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Latham AP, Zhu L, Sharon DA, Ye S, Willard AP, Zhang X, Zhang B. Microphase Separation Produces Interfacial Environment within Diblock Biomolecular Condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.03.30.534967. [PMID: 37034777 PMCID: PMC10081284 DOI: 10.1101/2023.03.30.534967] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The phase separation of intrinsically disordered proteins is emerging as an important mechanism for cellular organization. However, efforts to connect protein sequences to the physical properties of condensates, i.e., the molecular grammar, are hampered by a lack of effective approaches for probing high-resolution structural details. Using a combination of multiscale simulations and fluorescence lifetime imaging microscopy experiments, we systematically explored a series of systems consisting of diblock elastin-like polypeptides (ELP). The simulations succeeded in reproducing the variation of condensate stability upon amino acid substitution and revealed different microenvironments within a single condensate, which we verified with environmentally sensitive fluorophores. The interspersion of hydrophilic and hydrophobic residues and a lack of secondary structure formation result in an interfacial environment, which explains both the strong correlation between ELP condensate stability and interfacial hydrophobicity scales, as well as the prevalence of protein-water hydrogen bonds. Our study uncovers new mechanisms for condensate stability and organization that may be broadly applicable.
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Affiliation(s)
- Andrew P Latham
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Longchen Zhu
- Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China
- Westlake Laboratory of Life Sciences and Biomedicine, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Dina A Sharon
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Songtao Ye
- Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China
- Westlake Laboratory of Life Sciences and Biomedicine, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Adam P Willard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Xin Zhang
- Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China
- Westlake Laboratory of Life Sciences and Biomedicine, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Bin Zhang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
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2
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Wang SH, Zheng T, Fawzi NL. Structure and interactions of prion-like domains in transcription factor Efg1 phase separation. Biophys J 2024; 123:1481-1493. [PMID: 38297837 PMCID: PMC11163291 DOI: 10.1016/j.bpj.2024.01.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 01/08/2024] [Accepted: 01/25/2024] [Indexed: 02/02/2024] Open
Abstract
Candida albicans, a prominent member of the human microbiome, can make an opportunistic switch from commensal coexistence to pathogenicity accompanied by an epigenetic shift between the white and opaque cell states. This transcriptional switch is under precise regulation by a set of transcription factors (TFs), with Enhanced Filamentous Growth Protein 1 (Efg1) playing a central role. Previous research has emphasized the importance of Efg1's prion-like domain (PrLD) and the protein's ability to undergo phase separation for the white-to-opaque transition of C. albicans. However, the underlying molecular mechanisms of Efg1 phase separation have remained underexplored. In this study, we delved into the biophysical basis of Efg1 phase separation, revealing the significant contribution of both N-terminal (N) and C-terminal (C) PrLDs. Through NMR structural analysis, we found that Efg1 N-PrLD and C-PrLD are mostly disordered but have prominent partial α-helical secondary structures in both domains. NMR titration experiments suggest that the partially helical structures in N-PrLD act as hubs for self-interaction as well as Efg1 interaction with RNA. Using condensed-phase NMR spectroscopy, we uncovered diverse amino acid interactions underlying Efg1 phase separation. Particularly, we highlight the indispensable role of tyrosine residues within the transient α-helical structures of PrLDs particularly in the N-PrLD compared to the C-PrLD in stabilizing phase separation. Our study provides evidence that the transient α-helical structure is present in the phase-separated state and highlights the particular importance of aromatic residues within these structures for phase separation. Together, these results enhance the understanding of C. albicans transcription factor interactions that lead to virulence and provide a crucial foundation for potential antifungal therapies targeting the transcriptional switch.
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Affiliation(s)
- Szu-Huan Wang
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island
| | - Tongyin Zheng
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island.
| | - Nicolas L Fawzi
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island.
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3
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Chen Y, Pei X, Chen L, Chen L. A dynamic regulatory switch for phase separation of FUS protein: Zinc ions and zinc finger domain. Biochem Biophys Res Commun 2024; 710:149862. [PMID: 38593618 DOI: 10.1016/j.bbrc.2024.149862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/17/2024] [Accepted: 03/28/2024] [Indexed: 04/11/2024]
Abstract
Zinc is an important trace element in the human body, and its homeostasis is closely related to amyotrophic lateral sclerosis (ALS). Cytoplasmic FUS proteins from patients with ALS aggregate their important pathologic markers. Liquid-liquid phase separation (LLPS) of FUS can lead to its aggregation. However, whether and how zinc homeostasis affects the aggregation of disease-associated FUS proteins in the cytoplasm remains unclear. Here, we found that zinc ion enhances LLPS and promotes the aggregation in the cytoplasm for FUS protein. In the FUS, the cysteine of the zinc finger (ZnF), recognizes and binds to zinc ions, reducing droplet mobility and enhancing protein aggregation in the cytoplasm. The mutation of FUS cysteine disrupts the dynamic regulatory switch of zinc ions and ZnF, resulting in insensitivity to zinc ions. These results suggest that the dynamic regulation of LLPS by binding with zinc ions may be a widespread mechanism and provide a new understanding of neurological diseases such as ALS and other ZnF protein-related diseases.
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Affiliation(s)
- Yatao Chen
- Department of Biochemistry, School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaoying Pei
- Department of Biochemistry, School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Long Chen
- Department of Biochemistry, School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Liming Chen
- Department of Biochemistry, School of Life Sciences, Nanjing Normal University, Nanjing, China; Cancer Institute, School of Life Sciences, Nanjing Normal University, Nanjing, China.
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4
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Song J. Adenosine Triphosphate: The Primordial Molecule That Controls Protein Homeostasis and Shapes the Genome-Proteome Interface. Biomolecules 2024; 14:500. [PMID: 38672516 PMCID: PMC11048592 DOI: 10.3390/biom14040500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/15/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
Adenosine triphosphate (ATP) acts as the universal energy currency that drives various biological processes, while nucleic acids function to store and transmit genetic information for all living organisms. Liquid-liquid phase separation (LLPS) represents the common principle for the formation of membrane-less organelles (MLOs) composed of proteins rich in intrinsically disordered regions (IDRs) and nucleic acids. Currently, while IDRs are well recognized to facilitate LLPS through dynamic and multivalent interactions, the precise mechanisms by which ATP and nucleic acids affect LLPS still remain elusive. This review summarizes recent NMR results on the LLPS of human FUS, TDP-43, and the viral nucleocapsid (N) protein of SARS-CoV-2, as modulated by ATP and nucleic acids, revealing the following: (1) ATP binds to folded domains overlapping with nucleic-acid-binding interfaces; (2) ATP and nucleic acids interplay to biphasically modulate LLPS by competitively binding to overlapping pockets of folded domains and Arg/Lys within IDRs; (3) ATP energy-independently induces protein folding with the highest efficiency known so far. As ATP likely emerged in the prebiotic monomeric world, while LLPS represents a pivotal mechanism to concentrate and compartmentalize rare molecules for forming primordial cells, ATP appears to control protein homeostasis and shape genome-proteome interfaces throughout the evolutionary trajectory, from prebiotic origins to modern cells.
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Affiliation(s)
- Jianxing Song
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore
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5
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Rekhi S, Garcia CG, Barai M, Rizuan A, Schuster BS, Kiick KL, Mittal J. Expanding the molecular language of protein liquid-liquid phase separation. Nat Chem 2024:10.1038/s41557-024-01489-x. [PMID: 38553587 DOI: 10.1038/s41557-024-01489-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 02/27/2024] [Indexed: 04/07/2024]
Abstract
Understanding the relationship between a polypeptide sequence and its phase separation has important implications for analysing cellular function, treating disease and designing novel biomaterials. Several sequence features have been identified as drivers for protein liquid-liquid phase separation (LLPS), schematized as a 'molecular grammar' for LLPS. Here we further probe how sequence modulates phase separation and the material properties of the resulting condensates, targeting sequence features previously overlooked in the literature. We generate sequence variants of a repeat polypeptide with either no charged residues, high net charge, no glycine residues or devoid of aromatic or arginine residues. All but one of 12 variants exhibited LLPS, albeit to different extents, despite substantial differences in composition. Furthermore, we find that all the condensates formed behaved like viscous fluids, despite large differences in their viscosities. Our results support the model of multiple interactions between diverse residue pairs-not just a handful of residues-working in tandem to drive the phase separation and dynamics of condensates.
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Affiliation(s)
- Shiv Rekhi
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | | | - Mayur Barai
- Department of Chemical and Biochemical Engineering, Rutgers, the State University of New Jersey, Piscataway, NJ, USA
| | - Azamat Rizuan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Benjamin S Schuster
- Department of Chemical and Biochemical Engineering, Rutgers, the State University of New Jersey, Piscataway, NJ, USA.
| | - Kristi L Kiick
- Department of Materials Science and Engineering, University of Delaware, Newark, DE, USA.
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA.
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA.
- Department of Chemistry, Texas A&M University, College Station, TX, USA.
- Interdisciplinary Graduate Program in Genetics and Genomics, Texas A&M University, College Station, TX, USA.
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6
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Sundara Rajan S, Ebegboni VJ, Pichling P, Ludwig KR, Jones TL, Chari R, Tran A, Kruhlak MJ, Loncarek J, Caplen NJ. Endogenous EWSR1 Exists in Two Visual Modalities That Reflect Its Associations with Nucleic Acids and Concentration at Sites of Active Transcription. Mol Cell Biol 2024; 44:103-122. [PMID: 38506112 PMCID: PMC10986767 DOI: 10.1080/10985549.2024.2315425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 02/02/2024] [Indexed: 03/21/2024] Open
Abstract
EWSR1 is a member of the FET family of nucleic acid binding proteins that includes FUS and TAF15. Here, we report the systematic analysis of endogenous EWSR1's cellular organization in human cells. We demonstrate that EWSR1, which contains low complexity and nucleic acid binding domains, is present in cells in faster and slower-recovering fractions, indicative of a protein undergoing both rapid exchange and longer-term interactions. The employment of complementary high-resolution imaging approaches shows EWSR1 exists in two visual modalities, a distributed state which is present throughout the nucleoplasm, and a concentrated state consistent with the formation of foci. Both EWSR1 visual modalities localize with nascent RNA. EWSR1 foci concentrate in regions of euchromatin, adjacent to protein markers of transcriptional activation, and significantly colocalize with phosphorylated RNA polymerase II. Our results contribute to bridging the gap between our understanding of the biophysical and biochemical properties of FET proteins, including EWSR1, their functions as transcriptional regulators, and the participation of these proteins in tumorigenesis and neurodegenerative disease.
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Affiliation(s)
- Soumya Sundara Rajan
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Vernon J. Ebegboni
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Patricio Pichling
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Katelyn R. Ludwig
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Tamara L. Jones
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Raj Chari
- Genome Modification Core, Laboratory Animal Sciences Program, Frederick National Lab for Cancer Research, Frederick, Maryland, USA
| | - Andy Tran
- CCR Confocal Microscopy Core Facility, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael J. Kruhlak
- CCR Confocal Microscopy Core Facility, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jadranka Loncarek
- Centrosome Biology Section, Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Natasha J. Caplen
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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7
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Lin CC, Chang TC, Wang Y, Guo L, Gao Y, Bikorimana E, Lemoff A, Fang YV, Zhang H, Zhang Y, Ye D, Soria-Bretones I, Servetto A, Lee KM, Luo X, Otto JJ, Akamatsu H, Napolitano F, Mani R, Cescon DW, Xu L, Xie Y, Mendell JT, Hanker AB, Arteaga CL. PRMT5 is an actionable therapeutic target in CDK4/6 inhibitor-resistant ER+/RB-deficient breast cancer. Nat Commun 2024; 15:2287. [PMID: 38480701 PMCID: PMC10937713 DOI: 10.1038/s41467-024-46495-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 02/29/2024] [Indexed: 03/17/2024] Open
Abstract
CDK4/6 inhibitors (CDK4/6i) have improved survival of patients with estrogen receptor-positive (ER+) breast cancer. However, patients treated with CDK4/6i eventually develop drug resistance and progress. RB1 loss-of-function alterations confer resistance to CDK4/6i, but the optimal therapy for these patients is unclear. Through a genome-wide CRISPR screen, we identify protein arginine methyltransferase 5 (PRMT5) as a molecular vulnerability in ER+/RB1-knockout breast cancer cells. Inhibition of PRMT5 blocks the G1-to-S transition in the cell cycle independent of RB, leading to growth arrest in RB1-knockout cells. Proteomics analysis uncovers fused in sarcoma (FUS) as a downstream effector of PRMT5. Inhibition of PRMT5 results in dissociation of FUS from RNA polymerase II, leading to hyperphosphorylation of serine 2 in RNA polymerase II, intron retention, and subsequent downregulation of proteins involved in DNA synthesis. Furthermore, treatment with the PRMT5 inhibitor pemrametostat and a selective ER degrader fulvestrant synergistically inhibits growth of ER+/RB-deficient cell-derived and patient-derived xenografts. These findings highlight dual ER and PRMT5 blockade as a potential therapeutic strategy to overcome resistance to CDK4/6i in ER+/RB-deficient breast cancer.
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Affiliation(s)
- Chang-Ching Lin
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Tsung-Cheng Chang
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yunguan Wang
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Lei Guo
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yunpeng Gao
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Emmanuel Bikorimana
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Andrew Lemoff
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yisheng V Fang
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - He Zhang
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yanfeng Zhang
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dan Ye
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Alberto Servetto
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Kyung-Min Lee
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Life Science, Hanyang University, Seoul, South Korea
| | - Xuemei Luo
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Joseph J Otto
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Hiroaki Akamatsu
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Third Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan
| | - Fabiana Napolitano
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Ram Mani
- Department of Pathology, UT Southwestern Medical Center, Dallas, TX, USA
| | - David W Cescon
- Princess Margaret Cancer Centre, University of Toronto, Toronto, ON, Canada
| | - Lin Xu
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yang Xie
- Quantitative Biomedical Research Center, Department of Population & Data Sciences, Peter O'Donnell Jr. School of Public Health, UT Southwestern Medical Center, Dallas, TX, USA
| | - Joshua T Mendell
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ariella B Hanker
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Carlos L Arteaga
- Harold C. Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA.
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8
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Emmanouilidis L, Bartalucci E, Kan Y, Ijavi M, Pérez ME, Afanasyev P, Boehringer D, Zehnder J, Parekh SH, Bonn M, Michaels TCT, Wiegand T, Allain FHT. A solid beta-sheet structure is formed at the surface of FUS droplets during aging. Nat Chem Biol 2024:10.1038/s41589-024-01573-w. [PMID: 38467846 DOI: 10.1038/s41589-024-01573-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 02/07/2024] [Indexed: 03/13/2024]
Abstract
Phase transitions are important to understand cell dynamics, and the maturation of liquid droplets is relevant to neurodegenerative disorders. We combined NMR and Raman spectroscopies with microscopy to follow, over a period of days to months, droplet maturation of the protein fused in sarcoma (FUS). Our study reveals that the surface of the droplets plays a critical role in this process, while RNA binding prevents it. The maturation kinetics are faster in an agarose-stabilized biphasic sample compared with a monophasic condensed sample, owing to the larger surface-to-volume ratio. In addition, Raman spectroscopy reports structural differences upon maturation between the inside and the surface of droplets, which is comprised of β-sheet content, as revealed by solid-state NMR. In agreement with these observations, a solid crust-like shell is observed at the surface using microaspiration. Ultimately, matured droplets were converted into fibrils involving the prion-like domain as well as the first RGG motif.
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Affiliation(s)
- Leonidas Emmanouilidis
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.
- Bringing Materials to Life Initiative, ETH Zurich, Zurich, Switzerland.
| | - Ettore Bartalucci
- Max Planck Institute for Chemical Energy Conversion, Mülheim/Ruhr, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen, Germany
| | - Yelena Kan
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, USA
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Mahdiye Ijavi
- Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Maria Escura Pérez
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | | | | | - Johannes Zehnder
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
| | - Sapun H Parekh
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, USA
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Thomas C T Michaels
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
- Bringing Materials to Life Initiative, ETH Zurich, Zurich, Switzerland
| | - Thomas Wiegand
- Max Planck Institute for Chemical Energy Conversion, Mülheim/Ruhr, Germany.
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Aachen, Germany.
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland.
| | - Frédéric H-T Allain
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.
- Bringing Materials to Life Initiative, ETH Zurich, Zurich, Switzerland.
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9
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Esteban-Hofer L, Emmanouilidis L, Yulikov M, Allain FHT, Jeschke G. Ensemble structure of the N-terminal domain (1-267) of FUS in a biomolecular condensate. Biophys J 2024; 123:538-554. [PMID: 38279531 PMCID: PMC10938082 DOI: 10.1016/j.bpj.2024.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/06/2023] [Accepted: 01/22/2024] [Indexed: 01/28/2024] Open
Abstract
Solutions of some proteins phase separate into a condensed state of high protein concentration and a dispersed state of low concentration. Such behavior is observed in living cells for a number of RNA-binding proteins that feature intrinsically disordered domains. It is relevant for cell function via the formation of membraneless organelles and transcriptional condensates. On a basic level, the process can be studied in vitro on protein domains that are necessary and sufficient for liquid-liquid phase separation (LLPS). We have performed distance distribution measurements by electron paramagnetic resonance for 13 sections in an N-terminal domain (NTD) construct of the protein fused in sarcoma (FUS), consisting of the QGSY-rich domain and the RGG1 domain, in the denatured, dispersed, and condensed state. Using 10 distance distribution restraints for ensemble modeling and three such restraints for model validation, we have found that FUS NTD behaves as a random-coil polymer under good-solvent conditions in both the dispersed and condensed state. Conformation distribution in the biomolecular condensate is virtually indistinguishable from the one in an unrestrained ensemble, with the latter one being based on only residue-specific Ramachandran angle distributions. Over its whole length, FUS NTD is slightly more compact in the condensed than in the dispersed state, which is in line with the theory for random coils in good solvent proposed by de Gennes, Daoud, and Jannink. The estimated concentration in the condensate exceeds the overlap concentration resulting from this theory. The QGSY-rich domain is slightly more extended, slightly more hydrated, and has slightly higher propensity for LLPS than the RGG1 domain. Our results support previous suggestions that LLPS of FUS is driven by multiple transient nonspecific hydrogen bonding and π-sp2 interactions.
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Affiliation(s)
- Laura Esteban-Hofer
- ETH Zurich, Department of Chemistry and Applied Biosciences, Zurich, Switzerland
| | | | - Maxim Yulikov
- ETH Zurich, Department of Chemistry and Applied Biosciences, Zurich, Switzerland
| | | | - Gunnar Jeschke
- ETH Zurich, Department of Chemistry and Applied Biosciences, Zurich, Switzerland.
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10
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Holehouse AS, Kragelund BB. The molecular basis for cellular function of intrinsically disordered protein regions. Nat Rev Mol Cell Biol 2024; 25:187-211. [PMID: 37957331 DOI: 10.1038/s41580-023-00673-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2023] [Indexed: 11/15/2023]
Abstract
Intrinsically disordered protein regions exist in a collection of dynamic interconverting conformations that lack a stable 3D structure. These regions are structurally heterogeneous, ubiquitous and found across all kingdoms of life. Despite the absence of a defined 3D structure, disordered regions are essential for cellular processes ranging from transcriptional control and cell signalling to subcellular organization. Through their conformational malleability and adaptability, disordered regions extend the repertoire of macromolecular interactions and are readily tunable by their structural and chemical context, making them ideal responders to regulatory cues. Recent work has led to major advances in understanding the link between protein sequence and conformational behaviour in disordered regions, yet the link between sequence and molecular function is less well defined. Here we consider the biochemical and biophysical foundations that underlie how and why disordered regions can engage in productive cellular functions, provide examples of emerging concepts and discuss how protein disorder contributes to intracellular information processing and regulation of cellular function.
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Affiliation(s)
- Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO, USA.
- Center for Biomolecular Condensates, Washington University in St Louis, St Louis, MO, USA.
| | - Birthe B Kragelund
- REPIN, Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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11
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Li S, Zhang Y, Chen J. Backbone interactions and secondary structures in phase separation of disordered proteins. Biochem Soc Trans 2024; 52:319-329. [PMID: 38348795 DOI: 10.1042/bst20230618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/29/2024]
Abstract
Intrinsically disordered proteins (IDPs) are one of the major drivers behind the formation and characteristics of biomolecular condensates. Due to their inherent flexibility, the backbones of IDPs are significantly exposed, rendering them highly influential and susceptible to biomolecular phase separation. In densely packed condensates, exposed backbones have a heightened capacity to interact with neighboring protein chains, which might lead to strong coupling between the secondary structures and phase separation and further modulate the subsequent transitions of the condensates, such as aging and fibrillization. In this mini-review, we provide an overview of backbone-mediated interactions and secondary structures within biomolecular condensates to underscore the importance of protein backbones in phase separation. We further focus on recent advances in experimental techniques and molecular dynamics simulation methods for probing and exploring the roles of backbone interactions and secondary structures in biomolecular phase separation involving IDPs.
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Affiliation(s)
- Shanlong Li
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, U.S.A
| | - Yumeng Zhang
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, U.S.A
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, U.S.A
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12
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Doan VS, Alshareedah I, Singh A, Banerjee PR, Shin S. Diffusiophoresis promotes phase separation and transport of biomolecular condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.03.547532. [PMID: 37461689 PMCID: PMC10350024 DOI: 10.1101/2023.07.03.547532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
The internal microenvironment of a living cell is heterogeneous and comprises a multitude of organelles with distinct biochemistry. Amongst them are biomolecular condensates, which are membrane-less, phase-separated compartments enriched in system-specific proteins and nucleic acids. The heterogeneity of the cell engenders the presence of multiple spatiotemporal gradients in chemistry, charge, concentration, temperature, and pressure. Such thermodynamic gradients can lead to non-equilibrium driving forces for the formation and transport of biomolecular condensates. Here, we report how ion gradients impact the transport processes of biomolecular condensates on the mesoscale and biomolecules on the microscale. Utilizing a microfluidic platform, we demonstrate that the presence of ion concentration gradients can accelerate the transport of biomolecules, including nucleic acids and proteins, via diffusiophoresis. This hydrodynamic transport process allows localized enrichment of biomolecules, thereby promoting the location-specific formation of biomolecular condensates via phase separation. The ion gradients further impart active motility of condensates, allowing them to exhibit enhanced diffusion along the gradient. Coupled with a reentrant phase behavior, the gradient-induced active motility leads to a dynamical redistribution of condensates that ultimately extends their lifetime. Together, our results demonstrate diffusiophoresis as a non-equilibrium thermodynamic force that governs the formation and transport of biomolecular condensates.
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Affiliation(s)
- Viet Sang Doan
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Ibraheem Alshareedah
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Anurag Singh
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Priya R Banerjee
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Sangwoo Shin
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260
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13
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Wake N, Weng SL, Zheng T, Wang SH, Kirilenko V, Mittal J, Fawzi NL. Expanding the molecular grammar of polar residues and arginine in FUS prion-like domain phase separation and aggregation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.15.580391. [PMID: 38405719 PMCID: PMC10888811 DOI: 10.1101/2024.02.15.580391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
A molecular grammar governing low-complexity prion-like domains phase separation (PS) has been proposed based on mutagenesis experiments that identified tyrosine and arginine as primary drivers of phase separation via aromatic-aromatic and aromatic-arginine interactions. Here we show that additional residues make direct favorable contacts that contribute to phase separation, highlighting the need to account for these contributions in PS theories and models. We find that tyrosine and arginine make important contacts beyond only tyrosine-tyrosine and tyrosine-arginine, including arginine-arginine contacts. Among polar residues, glutamine in particular contributes to phase separation with sequence/position-specificity, making contacts with both tyrosine and arginine as well as other residues, both before phase separation and in condensed phases. For glycine, its flexibility, not its small solvation volume, favors phase separation by allowing favorable contacts between other residues and inhibits the liquid-to-solid (LST) transition. Polar residue types also make sequence-specific contributions to aggregation that go beyond simple rules, which for serine positions is linked to formation of an amyloid-core structure by the FUS low-complexity domain. Hence, here we propose a revised molecular grammar expanding the role of arginine and polar residues in prion-like domain protein phase separation and aggregation.
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Affiliation(s)
- Noah Wake
- Therapeutic Sciences Graduate Program, Brown University, Providence, RI 02912
| | - Shuo-Lin Weng
- Department of Chemistry, Texas A&M University, College Station, TX 77843
| | - Tongyin Zheng
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI 02912
| | - Szu-Huan Wang
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI 02912
| | - Valentin Kirilenko
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI 02912
| | - Jeetain Mittal
- Department of Chemistry, Texas A&M University, College Station, TX 77843
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
- Interdisciplinary Graduate Program in Genetics and Genomics, Texas A&M University, College Station, TX 77843
| | - Nicolas L Fawzi
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI 02912
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14
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Welles RM, Sojitra KA, Garabedian MV, Xia B, Wang W, Guan M, Regy RM, Gallagher ER, Hammer DA, Mittal J, Good MC. Determinants that enable disordered protein assembly into discrete condensed phases. Nat Chem 2024:10.1038/s41557-023-01423-7. [PMID: 38316988 DOI: 10.1038/s41557-023-01423-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 12/13/2023] [Indexed: 02/07/2024]
Abstract
Cells harbour numerous mesoscale membraneless compartments that house specific biochemical processes and perform distinct cellular functions. These protein- and RNA-rich bodies are thought to form through multivalent interactions among proteins and nucleic acids, resulting in demixing via liquid-liquid phase separation. Proteins harbouring intrinsically disordered regions (IDRs) predominate in membraneless organelles. However, it is not known whether IDR sequence alone can dictate the formation of distinct condensed phases. We identified a pair of IDRs capable of forming spatially distinct condensates when expressed in cells. When reconstituted in vitro, these model proteins do not co-partition, suggesting condensation specificity is encoded directly in the polypeptide sequences. Through computational modelling and mutagenesis, we identified the amino acids and chain properties governing homotypic and heterotypic interactions that direct selective condensation. These results form the basis of physicochemical principles that may direct subcellular organization of IDRs into specific condensates and reveal an IDR code that can guide construction of orthogonal membraneless compartments.
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Affiliation(s)
- Rachel M Welles
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kandarp A Sojitra
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Mikael V Garabedian
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Boao Xia
- Bioengineering Graduate Program, Rice University, Houston, TX, USA
| | - Wentao Wang
- Bioengineering Graduate Program, University of Pennsylvania, Philadelphia, PA, USA
| | - Muyang Guan
- Chemical and Biomolecular Engineering Graduate Program, University of Pennsylvania, Philadelphia, PA, USA
| | - Roshan M Regy
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Elizabeth R Gallagher
- Cell and Molecular Biology Graduate Program, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel A Hammer
- Bioengineering Graduate Program, University of Pennsylvania, Philadelphia, PA, USA
- Chemical and Biomolecular Engineering Graduate Program, University of Pennsylvania, Philadelphia, PA, USA
- Chemical and Biomolecular Engineering Department, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA.
- Department of Chemistry, Texas A&M University, College Station, TX, USA.
- Interdisciplinary Graduate Program in Genetics and Genomics, Texas A&M University, College Station, TX, USA.
| | - Matthew C Good
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Bioengineering Graduate Program, University of Pennsylvania, Philadelphia, PA, USA.
- Cell and Molecular Biology Graduate Program, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
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15
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Ganser LR, Niaki AG, Yuan X, Huang E, Deng D, Djaja NA, Ge Y, Craig A, Langlois O, Myong S. The roles of FUS-RNA binding domain and low complexity domain in RNA-dependent phase separation. Structure 2024; 32:177-187.e5. [PMID: 38070499 PMCID: PMC10997494 DOI: 10.1016/j.str.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/24/2023] [Accepted: 11/14/2023] [Indexed: 02/04/2024]
Abstract
Fused in sarcoma (FUS) is an archetypal phase separating protein asymmetrically divided into a low complexity domain (LCD) and an RNA binding domain (RBD). Here, we explore how the two domains contribute to RNA-dependent phase separation, RNA recognition, and multivalent complex formation. We find that RBD drives RNA-dependent phase separation but forms large and irregularly shaped droplets that are rescued by LCD in trans. Electrophoretic mobility shift assay (EMSA) and single-molecule fluorescence assays reveal that, while both LCD and RBD bind RNA, RBD drives RNA engagement and multivalent complex formation. While RBD alone exhibits delayed RNA recognition and a less dynamic RNP complex compared to full-length FUS, LCD in trans rescues full-length FUS activity. Likewise, cell-based data show RBD forms nucleolar condensates while LCD in trans rescues the diffuse nucleoplasm localization of full-length FUS. Our results point to a regulatory role of LCD in tuning the RNP interaction and buffering phase separation.
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Affiliation(s)
- Laura R Ganser
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | | | - Xincheng Yuan
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA; Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA; Department of Biology, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA
| | - Ethan Huang
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Dahlia Deng
- Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA; Department of Biology, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA
| | - Nathalie A Djaja
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA; Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA; Department of Biology, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA
| | - Yingda Ge
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Alanna Craig
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Olivia Langlois
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sua Myong
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA; Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA; Department of Biology, Johns Hopkins University, 3400 N Charles St, Baltimore, MD 21218, USA.
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16
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Krevert C, Chavez D, Chatterjee S, Stelzl LS, Pütz S, Roeters SJ, Rudzinski JF, Fawzi NL, Girard M, Parekh SH, Hunger J. Liquid-Liquid Phase Separation of the Intrinsically Disordered Domain of the Fused in Sarcoma Protein Results in Substantial Slowing of Hydration Dynamics. J Phys Chem Lett 2023; 14:11224-11234. [PMID: 38056002 PMCID: PMC10726384 DOI: 10.1021/acs.jpclett.3c02790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/08/2023]
Abstract
Formation of liquid condensates plays a critical role in biology via localization of different components or via altered hydrodynamic transport, yet the hydrogen-bonding environment within condensates, pivotal for solvation, has remained elusive. We explore the hydrogen-bond dynamics within condensates formed by the low-complexity domain of the fused in sarcoma protein. Probing the hydrogen-bond dynamics sensed by condensate proteins using two-dimensional infrared spectroscopy of the protein amide I vibrations, we find that frequency-frequency correlations of the amide I vibration decay on a picosecond time scale. Interestingly, these dynamics are markedly slower for proteins in the condensate than in a homogeneous protein solution, indicative of different hydration dynamics. All-atom molecular dynamics simulations confirm that lifetimes of hydrogen-bonds between water and the protein are longer in the condensates than in the protein in solution. Altered hydrogen-bonding dynamics may contribute to unique solvation and reaction dynamics in such condensates.
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Affiliation(s)
- Carola
S. Krevert
- Department
of Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Daniel Chavez
- Department
of Polymer Theory, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sayantan Chatterjee
- Department
of Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department
of Biomedical Engineering, The University
of Texas at Austin, 107
West Dean Keeton Street, Stop C0800, Austin, Texas 78712, United States
| | - Lukas S. Stelzl
- KOMET 1,
Institute of Physics, Johannes Gutenberg
University, Staudingerweg 7, 55099 Mainz, Germany
- Faculty of
Biology, Johannes Gutenberg University Mainz, Gresemundweg 2, 55128 Mainz, Germany
- Institute
of Molecular Biology (IMB), Ackermannweg 2, 55128 Mainz, Germany
| | - Sabine Pütz
- Department
of Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Steven J. Roeters
- Department
of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- Department
of Anatomy and Neurosciences, Amsterdam
UMC, Vrije Universiteit, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Joseph F. Rudzinski
- Department
of Polymer Theory, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- IRIS
Adlershof, Humboldt-Universität zu
Berlin, Zum Großen
Windkanal 2, 12489 Berlin, Germany
| | - Nicolas L. Fawzi
- Department
of Molecular Biology, Cell Biology, and Biochemistry, Brown University, 70 Ship Street, Providence, Rhode Island 02912, United States
| | - Martin Girard
- Department
of Polymer Theory, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sapun H. Parekh
- Department
of Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department
of Biomedical Engineering, The University
of Texas at Austin, 107
West Dean Keeton Street, Stop C0800, Austin, Texas 78712, United States
| | - Johannes Hunger
- Department
of Molecular Spectroscopy, Max Planck Institute
for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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17
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McConnell BS, Parker MW. Protein intrinsically disordered regions have a non-random, modular architecture. Bioinformatics 2023; 39:btad732. [PMID: 38039154 PMCID: PMC10719218 DOI: 10.1093/bioinformatics/btad732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/03/2023] [Accepted: 11/30/2023] [Indexed: 12/03/2023] Open
Abstract
MOTIVATION Protein sequences can be broadly categorized into two classes: those which adopt stable secondary structure and fold into a domain (i.e. globular proteins), and those that do not. The sequences belonging to this latter class are conformationally heterogeneous and are described as being intrinsically disordered. Decades of investigation into the structure and function of globular proteins has resulted in a suite of computational tools that enable their sub-classification by domain type, an approach that has revolutionized how we understand and predict protein functionality. Conversely, it is unknown if sequences of disordered protein regions are subject to broadly generalizable organizational principles that would enable their sub-classification. RESULTS Here, we report the development of a statistical approach that quantifies linear variance in amino acid composition across a sequence. With multiple examples, we provide evidence that intrinsically disordered regions are organized into statistically non-random modules of unique compositional bias. Modularity is observed for both low and high-complexity sequences and, in some cases, we find that modules are organized in repetitive patterns. These data demonstrate that disordered sequences are non-randomly organized into modular architectures and motivate future experiments to comprehensively classify module types and to determine the degree to which modules constitute functionally separable units analogous to the domains of globular proteins. AVAILABILITY AND IMPLEMENTATION The source code, documentation, and data to reproduce all figures are freely available at https://github.com/MWPlabUTSW/Chi-Score-Analysis.git. The analysis is also available as a Google Colab Notebook (https://colab.research.google.com/github/MWPlabUTSW/Chi-Score-Analysis/blob/main/ChiScore_Analysis.ipynb).
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Affiliation(s)
- Brendan S McConnell
- Department of Biophysics, , University of Texas Southwestern Medical Center, Dallas, TX 75235, United States
| | - Matthew W Parker
- Department of Biophysics, , University of Texas Southwestern Medical Center, Dallas, TX 75235, United States
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18
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Balasubramanian S, Maharana S, Srivastava A. "Boundary residues" between the folded RNA recognition motif and disordered RGG domains are critical for FUS-RNA binding. J Biol Chem 2023; 299:105392. [PMID: 37890778 PMCID: PMC10687056 DOI: 10.1016/j.jbc.2023.105392] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 09/19/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
Fused in sarcoma (FUS) is an abundant RNA-binding protein, which drives phase separation of cellular condensates and plays multiple roles in RNA regulation. The RNA-binding ability of FUS protein is crucial to its cellular function. Here, our molecular simulation study on the FUS-RNA complex provides atomic resolution insights into the observations from biochemical studies and also illuminates our understanding of molecular driving forces that mediate the structure, stability, and interaction of the RNA recognition motif (RRM) and RGG domains of FUS with a stem-loop junction RNA. We observe clear cooperativity and division of labor among the ordered (RRM) and disordered domains (RGG1 and RGG2) of FUS that leads to an organized and tighter RNA binding. Irrespective of the length of RGG2, the RGG2-RNA interaction is confined to the stem-loop junction and the proximal stem regions. On the other hand, the RGG1 interactions are primarily with the longer RNA stem. We find that the C terminus of RRM, which make up the "boundary residues" that connect the folded RRM with the long disordered RGG2 stretch of the protein, plays a critical role in FUS-RNA binding. Our study provides high-resolution molecular insights into the FUS-RNA interactions and forms the basis for understanding the molecular origins of full-length FUS interaction with RNA.
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Affiliation(s)
| | - Shovamayee Maharana
- Department of Molecular and Cell Biology, Indian Institute of Science Bangalore, Bangalore, Karnataka, India
| | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science Bangalore, Bangalore, Karnataka, India.
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19
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Shi G, Schweizer KS. Theory of the center-of-mass diffusion and viscosity of microstructured and variable sequence copolymer liquids. SOFT MATTER 2023; 19:8893-8910. [PMID: 37955602 DOI: 10.1039/d3sm01193c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Biomolecular condensates formed through the phase separation of proteins and nucleic acids are widely observed, offering a fundamental means of organizing intracellular materials in a membrane-less fashion. Traditionally, these condensates have been regarded as homogeneous isotropic liquids. However, in analogy with some synthetic copolymer systems, our recent theoretical research has demonstrated that model biomolecular condensates can exhibit a microemulsion-like internal structure, contingent upon the specific sequence, inter-chain site-site interactions, and concentrated phase polymer density. Motivated by these considerations, here we present a microscopic dynamical theory for the self-diffusion constant and viscosity of a simpler class of model systems - concentrated unentangled A/B regular multiblock copolymer solutions. Our approach integrates static equilibrium local and microdomain scale structural information obtained from PRISM integral equation theory and the time evolution of the autocorrelation function of monomer scale forces at the center-of-mass level to determine the polymer diffusion constant and viscosity in a weak caging regime far from a glass or gel transition. We focus on regular multi-block systems both for simplicity and for its relevance to synthetic macromolecular science. The impact of sequence and inter-chain attraction strength on the slowing down of copolymer mass transport and flow due to local clustering enhanced collisional friction and emergent microdomain scale ordering are established. Analytic analysis and metrics employed in the study of biomolecular condensates are employed to identify key order parameters that quantity how attractive forces, packing structure, multiblock sequence, and copolymer density determine dynamical slowing down above and below the crossover to a fluctuating polymeric microemulsion state.
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Affiliation(s)
- Guang Shi
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, USA.
| | - Kenneth S Schweizer
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, USA.
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801, USA
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA
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20
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Song J. Molecular mechanisms of phase separation and amyloidosis of ALS/FTD-linked FUS and TDP-43. Aging Dis 2023:AD.2023.1118. [PMID: 38029395 DOI: 10.14336/ad.2023.1118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/18/2023] [Indexed: 12/01/2023] Open
Abstract
FUS and TDP-43, two RNA-binding proteins from the heterogeneous nuclear ribonucleoprotein family, have gained significant attention in the field of neurodegenerative diseases due to their association with amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). They possess folded domains for binding ATP and various nucleic acids including DNA and RNA, as well as substantial intrinsically disordered regions (IDRs) including prion-like domains (PLDs) and RG-/RGG-rich regions. They play vital roles in various cellular processes, including transcription, splicing, microRNA maturation, RNA stability and transport and DNA repair. In particular, they are key components for forming ribonucleoprotein granules and stress granules (SGs) through homotypic or heterotypic liquid-liquid phase separation (LLPS). Strikingly, liquid-like droplets formed by FUS and TDP-43 may undergo aging to transform into less dynamic assemblies such as hydrogels, inclusions, and amyloid fibrils, which are the pathological hallmarks of ALS and FTD. This review aims to synthesize and consolidate the biophysical knowledge of the sequences, structures, stability, dynamics, and inter-domain interactions of FUS and TDP-43 domains, so as to shed light on the molecular mechanisms underlying their liquid-liquid phase separation (LLPS) and amyloidosis. The review further delves into the mechanisms through which ALS-causing mutants of the well-folded hPFN1 disrupt the dynamics of LLPS of FUS prion-like domain, providing key insights into a potential mechanism for misfolding/aggregation-prone proteins to cause neurodegenerative diseases and aging by gain of functions. With better understanding of different biophysical aspects of FUS and TDP-43, the ultimate goal is to develop drugs targeting LLPS and amyloidosis, which could mediate protein homeostasis within cells and lead to new treatments for currently intractable diseases, particularly neurodegenerative diseases such as ALS, FTD and aging. However, the study of membrane-less organelles and condensates is still in its infancy and therefore the review also highlights key questions that require future investigation.
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21
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Joshi A, Walimbe A, Avni A, Rai SK, Arora L, Sarkar S, Mukhopadhyay S. Single-molecule FRET unmasks structural subpopulations and crucial molecular events during FUS low-complexity domain phase separation. Nat Commun 2023; 14:7331. [PMID: 37957147 PMCID: PMC10643395 DOI: 10.1038/s41467-023-43225-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 11/03/2023] [Indexed: 11/15/2023] Open
Abstract
Biomolecular condensates formed via phase separation of proteins and nucleic acids are thought to be associated with a wide range of cellular functions and dysfunctions. We dissect critical molecular events associated with phase separation of an intrinsically disordered prion-like low-complexity domain of Fused in Sarcoma by performing single-molecule studies permitting us to access the wealth of molecular information that is skewed in conventional ensemble experiments. Our single-molecule FRET experiments reveal the coexistence of two conformationally distinct subpopulations in the monomeric form. Single-droplet single-molecule FRET studies coupled with fluorescence correlation spectroscopy, picosecond time-resolved fluorescence anisotropy, and vibrational Raman spectroscopy indicate that structural unwinding switches intramolecular interactions into intermolecular contacts allowing the formation of a dynamic network within condensates. A disease-related mutation introduces enhanced structural plasticity engendering greater interchain interactions that can accelerate pathological aggregation. Our findings provide key mechanistic underpinnings of sequence-encoded dynamically-controlled structural unzipping resulting in biological phase separation.
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Affiliation(s)
- Ashish Joshi
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Anuja Walimbe
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Anamika Avni
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Sandeep K Rai
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Lisha Arora
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Snehasis Sarkar
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India.
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India.
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India.
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22
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Wang SH, Zheng T, Fawzi NL. Structure and position-specific interactions of prion-like domains in transcription factor Efg1 phase separation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.09.566450. [PMID: 37986834 PMCID: PMC10659382 DOI: 10.1101/2023.11.09.566450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Candida albicans, a prominent member of the human microbiome, can make an opportunistic switch from commensal coexistence to pathogenicity accompanied by an epigenetic shift between the white and opaque cell states. This transcriptional switch is under precise regulation by a set of transcription factors (TFs), with Enhanced Filamentous Growth Protein 1 (Efg1) playing a central role. Previous research has emphasized the importance of Egf1's prion-like domain (PrLD) and the protein's ability to undergo phase separation for the white-to-opaque transition of C. albicans. However, the underlying molecular mechanisms of Efg1 phase separation have remained underexplored. In this study, we delved into the biophysical basis of Efg1 phase separation, revealing the significant contribution of both N-terminal (N) and C-terminal (C) PrLDs. Through NMR structural analysis, we found that Efg1 N-PrLD and C-PrLD are mostly disordered though have prominent partial α-helical secondary structures in both domains. NMR titration experiments suggest that the partially helical structures in N-PrLD act as hubs for self-interaction as well as Efg1 interaction with RNA. Using condensed-phase NMR spectroscopy, we uncovered diverse amino acid interactions underlying Efg1 phase separation. Particularly, we highlight the indispensable role of tyrosine residues within the transient α-helical structures of PrLDs particularly in the N-PrLD compared to the C-PrLD in stabilizing phase separation. Our study provides evidence that the transient α-helical structure is present in the phase separated state and highlights the particular importance of aromatic residues within these structures for phase separation. Together, these results enhance the understanding of C. albicans TF interactions that lead to virulence and provide a crucial foundation for potential antifungal therapies targeting the transcriptional switch.
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Affiliation(s)
- Szu-Huan Wang
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence Rhode Island, 02912, USA
- These authors contributed equally to this work
| | - Tongyin Zheng
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence Rhode Island, 02912, USA
- These authors contributed equally to this work
| | - Nicolas L. Fawzi
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence Rhode Island, 02912, USA
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23
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Amith W, Dutagaci B. Complex Conformational Space of the RNA Polymerase II C-Terminal Domain upon Phosphorylation. J Phys Chem B 2023; 127:9223-9235. [PMID: 37870995 PMCID: PMC10626582 DOI: 10.1021/acs.jpcb.3c02655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 10/03/2023] [Indexed: 10/25/2023]
Abstract
Intrinsically disordered proteins (IDPs) have been closely studied during the past decade due to their importance in many biological processes. The disordered nature of this group of proteins makes it difficult to observe its full span of the conformational space using either experimental or computational studies. In this article, we explored the conformational space of the C-terminal domain (CTD) of RNA polymerase II (Pol II), which is also an intrinsically disordered low complexity domain, using enhanced sampling methods. We provided a detailed conformational analysis of model systems of CTD with different lengths; first with the last 44 residues of the human CTD sequence and finally the CTD model with 2-heptapeptide repeating units. We then investigated the effects of phosphorylation on CTD conformations by performing simulations at different phosphorylated states. We obtained broad conformational spaces in nonphosphorylated CTD models, and phosphorylation has complex effects on the conformations of the CTD. These complex effects depend on the length of the CTD, spacing between the multiple phosphorylation sites, ion coordination, and interactions with the nearby residues.
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Affiliation(s)
- Weththasinghage
D. Amith
- Department of Molecular and
Cell Biology, University of California,
Merced, Merced, California 95343, United States
| | - Bercem Dutagaci
- Department of Molecular and
Cell Biology, University of California,
Merced, Merced, California 95343, United States
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24
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Lewis BA, Das SK, Jha RK, Levens D. Self-assembly of promoter DNA and RNA Pol II machinery into transcriptionally active biomolecular condensates. SCIENCE ADVANCES 2023; 9:eadi4565. [PMID: 37851801 PMCID: PMC10584347 DOI: 10.1126/sciadv.adi4565] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 09/13/2023] [Indexed: 10/20/2023]
Abstract
Transcription in the nucleus occurs in a concentrated, dense environment, and no reasonable biochemical facsimile of this milieu exists. Such a biochemical environment would be important for further understanding transcriptional regulation. We describe here the formation of dense, transcriptionally active bodies in vitro with only nuclear extracts and promoter DNA. These biomolecular condensates (BMCs) are 0.5 to 1 μm in diameter, have a macromolecular density of approximately 100 mg/ml, and are a consequence of a phase transition between promoter DNA and nuclear extract proteins. BMCs are physically associated with transcription as any disruption of one compromised the other. The BMCs contain RNA polymerase II and elongation factors, as well as factors necessary for BMC formation in vivo. We suggest that BMCs are representative of the in vivo nuclear environment and a more physiologically relevant manifestation of the preinitiation complex/elongation machinery.
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Affiliation(s)
- Brian A. Lewis
- Gene Regulation Section, LP/CCR/NCI/NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Subhendu Kumar Das
- Gene Regulation Section, LP/CCR/NCI/NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Rajiv Kumar Jha
- Gene Regulation Section, LP/CCR/NCI/NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - David Levens
- Gene Regulation Section, LP/CCR/NCI/NIH, 9000 Rockville Pike, Bethesda, MD 20892, USA
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25
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Welles RM, Sojitra KA, Garabedian MV, Xia B, Wang W, Guan M, Regy RM, Gallagher ER, Hammer DA, Mittal J, Good MC. Determinants of Disordered Protein Co-Assembly Into Discrete Condensed Phases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.10.532134. [PMID: 36945618 PMCID: PMC10028963 DOI: 10.1101/2023.03.10.532134] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Cells harbor numerous mesoscale membraneless compartments that house specific biochemical processes and perform distinct cellular functions. These protein and RNA-rich bodies are thought to form through multivalent interactions among proteins and nucleic acids resulting in demixing via liquid-liquid phase separation (LLPS). Proteins harboring intrinsically disordered regions (IDRs) predominate in membraneless organelles. However, it is not known whether IDR sequence alone can dictate the formation of distinct condensed phases. We identified a pair of IDRs capable of forming spatially distinct condensates when expressed in cells. When reconstituted in vitro, these model proteins do not co-partition, suggesting condensation specificity is encoded directly in the polypeptide sequences. Through computational modeling and mutagenesis, we identified the amino acids and chain properties governing homotypic and heterotypic interactions that direct selective condensation. These results form the basis of physicochemical principles that may direct subcellular organization of IDRs into specific condensates and reveal an IDR code that can guide construction of orthogonal membraneless compartments.
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26
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Chakraborty P, Zweckstetter M. Role of aberrant phase separation in pathological protein aggregation. Curr Opin Struct Biol 2023; 82:102678. [PMID: 37604044 DOI: 10.1016/j.sbi.2023.102678] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 08/23/2023]
Abstract
Neurodegenerative diseases are associated with the pathological deposition of many different intrinsically disordered proteins or proteins with intrinsically disordered regions. Recent evidence suggests that these proteins can undergo liquid-liquid phase separation and also form membrane-less organelles in cells. Additionally, the biomolecular condensates formed by these proteins may undergo liquid-to-solid phase transition thereby maturating to amyloid fibrils, oligomeric species, or amorphous aggregates and contributing to the pathology of several neurodegenerative diseases. Here we discuss the role of phase separation of the neuronal proteins tau, α-synuclein, fused in sarcoma (FUS), and the transactive response DNA-binding protein of 43 kDa (TDP-43) that are associated with neurodegeneration in the context of pathological protein aggregation.
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Affiliation(s)
- Pijush Chakraborty
- Department for NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Markus Zweckstetter
- Department for NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany; German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075 Göttingen, Germany.
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27
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Thompson VF, Wieland DR, Mendoza-Leon V, Janis HI, Lay MA, Harrell LM, Schwartz JC. Binding of the nuclear ribonucleoprotein family member FUS to RNA prevents R-loop RNA:DNA hybrid structures. J Biol Chem 2023; 299:105237. [PMID: 37690693 PMCID: PMC10556777 DOI: 10.1016/j.jbc.2023.105237] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 08/17/2023] [Accepted: 08/25/2023] [Indexed: 09/12/2023] Open
Abstract
The protein FUS (FUSed in sarcoma) is a metazoan RNA-binding protein that influences RNA production by all three nuclear polymerases. FUS also binds nascent transcripts, RNA processing factors, RNA polymerases, and transcription machinery. Here, we explored the role of FUS binding interactions for activity during transcription. In vitro run-off transcription assays revealed FUS-enhanced RNA produced by a non-eukaryote polymerase. The activity also reduced the formation of R-loops between RNA products and their DNA template. Analysis by domain mutation and deletion indicated RNA-binding was required for activity. We interpret that FUS binds and sequesters nascent transcripts to prevent R-loops from forming with nearby DNA. DRIP-seq analysis showed that a knockdown of FUS increased R-loop enrichment near expressed genes. Prevention of R-loops by FUS binding to nascent transcripts has the potential to affect transcription by any RNA polymerase, highlighting the broad impact FUS can have on RNA metabolism in cells and disease.
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Affiliation(s)
- Valery F Thompson
- Department of Pharmacology, University of Arizona, Tucson, Arizona, USA; University of Arizona Cancer Center, Tucson, Arizona, USA
| | - Daniel R Wieland
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Vivian Mendoza-Leon
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Helen I Janis
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Michelle A Lay
- Department of Pharmacology, University of Arizona, Tucson, Arizona, USA; University of Arizona Cancer Center, Tucson, Arizona, USA; Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Lucas M Harrell
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Jacob C Schwartz
- Department of Pharmacology, University of Arizona, Tucson, Arizona, USA; University of Arizona Cancer Center, Tucson, Arizona, USA.
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28
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Hazra M, Levy Y. Cross-Talk of Cation-π Interactions with Electrostatic and Aromatic Interactions: A Salt-Dependent Trade-off in Biomolecular Condensates. J Phys Chem Lett 2023; 14:8460-8469. [PMID: 37721444 PMCID: PMC10544028 DOI: 10.1021/acs.jpclett.3c01642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
Biomolecular condensates are essential for cellular functionality, yet the complex interplay among the diverse molecular interactions that mediate their formation remains poorly understood. Here, using coarse-grained molecular dynamics simulations, we address the contribution of cation-π interactions to the stability of condensates formed via liquid-liquid phase separation. We found greater stabilization of up to 80% via cation-π interactions in condensates formed from peptides with higher aromatic residue content or less charge clustering. The contribution of cation-π interactions to droplet stability increases with increasing ionic strength, suggesting a trade-off between cation-π and electrostatic interactions. Cation-π interactions, therefore, can compensate for reduced electrostatic interactions, such as occurs at higher salt concentrations and in sequences with less charged residue content or clustering. Designing condensates with desired biophysical characteristics therefore requires quantification not only of the individual interactions but also cross-talks involving charge-charge, π-π, and cation-π interactions.
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Affiliation(s)
- Milan
Kumar Hazra
- Department of Chemical and
Structural Biology, Weizmann Institute of
Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Chemical and
Structural Biology, Weizmann Institute of
Science, Rehovot 76100, Israel
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29
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Flores-Solis D, Lushpinskaia IP, Polyansky AA, Changiarath A, Boehning M, Mirkovic M, Walshe J, Pietrek LM, Cramer P, Stelzl LS, Zagrovic B, Zweckstetter M. Driving forces behind phase separation of the carboxy-terminal domain of RNA polymerase II. Nat Commun 2023; 14:5979. [PMID: 37749095 PMCID: PMC10519987 DOI: 10.1038/s41467-023-41633-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 09/10/2023] [Indexed: 09/27/2023] Open
Abstract
Eukaryotic gene regulation and pre-mRNA transcription depend on the carboxy-terminal domain (CTD) of RNA polymerase (Pol) II. Due to its highly repetitive, intrinsically disordered sequence, the CTD enables clustering and phase separation of Pol II. The molecular interactions that drive CTD phase separation and Pol II clustering are unclear. Here, we show that multivalent interactions involving tyrosine impart temperature- and concentration-dependent self-coacervation of the CTD. NMR spectroscopy, molecular ensemble calculations and all-atom molecular dynamics simulations demonstrate the presence of diverse tyrosine-engaging interactions, including tyrosine-proline contacts, in condensed states of human CTD and other low-complexity proteins. We further show that the network of multivalent interactions involving tyrosine is responsible for the co-recruitment of the human Mediator complex and CTD during phase separation. Our work advances the understanding of the driving forces of CTD phase separation and thus provides the basis to better understand CTD-mediated Pol II clustering in eukaryotic gene transcription.
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Affiliation(s)
- David Flores-Solis
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold Straße 3A, 35075, Göttingen, Germany
| | - Irina P Lushpinskaia
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold Straße 3A, 35075, Göttingen, Germany
| | - Anton A Polyansky
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Campus Vienna Biocenter 5, 1030, Vienna, Austria
- University of Vienna, Center for Molecular Biology, Department of Structural and Computational Biology, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Arya Changiarath
- Faculty of Biology, Johannes Gutenberg University Mainz (JGU), Gresemundweg 2, 55128, Mainz, Germany
- KOMET1, Institute of Physics, Johannes Gutenberg University Mainz (JGU), Staudingerweg 9, 55099, Mainz, Germany
| | - Marc Boehning
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077, Göttingen, Germany
| | - Milana Mirkovic
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Campus Vienna Biocenter 5, 1030, Vienna, Austria
- University of Vienna, Center for Molecular Biology, Department of Structural and Computational Biology, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - James Walshe
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077, Göttingen, Germany
| | - Lisa M Pietrek
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue Strasße 3, 60438, Frankfurt am Main, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077, Göttingen, Germany
| | - Lukas S Stelzl
- Faculty of Biology, Johannes Gutenberg University Mainz (JGU), Gresemundweg 2, 55128, Mainz, Germany
- KOMET1, Institute of Physics, Johannes Gutenberg University Mainz (JGU), Staudingerweg 9, 55099, Mainz, Germany
- Institute of Molecular Biology (IMB), 55128, Mainz, Germany
| | - Bojan Zagrovic
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Campus Vienna Biocenter 5, 1030, Vienna, Austria
- University of Vienna, Center for Molecular Biology, Department of Structural and Computational Biology, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold Straße 3A, 35075, Göttingen, Germany.
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077, Göttingen, Germany.
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30
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Blazquez S, Sanchez‐Burgos I, Ramirez J, Higginbotham T, Conde MM, Collepardo‐Guevara R, Tejedor AR, Espinosa JR. Location and Concentration of Aromatic-Rich Segments Dictates the Percolating Inter-Molecular Network and Viscoelastic Properties of Ageing Condensates. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2207742. [PMID: 37386790 PMCID: PMC10477902 DOI: 10.1002/advs.202207742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 05/03/2023] [Indexed: 07/01/2023]
Abstract
Maturation of functional liquid-like biomolecular condensates into solid-like aggregates has been linked to the onset of several neurodegenerative disorders. Low-complexity aromatic-rich kinked segments (LARKS) contained in numerous RNA-binding proteins can promote aggregation by forming inter-protein β-sheet fibrils that accumulate over time and ultimately drive the liquid-to-solid transition of the condensates. Here, atomistic molecular dynamics simulations are combined with sequence-dependent coarse-grained models of various resolutions to investigate the role of LARKS abundance and position within the amino acid sequence in the maturation of condensates. Remarkably, proteins with tail-located LARKS display much higher viscosity over time than those in which the LARKS are placed toward the center. Yet, at very long timescales, proteins with a single LARKS-independently of its location-can still relax and form high viscous liquid condensates. However, phase-separated condensates of proteins containing two or more LARKS become kinetically trapped due to the formation of percolated β-sheet networks that display gel-like behavior. Furthermore, as a work case example, they demonstrate how shifting the location of the LARKS-containing low-complexity domain of FUS protein toward its center effectively precludes the accumulation of β-sheet fibrils in FUS-RNA condensates, maintaining functional liquid-like behavior without ageing.
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Affiliation(s)
- Samuel Blazquez
- Department of Physical‐ChemistryUniversidad Complutense de MadridAv. Complutense s/nMadrid28040Spain
- Maxwell Centre, Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJ J Thomson AvenueCambridgeCB3 0HEUK
| | - Ignacio Sanchez‐Burgos
- Maxwell Centre, Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJ J Thomson AvenueCambridgeCB3 0HEUK
| | - Jorge Ramirez
- Department of Chemical EngineeringUniversidad Politécnica de MadridJosé Gutiérrez Abascal 2Madrid28006Spain
| | - Tim Higginbotham
- Maxwell Centre, Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJ J Thomson AvenueCambridgeCB3 0HEUK
| | - Maria M. Conde
- Department of Chemical EngineeringUniversidad Politécnica de MadridJosé Gutiérrez Abascal 2Madrid28006Spain
| | - Rosana Collepardo‐Guevara
- Maxwell Centre, Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJ J Thomson AvenueCambridgeCB3 0HEUK
- Yusuf Hamied Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeCB2 1EWUK
- Department of GeneticsUniversity of CambridgeCambridgeCB2 3EH, UK
| | - Andres R. Tejedor
- Maxwell Centre, Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJ J Thomson AvenueCambridgeCB3 0HEUK
- Department of Chemical EngineeringUniversidad Politécnica de MadridJosé Gutiérrez Abascal 2Madrid28006Spain
| | - Jorge R. Espinosa
- Department of Physical‐ChemistryUniversidad Complutense de MadridAv. Complutense s/nMadrid28040Spain
- Maxwell Centre, Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJ J Thomson AvenueCambridgeCB3 0HEUK
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31
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Mohanty P, Shenoy J, Rizuan A, Mercado-Ortiz JF, Fawzi NL, Mittal J. A synergy between site-specific and transient interactions drives the phase separation of a disordered, low-complexity domain. Proc Natl Acad Sci U S A 2023; 120:e2305625120. [PMID: 37579155 PMCID: PMC10450430 DOI: 10.1073/pnas.2305625120] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/17/2023] [Indexed: 08/16/2023] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is involved in key processes in RNA metabolism and is frequently implicated in many neurodegenerative diseases, including amyotrophic lateral sclerosis and frontotemporal dementia. The prion-like, disordered C-terminal domain (CTD) of TDP-43 is aggregation-prone, can undergo liquid-liquid phase separation (LLPS) in isolation, and is critical for phase separation (PS) of the full-length protein under physiological conditions. While a short conserved helical region (CR, spanning residues 319-341) promotes oligomerization and is essential for LLPS, aromatic residues in the flanking disordered regions (QN-rich, IDR1/2) are also found to play a critical role in PS and aggregation. Compared with other phase-separating proteins, TDP-43 CTD has a notably distinct sequence composition including many aliphatic residues such as methionine and leucine. Aliphatic residues were previously suggested to modulate the apparent viscosity of the resulting phases, but their direct contribution toward CTD phase separation has been relatively ignored. Using multiscale simulations coupled with in vitro saturation concentration (csat) measurements, we identified the importance of aromatic residues while also suggesting an essential role for aliphatic methionine residues in promoting single-chain compaction and LLPS. Surprisingly, NMR experiments showed that transient interactions involving phenylalanine and methionine residues in the disordered flanking regions can directly enhance site-specific, CR-mediated intermolecular association. Overall, our work highlights an underappreciated mode of biomolecular recognition, wherein both transient and site-specific hydrophobic interactions act synergistically to drive the oligomerization and phase separation of a disordered, low-complexity domain.
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Affiliation(s)
- Priyesh Mohanty
- Artie McFerrinDepartment of Chemical Engineering, Texas A&M University, College Station, TX77843
| | - Jayakrishna Shenoy
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI02912
| | - Azamat Rizuan
- Artie McFerrinDepartment of Chemical Engineering, Texas A&M University, College Station, TX77843
| | - José F. Mercado-Ortiz
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI02912
| | - Nicolas L. Fawzi
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI02912
| | - Jeetain Mittal
- Artie McFerrinDepartment of Chemical Engineering, Texas A&M University, College Station, TX77843
- Department of Chemistry, Texas A&M University, College Station, TX77843
- Interdisciplinary Graduate Program in Genetics and Genomics, Texas A&M University, College Station, TX77843
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32
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Rajan SS, Ebegboni VJ, Pichling P, Ludwig KR, Jones TL, Chari R, Tran A, Kruhlak MJ, Loncarek J, Caplen NJ. EWSR1's visual modalities are defined by its association with nucleic acids and RNA polymerase II. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.16.553246. [PMID: 37645932 PMCID: PMC10462028 DOI: 10.1101/2023.08.16.553246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
We report systematic analysis of endogenous EWSR1's cellular organization. We demonstrate that EWSR1, which contains low complexity and nucleic acid binding domains, is present in cells in faster and slower-recovering fractions, indicative of a protein undergoing both rapid exchange and longer-term interactions. The employment of complementary high-resolution imaging approaches shows EWSR1 exists in in two visual modalities, a distributed state which is present throughout the nucleoplasm, and a concentrated state consistent with the formation of foci. Both EWSR1 visual modalities localize with nascent RNA. EWSR1 foci concentrate in regions of euchromatin, adjacent to protein markers of transcriptional activation, and significantly colocalize with phosphorylated RNA polymerase II. Interestingly, EWSR1 and FUS, another FET protein, exhibit distinct spatial organizations. Our results contribute to bridging the gap between our understanding of the biophysical and biochemical properties of FET proteins, including EWSR1, their functions as transcriptional regulators, and the participation of these proteins in tumorigenesis and neurodegenerative disease.
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Affiliation(s)
- Soumya Sundara Rajan
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health MD 20892, USA
| | - Vernon J. Ebegboni
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health MD 20892, USA
| | - Patricio Pichling
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health MD 20892, USA
| | - Katelyn R. Ludwig
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health MD 20892, USA
| | - Tamara L. Jones
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health MD 20892, USA
| | - Raj Chari
- Genome Modification Core, Laboratory Animal Sciences Program at the Frederick National Lab for Cancer Research, Frederick, MD 21702, USA
| | - Andy Tran
- CCR Confocal Microscopy Core Facility, Laboratory of Cancer Biology and Genetics, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michael J. Kruhlak
- CCR Confocal Microscopy Core Facility, Laboratory of Cancer Biology and Genetics, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jadranka Loncarek
- Centrosome Biology Section, Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702 USA
| | - Natasha J. Caplen
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health MD 20892, USA
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33
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Tzeplaeff L, Seguin J, Le Gras S, Megat S, Cosquer B, Plassard D, Dieterlé S, Paiva I, Picchiarelli G, Decraene C, Alcala-Vida R, Cassel JC, Merienne K, Dupuis L, Boutillier AL. Mutant FUS induces chromatin reorganization in the hippocampus and alters memory processes. Prog Neurobiol 2023; 227:102483. [PMID: 37327984 DOI: 10.1016/j.pneurobio.2023.102483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 05/12/2023] [Accepted: 06/09/2023] [Indexed: 06/18/2023]
Abstract
Cytoplasmic mislocalization of the nuclear Fused in Sarcoma (FUS) protein is associated to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Cytoplasmic FUS accumulation is recapitulated in the frontal cortex and spinal cord of heterozygous Fus∆NLS/+ mice. Yet, the mechanisms linking FUS mislocalization to hippocampal function and memory formation are still not characterized. Herein, we show that in these mice, the hippocampus paradoxically displays nuclear FUS accumulation. Multi-omic analyses showed that FUS binds to a set of genes characterized by the presence of an ETS/ELK-binding motifs, and involved in RNA metabolism, transcription, ribosome/mitochondria and chromatin organization. Importantly, hippocampal nuclei showed a decompaction of the neuronal chromatin at highly expressed genes and an inappropriate transcriptomic response was observed after spatial training of Fus∆NLS/+ mice. Furthermore, these mice lacked precision in a hippocampal-dependent spatial memory task and displayed decreased dendritic spine density. These studies shows that mutated FUS affects epigenetic regulation of the chromatin landscape in hippocampal neurons, which could participate in FTD/ALS pathogenic events. These data call for further investigation in the neurological phenotype of FUS-related diseases and open therapeutic strategies towards epigenetic drugs.
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Affiliation(s)
- Laura Tzeplaeff
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France; CNRS, UMR 7364, Strasbourg 67000, France; Université de Strasbourg, INSERM, UMR-S1118, Strasbourg, France
| | - Jonathan Seguin
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France; CNRS, UMR 7364, Strasbourg 67000, France
| | - Stéphanie Le Gras
- Université de Strasbourg, CNRS UMR 7104, INSERM U1258, GenomEast Platform, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Université de Strasbourg, Illkirch, France
| | - Salim Megat
- Université de Strasbourg, INSERM, UMR-S1118, Strasbourg, France
| | - Brigitte Cosquer
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France; CNRS, UMR 7364, Strasbourg 67000, France
| | - Damien Plassard
- Université de Strasbourg, CNRS UMR 7104, INSERM U1258, GenomEast Platform, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Université de Strasbourg, Illkirch, France
| | | | - Isabel Paiva
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France; CNRS, UMR 7364, Strasbourg 67000, France
| | | | - Charles Decraene
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France; CNRS, UMR 7364, Strasbourg 67000, France
| | - Rafael Alcala-Vida
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France; CNRS, UMR 7364, Strasbourg 67000, France
| | - Jean-Christophe Cassel
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France; CNRS, UMR 7364, Strasbourg 67000, France
| | - Karine Merienne
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France; CNRS, UMR 7364, Strasbourg 67000, France
| | - Luc Dupuis
- Université de Strasbourg, INSERM, UMR-S1118, Strasbourg, France.
| | - Anne-Laurence Boutillier
- Université de Strasbourg, Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), Strasbourg, France.
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34
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Doan VS, Alshareedah I, Singh A, Banerjee PR, Shin S. Diffusiophoresis promotes phase separation and transport of biomolecular condensates. RESEARCH SQUARE 2023:rs.3.rs-3171749. [PMID: 37546778 PMCID: PMC10402192 DOI: 10.21203/rs.3.rs-3171749/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
The internal microenvironment of a living cell is heterogeneous and comprises a multitude of organelles with distinct biochemistry. Amongst them are biomolecular condensates, which are membrane-less, phase-separated compartments enriched in system-specific proteins and nucleic acids. The heterogeneity of the cell engenders the presence of multiple spatiotemporal gradients in chemistry, charge, concentration, temperature, and pressure. Such thermodynamic gradients can lead to non-equilibrium driving forces for the formation and transport of biomolecular condensates. Here, we report how ion gradients impact the transport processes of biomolecular condensates on the mesoscale and biomolecules on the microscale. Utilizing a microfluidic platform, we demonstrate that the presence of ion concentration gradients can accelerate the transport of biomolecules, including nucleic acids and proteins, via diffusiophoresis. This hydrodynamic transport process allows localized enrichment of biomolecules, thereby promoting the location-specific formation of biomolecular condensates via phase separation. The ion gradients further impart active motility of condensates, allowing them to exhibit enhanced diffusion along the gradient. Coupled with reentrant phase behavior, the gradient-induced active motility leads to a dynamical redistribution of condensates that ultimately extends their lifetime. Together, our results demonstrate diffusiophoresis as a non-equilibrium thermodynamic force that governs the formation and active transport of biomolecular condensates.
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Affiliation(s)
- Viet Sang Doan
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Ibraheem Alshareedah
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Anurag Singh
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Priya R. Banerjee
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260
| | - Sangwoo Shin
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260
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35
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Lushpinskaia IP, Flores-Solis D, Zweckstetter M. Structure and phase separation of the C-terminal domain of RNA polymerase II. Biol Chem 2023; 404:839-844. [PMID: 37331973 DOI: 10.1515/hsz-2023-0136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 06/01/2023] [Indexed: 06/20/2023]
Abstract
The repetitive heptads in the C-terminal domain (CTD) of RPB1, the largest subunit of RNA Polymerase II (Pol II), play a critical role in the regulation of Pol II-based transcription. Recent findings on the structure of the CTD in the pre-initiation complex determined by cryo-EM and the novel phase separation properties of key transcription components offers an expanded mechanistic interpretation of the spatiotemporal distribution of Pol II during transcription. Current experimental evidence further suggests an exquisite balance between CTD's local structure and an array of multivalent interactions that drive phase separation of Pol II and thus shape its transcriptional activity.
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Affiliation(s)
- Irina P Lushpinskaia
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold Straße 3A, D-35075 Göttingen, Germany
| | - David Flores-Solis
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold Straße 3A, D-35075 Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold Straße 3A, D-35075 Göttingen, Germany
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, D-37077 Göttingen, Germany
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36
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Guo G, Wang X, Zhang Y, Li T. Sequence variations of phase-separating proteins and resources for studying biomolecular condensates. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1119-1132. [PMID: 37464880 PMCID: PMC10423696 DOI: 10.3724/abbs.2023131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 06/06/2023] [Indexed: 07/20/2023] Open
Abstract
Phase separation (PS) is an important mechanism underlying the formation of biomolecular condensates. Physiological condensates are associated with numerous biological processes, such as transcription, immunity, signaling, and synaptic transmission. Changes in particular amino acids or segments can disturb the protein's phase behavior and interactions with other biomolecules in condensates. It is thus presumed that variations in the phase-separating-prone domains can significantly impact the properties and functions of condensates. The dysfunction of condensates contributes to a number of pathological processes. Pharmacological perturbation of these condensates is proposed as a promising way to restore physiological states. In this review, we characterize the variations observed in PS proteins that lead to aberrant biomolecular compartmentalization. We also showcase recent advancements in bioinformatics of membraneless organelles (MLOs), focusing on available databases useful for screening PS proteins and describing endogenous condensates, guiding researchers to seek the underlying pathogenic mechanisms of biomolecular condensates.
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Affiliation(s)
- Gaigai Guo
- Department of Biomedical InformaticsSchool of Basic Medical SciencesPeking University Health Science CenterBeijing100191China
| | - Xinxin Wang
- Department of Biomedical InformaticsSchool of Basic Medical SciencesPeking University Health Science CenterBeijing100191China
| | - Yi Zhang
- Department of Biomedical InformaticsSchool of Basic Medical SciencesPeking University Health Science CenterBeijing100191China
| | - Tingting Li
- Department of Biomedical InformaticsSchool of Basic Medical SciencesPeking University Health Science CenterBeijing100191China
- Key Laboratory for NeuroscienceMinistry of Education/National Health Commission of ChinaPeking UniversityBeijing100191China
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37
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Ma S, Liao K, Li M, Wang X, Lv J, Zhang X, Huang H, Li L, Huang T, Guo X, Lin Y, Rong Z. Phase-separated DropCRISPRa platform for efficient gene activation in mammalian cells and mice. Nucleic Acids Res 2023; 51:5271-5284. [PMID: 37094074 PMCID: PMC10250237 DOI: 10.1093/nar/gkad301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 04/05/2023] [Accepted: 04/21/2023] [Indexed: 04/26/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) plays a critical role in regulating gene transcription via the formation of transcriptional condensates. However, LLPS has not been reported to be engineered as a tool to activate endogenous gene expression in mammalian cells or in vivo. Here, we developed a droplet-forming CRISPR (clustered regularly interspaced short palindromic repeats) gene activation system (DropCRISPRa) to activate transcription with high efficiency via combining the CRISPR-SunTag system with FETIDR-AD fusion proteins, which contain an N-terminal intrinsically disordered region (IDR) of a FET protein (FUS or TAF15) and a transcription activation domain (AD, VP64/P65/VPR). In this system, the FETIDR-AD fusion protein formed phase separation condensates at the target sites, which could recruit endogenous BRD4 and RNA polymerase II with an S2 phosphorylated C-terminal domain (CTD) to enhance transcription elongation. IDR-FUS9Y>S and IDR-FUSG156E, two mutants with deficient and aberrant phase separation respectively, confirmed that appropriate phase separation was required for efficient gene activation. Further, the DropCRISPRa system was compatible with a broad set of CRISPR-associated (Cas) proteins and ADs, including dLbCas12a, dAsCas12a, dSpCas9 and the miniature dUnCas12f1, and VP64, P65 and VPR. Finally, the DropCRISPRa system could activate target genes in mice. Therefore, this study provides a robust tool to activate gene expression for foundational research and potential therapeutics.
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Affiliation(s)
- Shufeng Ma
- Department of Nephrology, Shenzhen Hospital, Southern Medical University, Shenzhen 518110, China
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
| | - Kaitong Liao
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
| | - Mengrao Li
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
| | - Xinlong Wang
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
| | - Jie Lv
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
| | - Xin Zhang
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
- Affiliated Dongguan Hospital, Southern Medical University, (Dongguan People's Hospital), Dongguan 523058, China
| | - Hongxin Huang
- Dermatology Hospital, Southern Medical University, Guangzhou 510091, China
| | - Lian Li
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
| | - Tao Huang
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
- Dermatology Hospital, Southern Medical University, Guangzhou 510091, China
| | - Xiaohua Guo
- Department of Nephrology, Shenzhen Hospital, Southern Medical University, Shenzhen 518110, China
| | - Ying Lin
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
- Experimental Education/Administration Center, School of Basic Medical Science, Southern Medical University, Guangzhou 510515, China
| | - Zhili Rong
- Cancer Research Institute, School of Basic Medical Sciences, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Key Laboratory of Organ Failure Research (Ministry of Education), Southern Medical University, Guangzhou 510515, China
- Dermatology Hospital, Southern Medical University, Guangzhou 510091, China
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38
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Alston JJ, Ginell GM, Soranno A, Holehouse AS. The Analytical Flory Random Coil Is a Simple-to-Use Reference Model for Unfolded and Disordered Proteins. J Phys Chem B 2023; 127:4746-4760. [PMID: 37200094 PMCID: PMC10875986 DOI: 10.1021/acs.jpcb.3c01619] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Denatured, unfolded, and intrinsically disordered proteins (collectively referred to here as unfolded proteins) can be described using analytical polymer models. These models capture various polymeric properties and can be fit to simulation results or experimental data. However, the model parameters commonly require users' decisions, making them useful for data interpretation but less clearly applicable as stand-alone reference models. Here we use all-atom simulations of polypeptides in conjunction with polymer scaling theory to parameterize an analytical model of unfolded polypeptides that behave as ideal chains (ν = 0.50). The model, which we call the analytical Flory random coil (AFRC), requires only the amino acid sequence as input and provides direct access to probability distributions of global and local conformational order parameters. The model defines a specific reference state to which experimental and computational results can be compared and normalized. As a proof-of-concept, we use the AFRC to identify sequence-specific intramolecular interactions in simulations of disordered proteins. We also use the AFRC to contextualize a curated set of 145 different radii of gyration obtained from previously published small-angle X-ray scattering experiments of disordered proteins. The AFRC is implemented as a stand-alone software package and is also available via a Google Colab notebook. In summary, the AFRC provides a simple-to-use reference polymer model that can guide intuition and aid in interpreting experimental or simulation results.
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Affiliation(s)
- Jhullian J. Alston
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, USA
| | - Garrett M. Ginell
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, USA
| | - Andrea Soranno
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, USA
| | - Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, USA
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39
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Vendruscolo M, Fuxreiter M. Towards sequence-based principles for protein phase separation predictions. Curr Opin Chem Biol 2023; 75:102317. [PMID: 37207400 DOI: 10.1016/j.cbpa.2023.102317] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/07/2023] [Accepted: 04/11/2023] [Indexed: 05/21/2023]
Abstract
The phenomenon of protein phase separation, which underlies the formation of biomolecular condensates, has been associated with numerous cellular functions. Recent studies indicate that the amino acid sequences of most proteins may harbour not only the code for folding into the native state but also for condensing into the liquid-like droplet state and the solid-like amyloid state. Here we review the current understanding of the principles for sequence-based methods for predicting the propensity of proteins for phase separation. A guiding concept is that entropic contributions are generally more important to stabilise the droplet state than they are for the native and amyloid states. Although estimating these entropic contributions has proven difficult, we describe some progress that has been recently made in this direction. To conclude, we discuss the challenges ahead to extend sequence-based prediction methods of protein phase separation to include quantitative in vivo characterisations of this process.
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Affiliation(s)
- Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.
| | - Monika Fuxreiter
- Department of Biomedical Sciences, University of Padova, PD 35131, Italy; Department of Physics and Astronomy, University of Padova, PD 35131, Italy.
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40
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Ranganathan S, Dasmeh P, Furniss S, Shakhnovich E. Phosphorylation sites are evolutionary checkpoints against liquid-solid transition in protein condensates. Proc Natl Acad Sci U S A 2023; 120:e2215828120. [PMID: 37155880 PMCID: PMC10193986 DOI: 10.1073/pnas.2215828120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 03/30/2023] [Indexed: 05/10/2023] Open
Abstract
Assemblies of multivalent RNA-binding protein fused in sarcoma (FUS) can exist in the functional liquid-like state as well as less dynamic and potentially toxic amyloid- and hydrogel-like states. How could then cells form liquid-like condensates while avoiding their transformation to amyloids? Here, we show how posttranslational phosphorylation can provide a "handle" that prevents liquid-solid transition of intracellular condensates containing FUS. Using residue-specific coarse-grained simulations, for 85 different mammalian FUS sequences, we show how the number of phosphorylation sites and their spatial arrangement affect intracluster dynamics preventing conversion to amyloids. All atom simulations further confirm that phosphorylation can effectively reduce the β-sheet propensity in amyloid-prone fragments of FUS. A detailed evolutionary analysis shows that mammalian FUS PLDs are enriched in amyloid-prone stretches compared to control neutrally evolved sequences, suggesting that mammalian FUS proteins evolved to self-assemble. However, in stark contrast to proteins that do not phase-separate for their function, mammalian sequences have phosphosites in close proximity to these amyloid-prone regions. These results suggest that evolution uses amyloid-prone sequences in prion-like domains to enhance phase separation of condensate proteins while enriching phosphorylation sites in close proximity to safeguard against liquid-solid transitions.
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Affiliation(s)
- Srivastav Ranganathan
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA02138
| | - Pouria Dasmeh
- Center for Human Genetics, Marburg University, Marburg35033, Germany
| | - Seth Furniss
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA02138
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, OxfordOX1 3QZ, United Kingdom
| | - Eugene Shakhnovich
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA02138
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41
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Pavlova I, Iudin M, Surdina A, Severov V, Varizhuk A. G-Quadruplexes in Nuclear Biomolecular Condensates. Genes (Basel) 2023; 14:genes14051076. [PMID: 37239436 DOI: 10.3390/genes14051076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
G-quadruplexes (G4s) have long been implicated in the regulation of chromatin packaging and gene expression. These processes require or are accelerated by the separation of related proteins into liquid condensates on DNA/RNA matrices. While cytoplasmic G4s are acknowledged scaffolds of potentially pathogenic condensates, the possible contribution of G4s to phase transitions in the nucleus has only recently come to light. In this review, we summarize the growing evidence for the G4-dependent assembly of biomolecular condensates at telomeres and transcription initiation sites, as well as nucleoli, speckles, and paraspeckles. The limitations of the underlying assays and the remaining open questions are outlined. We also discuss the molecular basis for the apparent permissive role of G4s in the in vitro condensate assembly based on the interactome data. To highlight the prospects and risks of G4-targeting therapies with respect to the phase transitions, we also touch upon the reported effects of G4-stabilizing small molecules on nuclear biomolecular condensates.
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Affiliation(s)
- Iuliia Pavlova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Mikhail Iudin
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Anastasiya Surdina
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
| | - Vjacheslav Severov
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
| | - Anna Varizhuk
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
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42
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Rekhi S, Sundaravadivelu Devarajan D, Howard MP, Kim YC, Nikoubashman A, Mittal J. Role of Strong Localized vs Weak Distributed Interactions in Disordered Protein Phase Separation. J Phys Chem B 2023; 127:3829-3838. [PMID: 37079924 PMCID: PMC10187732 DOI: 10.1021/acs.jpcb.3c00830] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/03/2023] [Indexed: 04/22/2023]
Abstract
Interaction strength and localization are critical parameters controlling the single-chain and condensed-state properties of intrinsically disordered proteins (IDPs). Here, we decipher these relationships using coarse-grained heteropolymers comprised of hydrophobic (H) and polar (P) monomers as model IDPs. We systematically vary the fraction of P monomers XP and employ two distinct particle-based models that include either strong localized attractions between only H-H pairs (HP model) or weak distributed attractions between both H-H and H-P pairs (HP+ model). To compare different sequences and models, we first carefully tune the attraction strength for all sequences to match the single-chain radius of gyration. Interestingly, we find that this procedure produces similar conformational ensembles, nonbonded potential energies, and chain-level dynamics for single chains of almost all sequences in both models, with some deviations for the HP model at large XP. However, we observe a surprisingly rich phase behavior for the sequences in both models that deviates from the expectation that similarity at the single-chain level will translate to a similar phase-separation propensity. Coexistence between dilute and dense phases is only observed up to a model-dependent XP, despite the presence of favorable interchain interactions, which we quantify using the second virial coefficient. Instead, the limited number of attractive sites (H monomers) leads to the self-assembly of finite-sized clusters of different sizes depending on XP. Our findings strongly suggest that models with distributed interactions favor the formation of liquid-like condensates over a much larger range of sequence compositions compared to models with localized interactions.
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Affiliation(s)
- Shiv Rekhi
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | | | - Michael P. Howard
- Department
of Chemical Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Young C. Kim
- Center
for Materials Physics and Technology, Naval
Research Laboratory, Washington, D.C. 20375, United States
| | - Arash Nikoubashman
- Institute
of Physics, Johannes Gutenberg University
Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Jeetain Mittal
- Artie
McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
- Interdisciplinary
Graduate Program in Genetics and Genomics, Texas A&M University, College
Station, Texas 77843, United States
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43
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Kumar MS, Stallworth KM, Murthy AC, Lim SM, Li N, Jain A, Munro JB, Fawzi NL, Lagier-Tourenne C, Bosco DA. Interactions between FUS and the C-terminal Domain of Nup62 are Sufficient for their Co-phase Separation into Amorphous Assemblies. J Mol Biol 2023; 435:167972. [PMID: 36690069 PMCID: PMC10329203 DOI: 10.1016/j.jmb.2023.167972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/29/2022] [Accepted: 01/15/2023] [Indexed: 01/22/2023]
Abstract
Deficient nucleocytoplasmic transport is emerging as a pathogenic feature of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), including in ALS caused by mutations in Fused in Sarcoma (FUS). Recently, both wild-type and ALS-linked mutant FUS were shown to directly interact with the phenylalanine-glycine (FG)-rich nucleoporin 62 (Nup62) protein, where FUS WT/ Nup62 interactions were enriched within the nucleus but ALS-linked mutant FUS/ Nup62 interactions were enriched within the cytoplasm of cells. Nup62 is a central channel Nup that has a prominent role in forming the selectivity filter within the nuclear pore complex and in regulating effective nucleocytoplasmic transport. Under conditions where FUS phase separates into liquid droplets in vitro, the addition of Nup62 caused the synergistic formation of amorphous assemblies containing both FUS and Nup62. Here, we examined the molecular determinants of this process using recombinant FUS and Nup62 proteins and biochemical approaches. We demonstrate that the structured C-terminal domain of Nup62 containing an alpha-helical coiled-coil region plays a dominant role in binding FUS and is sufficient for inducing the formation of FUS/Nup62 amorphous assemblies. In contrast, the natively unstructured, F/G repeat-rich N-terminal domain of Nup62 modestly contributed to FUS/Nup62 phase separation behavior. Expression of individual Nup62 domain constructs in human cells confirmed that the Nup62 C-terminal domain is essential for localization of the protein to the nuclear envelope. Our results raise the possibility that interactions between FUS and the C-terminal domain of Nup62 can influence the function of Nup62 under physiological and/or pathological conditions.
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Affiliation(s)
- Meenakshi Sundaram Kumar
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, MA 01605, USA; Biochemistry and Molecular Biotechnology Program, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Karly M Stallworth
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, MA 01605, USA
| | - Anastasia C Murthy
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Su Min Lim
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Nan Li
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Aastha Jain
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - James B Munro
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Nicolas L Fawzi
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Clotilde Lagier-Tourenne
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Daryl A Bosco
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, MA 01605, USA.
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Alston JJ, Ginell GM, Soranno A, Holehouse AS. The analytical Flory random coil is a simple-to-use reference model for unfolded and disordered proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.12.531990. [PMID: 36993592 PMCID: PMC10054940 DOI: 10.1101/2023.03.12.531990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Denatured, unfolded, and intrinsically disordered proteins (collectively referred to here as unfolded proteins) can be described using analytical polymer models. These models capture various polymeric properties and can be fit to simulation results or experimental data. However, the model parameters commonly require users' decisions, making them useful for data interpretation but less clearly applicable as stand-alone reference models. Here we use all-atom simulations of polypeptides in conjunction with polymer scaling theory to parameterize an analytical model of unfolded polypeptides that behave as ideal chains (ν = 0.50). The model, which we call the analytical Flory Random Coil (AFRC), requires only the amino acid sequence as input and provides direct access to probability distributions of global and local conformational order parameters. The model defines a specific reference state to which experimental and computational results can be compared and normalized. As a proof-of-concept, we use the AFRC to identify sequence-specific intramolecular interactions in simulations of disordered proteins. We also use the AFRC to contextualize a curated set of 145 different radii of gyration obtained from previously published small-angle X-ray scattering experiments of disordered proteins. The AFRC is implemented as a stand-alone software package and is also available via a Google colab notebook. In summary, the AFRC provides a simple-to-use reference polymer model that can guide intuition and aid in interpreting experimental or simulation results.
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Affiliation(s)
- Jhullian J. Alston
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, USA
| | - Garrett M. Ginell
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, USA
| | - Andrea Soranno
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, USA
| | - Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, USA
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45
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Macromolecular Crowding Is Surprisingly Unable to Deform the Structure of a Model Biomolecular Condensate. BIOLOGY 2023; 12:biology12020181. [PMID: 36829460 PMCID: PMC9952705 DOI: 10.3390/biology12020181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/27/2023]
Abstract
The crowded interior of a living cell makes performing experiments on simpler in vitro systems attractive. Although these reveal interesting phenomena, their biological relevance can be questionable. A topical example is the phase separation of intrinsically disordered proteins into biomolecular condensates, which is proposed to underlie the membrane-less compartmentalization of many cellular functions. How a cell reliably controls biochemical reactions in compartments open to the compositionally-varying cytoplasm is an important question for understanding cellular homeostasis. Computer simulations are often used to study the phase behavior of model biomolecular condensates, but the number of relevant parameters increases as the number of protein components increases. It is unfeasible to exhaustively simulate such models for all parameter combinations, although interesting phenomena are almost certainly hidden in their high-dimensional parameter space. Here, we have studied the phase behavior of a model biomolecular condensate in the presence of a polymeric crowding agent. We used a novel compute framework to execute dozens of simultaneous simulations spanning the protein/crowder concentration space. We then combined the results into a graphical representation for human interpretation, which provided an efficient way to search the model's high-dimensional parameter space. We found that steric repulsion from the crowder drives a near-critical system across the phase boundary, but the molecular arrangement within the resulting biomolecular condensate is rather insensitive to the crowder concentration and molecular weight. We propose that a cell may use the local cytoplasmic concentration to assist the formation of biomolecular condensates, while relying on the dense phase to reliably provide a stable, structured, fluid milieu for cellular biochemistry despite being open to its changing environment.
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46
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Ibrahim AY, Khaodeuanepheng NP, Amarasekara DL, Correia JJ, Lewis KA, Fitzkee NC, Hough LE, Whitten ST. Intrinsically disordered regions that drive phase separation form a robustly distinct protein class. J Biol Chem 2022; 299:102801. [PMID: 36528065 PMCID: PMC9860499 DOI: 10.1016/j.jbc.2022.102801] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 11/29/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Protein phase separation is thought to be a primary driving force for the formation of membrane-less organelles, which control a wide range of biological functions from stress response to ribosome biogenesis. Among phase-separating (PS) proteins, many have intrinsically disordered regions (IDRs) that are needed for phase separation to occur. Accurate identification of IDRs that drive phase separation is important for testing the underlying mechanisms of phase separation, identifying biological processes that rely on phase separation, and designing sequences that modulate phase separation. To identify IDRs that drive phase separation, we first curated datasets of folded, ID, and PS ID sequences. We then used these sequence sets to examine how broadly existing amino acid property scales can be used to distinguish between the three classes of protein regions. We found that there are robust property differences between the classes and, consequently, that numerous combinations of amino acid property scales can be used to make robust predictions of protein phase separation. This result indicates that multiple, redundant mechanisms contribute to the formation of phase-separated droplets from IDRs. The top-performing scales were used to further optimize our previously developed predictor of PS IDRs, ParSe. We then modified ParSe to account for interactions between amino acids and obtained reasonable predictive power for mutations that have been designed to test the role of amino acid interactions in driving protein phase separation. Collectively, our findings provide further insight into the classification of IDRs and the elements involved in protein phase separation.
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Affiliation(s)
- Ayyam Y. Ibrahim
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas, USA
| | | | | | - John J. Correia
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Karen A. Lewis
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas, USA
| | | | - Loren E. Hough
- Department of Physics, University of Colorado Boulder, Boulder, Colorado, USA,BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, USA,For correspondence: Steven T. Whitten; Loren E. Hough
| | - Steven T. Whitten
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas, USA,For correspondence: Steven T. Whitten; Loren E. Hough
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47
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Mohanty P, Kapoor U, Sundaravadivelu Devarajan D, Phan TM, Rizuan A, Mittal J. Principles Governing the Phase Separation of Multidomain Proteins. Biochemistry 2022; 61:2443-2455. [PMID: 35802394 PMCID: PMC9669140 DOI: 10.1021/acs.biochem.2c00210] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A variety of membraneless organelles, often termed "biological condensates", play an important role in the regulation of cellular processes such as gene transcription, translation, and protein quality control. On the basis of experimental and theoretical investigations, liquid-liquid phase separation (LLPS) has been proposed as a possible mechanism for the origin of biological condensates. LLPS requires multivalent macromolecules that template the formation of long-range, intermolecular interaction networks and results in the formation of condensates with defined composition and material properties. Multivalent interactions driving LLPS exhibit a wide range of modes from highly stereospecific to nonspecific and involve both folded and disordered regions. Multidomain proteins serve as suitable macromolecules for promoting phase separation and achieving disparate functions due to their potential for multivalent interactions and regulation. Here, we aim to highlight the influence of the domain architecture and interdomain interactions on the phase separation of multidomain protein condensates. First, the general principles underlying these interactions are illustrated on the basis of examples of multidomain proteins that are predominantly associated with nucleic acid binding and protein quality control and contain both folded and disordered regions. Next, the examples showcase how LLPS properties of folded and disordered regions can be leveraged to engineer multidomain constructs that form condensates with the desired assembly and functional properties. Finally, we highlight the need for improvements in coarse-grained computational models that can provide molecular-level insights into multidomain protein condensates in conjunction with experimental efforts.
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Affiliation(s)
- Priyesh Mohanty
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Utkarsh Kapoor
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | | | - Tien Minh Phan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Azamat Rizuan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
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48
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Ji Y, Li F, Qiao Y. Modulating liquid-liquid phase separation of FUS: mechanisms and strategies. J Mater Chem B 2022; 10:8616-8628. [PMID: 36268634 DOI: 10.1039/d2tb01688e] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Liquid-liquid phase separation (LLPS) of biomolecules inspires the construction of protocells and drives the formation of cellular membraneless organelles. The resulting biomolecular condensates featuring dynamic assembly, disassembly, and phase transition play significant roles in a series of biological processes, including RNA metabolism, DNA damage response, signal transduction and neurodegenerative disease. Intensive investigations have been conducted for understanding and manipulating intracellular phase-separated disease-related proteins (e.g., FUS, tau and TDP-43). Herein, we review current studies on the regulation strategies of intracellular LLPS focusing on FUS, which are categorized into physical stimuli, biochemical modulators, and protein structural modifications, with summarized molecular mechanisms. This review is expected to provide a sketch of the modulation of FUS LLPS with its pros and cons, and an outlook for the potential clinical treatments of neurodegenerative diseases.
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Affiliation(s)
- Yanglimin Ji
- Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fen Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yan Qiao
- Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of Polymer Physics and Chemistry, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China
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49
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Global profiling of arginine dimethylation in regulating protein phase separation by a steric effect-based chemical-enrichment method. Proc Natl Acad Sci U S A 2022; 119:e2205255119. [PMID: 36256816 PMCID: PMC9618127 DOI: 10.1073/pnas.2205255119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein arginine methylation plays an important role in regulating protein functions in different cellular processes, and its dysregulation may lead to a variety of human diseases. Recently, arginine methylation was found to be involved in modulating protein liquid-liquid phase separation (LLPS), which drives the formation of different membraneless organelles (MLOs). Here, we developed a steric effect-based chemical-enrichment method (SECEM) coupled with liquid chromatography-tandem mass spectrometry to analyze arginine dimethylation (DMA) at the proteome level. We revealed by SECEM that, in mammalian cells, the DMA sites occurring in the RG/RGG motifs are preferentially enriched within the proteins identified in different MLOs, especially stress granules (SGs). Notably, global decrease of protein arginine methylation severely impairs the dynamic assembly and disassembly of SGs. By further profiling the dynamic change of DMA upon SG formation by SECEM, we identified that the most dramatic change of DMA occurs at multiple sites of RG/RGG-rich regions from several key SG-contained proteins, including G3BP1, FUS, hnRNPA1, and KHDRBS1. Moreover, both in vitro arginine methylation and mutation of the identified DMA sites significantly impair LLPS capability of the four different RG/RGG-rich regions. Overall, we provide a global profiling of the dynamic changes of protein DMA in the mammalian cells under different stress conditions by SECEM and reveal the important role of DMA in regulating protein LLPS and SG dynamics.
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50
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Shillcock JC, Lagisquet C, Alexandre J, Vuillon L, Ipsen JH. Model biomolecular condensates have heterogeneous structure quantitatively dependent on the interaction profile of their constituent macromolecules. SOFT MATTER 2022; 18:6674-6693. [PMID: 36004748 DOI: 10.1039/d2sm00387b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Biomolecular condensates play numerous roles in cells by selectively concentrating client proteins while excluding others. These functions are likely to be sensitive to the spatial organization of the scaffold proteins forming the condensate. We use coarse-grained molecular simulations to show that model intrinsically-disordered proteins phase separate into a heterogeneous, structured fluid characterized by a well-defined length scale. The proteins are modelled as semi-flexible polymers with punctate, multifunctional binding sites in good solvent conditions. Their dense phase is highly solvated with a spatial structure that is more sensitive to the separation of the binding sites than their affinity. We introduce graph theoretic measures to quantify their heterogeneity, and find that it increases with increasing binding site number, and exhibits multi-timescale dynamics. The model proteins also swell on passing from the dilute solution to the dense phase. The simulations predict that the structure of the dense phase is modulated by the location and affinity of binding sites distant from the termini of the proteins, while sites near the termini more strongly affect its phase behaviour. The relations uncovered between the arrangement of weak interaction sites on disordered proteins and the material properties of their dense phase can be experimentally tested to give insight into the biophysical properties, pathological effects, and rational design of biomolecular condensates.
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Affiliation(s)
- Julian C Shillcock
- Blue Brain Project and Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Clément Lagisquet
- LAMA, Univ. Savoie Mont Blanc, CNRS, LAMA, 73376 Le Bourget du Lac, France.
| | - Jérémy Alexandre
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Laurent Vuillon
- LAMA, Univ. Savoie Mont Blanc, CNRS, LAMA, 73376 Le Bourget du Lac, France.
| | - John H Ipsen
- Dept. of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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