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Xu X, Zheng C, Lu D, Song CP, Zhang L. Phase separation in plants: New insights into cellular compartmentalization. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:1835-1855. [PMID: 34314106 DOI: 10.1111/jipb.13152] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/16/2021] [Indexed: 05/16/2023]
Abstract
A fundamental challenge for cells is how to coordinate various biochemical reactions in space and time. To achieve spatiotemporal control, cells have developed organelles that are surrounded by lipid bilayer membranes. Further, membraneless compartmentalization, a process induced by dynamic physical association of biomolecules through phase transition offers another efficient mechanism for intracellular organization. While our understanding of phase separation was predominantly dependent on yeast and animal models, recent findings have provided compelling evidence for emerging roles of phase separation in plants. In this review, we first provide an overview of the current knowledge of phase separation, including its definition, biophysical principles, molecular features and regulatory mechanisms. Then we summarize plant-specific phase separation phenomena and describe their functions in plant biological processes in great detail. Moreover, we propose that phase separation is an evolutionarily conserved and efficient mechanism for cellular compartmentalization which allows for distinct metabolic processes and signaling pathways, and is especially beneficial for the sessile lifestyle of plants to quickly and efficiently respond to the changing environment.
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Affiliation(s)
- Xiumei Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Canhui Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Dandan Lu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Chun-Peng Song
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
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52
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Zhang JF, Mehta S, Zhang J. Signaling Microdomains in the Spotlight: Visualizing Compartmentalized Signaling Using Genetically Encoded Fluorescent Biosensors. Annu Rev Pharmacol Toxicol 2021; 61:587-608. [PMID: 33411579 DOI: 10.1146/annurev-pharmtox-010617-053137] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
How cells muster a network of interlinking signaling pathways to faithfully convert diverse external cues to specific functional outcomes remains a central question in biology. Through their ability to convert dynamic biochemical activities to rapid and precise optical readouts, genetically encoded fluorescent biosensors have become instrumental in unraveling the molecular logic controlling the specificity of intracellular signaling. In this review, we discuss how the use of genetically encoded fluorescent biosensors to visualize dynamic signaling events within their native cellular context is elucidating the different strategies employed by cells to organize signaling activities into discrete compartments, or signaling microdomains, to ensure functional specificity.
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Affiliation(s)
- Jin-Fan Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA; .,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA;
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA; .,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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53
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Hallegger M, Chakrabarti AM, Lee FCY, Lee BL, Amalietti AG, Odeh HM, Copley KE, Rubien JD, Portz B, Kuret K, Huppertz I, Rau F, Patani R, Fawzi NL, Shorter J, Luscombe NM, Ule J. TDP-43 condensation properties specify its RNA-binding and regulatory repertoire. Cell 2021; 184:4680-4696.e22. [PMID: 34380047 PMCID: PMC8445024 DOI: 10.1016/j.cell.2021.07.018] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 04/12/2021] [Accepted: 07/15/2021] [Indexed: 11/20/2022]
Abstract
Mutations causing amyotrophic lateral sclerosis (ALS) often affect the condensation properties of RNA-binding proteins (RBPs). However, the role of RBP condensation in the specificity and function of protein-RNA complexes remains unclear. We created a series of TDP-43 C-terminal domain (CTD) variants that exhibited a gradient of low to high condensation propensity, as observed in vitro and by nuclear mobility and foci formation. Notably, a capacity for condensation was required for efficient TDP-43 assembly on subsets of RNA-binding regions, which contain unusually long clusters of motifs of characteristic types and density. These "binding-region condensates" are promoted by homomeric CTD-driven interactions and required for efficient regulation of a subset of bound transcripts, including autoregulation of TDP-43 mRNA. We establish that RBP condensation can occur in a binding-region-specific manner to selectively modulate transcriptome-wide RNA regulation, which has implications for remodeling RNA networks in the context of signaling, disease, and evolution.
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Affiliation(s)
- Martina Hallegger
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK.
| | - Anob M Chakrabarti
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Genetics, Evolution and Environment, UCL Genetics Institute, Gower Street, London WC1E 6BT, UK
| | - Flora C Y Lee
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Bo Lim Lee
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Aram G Amalietti
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK; National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
| | - Hana M Odeh
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Katie E Copley
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jack D Rubien
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bede Portz
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Klara Kuret
- National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
| | - Ina Huppertz
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Frédérique Rau
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Rickie Patani
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nicholas M Luscombe
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Genetics, Evolution and Environment, UCL Genetics Institute, Gower Street, London WC1E 6BT, UK; Okinawa Institute of Science & Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Jernej Ule
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK; National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia.
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54
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Intrinsically disordered protein regions and phase separation: sequence determinants of assembly or lack thereof. Emerg Top Life Sci 2021; 4:307-329. [PMID: 33078839 DOI: 10.1042/etls20190164] [Citation(s) in RCA: 130] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/23/2020] [Accepted: 09/28/2020] [Indexed: 02/07/2023]
Abstract
Intrinsically disordered protein regions (IDRs) - regions that do not fold into a fixed three-dimensional structure but instead exist in a heterogeneous ensemble of conformations - have recently entered mainstream cell biology in the context of liquid-liquid phase separation (LLPS). IDRs are frequently found to be enriched in phase-separated compartments. Due to this observation, the presence of an IDR in a protein is frequently assumed to be diagnostic of its ability to phase separate. In this review, we clarify the role of IDRs in biological assembly and explore the physical principles through which amino acids can confer the attractive molecular interactions that underlie phase separation. While some disordered regions will robustly drive phase separation, many others will not. We emphasize that rather than 'disorder' driving phase separation, multivalency drives phase separation. As such, whether or not a disordered region is capable of driving phase separation will depend on the physical chemistry encoded within its amino acid sequence. Consequently, an in-depth understanding of that physical chemistry is a prerequisite to make informed inferences on how and why an IDR may be involved in phase separation or, more generally, in protein-mediated intermolecular interactions.
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55
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Shi Q, Kang K, Chen YG. Liquid-liquid phase separation drives the β-catenin destruction complex formation. Bioessays 2021; 43:e2100138. [PMID: 34418117 DOI: 10.1002/bies.202100138] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 12/30/2022]
Abstract
The intracellular multiprotein complex β-catenin destruction complex plays a key role in Wnt/β-catenin signaling. Wnt stimulation induces the assembly of the receptor-associated signalosome and the inactivation of the destruction complex, leading to β-catenin accumulation and transcriptional activation of the target genes. The core components of the destruction complex include Axin, APC, GSK3β, CK1α and other proteins. Recent studies demonstrated that Axin and APC undergo liquid-liquid phase separation (LLPS), which is critical for their function to regulate Wnt/β-catenin signaling. Here, we discuss the possible roles of LLPS in Wnt/β-catenin signaling and regulation of Axin LLPS by post-translational modifications.
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Affiliation(s)
- Qiaoni Shi
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Kexin Kang
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ye-Guang Chen
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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56
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Sawada D, Asakura K, Banno T. Pathway-Dependent Phase Transitions of Supramolecular Self-assemblies Containing Cationic Amphiphiles with Azobenzene and Disulfide Groups. Chemistry 2021; 27:13840-13845. [PMID: 34398482 DOI: 10.1002/chem.202102143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Indexed: 11/11/2022]
Abstract
There have been several attempts to construct supramolecular chemical systems that mimic the phase transitions in living systems. However, most of these phase transitions are one-to-one and induced by one stimulus or chemical; there have been few reports on the pathway-dependent phase transition of supramolecular self-assemblies in multi-step. To induce multistep phase transitions, molecular crystals were prepared that contained a cationic amphiphile bearing azobenzene and disulfide groups. A reducing agent caused the crystals to become vesicles, and adjacent, non-touching vesicles fused under UV and subsequent visible light. Adding a reducing agent to the worm-like aggregates that were generated after UV irradiation of the original crystals resulted in the growth of sheet-like aggregates. 1 H NMR and fluorescence anisotropy measurements showed that a series of phase transitions was induced by changes in the phase structures from molecular conversions of the reactive amphiphiles. The multiple pathway-dependent phase transitions of supramolecular self-assemblies can provide a methodology for developing new stimuli-responsive materials that exhibit the desirable properties under specific circumstances from a systems chemistry viewpoint.
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Affiliation(s)
- Daichi Sawada
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | - Kouichi Asakura
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
| | - Taisuke Banno
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
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57
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Yang Y, Ye X, Dai R, Li Z, Zhang Y, Xue W, Zhu Y, Feng D, Qin L, Wang X, Lei B, Liao S, Hao B. Phase separation of Epstein-Barr virus EBNA2 protein reorganizes chromatin topology for epigenetic regulation. Commun Biol 2021; 4:967. [PMID: 34400762 PMCID: PMC8368186 DOI: 10.1038/s42003-021-02501-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 07/28/2021] [Indexed: 12/13/2022] Open
Abstract
Epstein-Barr virus nuclear antigen 2 (EBNA2) is a transactivator of viral and cellular gene expression, which plays a critical role in the Epstein-Barr virus-associated diseases. It was reported that EBNA2 regulates gene expression by reorganizing chromatin and manipulating epigenetics. Recent studies showed that liquid-liquid phase separation plays an essential role in epigenetic and transcriptional regulation. Here we show that EBNA2 reorganized chromatin topology to form accessible chromatin domains (ACDs) of the host genome by phase separation. The N-terminal region of EBNA2, which is necessary for phase separation, is sufficient to induce ACDs. The C-terminal domain of EBNA2 promotes the acetylation of accessible chromatin regions by recruiting histone acetylase p300 to ACDs. According to these observations, we proposed a model of EBNA2 reorganizing chromatin topology for its acetylation through phase separation to explain the mechanism of EBNA2 hijacking the host genome by controlling its epigenetics. Yang et al find that phase separation of the Epstein-Barr virus nuclear antigen 2 (EBNA2) is involved in the formation of accessible chromatin domains of the host genome. They also find that EBNA2 recruits histone acetyltransferase to promote histone acetylation on accessible chromatin regions and regulate gene expression and that these two functions are performed by the N- and Cterminus respectively.
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Affiliation(s)
- Yiting Yang
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xidong Ye
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Ranran Dai
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zhaoqiang Li
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yan Zhang
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Wei Xue
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yongchang Zhu
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Delong Feng
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Litao Qin
- Henan Medical Genetics Institute, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Xin Wang
- Henan Medical Genetics Institute, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Bo Lei
- Henan Eye Institute, Henan Eye Hospital, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China.
| | - Shixiu Liao
- Henan Medical Genetics Institute, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China. .,National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China.
| | - Bingtao Hao
- Cancer Research Institute, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China. .,Henan Medical Genetics Institute, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China. .,National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China.
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58
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Liquid-liquid phase separation: a principal organizer of the cell's biochemical activity architecture. Trends Pharmacol Sci 2021; 42:845-856. [PMID: 34373114 DOI: 10.1016/j.tips.2021.07.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/28/2021] [Accepted: 07/13/2021] [Indexed: 12/25/2022]
Abstract
Numerous processes occur simultaneously in the cell both for normal function and in response to changes in the environment. The ability of cells to segregate biochemical reactions into separate compartments is essential to ensure specificity and efficiency in cellular processes. The discovery of liquid-liquid phase separation as a mechanism of compartmentalization has revised our thinking regarding the intracellular organization of molecular pathways such as signal transduction. Here, we highlight recent studies that advance our understanding of how phase separation impacts the organization of biochemical processes, with a particular focus on the tools used to study the functional impact of phase separation. In addition, we offer some of our perspectives on the pathological consequences of dysregulated phase separation in biochemical pathways.
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59
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Dinic J, Marciel AB, Tirrell MV. Polyampholyte physics: Liquid–liquid phase separation and biological condensates. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101457] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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60
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Li L, Herzog M, Möbitz S, Winter R. Liquid droplets of protein LAF1 provide a vehicle to regulate storage of the signaling protein K-Ras4B and its transport to the lipid membrane. Phys Chem Chem Phys 2021; 23:5370-5375. [PMID: 33645620 DOI: 10.1039/d1cp00007a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Liquid-liquid phase separation has been shown to promote the formation of functional membraneless organelles involved in various cellular processes, including metabolism, stress response and signal transduction. Protein LAF1 found in P-granules phase separates into liquid-like droplets by patterned electrostatic interactions between acidic and basic tracts in LAF1 and has been used as model system in this study. We show that signaling proteins, such as K-Ras4B, a small GTPase that acts as a molecular switch and regulates many cellular processes including proliferation, apoptosis and cell growth, can colocalize in LAF1 droplets. Colocalization is facilitated by electrostatic interactions between the positively charged polybasic domain of K-Ras4B and the negatively charged motifs of LAF1. The interaction partners B- and C-Raf of K-Ras4B can also be recruited to the liquid droplets. Upon contact with an anionic lipid bilayer membrane, the liquid droplets dissolve and K-Ras4B is released, forming nanoclusters in the lipid membrane. Considering the high tuneability of liquid-liquid phase separation in the cell, the colocalization of signaling proteins and their effector molecules in liquid droplets may provide an additional vehicle for regulating storage and transport of membrane-associated signaling proteins such as K-Ras4B and offer an alternative strategy for high-fidelity signal output.
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Affiliation(s)
- Lei Li
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I - Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany.
| | - Marius Herzog
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I - Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany.
| | - Simone Möbitz
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I - Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany.
| | - Roland Winter
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I - Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany.
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61
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Jacobs WM. Self-Assembly of Biomolecular Condensates with Shared Components. PHYSICAL REVIEW LETTERS 2021; 126:258101. [PMID: 34241502 DOI: 10.1103/physrevlett.126.258101] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/13/2021] [Indexed: 06/13/2023]
Abstract
Biomolecular condensates self-assemble when proteins and nucleic acids spontaneously demix to form droplets within the crowded intracellular milieu. This simple mechanism underlies the formation of a wide variety of membraneless compartments in living cells. To understand how multiple condensates with distinct compositions can self-assemble in such a heterogeneous system, which may not be at thermodynamic equilibrium, we study a minimal model in which we can "program" the pairwise interactions among hundreds of species. We show that the number of distinct condensates that can be reliably assembled grows superlinearly with the number of species in the mixture when the condensates share components. Furthermore, we show that we can predict the maximum number of distinct condensates in a mixture without knowing the details of the pairwise interactions. Simulations of condensate growth confirm these predictions and suggest that the physical rules governing the achievable complexity of condensate-mediated spatial organization are broadly applicable to biomolecular mixtures.
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Affiliation(s)
- William M Jacobs
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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62
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Kashin AS, Boiko DA, Ananikov VP. Neural Network Analysis of Electron Microscopy Video Data Reveals the Temperature-Driven Microphase Dynamics in the Ions/Water System. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2007726. [PMID: 33938144 DOI: 10.1002/smll.202007726] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Real-time field-emission scanning electron microscopy (FE-SEM) measurements and neural network analysis were successfully merged to observe the temperature-induced behavior of soft liquid microdomains in mixtures of different ionic liquids with water. The combination of liquid FE-SEM and in situ heating techniques revealed temperature-driven solution restructuring for ions/water systems with different water states and their critical point behavior expressed in a rapid switch between thermal expansion and shrinkage of liquid microphases at temperatures of ≈100-130 °C, which was directly recorded on electron microscopy videos. Automation of FE-SEM video analysis by a neural network approach allowed quantification of the morphological changes in ions/water systems during heating on the basis of thousands of images processed with a speed almost equal to the frame rate of original electron microscopy videos. Tracking and evolution of the micro-heterogeneous domains, hypothesized in the Ioliomics concept, was mapped and quantified for the first time. The present study describes the concept for quick acquisition of big data in electron microscopy, develops rapid neural network analysis and shows how to link microscopic data to fundamental molecular properties.
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Affiliation(s)
- Alexey S Kashin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russian Federation
| | - Daniil A Boiko
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russian Federation
| | - Valentine P Ananikov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russian Federation
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63
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Zhu J, Li C, Peng X, Zhang X. RNA architecture influences plant biology. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4144-4160. [PMID: 33484251 PMCID: PMC8130982 DOI: 10.1093/jxb/erab030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/18/2021] [Indexed: 05/13/2023]
Abstract
The majority of the genome is transcribed to RNA in living organisms. RNA transcripts can form astonishing arrays of secondary and tertiary structures via Watson-Crick, Hoogsteen, or wobble base pairing. In vivo, RNA folding is not a simple thermodynamic event of minimizing free energy. Instead, the process is constrained by transcription, RNA-binding proteins, steric factors, and the microenvironment. RNA secondary structure (RSS) plays myriad roles in numerous biological processes, such as RNA processing, stability, transportation, and translation in prokaryotes and eukaryotes. Emerging evidence has also implicated RSS in RNA trafficking, liquid-liquid phase separation, and plant responses to environmental variations such as temperature and salinity. At molecular level, RSS is correlated with splicing, polyadenylation, protein synthesis, and miRNA biogenesis and functions. In this review, we summarize newly reported methods for probing RSS in vivo and functions and mechanisms of RSS in plant physiology.
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Affiliation(s)
- Jiaying Zhu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Changhao Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Xu Peng
- Department of Medical Physiology, College of Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Xiuren Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Correspondence:
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64
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Wessén J, Pal T, Das S, Lin YH, Chan HS. A Simple Explicit-Solvent Model of Polyampholyte Phase Behaviors and Its Ramifications for Dielectric Effects in Biomolecular Condensates. J Phys Chem B 2021; 125:4337-4358. [PMID: 33890467 DOI: 10.1021/acs.jpcb.1c00954] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Biomolecular condensates such as membraneless organelles, underpinned by liquid-liquid phase separation (LLPS), are important for physiological function, with electrostatics, among other interaction types, being a prominent force in their assembly. Charge interactions of intrinsically disordered proteins (IDPs) and other biomolecules are sensitive to the aqueous dielectric environment. Because the relative permittivity of protein is significantly lower than that of water, the interior of an IDP condensate is expected to be a relatively low-dielectric regime, which aside from its possible functional effects on client molecules should facilitate stronger electrostatic interactions among the scaffold IDPs. To gain insight into this LLPS-induced dielectric heterogeneity, addressing in particular whether a low-dielectric condensed phase entails more favorable LLPS than that posited by assuming IDP electrostatic interactions are uniformly modulated by the higher dielectric constant of the pure solvent, we consider a simplified multiple-chain model of polyampholytes immersed in explicit solvents that are either polarizable or possess a permanent dipole. Notably, simulated phase behaviors of these systems exhibit only minor to moderate differences from those obtained using implicit-solvent models with a uniform relative permittivity equals to that of pure solvent. Buttressed by theoretical treatments developed here using random phase approximation and polymer field-theoretic simulations, these observations indicate a partial compensation of effects between favorable solvent-mediated interactions among the polyampholytes in the condensed phase and favorable polyampholyte-solvent interactions in the dilute phase, often netting only a minor enhancement of overall LLPS propensity from the very dielectric heterogeneity that arises from the LLPS itself. Further ramifications of this principle are discussed.
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Affiliation(s)
- Jonas Wessén
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Tanmoy Pal
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Suman Das
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Yi-Hsuan Lin
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.,Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Hue Sun Chan
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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65
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Schisa JA, Elaswad MT. An Emerging Role for Post-translational Modifications in Regulating RNP Condensates in the Germ Line. Front Mol Biosci 2021; 8:658020. [PMID: 33898525 PMCID: PMC8060454 DOI: 10.3389/fmolb.2021.658020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022] Open
Abstract
RNA-binding proteins undergo regulated phase transitions in an array of cell types. The phase separation of RNA-binding proteins, and subsequent formation of RNP condensates or granules, occurs during physiological conditions and can also be induced by stress. Some RNP granules have roles in post-transcriptionally regulating mRNAs, and mutations that prevent the condensation of RNA-binding proteins can reduce an organism's fitness. The reversible and multivalent interactions among RNP granule components can result in RNP complexes that transition among diffuse and condensed states, the latter of which can be pathological; for example, in neurons solid RNP aggregates contribute to disease states such as amyotrophic lateral sclerosis (ALS), and the dysregulation of RNP granules in human germ cells may be involved in Fragile X-associated primary ovarian insufficiency. Thus, regulating the assembly of mRNAs and RNA-binding proteins into discrete granules appears to provide important functions at both cellular and physiological levels. Here we review our current understanding of the role of post-translational modifications (PTMs) in regulating the condensation of RNA-binding proteins in the germ line. We compare and contrast the in vitro evidence that methylation inhibits phase separation of RNA binding proteins, with the extent to which these results apply to the in vivo germ line environment of several model systems. We also focus on the role of phosphorylation in modulating the dynamics of RNP granules in the germ line. Finally, we consider the gaps that exist in our understanding of the role of PTMs in regulating germ line RNP granules.
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Affiliation(s)
- Jennifer A Schisa
- Department of Biology, Central Michigan University, Mount Pleasant, MI, United States
| | - Mohamed T Elaswad
- Department of Biology, Central Michigan University, Mount Pleasant, MI, United States
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66
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King JT, Shakya A. Phase separation of DNA: From past to present. Biophys J 2021; 120:1139-1149. [PMID: 33582138 PMCID: PMC8059212 DOI: 10.1016/j.bpj.2021.01.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/11/2021] [Accepted: 01/22/2021] [Indexed: 02/08/2023] Open
Abstract
Phase separation of biological molecules, such as nucleic acids and proteins, has garnered widespread attention across many fields in recent years. For instance, liquid-liquid phase separation has been implicated not only in membraneless intracellular organization but also in many biochemical processes, including transcription, translation, and cellular signaling. Here, we present a historical background of biological phase separation and survey current work on nuclear organization and its connection to DNA phase separation from the perspective of DNA sequence, structure, and genomic context.
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Affiliation(s)
- John T King
- Center for Soft and Living Matter, Institute for Basic Science, Ulsan, Republic of Korea.
| | - Anisha Shakya
- Center for Soft and Living Matter, Institute for Basic Science, Ulsan, Republic of Korea.
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67
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68
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Luo J, Qu L, Gao F, Lin J, Liu J, Lin A. LncRNAs: Architectural Scaffolds or More Potential Roles in Phase Separation. Front Genet 2021; 12:626234. [PMID: 33868368 PMCID: PMC8044363 DOI: 10.3389/fgene.2021.626234] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 02/25/2021] [Indexed: 12/12/2022] Open
Abstract
Biomolecules specifically aggregate in the cytoplasm and nucleus, driving liquid-liquid phase separation (LLPS) formation and diverse biological processes. Extensive studies have focused on revealing multiple functional membraneless organelles in both the nucleus and cytoplasm. Condensation compositions of LLPS, such as proteins and RNAs affecting the formation of phase separation, have been gradually unveiled. LncRNAs possessing abundant second structures usually promote phase separation formation by providing architectural scaffolds for diverse RNAs and proteins interaction in both the nucleus and cytoplasm. Beyond scaffolds, lncRNAs may possess more diverse functions, such as functioning as enhancer RNAs or buffers. In this review, we summarized current studies on the function of phase separation and its related lncRNAs, mainly in the nucleus. This review will facilitate our understanding of the formation and function of phase separation and the role of lncRNAs in these processes and related biological activities. A deeper understanding of the formation and maintaining of phase separation will be beneficial for disease diagnosis and treatment.
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Affiliation(s)
- Jie Luo
- Department of Obstetrics and Gynecology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Lei Qu
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Feiran Gao
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China.,Zhejiang University-University of Edinburgh Institute (ZJU-UoE Institute), Zhejiang University School of Medicine, Zhejiang University, Haining, China
| | - Jun Lin
- Department of Obstetrics and Gynecology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jian Liu
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China.,Zhejiang University-University of Edinburgh Institute (ZJU-UoE Institute), Zhejiang University School of Medicine, Zhejiang University, Haining, China
| | - Aifu Lin
- College of Life Sciences, Zhejiang University, Hangzhou, China.,Breast Center of The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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69
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Taniue K, Akimitsu N. Aberrant phase separation and cancer. FEBS J 2021; 289:17-39. [PMID: 33583140 DOI: 10.1111/febs.15765] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/24/2021] [Accepted: 02/12/2021] [Indexed: 01/10/2023]
Abstract
Eukaryotic cells are intracellularly divided into numerous compartments or organelles, which coordinate specific molecules and biological reactions. Membrane-bound organelles are physically separated by lipid bilayers from the surrounding environment. Biomolecular condensates, also referred to membraneless organelles, are micron-scale cellular compartments that lack membranous enclosures but function to concentrate proteins and RNA molecules, and these are involved in diverse processes. Liquid-liquid phase separation (LLPS) driven by multivalent weak macromolecular interactions is a critical principle for the formation of biomolecular condensates, and a multitude of combinations among multivalent interactions may drive liquid-liquid phase transition (LLPT). Dysregulation of LLPS and LLPT leads to aberrant condensate and amyloid formation, which causes many human diseases, including neurodegeneration and cancer. Here, we describe recent findings regarding abnormal forms of biomolecular condensates and aggregation via aberrant LLPS and LLPT of cancer-related proteins in cancer development driven by mutation and fusion of genes. Moreover, we discuss the regulatory mechanisms by which aberrant LLPS and LLPT occur in cancer and the drug candidates targeting these mechanisms. Further understanding of the molecular events regulating how biomolecular condensates and aggregation form in cancer tissue is critical for the development of therapeutic strategies against tumorigenesis.
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Affiliation(s)
- Kenzui Taniue
- Isotope Science Center, The University of Tokyo, Japan.,Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan
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70
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Boija A, Klein IA, Young RA. Biomolecular Condensates and Cancer. Cancer Cell 2021; 39:174-192. [PMID: 33417833 PMCID: PMC8721577 DOI: 10.1016/j.ccell.2020.12.003] [Citation(s) in RCA: 140] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/02/2020] [Accepted: 12/04/2020] [Indexed: 12/14/2022]
Abstract
Malignant transformation is characterized by dysregulation of diverse cellular processes that have been the subject of detailed genetic, biochemical, and structural studies, but only recently has evidence emerged that many of these processes occur in the context of biomolecular condensates. Condensates are membrane-less bodies, often formed by liquid-liquid phase separation, that compartmentalize protein and RNA molecules with related functions. New insights from condensate studies portend a profound transformation in our understanding of cellular dysregulation in cancer. Here we summarize key features of biomolecular condensates, note where they have been implicated-or will likely be implicated-in oncogenesis, describe evidence that the pharmacodynamics of cancer therapeutics can be greatly influenced by condensates, and discuss some of the questions that must be addressed to further advance our understanding and treatment of cancer.
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Affiliation(s)
- Ann Boija
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.
| | - Isaac A Klein
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA.
| | - Richard A Young
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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71
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Siegert A, Rankovic M, Favretto F, Ukmar-Godec T, Strohäker T, Becker S, Zweckstetter M. Interplay between tau and α-synuclein liquid-liquid phase separation. Protein Sci 2021; 30:1326-1336. [PMID: 33452693 PMCID: PMC8197422 DOI: 10.1002/pro.4025] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 01/07/2023]
Abstract
In Parkinson's disease with dementia, up to 50% of patients develop a high number of tau‐containing neurofibrillary tangles. Tau‐based pathologies may thus act synergistically with the α‐synuclein pathology to confer a worse prognosis. A better understanding of the relationship between the two distinct pathologies is therefore required. Liquid–liquid phase separation (LLPS) of proteins has recently been shown to be important for protein aggregation involved in amyotrophic lateral sclerosis, whereas tau phase separation has been linked to Alzheimer's disease. We therefore investigated the interaction of α‐synuclein with tau and its consequences on tau LLPS. We find α‐synuclein to have a low propensity for both, self‐coacervation and RNA‐mediated LLPS at pH 7.4. However, full‐length but not carboxy‐terminally truncated α‐synuclein efficiently partitions into tau/RNA droplets. We further demonstrate that Cdk2‐phosphorylation promotes the concentration of tau into RNA‐induced droplets, but at the same time decreases the amount of α‐synuclein inside the droplets. NMR spectroscopy reveals that the interaction of the carboxy‐terminal domain of α‐synuclein with the proline‐rich region P2 of tau is required for the recruitment of α‐synuclein into tau droplets. The combined data suggest that the concentration of α‐synuclein into tau‐associated condensates can contribute to synergistic aSyn/tau pathologies.
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Affiliation(s)
- Anna Siegert
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Marija Rankovic
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Filippo Favretto
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Tina Ukmar-Godec
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Timo Strohäker
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Stefan Becker
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.,Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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72
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Uversky VN. Recent Developments in the Field of Intrinsically Disordered Proteins: Intrinsic Disorder-Based Emergence in Cellular Biology in Light of the Physiological and Pathological Liquid-Liquid Phase Transitions. Annu Rev Biophys 2021; 50:135-156. [PMID: 33503380 DOI: 10.1146/annurev-biophys-062920-063704] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review deals with two important concepts-protein intrinsic disorder and proteinaceous membrane-less organelles (PMLOs). The past 20 years have seen an upsurge of scientific interest in these phenomena. However, neither are new discoveries made in this century, but instead are timely reincarnations of old ideas that were mostly ignored by the scientific community for a long time. Merging these concepts in the form of the intrinsic disorder-based biological liquid-liquid phase separation provides a basis for understanding the molecular mechanisms of PMLO biogenesis.
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Affiliation(s)
- Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, USA; .,Institute for Biological Instrumentation, Pushchino Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russia
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73
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Assembling the right type of switch: Protein condensation to signal cell death. Curr Opin Cell Biol 2021; 69:55-61. [PMID: 33461073 DOI: 10.1016/j.ceb.2020.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/30/2020] [Accepted: 12/12/2020] [Indexed: 11/22/2022]
Abstract
Protein phase transitions are particularly amenable for cell signalling as these highly cooperative processes allow cells to make binary decisions in response to relatively small intracellular changes. The different processes of condensate formation and the distinct material properties of the resulting condensates provide a dictionary to modulate a range of decisions on cell fate. We argue that, on the one hand, the reversibility of liquid demixing offers a chance to arrest cell growth under specific circumstances. On the other hand, the transition to amyloids is better suited for terminal decisions such as those leading to apoptosis and necrosis. Here, we review recent examples of both scenarios, highlighting how mutations in signalling proteins affect the formation of biomolecular condensates with drastic effects on cell survival.
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74
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Chambers IG, Willoughby MM, Hamza I, Reddi AR. One ring to bring them all and in the darkness bind them: The trafficking of heme without deliverers. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2021; 1868:118881. [PMID: 33022276 PMCID: PMC7756907 DOI: 10.1016/j.bbamcr.2020.118881] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/22/2020] [Accepted: 09/25/2020] [Indexed: 02/07/2023]
Abstract
Heme, as a hydrophobic iron-containing organic ring, is lipid soluble and can interact with biological membranes. The very same properties of heme that nature exploits to support life also renders heme potentially cytotoxic. In order to utilize heme, while also mitigating its toxicity, cells are challenged to tightly control the concentration and bioavailability of heme. On the bright side, it is reasonable to envision that, analogous to other transition metals, a combination of membrane-bound transporters, soluble carriers, and chaperones coordinate heme trafficking to subcellular compartments. However, given the dual properties exhibited by heme as a transition metal and lipid, it is compelling to consider the dark side: the potential role of non-proteinaceous biomolecules including lipids and nucleic acids that bind, sequester, and control heme trafficking and bioavailability. The emergence of inter-organellar membrane contact sites, as well as intracellular vesicles derived from various organelles, have raised the prospect that heme can be trafficked through hydrophobic channels. In this review, we aim to focus on heme delivery without deliverers - an alternate paradigm for the regulation of heme homeostasis through chaperone-less pathways for heme trafficking.
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Affiliation(s)
- Ian G Chambers
- Department of Animal and Avian Sciences, Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20740, United States of America
| | - Mathilda M Willoughby
- School of Chemistry and Biochemistry, Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, United States of America
| | - Iqbal Hamza
- Department of Animal and Avian Sciences, Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20740, United States of America.
| | - Amit R Reddi
- School of Chemistry and Biochemistry, Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, United States of America.
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75
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Xie D, Chen M, Niu J, Wang L, Li Y, Fang X, Li P, Qi Y. Phase separation of SERRATE drives dicing body assembly and promotes miRNA processing in Arabidopsis. Nat Cell Biol 2021; 23:32-39. [PMID: 33288888 DOI: 10.1038/s41556-020-00606-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/26/2020] [Indexed: 01/28/2023]
Abstract
MicroRNA (miRNA) production entails the step-wise processing of primary miRNAs (pri-miRNAs) into precursor miRNAs (pre-miRNAs) and miRNA/* duplexes by Dicing complexes containing DCL1, HYL1 and SE, which are localized in nuclear dicing bodies (D-bodies)1,2. Here, we show that D-bodies are phase-separated condensates. SE forms droplets and drives DCL1, HYL1 and pri/pre-miRNAs into the droplets in vitro, and mutation of SE abrogates the formation of D-bodies in vivo, which indicates that D-bodies arise through SE-mediated phase separation. Disruption of SE phase separation greatly reduces its activity in promoting miRNA processing both in vitro and in vivo. We further show that pre-miRNAs are processed into miRNA/* duplexes in the droplets and, after processing, miRNA/* duplexes are bound by HYL1 and released from the droplets. Our findings provide evidence that efficient miRNA processing depends on the SE-phase-separation-mediated formation of D-bodies and suggest a paradigm that the products made in phase-separated condensates can be shipped out for subsequent processes.
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Affiliation(s)
- Dongqi Xie
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Min Chen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Jinrong Niu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Liang Wang
- Tsinghua-Peking Center for Life Sciences, Beijing, China.,Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
| | - Yan Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Xiaofeng Fang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Pilong Li
- Tsinghua-Peking Center for Life Sciences, Beijing, China.,Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China
| | - Yijun Qi
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China. .,Tsinghua-Peking Center for Life Sciences, Beijing, China. .,Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua University, Beijing, China.
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76
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Das S, Lin YH, Vernon RM, Forman-Kay JD, Chan HS. Comparative roles of charge, π, and hydrophobic interactions in sequence-dependent phase separation of intrinsically disordered proteins. Proc Natl Acad Sci U S A 2020; 117:28795-28805. [PMID: 33139563 PMCID: PMC7682375 DOI: 10.1073/pnas.2008122117] [Citation(s) in RCA: 131] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Endeavoring toward a transferable, predictive coarse-grained explicit-chain model for biomolecular condensates underlain by liquid-liquid phase separation (LLPS) of proteins, we conducted multiple-chain simulations of the N-terminal intrinsically disordered region (IDR) of DEAD-box helicase Ddx4, as a test case, to assess roles of electrostatic, hydrophobic, cation-π, and aromatic interactions in amino acid sequence-dependent LLPS. We evaluated three different residue-residue interaction schemes with a shared electrostatic potential. Neither a common hydrophobicity scheme nor one augmented with arginine/lysine-aromatic cation-π interactions consistently accounted for available experimental LLPS data on the wild-type, a charge-scrambled, a phenylalanine-to-alanine (FtoA), and an arginine-to-lysine (RtoK) mutant of Ddx4 IDR. In contrast, interactions based on contact statistics among folded globular protein structures reproduce the overall experimental trend, including that the RtoK mutant has a much diminished LLPS propensity. Consistency between simulation and experiment was also found for RtoK mutants of P-granule protein LAF-1, underscoring that, to a degree, important LLPS-driving π-related interactions are embodied in classical statistical potentials. Further elucidation is necessary, however, especially of phenylalanine's role in condensate assembly because experiments on FtoA and tyrosine-to-phenylalanine mutants suggest that LLPS-driving phenylalanine interactions are significantly weaker than posited by common statistical potentials. Protein-protein electrostatic interactions are modulated by relative permittivity, which in general depends on aqueous protein concentration. Analytical theory suggests that this dependence entails enhanced interprotein interactions in the condensed phase but more favorable protein-solvent interactions in the dilute phase. The opposing trends lead to only a modest overall impact on LLPS.
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Affiliation(s)
- Suman Das
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Yi-Hsuan Lin
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Robert M Vernon
- Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Julie D Forman-Kay
- Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Hue Sun Chan
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada;
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77
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SAXS methods for investigating macromolecular and self-assembled polyelectrolyte complexes. Methods Enzymol 2020; 646:223-259. [PMID: 33453927 DOI: 10.1016/bs.mie.2020.09.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Polyelectrolyte complexation is driven by associative interactions between oppositely charged polyelectrolytes, resulting in formation of a macroscopic polymer dense phase and a polymer dilute phase with applications in coatings, adhesives, and purification membranes. Beyond macroscale phase separation, precision polymer synthesis has enabled further development of polyelectrolyte complex (PEC)-based self-assembled micelles and hydrogels with applications in biotechnology. Interestingly, it has been suggested that mechanisms similar to polyelectrolyte complexation drive formation of biological condensates that play an indispensable role in cellular biogenesis. The formation pathways and functionality of these complex materials is dependent on the physical properties that are built into polymer structure and the resulting physical conformation in the dilute and dense phase. Scattering techniques have enabled in situ investigation of structure-function relationships in PEC materials that may address unresolved biophysical questions in cellular processes as well as catalyze the development of novel materials for diverse applications. We describe preparation of PEC materials with controlled polymer characteristics (length, blockiness, charge density), small-angle X-ray scattering (SAXS) techniques employed to probe appropriate length scales, and the data analysis routines from a practical standpoint for new users. This article deals with bulk complexes and not with the related, important and interesting area of non-equilibrium layer-by-layer assembly of polyelectrolytes.
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78
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Lee SG, Kim N, Kim SM, Park IB, Kim H, Kim S, Kim BG, Hwang JM, Baek IJ, Gartner A, Park JH, Myung K. Ewing sarcoma protein promotes dissociation of poly(ADP-ribose) polymerase 1 from chromatin. EMBO Rep 2020; 21:e48676. [PMID: 33006225 DOI: 10.15252/embr.201948676] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 08/30/2020] [Accepted: 09/15/2020] [Indexed: 12/19/2022] Open
Abstract
Poly(ADP-ribose) polymerase 1 (PARP1) facilitates DNA damage response (DDR). While the Ewing's sarcoma breakpoint region 1 (EWS) protein fused to FLI1 triggers sarcoma formation, the physiological function of EWS is largely unknown. Here, we investigate the physiological role of EWS in regulating PARP1. We show that EWS is required for PARP1 dissociation from damaged DNA. Abnormal PARP1 accumulation caused by EWS inactivation leads to excessive Poly(ADP-Ribosy)lation (PARylation) and triggers cell death in both in vitro and in vivo models. Consistent with previous work, the arginine-glycine-glycine (RGG) domain of EWS is essential for PAR chain interaction and PARP1 dissociation from damaged DNA. Ews and Parp1 double mutant mice do not show improved survival, but supplementation with nicotinamide mononucleotides extends Ews-mutant pups' survival, which might be due to compensatory activation of other PARP proteins. Consistently, PARP1 accumulates on chromatin in Ewing's sarcoma cells expressing an EWS fusion protein that cannot interact with PARP1, and tissues derived from Ewing's sarcoma patients show increased PARylation. Taken together, our data reveal that EWS is important for removing PARP1 from damaged chromatin.
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Affiliation(s)
- Seon-Gyeong Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea.,Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Namwoo Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea.,Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Su-Min Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea.,Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - In Bae Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea
| | - Hyejin Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea
| | - Shinseog Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea
| | - Byung-Gyu Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea
| | - Jung Me Hwang
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea
| | - In-Joon Baek
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea
| | - Anton Gartner
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea.,Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Jun Hong Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea.,Herbal Medicine Resources Research Center, Korea Institute of Oriental Medicine, Naju, Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea.,Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea
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79
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Yu C, Shen B, You K, Huang Q, Shi M, Wu C, Chen Y, Zhang C, Li T. Proteome-scale analysis of phase-separated proteins in immunofluorescence images. Brief Bioinform 2020; 22:5900570. [PMID: 34020549 DOI: 10.1093/bib/bbaa187] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 07/16/2020] [Accepted: 07/21/2020] [Indexed: 12/25/2022] Open
Abstract
Phase separation is an important mechanism that mediates the spatial distribution of proteins in different cellular compartments. While phase-separated proteins share certain sequence characteristics, including intrinsically disordered regions (IDRs) and prion-like domains, such characteristics are insufficient for making accurate predictions; thus, a proteome-wide understanding of phase separation is currently lacking. Here, we define phase-separated proteomes based on the systematic analysis of immunofluorescence images of 12 073 proteins in the Human Protein Atlas. The analysis of these proteins reveals that phase-separated candidate proteins exhibit higher IDR contents, higher mean net charge and lower hydropathy and prefer to bind to RNA. Kinases and transcription factors are also enriched among these candidate proteins. Strikingly, both phase-separated kinases and phase-separated transcription factors display significantly reduced substrate specificity. Our work provides the first global view of the phase-separated proteome and suggests that the spatial proximity resulting from phase separation reduces the requirement for motif specificity and expands the repertoire of substrates. The source code and data are available at https://github.com/cheneyyu/deepphase.
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Affiliation(s)
- Chunyu Yu
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Boyan Shen
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Kaiqiang You
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Qi Huang
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Minglei Shi
- MOE Key Laboratory of Bioinformatics; Bioinformatics Division and Center for Synthetic & Systems Biology, TNLIST; School of Medicine, Tsinghua University, Beijing, China
| | - Congying Wu
- Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Yang Chen
- MOE Key Laboratory of Bioinformatics; Bioinformatics Division and Center for Synthetic & Systems Biology, TNLIST; School of Medicine, Tsinghua University, Beijing, China
| | - Chaolin Zhang
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, USA
| | - Tingting Li
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
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80
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Bienz M. Head-to-Tail Polymerization in the Assembly of Biomolecular Condensates. Cell 2020; 182:799-811. [PMID: 32822572 DOI: 10.1016/j.cell.2020.07.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022]
Abstract
Clustering of macromolecules is a fundamental cellular device underlying diverse biological processes that require high-avidity binding to effectors and substrates. Often, this involves a transition between diffuse and locally concentrated molecules akin to biophysical phase separation observable in vitro. One simple mechanistic paradigm underlying physiologically relevant phase transitions in cells is the reversible head-to-tail polymerization of hub proteins into filaments that are cross-linked by dimerization into dynamic three-dimensional molecular condensates. While many diverse folds and motifs can mediate dimerization, only two structurally distinct domains have been discovered so far to undergo head-to-tail polymerization, though these are widespread among all living kingdoms.
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Affiliation(s)
- Mariann Bienz
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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81
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Liquid-Liquid Phase Separation in Crowded Environments. Int J Mol Sci 2020; 21:ijms21165908. [PMID: 32824618 PMCID: PMC7460619 DOI: 10.3390/ijms21165908] [Citation(s) in RCA: 129] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 08/13/2020] [Indexed: 12/23/2022] Open
Abstract
Biomolecular condensates play a key role in organizing cellular fluids such as the cytoplasm and nucleoplasm. Most of these non-membranous organelles show liquid-like properties both in cells and when studied in vitro through liquid–liquid phase separation (LLPS) of purified proteins. In general, LLPS of proteins is known to be sensitive to variations in pH, temperature and ionic strength, but the role of crowding remains underappreciated. Several decades of research have shown that macromolecular crowding can have profound effects on protein interactions, folding and aggregation, and it must, by extension, also impact LLPS. However, the precise role of crowding in LLPS is far from trivial, as most condensate components have a disordered nature and exhibit multiple weak attractive interactions. Here, we discuss which factors determine the scope of LLPS in crowded environments, and we review the evidence for the impact of macromolecular crowding on phase boundaries, partitioning behavior and condensate properties. Based on a comparison of both in vivo and in vitro LLPS studies, we propose that phase separation in cells does not solely rely on attractive interactions, but shows important similarities to segregative phase separation.
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82
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Shillcock JC, Brochut M, Chénais E, Ipsen JH. Phase behaviour and structure of a model biomolecular condensate. SOFT MATTER 2020; 16:6413-6423. [PMID: 32584357 DOI: 10.1039/d0sm00813c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Phase separation of immiscible fluids is a common phenomenon in polymer chemistry, and is recognized as an important mechanism by which cells compartmentalize their biochemical reactions. Biomolecular condensates are condensed fluid droplets in cells that form by liquid-liquid phase separation of intrinsically-disordered proteins. They have a wide range of functions and are associated with chronic neurodegenerative diseases in which they become pathologically rigid. However, it remains unclear how their material properties depend on the molecular structure of the proteins. Here we explore the phase behaviour and structure of a model biomolecular condensate composed of semi-flexible polymers with attractive end-caps using coarse-grained simulations. The model contains the minimal molecular features that are sufficient to observe liquid-liquid phase separation of soluble polymers into a porous, three-dimensional network in which their end-caps reversibly bind at junctions. The distance between connected junctions scales with the polymer length as a self-avoiding random walk over a wide range of concentration with a weak affinity-dependent prefactor. By contrast, the average number of polymers that meet at the junctions depends on the end-cap affinity but only weakly on the polymer length. The structured porosity of the condensed phase suggests a mechanism for cells to regulate biomolecular condensates. Protein interaction sites may be turned on or off to modulate the condensate's porosity and therefore the diffusion and interaction of additional proteins.
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Affiliation(s)
- J C Shillcock
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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83
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Jing H, Bai Q, Lin Y, Chang H, Yin D, Liang D. Fission and Internal Fusion of Protocell with Membraneless "Organelles" Formed by Liquid-Liquid Phase Separation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8017-8026. [PMID: 32584581 DOI: 10.1021/acs.langmuir.0c01864] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Construction of protocells with hierarchical structures and living functions is still a great challenge. Growing evidence demonstrates that the membraneless organelles, which facilitate many essential cellular processes, are formed by RNA, protein, and other biopolymers via liquid-liquid phase separation (LLPS). The formation of the protocell in the early days of Earth could follow the same principle. In this work, we develop a novel coacervate-based protocell containing membraneless subcompartments via spontaneous liquid-liquid phase separation by simply mixing single-stranded oligonucleotides (ss-oligo), quaternized dextran (Q-dextran), and poly(l-lysine) (PLL) together. The resulting biphasic droplet, with PLL/ss-oligo phase being the internal subcompartments and Q-dextran/ss-oligo phase as the surrounding medium, is capable of sequestering and partitioning biomolecules into distinct regions. When the droplet is exposed to salt or Dextranase, the surrounding Q-dextran/ss-oligo phase will be gradually dissociated, resulting in the chaotic movement and fusion of internal subcompartments. Besides, the external electric field at a lower strength can drive the biphasic droplet to undergo a deviated circulation concomitant with the fusion of localized subcompartments, while a high-strength electric field can polarize the whole droplet, resulting in the release of daughter droplets in a controllable manner. Our study highlights that liquid-liquid phase separation of biopolymers is a powerful strategy to construct hierarchically structured protocells resembling the morphology and functions of living cells and provides a step toward a better understanding of the transition mechanism from nonliving to living matter under prebiotic conditions.
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Affiliation(s)
- Hairong Jing
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Polymer Chemistry and Physics, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Qingwen Bai
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Polymer Chemistry and Physics, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ya'nan Lin
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Polymer Chemistry and Physics, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Haojing Chang
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Polymer Chemistry and Physics, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Dongxiao Yin
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Polymer Chemistry and Physics, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Dehai Liang
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Polymer Chemistry and Physics, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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84
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Clustering of human prion protein and α-synuclein oligomers requires the prion protein N-terminus. Commun Biol 2020; 3:365. [PMID: 32647130 PMCID: PMC7347944 DOI: 10.1038/s42003-020-1085-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 06/18/2020] [Indexed: 12/31/2022] Open
Abstract
The interaction of prion protein (PrP) and α-synuclein (αSyn) oligomers causes synaptic impairment that might trigger Parkinson’s disease and other synucleinopathies. Here, we report that αSyn oligomers (αSynO) cluster with human PrP (huPrP) into micron-sized condensates. Multivalency of αSyn within oligomers is required for condensation, since clustering with huPrP is not observed for monomeric αSyn. The stoichiometry of the heteroassemblies is well defined with an αSyn:huPrP molar ratio of about 1:1. The αSynO−huPrP interaction is of high affinity, signified by slow dissociation. The huPrP region responsible for condensation of αSynO, residues 95−111 in the intrinsically disordered N-terminus, corresponds to the region required for αSynO-mediated cognitive impairment. HuPrP, moreover, achieves co-clustering of αSynO and Alzheimer’s disease-associated amyloid-β oligomers, providing a case of a cross-interaction of two amyloidogenic proteins through an interlinking intrinsically disordered protein region. The results suggest that αSynO-mediated condensation of huPrP is involved in the pathogenesis of synucleinopathies. Nadine S. Rösener et al. show that α-synuclein oligomers can cluster with human prion protein (huPrP) into condensates. The intrinsically disordered N-terminus of huPrP is necessary for this high-affinity interaction, suggesting a link between cluster formation and toxicity.
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85
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Ivanov SM, Atanasova M, Dimitrov I, Doytchinova IA. Cellular polyamines condense hyperphosphorylated Tau, triggering Alzheimer's disease. Sci Rep 2020; 10:10098. [PMID: 32572101 PMCID: PMC7308275 DOI: 10.1038/s41598-020-67119-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 06/03/2020] [Indexed: 12/27/2022] Open
Abstract
Many gaps in our understanding of Alzheimer's disease remain despite intense research efforts. One such prominent gap is the mechanism of Tau condensation and fibrillization. One viewpoint is that positively charged Tau is condensed by cytosolic polyanions. However, this hypothesis is likely based on an overestimation of the abundance and stability of cytosolic polyanions and an underestimation of crucial intracellular constituents - the cationic polyamines. Here, we propose an alternative mechanism grounded in cellular biology. We describe extensive molecular dynamics simulations and analysis on physiologically relevant model systems, which suggest that it is not positively charged, unmodified Tau that is condensed by cytosolic polyanions but negatively charged, hyperphosphorylated Tau that is condensed by cytosolic polycations. Our work has broad implications for anti-Alzheimer's research and drug development and the broader field of tauopathies in general, potentially paving the way to future etiologic therapies.
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Affiliation(s)
- Stefan M Ivanov
- Faculty of Pharmacy, Medical University of Sofia, Dunav 2 st., Sofia, 1000, Bulgaria.
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA.
| | - Mariyana Atanasova
- Faculty of Pharmacy, Medical University of Sofia, Dunav 2 st., Sofia, 1000, Bulgaria
| | - Ivan Dimitrov
- Faculty of Pharmacy, Medical University of Sofia, Dunav 2 st., Sofia, 1000, Bulgaria
| | - Irini A Doytchinova
- Faculty of Pharmacy, Medical University of Sofia, Dunav 2 st., Sofia, 1000, Bulgaria
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86
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Ning W, Guo Y, Lin S, Mei B, Wu Y, Jiang P, Tan X, Zhang W, Chen G, Peng D, Chu L, Xue Y. DrLLPS: a data resource of liquid-liquid phase separation in eukaryotes. Nucleic Acids Res 2020; 48:D288-D295. [PMID: 31691822 PMCID: PMC7145660 DOI: 10.1093/nar/gkz1027] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/21/2019] [Accepted: 10/21/2019] [Indexed: 01/08/2023] Open
Abstract
Here, we presented an integrative database named DrLLPS (http://llps.biocuckoo.cn/) for proteins involved in liquid–liquid phase separation (LLPS), which is a ubiquitous and crucial mechanism for spatiotemporal organization of various biochemical reactions, by creating membraneless organelles (MLOs) in eukaryotic cells. From the literature, we manually collected 150 scaffold proteins that are drivers of LLPS, 987 regulators that contribute in modulating LLPS, and 8148 potential client proteins that might be dispensable for the formation of MLOs, which were then categorized into 40 biomolecular condensates. We searched potential orthologs of these known proteins, and in total DrLLPS contained 437 887 known and potential LLPS-associated proteins in 164 eukaryotes. Furthermore, we carefully annotated LLPS-associated proteins in eight model organisms, by using the knowledge integrated from 110 widely used resources that covered 16 aspects, including protein disordered regions, domain annotations, post-translational modifications (PTMs), genetic variations, cancer mutations, molecular interactions, disease-associated information, drug-target relations, physicochemical property, protein functional annotations, protein expressions/proteomics, protein 3D structures, subcellular localizations, mRNA expressions, DNA & RNA elements, and DNA methylations. We anticipate DrLLPS can serve as a helpful resource for further analysis of LLPS.
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Affiliation(s)
- Wanshan Ning
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yaping Guo
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shaofeng Lin
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Bin Mei
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Yu Wu
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Peiran Jiang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xiaodan Tan
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Weizhi Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Guowei Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Di Peng
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Liang Chu
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Yu Xue
- Key Laboratory of Molecular Biophysics of Ministry of Education, Hubei Bioinformatics and Molecular Imaging Key Laboratory, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
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87
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Li DW, Xie M, Brüschweiler R. Quantitative Cooperative Binding Model for Intrinsically Disordered Proteins Interacting with Nanomaterials. J Am Chem Soc 2020; 142:10730-10738. [DOI: 10.1021/jacs.0c01885] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Da-Wei Li
- Campus Chemical Instrument Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Mouzhe Xie
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Rafael Brüschweiler
- Campus Chemical Instrument Center, The Ohio State University, Columbus, Ohio 43210, United States
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio 43210, United States
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88
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Abstract
Many critical biological events, including biochemical signaling, membrane traffic, and cell motility, originate at membrane surfaces. Each such event requires that members of a specific group of proteins and lipids rapidly assemble together at a specific site on the membrane surface. Understanding the biophysical mechanisms that stabilize these assemblies is critical to decoding and controlling cellular functions. In this article, we review progress toward a quantitative biophysical understanding of the mechanisms that drive membrane heterogeneity and organization. We begin from a physical perspective, reviewing the fundamental principles and key experimental evidence behind each proposed mechanism. We then shift to a biological perspective, presenting key examples of the role of heterogeneity in biology and asking which physical mechanisms may be responsible. We close with an applied perspective, noting that membrane heterogeneity provides a novel therapeutic target that is being exploited by a growing number of studies at the interface of biology, physics, and engineering.
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Affiliation(s)
- Wade F Zeno
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA;
| | - Kasey J Day
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA;
| | - Vernita D Gordon
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA;
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
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89
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Abstract
Multiple studies have confirmed that speckle-type pox virus and zinc finger (POZ) protein (SPOP) functions as a substrate adaptor of cullin 3-based E3 ligase and has a crucial role in various cellular processes via specific targeting of proteins for ubiquitination and subsequent proteasomal degradation. Dysregulation of SPOP-mediated proteolysis might be involved in the development and progression of human prostate and kidney cancers. In prostate cancer, SPOP seems to function as a tumour suppressor by targeting several proteins, including androgen receptor (AR), steroid receptor coactivator 3 (SRC3) and BRD4, for degradation, whereas it might function as an oncoprotein in kidney cancer, for example, by targeting phosphatase and tensin homologue (PTEN) for proteasomal degradation. In addition, nuclear SPOP targets AR for degradation and has a role as a tumour suppressor in prostate cancer; however, in kidney cancer, SPOP largely accumulates in the cytoplasm and fails to promote degradation of AR located in the nucleus, resulting in activation of AR-driven pathways and cancer progression. Owing to the context-dependent function of SPOP in human malignancies, further assessment of the molecular mechanisms involving SPOP in prostate and kidney cancers is needed to improve our understanding of its role in the development of these cancer types. Treatments that target SPOP might become therapeutic strategies in these malignancies in the future.
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90
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Last MG, Deshpande S, Dekker C. pH-Controlled Coacervate-Membrane Interactions within Liposomes. ACS NANO 2020; 14:4487-4498. [PMID: 32239914 PMCID: PMC7199211 DOI: 10.1021/acsnano.9b10167] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 04/02/2020] [Indexed: 05/19/2023]
Abstract
Membraneless organelles formed by liquid-liquid phase separation are dynamic structures that are employed by cells to spatiotemporally regulate their interior. Indeed, complex coacervation-based phase separation is involved in a multitude of biological tasks ranging from photosynthesis to cell division to chromatin organization, and more. Here, we use an on-chip microfluidic method to control and study the formation of membraneless organelles within liposomes, using pH as the main control parameter. We show that a transmembrane proton flux that is created by a stepwise change in the external pH can readily bring about the coacervation of encapsulated components in a controlled manner. We employ this strategy to induce and study electrostatic as well as hydrophobic interactions between the coacervate and the lipid membrane. Electrostatic interactions using charged lipids efficiently recruit coacervates to the membrane and restrict their movement along the inner leaflet. Hydrophobic interactions via cholesterol-tagged RNA molecules provide even stronger interactions, causing coacervates to wet the membrane and affect the local lipid-membrane structure, reminiscent of coacervate-membrane interactions in cells. The presented technique of pH-triggered coacervation within cell-sized liposomes may find applications in synthetic cells and in studying biologically relevant phase separation reactions in a bottom-up manner.
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Affiliation(s)
- Mart G.
F. Last
- Department
of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Siddharth Deshpande
- Department
of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
- Physical
Chemistry and Soft Matter, Wageningen University
and Research, Stippenweg 4, 6708 WE Wageningen, The Netherlands
| | - Cees Dekker
- Department
of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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91
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Guo C, Che Z, Yue J, Xie P, Hao S, Xie W, Luo Z, Lin C. ENL initiates multivalent phase separation of the super elongation complex (SEC) in controlling rapid transcriptional activation. SCIENCE ADVANCES 2020; 6:eaay4858. [PMID: 32270036 PMCID: PMC7112754 DOI: 10.1126/sciadv.aay4858] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 01/08/2020] [Indexed: 05/14/2023]
Abstract
Release of paused RNA polymerase II (Pol II) requires incorporation of the positive transcription elongation factor b (P-TEFb) into the super elongation complex (SEC), thus resulting in rapid yet synchronous transcriptional activation. However, the mechanism underlying dynamic transition of P-TEFb from inactive to active state remains unclear. Here, we found that the SEC components are able to compartmentalize and concentrate P-TEFb via liquid-liquid phase separation from the soluble inactive HEXIM1 containing the P-TEFb complex. Specifically, ENL or its intrinsically disordered region is sufficient to initiate the liquid droplet formation of SEC. AFF4 functions together with ENL in fluidizing SEC droplets. SEC droplets are fast and dynamically formed upon serum exposure and required for rapid transcriptional induction. We also found that the fusion of ENL with MLL can boost SEC phase separation. In summary, our results suggest a critical role of multivalent phase separation of SEC in controlling transcriptional pause release.
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Affiliation(s)
- Chenghao Guo
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Zhuanzhuan Che
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Junjie Yue
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Peng Xie
- Southeast University-Allen Institute Joint Center, Institute for Brain and Intelligence, Southeast University, Nanjing, 210096, China
| | - Shaohua Hao
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Wei Xie
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
- Southeast University-Allen Institute Joint Center, Institute for Brain and Intelligence, Southeast University, Nanjing, 210096, China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Zhuojuan Luo
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
- Corresponding author. (C.L.); (Z.L.)
| | - Chengqi Lin
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
- Corresponding author. (C.L.); (Z.L.)
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92
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Common Functions of Disordered Proteins across Evolutionary Distant Organisms. Int J Mol Sci 2020; 21:ijms21062105. [PMID: 32204351 PMCID: PMC7139818 DOI: 10.3390/ijms21062105] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 12/14/2022] Open
Abstract
Intrinsically disordered proteins and regions typically lack a well-defined structure and thus fall outside the scope of the classic sequence–structure–function relationship. Hence, classic sequence- or structure-based bioinformatic approaches are often not well suited to identify homology or predict the function of unknown intrinsically disordered proteins. Here, we give selected examples of intrinsic disorder in plant proteins and present how protein function is shared, altered or distinct in evolutionary distant organisms. Furthermore, we explore how examining the specific role of disorder across different phyla can provide a better understanding of the common features that protein disorder contributes to the respective biological mechanism.
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93
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Reading Targeted DNA Damage in the Active Demethylation Pathway: Role of Accessory Domains of Eukaryotic AP Endonucleases and Thymine-DNA Glycosylases. J Mol Biol 2020:S0022-2836(19)30720-X. [DOI: 10.1016/j.jmb.2019.12.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/24/2019] [Accepted: 12/05/2019] [Indexed: 01/07/2023]
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94
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Abstract
Effective maintenance and stability of our genomes is essential for normal cell division, tissue homeostasis, and cellular and organismal fitness. The processes of chromosome replication and segregation require continual surveillance to insure fidelity. Accurate and efficient repair of DNA damage preserves genome integrity, which if lost can lead to multiple diseases, including cancer. Poly(ADP-ribose) a dynamic and reversible posttranslational modification and the enzymes that catalyze it (PARP1, PARP2, tankyrase 1, and tankyrase 2) function to maintain genome stability through diverse mechanisms. Here we review the role of these enzymes and the modification in genome repair, replication, and resolution in human cells.
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Affiliation(s)
- Kameron Azarm
- Department of Pathology, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York 10016, USA
| | - Susan Smith
- Department of Pathology, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York 10016, USA
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95
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Munari F, D'Onofrio M, Assfalg M. Solution NMR insights into dynamic supramolecular assemblies of disordered amyloidogenic proteins. Arch Biochem Biophys 2020; 683:108304. [PMID: 32097611 DOI: 10.1016/j.abb.2020.108304] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 12/29/2022]
Abstract
The extraordinary flexibility and structural heterogeneity of intrinsically disordered proteins (IDP) make them functionally versatile molecules. We have now begun to better understand their fundamental role in biology, however many aspects of their behaviour remain difficult to grasp experimentally. This is especially true for the intermolecular interactions which lead to the formation of transient or highly dynamic supramolecular self-assemblies, such as oligomers, aggregation intermediates and biomolecular condensates. Both the emerging functions and pathogenicity of these structures have stimulated great efforts to develop methodologies capable of providing useful insights. Significant progress in solution NMR spectroscopy has made this technique one of the most powerful to describe structural and dynamic features of IDPs within such assemblies at atomic resolution. Here, we review the most recent works that have illuminated key aspects of IDP assemblies and contributed significant advancements towards our understanding of the complex conformational landscape of prototypical disease-associated proteins. We also include a primer on some of the fundamental and innovative NMR methods being used in the discussed studies.
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Affiliation(s)
- Francesca Munari
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Mariapina D'Onofrio
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Michael Assfalg
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy.
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96
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Paraschiv A, Hegde S, Ganti R, Pilizota T, Šarić A. Dynamic Clustering Regulates Activity of Mechanosensitive Membrane Channels. PHYSICAL REVIEW LETTERS 2020; 124:048102. [PMID: 32058787 DOI: 10.1103/physrevlett.124.048102] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Indexed: 06/10/2023]
Abstract
Experiments have suggested that bacterial mechanosensitive channels separate into 2D clusters, the role of which is unclear. By developing a coarse-grained computer model we find that clustering promotes the channel closure, which is highly dependent on the channel concentration and membrane stress. This behaviour yields a tightly regulated gating system, whereby at high tensions channels gate individually, and at lower tensions the channels spontaneously aggregate and inactivate. We implement this positive feedback into the model for cell volume regulation, and find that the channel clustering protects the cell against excessive loss of cytoplasmic content.
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Affiliation(s)
- Alexandru Paraschiv
- Department of Physics and Astronomy, Institute for the Physics of Living Systems University College London, London WC1E 6BT, United Kingdom
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Smitha Hegde
- Centre for Synthetic and Systems Biology University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Raman Ganti
- Institute for Medical Engineering and Science Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology University of Edinburgh, Edinburgh EH9 3FF, United Kingdom
| | - Anđela Šarić
- Department of Physics and Astronomy, Institute for the Physics of Living Systems University College London, London WC1E 6BT, United Kingdom
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
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97
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Song Y, Xu Y, Pan C, Yan L, Wang ZW, Zhu X. The emerging role of SPOP protein in tumorigenesis and cancer therapy. Mol Cancer 2020; 19:2. [PMID: 31901237 DOI: 10.1186/s12943019-1124-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/23/2019] [Indexed: 05/26/2023] Open
Abstract
The nuclear speckle-type pox virus and zinc finger (POZ) protein (SPOP), a representative substrate-recognition subunit of the cullin-RING E3 ligase, has been characterized to play a dual role in tumorigenesis and cancer progression. Numerous studies have determined that SPOP suppresses tumorigenesis in a variety of human malignancies such as prostate, lung, colon, gastric, and liver cancers. However, several studies revealed that SPOP exhibited oncogenic function in kidney cancer, suggesting that SPOP could exert its biological function in a cancer type-specific manner. The role of SPOP in thyroid, cervical, ovarian, bone and neurologic cancers has yet to be determined. In this review article, we describe the structure and regulation of SPOP in human cancer. Moreover, we highlight the critical role of SPOP in tumorigenesis based on three major categories: physiological evidence (animal models), pathological evidence (human cancer specimens) and biochemical evidence (downstream ubiquitin substrates). Furthermore, we note that SPOP could be a promising therapeutic target for cancer treatment.
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Affiliation(s)
- Yizuo Song
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China
| | - Yichi Xu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China
| | - Chunyu Pan
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China
| | - Linzhi Yan
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China
| | - Zhi-Wei Wang
- Center of Scientific Research, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China.
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Xueqiong Zhu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China.
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98
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Song Y, Xu Y, Pan C, Yan L, Wang ZW, Zhu X. The emerging role of SPOP protein in tumorigenesis and cancer therapy. Mol Cancer 2020; 19:2. [PMID: 31901237 PMCID: PMC6942384 DOI: 10.1186/s12943-019-1124-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/23/2019] [Indexed: 12/24/2022] Open
Abstract
The nuclear speckle-type pox virus and zinc finger (POZ) protein (SPOP), a representative substrate-recognition subunit of the cullin-RING E3 ligase, has been characterized to play a dual role in tumorigenesis and cancer progression. Numerous studies have determined that SPOP suppresses tumorigenesis in a variety of human malignancies such as prostate, lung, colon, gastric, and liver cancers. However, several studies revealed that SPOP exhibited oncogenic function in kidney cancer, suggesting that SPOP could exert its biological function in a cancer type-specific manner. The role of SPOP in thyroid, cervical, ovarian, bone and neurologic cancers has yet to be determined. In this review article, we describe the structure and regulation of SPOP in human cancer. Moreover, we highlight the critical role of SPOP in tumorigenesis based on three major categories: physiological evidence (animal models), pathological evidence (human cancer specimens) and biochemical evidence (downstream ubiquitin substrates). Furthermore, we note that SPOP could be a promising therapeutic target for cancer treatment.
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Affiliation(s)
- Yizuo Song
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China
| | - Yichi Xu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China
| | - Chunyu Pan
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China
| | - Linzhi Yan
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China
| | - Zhi-Wei Wang
- Center of Scientific Research, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China. .,Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Xueqiong Zhu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, No. 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China.
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99
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Abstract
The endoplasmic reticulum (ER) is the site for folding and maturation of secreted and membrane proteins. When the ER protein-folding machinery is overwhelmed, misfolded proteins trigger ER stress, which is frequently linked to human diseases, including cancer and neurodegeneration. Inositol-requiring enzyme 1 (IRE1) is an ER membrane-resident sensor that assembles into large clusters of previously unknown organization upon its activation by unfolded peptides. We demonstrate that IRE1 clusters are topologically complex dynamic structures that remain contiguous with the ER membrane throughout their lifetime. The majority of clustered IRE1 molecules are diffusionally trapped inside the clusters until IRE1 signaling attenuates, at which point they are released back into the ER through a pathway that is functionally distinct from cluster assembly. The endoplasmic reticulum (ER) membrane-resident stress sensor inositol-requiring enzyme 1 (IRE1) governs the most evolutionarily conserved branch of the unfolded protein response. Upon sensing an accumulation of unfolded proteins in the ER lumen, IRE1 activates its cytoplasmic kinase and ribonuclease domains to transduce the signal. IRE1 activity correlates with its assembly into large clusters, yet the biophysical characteristics of IRE1 clusters remain poorly characterized. We combined superresolution microscopy, single-particle tracking, fluorescence recovery, and photoconversion to examine IRE1 clustering quantitatively in living human and mouse cells. Our results revealed that: 1) In contrast to qualitative impressions gleaned from microscopic images, IRE1 clusters comprise only a small fraction (∼5%) of the total IRE1 in the cell; 2) IRE1 clusters have complex topologies that display features of higher-order organization; 3) IRE1 clusters contain a diffusionally constrained core, indicating that they are not phase-separated liquid condensates; 4) IRE1 molecules in clusters remain diffusionally accessible to the free pool of IRE1 molecules in the general ER network; 5) when IRE1 clusters disappear at later time points of ER stress as IRE1 signaling attenuates, their constituent molecules are released back into the ER network and not degraded; 6) IRE1 cluster assembly and disassembly are mechanistically distinct; and 7) IRE1 clusters’ mobility is nearly independent of cluster size. Taken together, these insights define the clusters as dynamic assemblies with unique properties. The analysis tools developed for this study will be widely applicable to investigations of clustering behaviors in other signaling proteins.
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100
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Zhang Y, Yang M, Duncan S, Yang X, Abdelhamid MAS, Huang L, Zhang H, Benfey PN, Waller ZAE, Ding Y. G-quadruplex structures trigger RNA phase separation. Nucleic Acids Res 2019; 47:11746-11754. [PMID: 31722410 PMCID: PMC7145655 DOI: 10.1093/nar/gkz978] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/09/2019] [Accepted: 10/17/2019] [Indexed: 02/04/2023] Open
Abstract
Liquid-liquid phase separation plays an important role in a variety of cellular processes, including the formation of membrane-less organelles, the cytoskeleton, signalling complexes, and many other biological supramolecular assemblies. Studies on the molecular basis of phase separation in cells have focused on protein-driven phase separation. In contrast, there is limited understanding on how RNA specifically contributes to phase separation. Here, we described a phase-separation-like phenomenon that SHORT ROOT (SHR) RNA undergoes in cells. We found that an RNA G-quadruplex (GQ) forms in SHR mRNA and is capable of triggering RNA phase separation under physiological conditions, suggesting that GQs might be responsible for the formation of the SHR phase-separation-like phenomenon in vivo. We also found the extent of GQ-triggered-phase-separation increases on exposure to conditions which promote GQ. Furthermore, GQs with more G-quartets and longer loops are more likely to form phase separation. Our studies provide the first evidence that RNA can adopt structural motifs to trigger and/or maintain the specificity of RNA-driven phase separation.
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Affiliation(s)
- Yueying Zhang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Minglei Yang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Susan Duncan
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
- Organisms and Ecosystems, Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Xiaofei Yang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Mahmoud A S Abdelhamid
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
- Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Lin Huang
- Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Huakun Zhang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Philip N Benfey
- Department of Biology, Duke University, Durham, NC 27708, USA
- Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
| | - Zoë A E Waller
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
- Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Yiliang Ding
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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