that specific reactions can occur without interference from the surrounding environment. BMCs are often made up of proteins that contain intrinsically disordered regions (IDRs), form phase-separated spherical puncta, form liquid-like droplets that undergo fusion and fission, contain molecules that are mobile, and are disrupted with phase-dissolving drugs such as 1,6-hexanediol. In addition to cellular proteins, many viruses, including influenza A, SARS-CoV-2, and human immunodeficiency virus type 1 (HIV-1) encode proteins that undergo phase separation and rely on BMC formation for replication. In prior studies of the retrovirus Rous sarcoma virus (RSV), we observed that the Gag protein forms discrete spherical puncta in the nucleus, cytoplasm, and at the plasma membrane that co-localize with viral RNA and host factors, raising the possibility that RSV Gag forms BMCs that participate in the virion intracellular assembly pathway. In our current studies, we found that Gag contains IDRs in the N-terminal (MAp2p10) and C-terminal (NC) regions of the protein and fulfills many criteria of BMCs. Although the role of BMC formation in RSV assembly requires further study, our results suggest the biophysical properties of condensates are required for the formation of Gag complexes in the nucleus and the cohesion of these complexes as they traffic through the nuclear pore, into the cytoplasm, and to the plasma membrane, where the final assembly and release of virus particles occurs.
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Jiang Y, Lei G, Lin T, Zhou N, Wu J, Wang Z, Fan Y, Sheng H, Mao R. 1,6-Hexanediol regulates angiogenesis via suppression of cyclin A1-mediated endothelial function. BMC Biol 2023; 21:75. [PMID: 37024934 PMCID: PMC10080975 DOI: 10.1186/s12915-023-01580-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 03/28/2023] [Indexed: 04/08/2023] Open
Abstract
BACKGROUND Angiogenesis plays important roles in physiological and pathologic conditions, but the mechanisms underlying this complex process often remain to be elucidated. In recent years, liquid-liquid phase separation (LLPS) has emerged as a new concept to explain many cellular functions and diseases. However, whether LLPS is involved in angiogenesis has not been studied until now. Here, we investigated the potential role of LLPS in angiogenesis and endothelial function. RESULTS We found 1,6-hexanediol (1,6-HD), an inhibitor of LLPS, but not 2,5-hexanediol (2,5-HD) dramatically decreases neovascularization of Matrigel plug and angiogenesis response of murine corneal in vivo. Moreover, 1,6-HD but not 2,5-HD inhibits microvessel outgrowth of aortic ring and endothelial network formation. The endothelial function of migration, proliferation, and cell growth is suppressed by 1,6-HD. Global transcriptional analysis by RNA-sequencing reveals that 1,6-HD specifically blocks cell cycle and downregulates cell cycle-related genes including cyclin A1. Further experimental data show that 1,6-HD treatment greatly reduces the expression of cyclin A1 but with minimal effect on cyclin D1, cyclin E1, CDK2, and CDK4. The inhibitory effect of 1,6-HD on cyclin A1 is mainly through transcriptional regulation because proteasome inhibitors fail to rescue its expression. Furthermore, overexpression of cyclin A1 in HUVECs largely rescues the dysregulated tube formation upon 1,6-HD treatment. CONCLUSIONS Our data reveal a critical role of LLPS inhibitor 1,6-HD in angiogenesis and endothelial function, which specifically affects endothelial G1/S transition through transcriptional suppression of CCNA1, implying LLPS as a possible novel player to modulate angiogenesis, and thus, it might represent an interesting therapeutic target to be investigated in clinic angiogenesis-related diseases in future.
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Affiliation(s)
- Yongying Jiang
- Department of Pathophysiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, Jiangsu, 226001, People's Republic of China
| | - Gongyun Lei
- Department of Pathophysiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, Jiangsu, 226001, People's Republic of China
| | - Ting Lin
- Department of Pathophysiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, Jiangsu, 226001, People's Republic of China
| | - Nan Zhou
- Department of Pathophysiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, Jiangsu, 226001, People's Republic of China
| | - Jintao Wu
- Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, People's Republic of China
| | - Zhou Wang
- Laboratory of Medical Science, School of Medicine, Nantong University, Nantong, Jiangsu, 226001, People's Republic of China
| | - Yihui Fan
- Department of Pathogenic Biology, School of Medicine, Nantong University, Nantong, Jiangsu, 226001, People's Republic of China
| | - Hongzhuan Sheng
- Department of Cardiology, Affiliated Hospital of Nantong University, Nantong University, 19 Qixiu Road, Nantong, Jiangsu, 226001, People's Republic of China.
| | - Renfang Mao
- Department of Pathophysiology, School of Medicine, Nantong University, 19 Qixiu Road, Nantong, Jiangsu, 226001, People's Republic of China.
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Staples MI, Frazer C, Fawzi NL, Bennett RJ. Phase separation in fungi. Nat Microbiol 2023; 8:375-386. [PMID: 36782025 PMCID: PMC10081517 DOI: 10.1038/s41564-022-01314-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 12/16/2022] [Indexed: 02/15/2023]
Abstract
Phase separation, in which macromolecules partition into a concentrated phase that is immiscible with a dilute phase, is involved with fundamental cellular processes across the tree of life. We review the principles of phase separation and highlight how it impacts diverse processes in the fungal kingdom. These include the regulation of autophagy, cell signalling pathways, transcriptional circuits and the establishment of asymmetry in fungal cells. We describe examples of stable, phase-separated assemblies including membraneless organelles such as the nucleolus as well as transient condensates that also arise through phase separation and enable cells to rapidly and reversibly respond to important environmental cues. We showcase how research into phase separation in model yeasts, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe, in conjunction with that in plant and human fungal pathogens, such as Ashbya gossypii and Candida albicans, is continuing to enrich our understanding of fundamental molecular processes.
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Affiliation(s)
- Mae I Staples
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Corey Frazer
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Nicolas L Fawzi
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Richard J Bennett
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA.
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42
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Little J, Levine AJ, Singh AR, Bruinsma R. Finite-strain elasticity theory and liquid-liquid phase separation in compressible gels. Phys Rev E 2023; 107:024418. [PMID: 36932516 DOI: 10.1103/physreve.107.024418] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
The theory of finite-strain elasticity is applied to the phenomenon of cavitation observed in polymer gels following liquid-liquid phase separation of the solvent, which opens a fascinating window on the role of finite-strain elasticity theory in soft materials in general. We show that compressibility effects strongly enhance cavitation in simple materials that obey neo-Hookean elasticity. On the other hand, cavitation phenomena in gels of flexible polymers in a binary solvent that phase separates are surprisingly similar to those of incompressible materials. We find that, as a function of the interfacial energy between the two solvent components, there is a sharp transition between cavitation and classical nucleation and growth. Next, biopolymer gels are characterized by strain hardening and even very low levels of strain hardening turn out to suppress cavitation in polymer gels that obey Flory-Huggins theory in the absence of strain hardening. Our results indicate that cavitation is, in essence, not possible for polymer networks that show strain hardening.
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Affiliation(s)
- Justin Little
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Alex J Levine
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
- Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
| | - Amit R Singh
- Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani, RJ 333031, India
| | - Robijn Bruinsma
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
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43
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Das B, Roychowdhury S, Mohanty P, Rizuan A, Chakraborty J, Mittal J, Chattopadhyay K. A Zn-dependent structural transition of SOD1 modulates its ability to undergo phase separation. EMBO J 2023; 42:e111185. [PMID: 36416085 PMCID: PMC9841336 DOI: 10.15252/embj.2022111185] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 11/24/2022] Open
Abstract
The misfolding and mutation of Cu/Zn superoxide dismutase (SOD1) is commonly associated with amyotrophic lateral sclerosis (ALS). SOD1 can accumulate within stress granules (SGs), a type of membraneless organelle, which is believed to form via liquid-liquid phase separation (LLPS). Using wild-type, metal-deficient, and different ALS disease mutants of SOD1 and computer simulations, we report here that the absence of Zn leads to structural disorder within two loop regions of SOD1, triggering SOD1 LLPS and amyloid formation. The addition of exogenous Zn to either metal-free SOD1 or to the severe ALS mutation I113T leads to the stabilization of the loops and impairs SOD1 LLPS and aggregation. Moreover, partial Zn-mediated inhibition of LLPS was observed for another severe ALS mutant, G85R, which shows perturbed Zn-binding. By contrast, the ALS mutant G37R, which shows reduced Cu-binding, does not undergo LLPS. In addition, SOD1 condensates induced by Zn-depletion exhibit greater cellular toxicity than aggregates formed by prolonged incubation under aggregating conditions. Overall, our work establishes a role for Zn-dependent modulation of SOD1 conformation and LLPS properties that may contribute to amyloid formation.
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Affiliation(s)
- Bidisha Das
- Structural Biology and Bioinformatics DivisionCSIR‐Indian Institute of Chemical BiologyKolkataIndia
- Academy of Scientific and Innovative Research (AcSIR)GhaziabadIndia
| | - Sumangal Roychowdhury
- Structural Biology and Bioinformatics DivisionCSIR‐Indian Institute of Chemical BiologyKolkataIndia
| | - Priyesh Mohanty
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTXUSA
| | - Azamat Rizuan
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTXUSA
| | - Joy Chakraborty
- Cell Biology and Physiology DivisionCSIR‐Indian Institute of Chemical BiologyKolkataIndia
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTXUSA
| | - Krishnananda Chattopadhyay
- Structural Biology and Bioinformatics DivisionCSIR‐Indian Institute of Chemical BiologyKolkataIndia
- Academy of Scientific and Innovative Research (AcSIR)GhaziabadIndia
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Liquid-liquid Phase Separation of α-Synuclein: A New Mechanistic Insight for α-Synuclein Aggregation Associated with Parkinson's Disease Pathogenesis. J Mol Biol 2023; 435:167713. [PMID: 35787838 DOI: 10.1016/j.jmb.2022.167713] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 02/04/2023]
Abstract
Aberrant aggregation of the misfolded presynaptic protein, α-Synuclein (α-Syn) into Lewy body (LB) and Lewy neuritis (LN) is a major pathological hallmark of Parkinson's disease (PD) and other synucleinopathies. Numerous studies have suggested that prefibrillar and fibrillar species of the misfolded α-Syn aggregates are responsible for cell death in PD pathogenesis. However, the precise molecular events during α-Syn aggregation, especially in the early stages, remain elusive. Emerging evidence has demonstrated that liquid-liquid phase separation (LLPS) of α-Syn occurs in the nucleation step of α-Syn aggregation, which offers an alternate non-canonical aggregation pathway in the crowded microenvironment. The liquid-like α-Syn droplets gradually undergo an irreversible liquid-to-solid phase transition into amyloid-like hydrogel entrapping oligomers and fibrils. This new mechanism of α-Syn LLPS and gel formation might represent the molecular basis of cellular toxicity associated with PD. This review aims to demonstrate the recent development of α-Syn LLPS, the underlying mechanism along with the microscopic events of aberrant phase transition. This review further discusses how several intrinsic and extrinsic factors regulate the thermodynamics and kinetics of α-Syn LLPS and co-LLPS with other proteins, which might explain the pathophysiology of α-Syn in various neurodegenerative diseases.
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45
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Thomas L, Putnam A, Folkmann A. Germ granules in development. Development 2023; 150:286764. [PMID: 36715566 PMCID: PMC10165536 DOI: 10.1242/dev.201037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A hallmark of all germ cells is the presence of germ granules: assemblies of proteins and RNA that lack a delineating membrane and are proposed to form via condensation. Germ granules across organisms share several conserved components, including factors required for germ cell fate determination and maintenance, and are thought to be linked to germ cell development. The molecular functions of germ granules, however, remain incompletely understood. In this Development at a Glance article, we survey germ granules across organisms and developmental stages, and highlight emerging themes regarding granule regulation, dynamics and proposed functions.
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Affiliation(s)
- Laura Thomas
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Andrea Putnam
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Andrew Folkmann
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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46
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Chen P, Levy DL. Regulation of organelle size and organization during development. Semin Cell Dev Biol 2023; 133:53-64. [PMID: 35148938 PMCID: PMC9357868 DOI: 10.1016/j.semcdb.2022.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/20/2022] [Accepted: 02/01/2022] [Indexed: 12/11/2022]
Abstract
During early embryogenesis, as cells divide in the developing embryo, the size of intracellular organelles generally decreases to scale with the decrease in overall cell size. Organelle size scaling is thought to be important to establish and maintain proper cellular function, and defective scaling may lead to impaired development and disease. However, how the cell regulates organelle size and organization are largely unanswered questions. In this review, we summarize the process of size scaling at both the cell and organelle levels and discuss recently discovered mechanisms that regulate this process during early embryogenesis. In addition, we describe how some recently developed techniques and Xenopus as an animal model can be used to investigate the underlying mechanisms of size regulation and to uncover the significance of proper organelle size scaling and organization.
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Affiliation(s)
- Pan Chen
- Institute of Biochemistry and Molecular Biology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
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47
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Bai Q, Liu Z, Chen J, Liang D. Crowded Environment Regulates the Coacervation of Biopolymers via Nonspecific Interactions. Biomacromolecules 2023; 24:283-293. [PMID: 36511362 DOI: 10.1021/acs.biomac.2c01129] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The membrane-less organelles (MLOs) with subcompartments are formed via liquid-liquid phase separation (LLPS) in the crowded cell interior whose background molecules are up to 400 mg/mL. It is still a puzzle how the background molecules regulate the formation, dynamics, and functions of MLOs. Using biphasic coacervate droplets formed by poly(l-lysine) (PLL), quaternized dextran (Q-dextran), and single-stranded oligonucleotides (ss-oligo) as a model of MLO, we online monitored the LLPS process in Bovine Serine Albumin (BSA) solution up to 200.0 mg/mL. Negatively charged BSA is able to form complex or coacervate with positively charged PLL and Q-dextran and thus participates in the LLPS via nonspecific interactions. Results show that BSA effectively regulates the LLPS by controlling the phase distribution, morphologies, and kinetics. With increasing BSA concentration, the spherical biphasic droplets evolve in sequence into phase-inverted flower-like structure, worm-like chains, network structures, and confined coacervates. Each kind of morphology is formed via its own specific growth and fusion pathway. Our work suggests that MLOs could be controlled solely by the crowded environment and provides a further step toward understanding the life process in cell.
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Affiliation(s)
- Qingwen Bai
- Beijing National Laboratory for Molecular Sciences, Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Zhijun Liu
- Beijing National Laboratory for Molecular Sciences, Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Jiaxin Chen
- Beijing National Laboratory for Molecular Sciences, Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
| | - Dehai Liang
- Beijing National Laboratory for Molecular Sciences, Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China
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48
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Félix SS, Laurents DV, Oroz J, Cabrita EJ. Fused in sarcoma undergoes cold denaturation: Implications for phase separation. Protein Sci 2023; 32:e4521. [PMID: 36453011 PMCID: PMC9793971 DOI: 10.1002/pro.4521] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/04/2022]
Abstract
The mediation of liquid-liquid phase separation (LLPS) for fused in sarcoma (FUS) protein is generally attributed to the low-complexity, disordered domains and is enhanced at low temperature. The role of FUS folded domains on the LLPS process remains relatively unknown since most studies are mainly based on fragmented FUS domains. Here, we investigate the effect of metabolites on full-length (FL) FUS LLPS using turbidity assays and differential interference contrast (DIC) microscopy, and explore the behavior of the folded domains by nuclear magnetic resonance (NMR) spectroscopy. FL FUS LLPS is maximal at low concentrations of glucose and glutamate, moderate concentrations of NaCl, Zn2+ , and Ca2+ and at the isoelectric pH. The FUS RNA recognition motif (RRM) and zinc-finger (ZnF) domains are found to undergo cold denaturation above 0°C at a temperature that is determined by the conformational stability of the ZnF domain. Cold unfolding exposes buried nonpolar residues that can participate in LLPS-promoting hydrophobic interactions. Therefore, these findings constitute the first evidence that FUS globular domains may have an active role in LLPS under cold stress conditions and in the assembly of stress granules, providing further insight into the environmental regulation of LLPS.
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Affiliation(s)
- Sara S. Félix
- UCIBIO, Department of ChemistryNOVA School of Science and Technology, Universidade NOVA de LisboaCaparicaPortugal,Associate Laboratory i4HB – Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de LisboaCaparicaPortugal,Instituto de Química Física Rocasolano (IQFR), CSICMadridSpain
| | | | - Javier Oroz
- Instituto de Química Física Rocasolano (IQFR), CSICMadridSpain
| | - Eurico J. Cabrita
- UCIBIO, Department of ChemistryNOVA School of Science and Technology, Universidade NOVA de LisboaCaparicaPortugal,Associate Laboratory i4HB – Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de LisboaCaparicaPortugal
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49
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Biological soft matter: intrinsically disordered proteins in liquid-liquid phase separation and biomolecular condensates. Essays Biochem 2022; 66:831-847. [PMID: 36350034 DOI: 10.1042/ebc20220052] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/10/2022]
Abstract
The facts that many proteins with crucial biological functions do not have unique structures and that many biological processes are compartmentalized into the liquid-like biomolecular condensates, which are formed via liquid-liquid phase separation (LLPS) and are not surrounded by the membrane, are revolutionizing the modern biology. These phenomena are interlinked, as the presence of intrinsic disorder represents an important requirement for a protein to undergo LLPS that drives biogenesis of numerous membrane-less organelles (MLOs). Therefore, one can consider these phenomena as crucial constituents of a new IDP-LLPS-MLO field. Furthermore, intrinsically disordered proteins (IDPs), LLPS, and MLOs represent a clear link between molecular and cellular biology and soft matter and condensed soft matter physics. Both IDP and LLPS/MLO fields are undergoing explosive development and generate the ever-increasing mountain of crucial data. These new data provide answers to so many long-standing questions that it is difficult to imagine that in the very recent past, protein scientists and cellular biologists operated without taking these revolutionary concepts into account. The goal of this essay is not to deliver a comprehensive review of the IDP-LLPS-MLO field but to provide a brief and rather subjective outline of some of the recent developments in these exciting fields.
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50
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Different states and the associated fates of biomolecular condensates. Essays Biochem 2022; 66:849-862. [PMID: 36350032 DOI: 10.1042/ebc20220054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/20/2022] [Accepted: 10/07/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Biomolecular condensates are functional assemblies, which can enrich intrinsically disordered proteins (IDPs) and/or RNAs at concentrations that are orders of magnitude higher than the bulk. In their native functional state, these structures can exist in multiple physical states including liquid-droplet phase, hydrogels, and solid assemblies. On the other hand, an aberrant transition between these physical states can result in loss-of-function or a gain-of-toxic-function. A prime example of such an aberrant transition is droplet aging—a phenomenon where some condensates may progressively transition into less dynamic material states at biologically relevant timescales. In this essay, we review structural and viscoelastic roots of aberrant liquid–solid transitions. Also, we highlight the different checkpoints and experimentally tunable handles, both active (ATP-dependent enzymes, post-translational modifications) and passive (colocalization of RNA molecules), that could alter the material state of assemblies.
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