1
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Strom AR, Eeftens JM, Polyachenko Y, Weaver CJ, Watanabe HF, Bracha D, Orlovsky ND, Jumper CC, Jacobs WM, Brangwynne CP. Interplay of condensation and chromatin binding underlies BRD4 targeting. Mol Biol Cell 2024:mbcE24010046. [PMID: 38656803 DOI: 10.1091/mbc.e24-01-0046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Nuclear compartments form via biomolecular phase separation, mediated through multivalent properties of biomolecules concentrated within condensates. Certain compartments are associated with specific chromatin regions, including transcriptional initiation condensates, which are composed of transcription factors and transcriptional machinery, and form at acetylated regions including enhancer and promoter loci. While protein self-interactions, especially within low-complexity and intrinsically disordered regions, are known to mediate condensation, the role of substrate-binding interactions in regulating the formation and function of biomolecular condensates is under-explored. Here, utilizing live-cell experiments in parallel with coarse-grained simulations, we investigate how chromatin interaction of the transcriptional activator BRD4 modulates its condensate formation. We find that both kinetic and thermodynamic properties of BRD4 condensation are affected by chromatin binding: nucleation rate is sensitive to BRD4-chromatin interactions, providing an explanation for the selective formation of BRD4 condensates at acetylated chromatin regions, and thermodynamically, multivalent acetylated chromatin sites provide a platform for BRD4 clustering below the concentration required for off-chromatin condensation. This provides a molecular and physical explanation of the relationship between nuclear condensates and epigenetically modified chromatin that results in their mutual spatiotemporal regulation, suggesting that epigenetic modulation is an important mechanism by which the cell targets transcriptional condensates to specific chromatin loci. [Media: see text].
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Affiliation(s)
- Amy R Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton NJ
| | - Jorine M Eeftens
- Department of Chemical and Biological Engineering, Princeton University, Princeton NJ
- Current address: Radboud University Nijmegen, Netherlands
| | | | - Claire J Weaver
- Department of Chemical and Biological Engineering, Princeton University, Princeton NJ
- Department of Molecular and Cellular Biology, Princeton University, Princeton NJ
| | | | - Dan Bracha
- Department of Chemical and Biological Engineering, Princeton University, Princeton NJ
- Current address: Department of Biotechnology and Food Engineering, Technion, Israel
| | - Natalia D Orlovsky
- Department of Chemical and Biological Engineering, Princeton University, Princeton NJ
- Current address: Biological and Biomedical Sciences Program, Harvard University, Boston
| | - Chanelle C Jumper
- Department of Chemical and Biological Engineering, Princeton University, Princeton NJ
- Current address: Nereid Therapeutics, Boston MA
| | | | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton NJ
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton NJ
- Howard Hughes Medical Institute
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2
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Rana U, Wingreen NS, Brangwynne CP, Panagiotopoulos AZ. Interfacial exchange dynamics of biomolecular condensates are highly sensitive to client interactions. J Chem Phys 2024; 160:145102. [PMID: 38591689 PMCID: PMC11006425 DOI: 10.1063/5.0188461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/22/2024] [Indexed: 04/10/2024] Open
Abstract
Phase separation of biomolecules can facilitate their spatiotemporally regulated self-assembly within living cells. Due to the selective yet dynamic exchange of biomolecules across condensate interfaces, condensates can function as reactive hubs by concentrating enzymatic components for faster kinetics. The principles governing this dynamic exchange between condensate phases, however, are poorly understood. In this work, we systematically investigate the influence of client-sticker interactions on the exchange dynamics of protein molecules across condensate interfaces. We show that increasing affinity between a model protein scaffold and its client molecules causes the exchange of protein chains between the dilute and dense phases to slow down and that beyond a threshold interaction strength, this slowdown in exchange becomes substantial. Investigating the impact of interaction symmetry, we found that chain exchange dynamics are also considerably slower when client molecules interact equally with different sticky residues in the protein. The slowdown of exchange is due to a sequestration effect, by which there are fewer unbound stickers available at the interface to which dilute phase chains may attach. These findings highlight the fundamental connection between client-scaffold interaction networks and condensate exchange dynamics.
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Affiliation(s)
- Ushnish Rana
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Ned S. Wingreen
- Lewis-Sigler Institute for Integrative Genomics and Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
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3
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Keber FC, Nguyen T, Mariossi A, Brangwynne CP, Wühr M. Evidence for widespread cytoplasmic structuring into mesoscale condensates. Nat Cell Biol 2024; 26:346-352. [PMID: 38424273 PMCID: PMC10981939 DOI: 10.1038/s41556-024-01363-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 01/23/2024] [Indexed: 03/02/2024]
Abstract
Compartmentalization is an essential feature of eukaryotic life and is achieved both via membrane-bound organelles, such as mitochondria, and membrane-less biomolecular condensates, such as the nucleolus. Known biomolecular condensates typically exhibit liquid-like properties and are visualized by microscopy on the scale of ~1 µm (refs. 1,2). They have been studied mostly by microscopy, examining select individual proteins. So far, several dozen biomolecular condensates are known, serving a multitude of functions, for example, in the regulation of transcription3, RNA processing4 or signalling5,6, and their malfunction can cause diseases7,8. However, it remains unclear to what extent biomolecular condensates are utilized in cellular organization and at what length scale they typically form. Here we examine native cytoplasm from Xenopus egg extract on a global scale with quantitative proteomics, filtration, size exclusion and dilution experiments. These assays reveal that at least 18% of the proteome is organized into mesoscale biomolecular condensates at the scale of ~100 nm and appear to be stabilized by RNA or gelation. We confirmed mesoscale sizes via imaging below the diffraction limit by investigating protein permeation into porous substrates with defined pore sizes. Our results show that eukaryotic cytoplasm organizes extensively via biomolecular condensates, but at surprisingly short length scales.
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Affiliation(s)
- Felix C Keber
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Thao Nguyen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Andrea Mariossi
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, USA.
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ, USA.
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
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4
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Rana U, Xu K, Narayanan A, Walls MT, Panagiotopoulos AZ, Avalos JL, Brangwynne CP. Asymmetric oligomerization state and sequence patterning can tune multiphase condensate miscibility. Nat Chem 2024:10.1038/s41557-024-01456-6. [PMID: 38383656 DOI: 10.1038/s41557-024-01456-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024]
Abstract
Endogenous biomolecular condensates, composed of a multitude of proteins and RNAs, can organize into multiphasic structures with compositionally distinct phases. This multiphasic organization is generally understood to be critical for facilitating their proper biological function. However, the biophysical principles driving multiphase formation are not completely understood. Here we use in vivo condensate reconstitution experiments and coarse-grained molecular simulations to investigate how oligomerization and sequence interactions modulate multiphase organization in biomolecular condensates. We demonstrate that increasing the oligomerization state of an intrinsically disordered protein results in enhanced immiscibility and multiphase formation. Interestingly, we find that oligomerization tunes the miscibility of intrinsically disordered proteins in an asymmetric manner, with the effect being more pronounced when the intrinsically disordered protein, exhibiting stronger homotypic interactions, is oligomerized. Our findings suggest that oligomerization is a flexible biophysical mechanism that cells can exploit to tune the internal organization of biomolecular condensates and their associated biological functions.
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Affiliation(s)
- Ushnish Rana
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Ke Xu
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Amal Narayanan
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, USA
| | - Mackenzie T Walls
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | | | - José L Avalos
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, USA.
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ, USA.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, USA.
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ, USA.
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5
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Patil A, Strom AR, Paulo JA, Collings CK, Ruff KM, Shinn MK, Sankar A, Cervantes KS, Wauer T, St Laurent JD, Xu G, Becker LA, Gygi SP, Pappu RV, Brangwynne CP, Kadoch C. A disordered region controls cBAF activity via condensation and partner recruitment. Cell 2023; 186:4936-4955.e26. [PMID: 37788668 PMCID: PMC10792396 DOI: 10.1016/j.cell.2023.08.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 07/16/2023] [Accepted: 08/24/2023] [Indexed: 10/05/2023]
Abstract
Intrinsically disordered regions (IDRs) represent a large percentage of overall nuclear protein content. The prevailing dogma is that IDRs engage in non-specific interactions because they are poorly constrained by evolutionary selection. Here, we demonstrate that condensate formation and heterotypic interactions are distinct and separable features of an IDR within the ARID1A/B subunits of the mSWI/SNF chromatin remodeler, cBAF, and establish distinct "sequence grammars" underlying each contribution. Condensation is driven by uniformly distributed tyrosine residues, and partner interactions are mediated by non-random blocks rich in alanine, glycine, and glutamine residues. These features concentrate a specific cBAF protein-protein interaction network and are essential for chromatin localization and activity. Importantly, human disease-associated perturbations in ARID1B IDR sequence grammars disrupt cBAF function in cells. Together, these data identify IDR contributions to chromatin remodeling and explain how phase separation provides a mechanism through which both genomic localization and functional partner recruitment are achieved.
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Affiliation(s)
- Ajinkya Patil
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Program in Virology, Harvard Medical School, Boston, MA 02115, USA
| | - Amy R Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Clayton K Collings
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Kiersten M Ruff
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Min Kyung Shinn
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Akshay Sankar
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Kasey S Cervantes
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Tobias Wauer
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Jessica D St Laurent
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA; Department of Obstetrics and Gynecology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Grace Xu
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Lindsay A Becker
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Chevy Chase, MD 21044, USA; Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ 08544, USA.
| | - Cigall Kadoch
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD 21044, USA.
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6
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Zhang Y, Lee DSW, Meir Y, Brangwynne CP, Wingreen NS. Erratum: Mechanical Frustration of Phase Separation in the Cell Nucleus by Chromatin [Phys. Rev. Lett. 126, 258102 (2021)]. Phys Rev Lett 2023; 131:169901. [PMID: 37925738 DOI: 10.1103/physrevlett.131.169901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Indexed: 11/07/2023]
Abstract
This corrects the article DOI: 10.1103/PhysRevLett.126.258102.
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7
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Choi CH, Lee DSW, Sanders DW, Brangwynne CP. Condensate interfaces can accelerate protein aggregation. Biophys J 2023:S0006-3495(23)00645-8. [PMID: 37837191 DOI: 10.1016/j.bpj.2023.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/16/2023] [Accepted: 10/10/2023] [Indexed: 10/15/2023] Open
Abstract
Protein aggregates, formed from the assembly of aberrant, misfolded proteins, are a hallmark of neurodegenerative diseases. Disease-associated aggregates such as mutant Huntingtin polyQ inclusions, are typically enriched in p62/SQSTM1, an oligomeric protein that binds to and sequesters aberrant proteins. p62 has been suggested to sequester proteins through formation of liquid-like biomolecular condensates, but the physical mechanisms by which p62 condensates may regulate pathological protein aggregation remain unclear. Here, we use a light-inducible biomimetic condensate system to show that p62 condensates enhance coarsening of mutant polyQ aggregates through interface-mediated sequestration, which accelerates polyQ accumulation into larger aggregates. However, the resulting large aggregates accumulate polyubiquitinated proteins, which depletes free p62, ultimately suppressing further p62 condensation. This dynamic interplay between interface-mediated coarsening of solid aggregates and downstream consequences on the phase behavior of associated regulatory proteins could contribute to the onset and progression of protein aggregation diseases.
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Affiliation(s)
- Chang-Hyun Choi
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey
| | - Daniel S W Lee
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey
| | - David W Sanders
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey; Omenn-Darling Bioengineering Institute, Princeton University, Princeton, New Jersey; Howard Hughes Medical Institute, Chevy Chase, Maryland.
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8
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Riback JA, Eeftens JM, Lee DSW, Quinodoz SA, Donlic A, Orlovsky N, Wiesner L, Beckers L, Becker LA, Strom AR, Rana U, Tolbert M, Purse BW, Kleiner R, Kriwacki R, Brangwynne CP. Viscoelasticity and advective flow of RNA underlies nucleolar form and function. Mol Cell 2023; 83:3095-3107.e9. [PMID: 37683610 DOI: 10.1016/j.molcel.2023.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 04/20/2023] [Accepted: 08/08/2023] [Indexed: 09/10/2023]
Abstract
The nucleolus is the largest biomolecular condensate and facilitates transcription, processing, and assembly of ribosomal RNA (rRNA). Although nucleolar function is thought to require multiphase liquid-like properties, nucleolar fluidity and its connection to the highly coordinated transport and biogenesis of ribosomal subunits are poorly understood. Here, we use quantitative imaging, mathematical modeling, and pulse-chase nucleotide labeling to examine nucleolar material properties and rRNA dynamics. The mobility of rRNA is several orders of magnitude slower than that of nucleolar proteins, with rRNA steadily moving away from the transcriptional sites in a slow (∼1 Å/s), radially directed fashion. This constrained but directional mobility, together with polymer physics-based calculations, suggests that nascent rRNA forms an entangled gel, whose constant production drives outward flow. We propose a model in which progressive maturation of nascent rRNA reduces its initial entanglement, fluidizing the nucleolar periphery to facilitate the release of assembled pre-ribosomal particles.
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Affiliation(s)
- Joshua A Riback
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Jorine M Eeftens
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Daniel S W Lee
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, Princeton, NJ 08544, USA
| | - Sofia A Quinodoz
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Anita Donlic
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Natalia Orlovsky
- Department of Molecular Biology, Princeton University, Princeton, Princeton, NJ 08544, USA
| | - Lennard Wiesner
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Lien Beckers
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton, Princeton, NJ 08544, USA
| | - Lindsay A Becker
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton, Princeton, NJ 08544, USA
| | - Amy R Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Ushnish Rana
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Michele Tolbert
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38103, USA
| | - Byron W Purse
- Department of Chemistry and Biochemistry and the Viral Information Institute, San Diego State University, San Diego, CA 92182, USA
| | - Ralph Kleiner
- Department of Chemistry, Princeton University, Princeton, Princeton, NJ 08544, USA
| | - Richard Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38103, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton, Princeton, NJ 08544, USA; Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ 08544, USA.
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9
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Park J, Wu Y, Shao W, Gendron TF, van der Spek SJF, Sultanakhmetov G, Basu A, Castellanos Otero P, Jones CJ, Jansen-West K, Daughrity LM, Phanse S, Del Rosso G, Tong J, Castanedes-Casey M, Jiang L, Libera J, Oskarsson B, Dickson DW, Sanders DW, Brangwynne CP, Emili A, Wolozin B, Petrucelli L, Zhang YJ. Poly(GR) interacts with key stress granule factors promoting its assembly into cytoplasmic inclusions. Cell Rep 2023; 42:112822. [PMID: 37471224 PMCID: PMC10528326 DOI: 10.1016/j.celrep.2023.112822] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 12/14/2022] [Accepted: 07/01/2023] [Indexed: 07/22/2023] Open
Abstract
C9orf72 repeat expansions are the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Poly(GR) proteins are toxic to neurons by forming cytoplasmic inclusions that sequester RNA-binding proteins including stress granule (SG) proteins. However, little is known of the factors governing poly(GR) inclusion formation. Here, we show that poly(GR) infiltrates a finely tuned network of protein-RNA interactions underpinning SG formation. It interacts with G3BP1, the key driver of SG assembly and a protein we found is critical for poly(GR) inclusion formation. Moreover, we discovered that N6-methyladenosine (m6A)-modified mRNAs and m6A-binding YTHDF proteins not only co-localize with poly(GR) inclusions in brains of c9FTD/ALS mouse models and patients with c9FTD, they promote poly(GR) inclusion formation via the incorporation of RNA into the inclusions. Our findings thus suggest that interrupting interactions between poly(GR) and G3BP1 or YTHDF1 proteins or decreasing poly(GR) altogether represent promising therapeutic strategies to combat c9FTD/ALS pathogenesis.
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Affiliation(s)
- Jinyoung Park
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Yanwei Wu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Wei Shao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Tania F Gendron
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - Sophie J F van der Spek
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Grigorii Sultanakhmetov
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo, 1920397, Japan
| | - Avik Basu
- Center for Network Systems Biology, Boston University School of Medicine, Boston, MA 02118, USA
| | | | - Caroline J Jones
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Karen Jansen-West
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Sadhna Phanse
- Center for Network Systems Biology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Giulia Del Rosso
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Jimei Tong
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Lulu Jiang
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Jenna Libera
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Björn Oskarsson
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - David W Sanders
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton, NJ 08544, USA
| | - Andrew Emili
- Center for Network Systems Biology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Benjamin Wolozin
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA.
| | - Yong-Jie Zhang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA.
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10
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Patil A, Strom AR, Collings CK, Paulo JA, Wauer T, Sankar A, St.Laurent JD, Cervantes KS, Gygi SP, Brangwynne CP, Kadoch C. Abstract 3485: Intrinsically disordered regions of the ARID1A/B tumor suppressors encode an interaction network within biomolecular condensates that directs mSWI/SNF chromatin remodeler complex activity. Cancer Res 2023. [DOI: 10.1158/1538-7445.am2023-3485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Abstract
The mammalian SWI/SNF (mSWI/SNF or BAF) ATP-dependent chromatin remodeling complexes collectively represent one of the most frequently mutated cellular entities in cancer, second only to TP53. Mutations across the 29 human genes that encode mSWI/SNF complex subunits occur in over 20% of human cancers, with mutations affecting ARID1A and ARID1B, the largest BAF subunits, being the most frequent. However, the functional contributions of these subunits, particularly their commonly mutated N-terminal intrinsically disordered regions (IDRs) and a highly conserved ARID DNA-binding domain, to BAF function remain poorly understood. Here, we demonstrate that the IDRs of ARID1A/B, coupled with the ARID domain, drive biomolecular condensate formation and BAF chromatin localization in cells. We define ARID1A/B IDRs as two-part systems, facilitating homotypic BAF complex interactions (i.e., valence generated by localized condensation) and heterotypic complex interactions, that together establish a highly specific, sequence-encoded protein interaction network within condensates. Both types of interactions are required for appropriate genome-wide targeting of BAF complexes, DNA accessibility generation, and appropriate gene expression. Replacement of the ARID1A N-terminal IDR with IDRs derived from two unrelated proteins FUS and DDX4, rescues generic condensation of BAF but not chromatin occupancy, DNA accessibility, and heterotypic interactions, highlighting the sequence-specificity embedded in the IDR of ARID1A. Taken together, these data establish a role for the largest and most frequently perturbed IDRs within a major chromatin remodeler and explain how biomolecular condensate formation enables both genomic localization and functional partner recruitment. Furthermore, these findings lay the groundwork for mapping IDR sequence specificity or “grammar”, that dictates the co-condensation network formation, and suggests that targeted disruption of these mechanisms may represent new targeted therapeutic opportunities across multiple cancers.
Citation Format: Ajinkya Patil, Amy R. Strom, Clayton K. Collings, Joao A. Paulo, Tobias Wauer, Akshay Sankar, Jessica D. St.Laurent, Kasey S. Cervantes, Steven P. Gygi, Clifford P. Brangwynne, Cigall Kadoch. Intrinsically disordered regions of the ARID1A/B tumor suppressors encode an interaction network within biomolecular condensates that directs mSWI/SNF chromatin remodeler complex activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3485.
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Affiliation(s)
- Ajinkya Patil
- 1Dana-Farber Cancer Institute/Harvard Medical School, Boston, MA
| | | | | | | | - Tobias Wauer
- 1Dana-Farber Cancer Institute/Harvard Medical School, Boston, MA
| | - Akshay Sankar
- 1Dana-Farber Cancer Institute/Harvard Medical School, Boston, MA
| | | | | | | | | | - Cigall Kadoch
- 1Dana-Farber Cancer Institute/Harvard Medical School, Boston, MA
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11
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Rana U, Xu K, Narayanan A, Walls MT, Avalos JL, Panagiotopoulos AZ, Brangwynne CP. Oligomerization and sequence patterning can tune multiphasic condensate miscibility. Biophys J 2023; 122:295a. [PMID: 36783468 DOI: 10.1016/j.bpj.2022.11.1669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Ushnish Rana
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Ke Xu
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Amal Narayanan
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Mackenzie T Walls
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Jose L Avalos
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | | | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
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12
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Choi CH, Lee DS, Sanders DW, Brangwynne CP. De novo p62 condensation facilitates aggregate coarsening in a size-dependent manner. Biophys J 2023; 122:483a. [PMID: 36784489 DOI: 10.1016/j.bpj.2022.11.2584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Chang-Hyun Choi
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Daniel S Lee
- Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA, USA
| | - David W Sanders
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
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13
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Jiang Y, Pyo A, Brangwynne CP, Stone HA, Wingreen NS, Zhang Y. Interface resistance of biomolecular condensates. Biophys J 2023; 122:442a. [PMID: 36784270 DOI: 10.1016/j.bpj.2022.11.2388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Yoyo Jiang
- Johns Hopkins University, Baltimore, MD, USA
| | - Andrew Pyo
- Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Yaojun Zhang
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA
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14
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Zhao J, Adamson B, Brangwynne CP. Mechanochemical induction of nuclear condensates during cell confined migration. Biophys J 2023; 122:485a. [PMID: 36784497 DOI: 10.1016/j.bpj.2022.11.2596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Jessica Zhao
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Britt Adamson
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA; Howard Hughes Medical Institute, Princeton, NJ, USA
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15
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Donlic A, Zheleznyakova E, Wiesner L, Brangwynne CP. Linking molecular-level RNA-protein interactions with mesoscale properties of the nucleolus. Biophys J 2023; 122:484a. [PMID: 36784492 DOI: 10.1016/j.bpj.2022.11.2589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Anita Donlic
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ, USA
| | | | - Lennard Wiesner
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ, USA
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16
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Abstract
Zygotic genome activation has been extensively studied in a variety of systems including flies, frogs, and mammals. However, there is comparatively little known about the precise timing of gene induction during the earliest phases of embryogenesis. Here we used high-resolution in situ detection methods, along with genetic and experimental manipulations, to study the timing of zygotic activation in the simple model chordate Ciona with minute-scale temporal precision. We found that two Prdm1 homologs in Ciona are the earliest genes that respond to FGF signaling. We present evidence for a FGF timing mechanism that is driven by ERK-mediated derepression of the ERF repressor. Depletion of ERF results in ectopic activation of FGF target genes throughout the embryo. A highlight of this timer is the sharp transition in FGF responsiveness between the eight- and 16-cell stages of development. We propose that this timer is an innovation of chordates that is also used by vertebrates.
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Affiliation(s)
- Nicholas Treen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA;
| | - Emily Chavarria
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Claire J Weaver
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Clifford P Brangwynne
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Michael Levine
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
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17
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Lee DSW, Choi CH, Sanders DW, Beckers L, Riback JA, Brangwynne CP, Wingreen NS. Size distributions of intracellular condensates reflect competition between coalescence and nucleation. Nat Phys 2023; 19:586-596. [PMID: 37073403 PMCID: PMC10104779 DOI: 10.1038/s41567-022-01917-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 12/12/2022] [Indexed: 05/03/2023]
Abstract
Phase separation of biomolecules into condensates has emerged as a mechanism for intracellular organization and affects many intracellular processes, including reaction pathways through the clustering of enzymes and pathway intermediates. Precise and rapid spatiotemporal control of reactions by condensates requires tuning of their sizes. However, the physical processes that govern the distribution of condensate sizes remain unclear. Here we show that both native and synthetic condensates display an exponential size distribution, which is captured by Monte Carlo simulations of fast nucleation followed by coalescence. In contrast, pathological aggregates exhibit a power-law size distribution. These distinct behaviours reflect the relative importance of nucleation and coalescence kinetics. We demonstrate this by utilizing a combination of synthetic and native condensates to probe the underlying physical mechanisms determining condensate size. The appearance of exponential distributions for abrupt nucleation versus power-law distributions under continuous nucleation may reflect a general principle that determines condensate size distributions.
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Affiliation(s)
- Daniel S. W. Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ USA
- Present Address: Department of Bioengineering, University of California, Berkeley, CA USA
| | - Chang-Hyun Choi
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ USA
| | - David W. Sanders
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ USA
| | - Lien Beckers
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ USA
- Howard Hughes Medical Institute, Princeton, NJ USA
| | - Joshua A. Riback
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ USA
- Present Address: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX USA
| | - Clifford P. Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ USA
- Howard Hughes Medical Institute, Princeton, NJ USA
| | - Ned S. Wingreen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ USA
- Department of Molecular Biology, Princeton University, Princeton, NJ USA
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18
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Gouveia B, Kim Y, Shaevitz JW, Petry S, Stone HA, Brangwynne CP. Capillary forces generated by biomolecular condensates. Nature 2022; 609:255-264. [PMID: 36071192 DOI: 10.1038/s41586-022-05138-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 07/25/2022] [Indexed: 12/21/2022]
Abstract
Liquid-liquid phase separation and related phase transitions have emerged as generic mechanisms in living cells for the formation of membraneless compartments or biomolecular condensates. The surface between two immiscible phases has an interfacial tension, generating capillary forces that can perform work on the surrounding environment. Here we present the physical principles of capillarity, including examples of how capillary forces structure multiphase condensates and remodel biological substrates. As with other mechanisms of intracellular force generation, for example, molecular motors, capillary forces can influence biological processes. Identifying the biomolecular determinants of condensate capillarity represents an exciting frontier, bridging soft matter physics and cell biology.
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Affiliation(s)
- Bernardo Gouveia
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Yoonji Kim
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | | | - Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA. .,The Howard Hughes Medical Institute, Princeton, NJ, USA.
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19
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Abstract
The cell nucleus can be thought of as a complex, dynamic, living material, which functions to organize and protect the genome and coordinate gene expression. These functions are achieved via intricate mechanical and biochemical interactions among its myriad components, including the nuclear lamina, nuclear bodies, and the chromatin itself. While the biophysical organization of the nuclear lamina and chromatin have been thoroughly studied, the concept that liquid–liquid phase separation and related phase transitions play a role in establishing nuclear structure has emerged only recently. Phase transitions are likely to be intimately coupled to the mechanobiology of structural elements in the nucleus, but their interplay with one another is still not understood. Here, we review recent developments on the role of phase separation and mechanics in nuclear organization and discuss the functional implications in cell physiology and disease states.
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Affiliation(s)
- Daniel S. W. Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
| | - Amy R. Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Clifford P. Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
- Howard Hughes Medical Institute, Princeton University, Princeton, New Jersey 08544, USA
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20
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Donlic A, Brangwynne CP. Fingerprinting Small Molecule Modulators of Nucleolar Biophysics. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.l7826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Anita Donlic
- Chemical and Biological EngineeringPrinceton UniversityPrincetonNJ
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21
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Riback JA, Eeftens JM, Lee DS, Quinodoz SA, Beckers L, Becker LA, Brangwynne CP. Viscoelastic RNA entanglement and advective flow underlies nucleolar form and function. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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22
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Jack A, Kim Y, Strom AR, Lee DS, Williams B, Schaub JM, Kellogg EH, Finkelstein IJ, Ferro L, Yildiz A, Brangwynne CP. Compartmentalization of telomeres through DNA-scaffolded phase separation. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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23
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Jack A, Kim Y, Strom AR, Lee DSW, Williams B, Schaub JM, Kellogg EH, Finkelstein IJ, Ferro LS, Yildiz A, Brangwynne CP. Compartmentalization of telomeres through DNA-scaffolded phase separation. Dev Cell 2022; 57:277-290.e9. [PMID: 35077681 PMCID: PMC8988007 DOI: 10.1016/j.devcel.2021.12.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 08/25/2021] [Accepted: 12/15/2021] [Indexed: 12/20/2022]
Abstract
Telomeres form unique nuclear compartments that prevent degradation and fusion of chromosome ends by recruiting shelterin proteins and regulating access of DNA damage repair factors. To understand how these dynamic components protect chromosome ends, we combine in vivo biophysical interrogation and in vitro reconstitution of human shelterin. We show that shelterin components form multicomponent liquid condensates with selective biomolecular partitioning on telomeric DNA. Tethering and anomalous diffusion prevent multiple telomeres from coalescing into a single condensate in mammalian cells. However, telomeres coalesce when brought into contact via an optogenetic approach. TRF1 and TRF2 subunits of shelterin drive phase separation, and their N-terminal domains specify interactions with telomeric DNA in vitro. Telomeric condensates selectively recruit telomere-associated factors and regulate access of DNA damage repair factors. We propose that shelterin mediates phase separation of telomeric chromatin, which underlies the dynamic yet persistent nature of the end-protection mechanism.
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Affiliation(s)
- Amanda Jack
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA
| | - Yoonji Kim
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Amy R Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Daniel S W Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Byron Williams
- Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | | | - Ilya J Finkelstein
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Luke S Ferro
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
| | - Ahmet Yildiz
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA; Physics Department, University of California, Berkeley, CA 94720, USA.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton NJ 08544, USA.
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24
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Abstract
Liquid-liquid phase separation (LLPS) is widely utilized by the cell to organize and regulate various biochemical processes. Although the LLPS of proteins is known to occur in a sequence-dependent manner, it is unclear how sequence properties dictate the nature of the phase transition and thereby influence condensed phase morphology. In this work, we have utilized grand canonical Monte Carlo simulations for a simple coarse-grained model of disordered proteins to systematically investigate how sequence distribution, sticker fraction, and chain length impact the formation of finite-size aggregates, which can preempt macroscopic phase separation for some sequences. We demonstrate that a normalized sequence charge decoration (SCD) parameter establishes a "soft" predictive criterion for distinguishing when a model protein undergoes macroscopic phase separation vs finite aggregation. Additionally, we find that this order parameter is strongly correlated with the critical density for phase separation, highlighting an unambiguous connection between sequence distribution and condensed phase density. Results obtained from an analysis of the order parameter reveal that at sufficiently long chain lengths, the vast majority of sequences are likely to phase separate. Our results suggest that classical LLPS should be the primary phase transition for disordered proteins when short-ranged attractive interactions dominate and suggest a possible reason behind recent findings of widespread phase separation throughout living cells.
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Affiliation(s)
- Ushnish Rana
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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25
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Safari MS, King MR, Brangwynne CP, Petry S. Interaction of spindle assembly factor TPX2 with importins-α/β inhibits protein phase separation. J Biol Chem 2021; 297:100998. [PMID: 34302807 PMCID: PMC8390506 DOI: 10.1016/j.jbc.2021.100998] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 07/12/2021] [Accepted: 07/20/2021] [Indexed: 12/30/2022] Open
Abstract
The microtubule-based mitotic spindle is responsible for equally partitioning the genome during each cell division, and its assembly is executed via several microtubule nucleation pathways. Targeting Protein for XKlp2 (TPX2) stimulates the branching microtubule nucleation pathway, where new microtubules are nucleated from preexisting ones within mitotic or meiotic spindles. TPX2, like other spindle assembly factors, is sequestered by binding to nuclear importins-α/β until the onset of mitosis, yet the molecular nature of this regulation remains unclear. Here we demonstrate that TPX2 interacts with importins-α/β with nanomolar affinity in a 1:1:1 monodispersed trimer. We also identify a new nuclear localization sequence in TPX2 that contributes to its high-affinity interaction with importin-α. In addition, we establish that TPX2 interacts with importin-β via dispersed, weak interactions. We show that interactions of both importin-α and -β with TPX2 inhibit its ability to undergo phase separation, which was recently shown to enhance the kinetics of branching microtubule nucleation. In summary, our study informs how importins regulate TPX2 to facilitate spindle assembly, and provides novel insight into the functional regulation of protein phase separation.
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Affiliation(s)
- Mohammad S Safari
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Matthew R King
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA; Howard Hughes Medical Institute, Princeton University, Princeton, New Jersey, USA
| | - Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA.
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26
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Zhang Y, Lee DS, Meir Y, Brangwynne CP, Wingreen NS. Mechanical Frustration of Phase Separation in the Cell Nucleus by Chromatin. Phys Rev Lett 2021; 126:258102. [PMID: 34241518 PMCID: PMC8604804 DOI: 10.1103/physrevlett.126.258102] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/18/2021] [Indexed: 05/07/2023]
Abstract
Liquid-liquid phase separation is a fundamental mechanism underlying subcellular organization. Motivated by the striking observation that optogenetically generated droplets in the nucleus display suppressed coarsening dynamics, we study the impact of chromatin mechanics on droplet phase separation. We combine theory and simulation to show that cross-linked chromatin can mechanically suppress droplets' coalescence and ripening, as well as quantitatively control their number, size, and placement. Our results highlight the role of the subcellular mechanical environment on condensate regulation.
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Affiliation(s)
- Yaojun Zhang
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Daniel S.W. Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Yigal Meir
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Physics, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Clifford P. Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Ned S. Wingreen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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27
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Strom AR, Biggs RJ, Banigan EJ, Wang X, Chiu K, Herman C, Collado J, Yue F, Ritland Politz JC, Tait LJ, Scalzo D, Telling A, Groudine M, Brangwynne CP, Marko JF, Stephens AD. HP1α is a chromatin crosslinker that controls nuclear and mitotic chromosome mechanics. eLife 2021; 10:63972. [PMID: 34106828 PMCID: PMC8233041 DOI: 10.7554/elife.63972] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/08/2021] [Indexed: 12/14/2022] Open
Abstract
Chromatin, which consists of DNA and associated proteins, contains genetic information and is a mechanical component of the nucleus. Heterochromatic histone methylation controls nucleus and chromosome stiffness, but the contribution of heterochromatin protein HP1α (CBX5) is unknown. We used a novel HP1α auxin-inducible degron human cell line to rapidly degrade HP1α. Degradation did not alter transcription, local chromatin compaction, or histone methylation, but did decrease chromatin stiffness. Single-nucleus micromanipulation reveals that HP1α is essential to chromatin-based mechanics and maintains nuclear morphology, separate from histone methylation. Further experiments with dimerization-deficient HP1αI165E indicate that chromatin crosslinking via HP1α dimerization is critical, while polymer simulations demonstrate the importance of chromatin-chromatin crosslinkers in mechanics. In mitotic chromosomes, HP1α similarly bolsters stiffness while aiding in mitotic alignment and faithful segregation. HP1α is therefore a critical chromatin-crosslinking protein that provides mechanical strength to chromosomes and the nucleus throughout the cell cycle and supports cellular functions.
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Affiliation(s)
- Amy R Strom
- Howard Hughes Medical Institute, Department of Chemical and Biological Engineering, Princeton University, Princeton, United States
| | - Ronald J Biggs
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Edward J Banigan
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, United States
| | - Xiaotao Wang
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Katherine Chiu
- Biology Department, University of Massachusetts Amherst, Amherst, United States
| | - Cameron Herman
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Jimena Collado
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Feng Yue
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | | | - Leah J Tait
- The Fred Hutchinson Cancer Research Center, Seattle, United States
| | - David Scalzo
- The Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Agnes Telling
- The Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Mark Groudine
- The Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Clifford P Brangwynne
- Howard Hughes Medical Institute, Department of Chemical and Biological Engineering, Princeton University, Princeton, United States
| | - John F Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, United States.,Department of Physics and Astronomy, Northwestern University, Evanston, United States
| | - Andrew D Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, United States
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28
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Sanders DW, Jumper CC, Ackerman PJ, Bracha D, Donlic A, Kim H, Kenney D, Castello-Serrano I, Suzuki S, Tamura T, Tavares AH, Saeed M, Holehouse AS, Ploss A, Levental I, Douam F, Padera RF, Levy BD, Brangwynne CP. SARS-CoV-2 requires cholesterol for viral entry and pathological syncytia formation. eLife 2021; 10:e65962. [PMID: 33890572 PMCID: PMC8104966 DOI: 10.7554/elife.65962] [Citation(s) in RCA: 128] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/01/2021] [Indexed: 12/27/2022] Open
Abstract
Many enveloped viruses induce multinucleated cells (syncytia), reflective of membrane fusion events caused by the same machinery that underlies viral entry. These syncytia are thought to facilitate replication and evasion of the host immune response. Here, we report that co-culture of human cells expressing the receptor ACE2 with cells expressing SARS-CoV-2 spike, results in synapse-like intercellular contacts that initiate cell-cell fusion, producing syncytia resembling those we identify in lungs of COVID-19 patients. To assess the mechanism of spike/ACE2-driven membrane fusion, we developed a microscopy-based, cell-cell fusion assay to screen ~6000 drugs and >30 spike variants. Together with quantitative cell biology approaches, the screen reveals an essential role for biophysical aspects of the membrane, particularly cholesterol-rich regions, in spike-mediated fusion, which extends to replication-competent SARS-CoV-2 isolates. Our findings potentially provide a molecular basis for positive outcomes reported in COVID-19 patients taking statins and suggest new strategies for therapeutics targeting the membrane of SARS-CoV-2 and other fusogenic viruses.
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Affiliation(s)
- David W Sanders
- Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - Chanelle C Jumper
- Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - Paul J Ackerman
- Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - Dan Bracha
- Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - Anita Donlic
- Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - Hahn Kim
- Princeton University Small Molecule Screening Center, Princeton UniversityPrincetonUnited States
- Department of Chemistry, Princeton UniversityPrincetonUnited States
| | - Devin Kenney
- Department of Microbiology, Boston University School of MedicineBostonUnited States
- National Emerging Infectious Diseases Laboratories, Boston UniversityBostonUnited States
| | - Ivan Castello-Serrano
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesvilleUnited States
| | - Saori Suzuki
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Tomokazu Tamura
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Alexander H Tavares
- National Emerging Infectious Diseases Laboratories, Boston UniversityBostonUnited States
- Department of Biochemistry, Boston University School of MedicineBostonUnited States
| | - Mohsan Saeed
- National Emerging Infectious Diseases Laboratories, Boston UniversityBostonUnited States
- Department of Biochemistry, Boston University School of MedicineBostonUnited States
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of MedicineSt. LouisUnited States
| | - Alexander Ploss
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Ilya Levental
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesvilleUnited States
| | - Florian Douam
- Department of Microbiology, Boston University School of MedicineBostonUnited States
- National Emerging Infectious Diseases Laboratories, Boston UniversityBostonUnited States
| | - Robert F Padera
- Department of Pathology, Brigham and Women’s Hospital and Harvard Medical SchoolBostonUnited States
| | - Bruce D Levy
- Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital and Harvard Medical SchoolBostonUnited States
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
- Howard Hughes Medical InstitutePrincetonUnited States
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29
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Treen N, Shimobayashi SF, Eeftens J, Brangwynne CP, Levine M. Properties of repression condensates in living Ciona embryos. Nat Commun 2021; 12:1561. [PMID: 33692345 PMCID: PMC7946874 DOI: 10.1038/s41467-021-21606-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 01/22/2021] [Indexed: 01/31/2023] Open
Abstract
Recent studies suggest that transcriptional activators and components of the pre-initiation complex (PIC) form higher order associations-clusters or condensates-at active loci. Considerably less is known about the distribution of repressor proteins responsible for gene silencing. Here, we develop an expression assay in living Ciona embryos that captures the liquid behavior of individual nucleoli undergoing dynamic fusion events. The assay is used to visualize puncta of Hes repressors, along with the Groucho/TLE corepressor. We observe that Hes.a/Gro puncta have the properties of viscous liquid droplets that undergo limited fusion events due to association with DNA. Hes.a mutants that are unable to bind DNA display hallmarks of liquid-liquid phase separation, including dynamic fusions of individual condensates to produce large droplets. We propose that the DNA template serves as a scaffold for the formation of Hes condensates, but limits the spread of transcriptional repressors to unwanted regions of the genome.
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Affiliation(s)
- Nicholas Treen
- grid.16750.350000 0001 2097 5006Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ USA
| | - Shunsuke F. Shimobayashi
- grid.16750.350000 0001 2097 5006Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ USA
| | - Jorine Eeftens
- grid.16750.350000 0001 2097 5006Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ USA
| | - Clifford P. Brangwynne
- grid.16750.350000 0001 2097 5006Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ USA ,grid.16750.350000 0001 2097 5006Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ USA ,grid.413575.10000 0001 2167 1581Howard Hughes Medical Institute, Chevy Chase, MD USA
| | - Michael Levine
- grid.16750.350000 0001 2097 5006Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ USA ,grid.16750.350000 0001 2097 5006Department of Molecular Biology, Princeton University, Princeton, NJ USA
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30
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Esposito M, Fang C, Cook KC, Park N, Wei Y, Spadazzi C, Bracha D, Gunaratna RT, Laevsky G, DeCoste CJ, Slabodkin H, Brangwynne CP, Cristea IM, Kang Y. TGF-β-induced DACT1 biomolecular condensates repress Wnt signalling to promote bone metastasis. Nat Cell Biol 2021; 23:257-267. [PMID: 33723425 PMCID: PMC7970447 DOI: 10.1038/s41556-021-00641-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 01/26/2021] [Indexed: 02/07/2023]
Abstract
The complexity of intracellular signalling requires both a diversity of molecular players and the sequestration of activity to unique compartments within the cell. Recent findings on the role of liquid-liquid phase separation provide a distinct mechanism for the spatial segregation of proteins to regulate signalling pathway crosstalk. Here, we discover that DACT1 is induced by TGFβ and forms protein condensates in the cytoplasm to repress Wnt signalling. These condensates do not localize to any known organelles but, rather, exist as phase-separated proteinaceous cytoplasmic bodies. The deletion of intrinsically disordered domains within the DACT1 protein eliminates its ability to both form protein condensates and suppress Wnt signalling. Isolation and mass spectrometry analysis of these particles revealed a complex of protein machinery that sequesters casein kinase 2-a Wnt pathway activator. We further demonstrate that DACT1 condensates are maintained in vivo and that DACT1 is critical to breast and prostate cancer bone metastasis.
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Affiliation(s)
- Mark Esposito
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Cao Fang
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Katelyn C Cook
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Nana Park
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Yong Wei
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Chiara Spadazzi
- Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Dan Bracha
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Ramesh T Gunaratna
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Gary Laevsky
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | | | - Hannah Slabodkin
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, USA
| | - Ileana M Cristea
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Yibin Kang
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA.
- Cancer Metabolism and Growth Program, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.
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31
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Riback JA, Lee DS, Eeftens JM, Sanders DW, Beckers L, Brangwynne CP. Spatially Constrained Transcriptional Sources Drive Asphericity of Intracellular Liquids. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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32
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Lee DS, Wingreen NS, Brangwynne CP. Chromatin Mechanics Dictates Subdiffusion and Coarsening Dynamics of Embedded Condensates. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.2012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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33
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Statt A, Casademunt H, Brangwynne CP, Panagiotopoulos AZ. Model for disordered proteins with strongly sequence-dependent liquid phase behavior. J Chem Phys 2020; 152:075101. [PMID: 32087632 DOI: 10.1063/1.5141095] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Phase separation of intrinsically disordered proteins is important for the formation of membraneless organelles or biomolecular condensates, which play key roles in the regulation of biochemical processes within cells. In this work, we investigated the phase separation of different sequences of a coarse-grained model for intrinsically disordered proteins and discovered a surprisingly rich phase behavior. We studied both the fraction of total hydrophobic parts and the distribution of hydrophobic parts. Not surprisingly, sequences with larger hydrophobic fractions showed conventional liquid-liquid phase separation. The location of the critical point was systematically influenced by the terminal beads of the sequence due to changes in interfacial composition and tension. For sequences with lower hydrophobicity, we observed not only conventional liquid-liquid phase separation but also re-entrant phase behavior in which the liquid phase density decreases at lower temperatures. For some sequences, we observed the formation of open phases consisting of aggregates, rather than a normal liquid. These aggregates had overall lower densities than the conventional liquid phases and exhibited complex geometries with large interconnected string-like or membrane-like clusters. Our findings suggest that minor alterations in the ordering of residues may lead to large changes in the phase behavior of the protein, a fact of significant potential relevance for biology.
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Affiliation(s)
- Antonia Statt
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Helena Casademunt
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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34
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Wei MT, Chang YC, Shimobayashi SF, Shin Y, Strom AR, Brangwynne CP. Nucleated transcriptional condensates amplify gene expression. Nat Cell Biol 2020; 22:1187-1196. [DOI: 10.1038/s41556-020-00578-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 08/14/2020] [Indexed: 02/07/2023]
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35
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Sanders DW, Kedersha N, Lee DSW, Strom AR, Drake V, Riback JA, Bracha D, Eeftens JM, Iwanicki A, Wang A, Wei MT, Whitney G, Lyons SM, Anderson P, Jacobs WM, Ivanov P, Brangwynne CP. Competing Protein-RNA Interaction Networks Control Multiphase Intracellular Organization. Cell 2020; 181:306-324.e28. [PMID: 32302570 PMCID: PMC7816278 DOI: 10.1016/j.cell.2020.03.050] [Citation(s) in RCA: 408] [Impact Index Per Article: 102.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 10/24/2019] [Accepted: 03/20/2020] [Indexed: 12/22/2022]
Abstract
Liquid-liquid phase separation (LLPS) mediates formation of membraneless condensates such as those associated with RNA processing, but the rules that dictate their assembly, substructure, and coexistence with other liquid-like compartments remain elusive. Here, we address the biophysical mechanism of this multiphase organization using quantitative reconstitution of cytoplasmic stress granules (SGs) with attached P-bodies in human cells. Protein-interaction networks can be viewed as interconnected complexes (nodes) of RNA-binding domains (RBDs), whose integrated RNA-binding capacity determines whether LLPS occurs upon RNA influx. Surprisingly, both RBD-RNA specificity and disordered segments of key proteins are non-essential, but modulate multiphase condensation. Instead, stoichiometry-dependent competition between protein networks for connecting nodes determines SG and P-body composition and miscibility, while competitive binding of unconnected proteins disengages networks and prevents LLPS. Inspired by patchy colloid theory, we propose a general framework by which competing networks give rise to compositionally specific and tunable condensates, while relative linkage between nodes underlies multiphase organization.
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Affiliation(s)
- David W Sanders
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Nancy Kedersha
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Daniel S W Lee
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Amy R Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Victoria Drake
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Joshua A Riback
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Dan Bracha
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Jorine M Eeftens
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Allana Iwanicki
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Alicia Wang
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Ming-Tzo Wei
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Gena Whitney
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Shawn M Lyons
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Paul Anderson
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - William M Jacobs
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton, NJ 08544, USA.
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36
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Affiliation(s)
- Joshua A Riback
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA. .,Howard Hughes Medical Institute, Princeton University, Princeton, NJ, USA
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37
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Bracha D, Walls MT, Brangwynne CP. Probing and engineering liquid-phase organelles. Nat Biotechnol 2019; 37:1435-1445. [DOI: 10.1038/s41587-019-0341-6] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/28/2019] [Indexed: 01/02/2023]
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38
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Abstract
Cells organize membrane-less internal compartments through a process called liquid-liquid phase separation (LLPS) to create chemically distinct compartments, referred to as condensates, which emerge from interactions among biological macromolecules. These condensates include various cytoplasmic structures such as P-granules and stress granules. However, an even wider array of condensates subcompartmentalize the cell nucleus, forming liquid-like structures that range from nucleoli and Cajal bodies to nuclear speckles and gems. Phase separation provides a biophysical assembly mechanism underlying this non-covalent form of fluid compartmentalization and functionalization. In this Cell Science at a Glance article and the accompanying poster, we term these phase-separated liquids that organize the nucleus the liquid nucleome; we discuss examples of biological phase transitions in the nucleus, how the cell utilizes biophysical aspects of phase separation to form and regulate condensates, and suggest interpretations for the role of phase separation in nuclear organization and function.
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Affiliation(s)
- Amy R Strom
- Department of Chemical and Biological Engineering, Howard Hughes Medical Institute, Princeton University, Princeton NJ 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Howard Hughes Medical Institute, Princeton University, Princeton NJ 08544, USA
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39
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Taylor NO, Wei MT, Stone HA, Brangwynne CP. Quantifying Dynamics in Phase-Separated Condensates Using Fluorescence Recovery after Photobleaching. Biophys J 2019; 117:1285-1300. [PMID: 31540706 DOI: 10.1016/j.bpj.2019.08.030] [Citation(s) in RCA: 151] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 07/20/2019] [Accepted: 08/22/2019] [Indexed: 12/22/2022] Open
Abstract
Cells contain numerous membraneless organelles that assemble by intracellular liquid-liquid phase separation. The viscous properties and associated biomolecular mobility within these condensed phase droplets, or condensates, are increasingly recognized as important for cellular function and also dysfunction, for example, in protein aggregation pathologies. Fluorescence recovery after photobleaching (FRAP) is widely used to assess condensate fluidity and to estimate protein diffusion coefficients. However, the models and assumptions utilized in FRAP analysis of protein condensates are often not carefully considered. Here, we combine FRAP experiments on both in vitro reconstituted droplets and intracellular condensates with systematic examination of different models that can be used to fit the data and evaluate the impact of model choice on measured values. A key finding is that model boundary conditions can give rise to widely divergent measured values. This has important implications, for example, in experiments that bleach subregions versus the entire condensate, two commonly employed experimental approaches. We suggest guidelines for determining the appropriate modeling framework and highlight emerging questions about the molecular dynamics at the droplet interface. The ability to accurately determine biomolecular mobility both in the condensate interior and at the interface is important for obtaining quantitative insights into condensate function, a key area for future research.
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Affiliation(s)
| | - Ming-Tzo Wei
- Department of Chemical and Biological Engineering
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering; Howard Hughes Medical Institute, Princeton University, Princeton, New Jersey.
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40
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Shin Y, Chang YC, Lee DSW, Berry J, Sanders DW, Ronceray P, Wingreen NS, Haataja M, Brangwynne CP. Liquid Nuclear Condensates Mechanically Sense and Restructure the Genome. Cell 2019; 176:1518. [PMID: 30849377 DOI: 10.1016/j.cell.2019.02.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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41
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Wei MT(S, Brangwynne CP. Sequence Determination of Liquid-Liquid Phase-Separated Assemblies of Engineered Disordered Proteins in Living Cells. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.2449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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42
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Bracha D, Walls MT, Wei MT, Zhu L, Kurian M, Avalos JL, Toettcher JE, Brangwynne CP. Mapping Local and Global Liquid Phase Behavior in Living Cells Using Photo-Oligomerizable Seeds. Cell 2019; 176:407. [PMID: 30633909 DOI: 10.1016/j.cell.2018.12.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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43
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Shin Y, Chang YC, Lee DSW, Berry J, Sanders DW, Ronceray P, Wingreen NS, Haataja M, Brangwynne CP. Liquid Nuclear Condensates Mechanically Sense and Restructure the Genome. Cell 2018; 175:1481-1491.e13. [PMID: 30500535 PMCID: PMC6724728 DOI: 10.1016/j.cell.2018.10.057] [Citation(s) in RCA: 373] [Impact Index Per Article: 62.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 09/28/2018] [Accepted: 10/26/2018] [Indexed: 01/19/2023]
Abstract
Phase transitions involving biomolecular liquids are a fundamental mechanism underlying intracellular organization. In the cell nucleus, liquid-liquid phase separation of intrinsically disordered proteins (IDPs) is implicated in assembly of the nucleolus, as well as transcriptional clusters, and other nuclear bodies. However, it remains unclear whether and how physical forces associated with nucleation, growth, and wetting of liquid condensates can directly restructure chromatin. Here, we use CasDrop, a novel CRISPR-Cas9-based optogenetic technology, to show that various IDPs phase separate into liquid condensates that mechanically exclude chromatin as they grow and preferentially form in low-density, largely euchromatic regions. A minimal physical model explains how this stiffness sensitivity arises from lower mechanical energy associated with deforming softer genomic regions. Targeted genomic loci can nonetheless be mechanically pulled together through surface tension-driven coalescence. Nuclear condensates may thus function as mechano-active chromatin filters, physically pulling in targeted genomic loci while pushing out non-targeted regions of the neighboring genome. VIDEO ABSTRACT.
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Affiliation(s)
- Yongdae Shin
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, South Korea
| | - Yi-Che Chang
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Daniel S W Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Joel Berry
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David W Sanders
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Pierre Ronceray
- Princeton Center for Theoretical Science, Princeton University, Princeton, NJ 08544, USA
| | - Ned S Wingreen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Mikko Haataja
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA.
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44
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Dine E, Gil AA, Uribe G, Brangwynne CP, Toettcher JE. Protein Phase Separation Provides Long-Term Memory of Transient Spatial Stimuli. Cell Syst 2018; 6:655-663.e5. [PMID: 29859829 PMCID: PMC6023754 DOI: 10.1016/j.cels.2018.05.002] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/29/2018] [Accepted: 05/02/2018] [Indexed: 12/13/2022]
Abstract
Protein/RNA clusters arise frequently in spatially regulated biological processes, from the asymmetric distribution of P granules and PAR proteins in developing embryos to localized receptor oligomers in migratory cells. This co-occurrence suggests that protein clusters might possess intrinsic properties that make them a useful substrate for spatial regulation. Here, we demonstrate that protein droplets show a robust form of spatial memory, maintaining the spatial pattern of an inhibitor of droplet formation long after it has been removed. Despite this persistence, droplets can be highly dynamic, continuously exchanging monomers with the diffuse phase. We investigate the principles of biophysical spatial memory in three contexts: a computational model of phase separation; a novel optogenetic system where light can drive rapid, localized dissociation of liquid-like protein droplets; and membrane-localized signal transduction from clusters of receptor tyrosine kinases. Our results suggest that the persistent polarization underlying many cellular and developmental processes could arise through a simple biophysical process, without any additional biochemical feedback loops.
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Affiliation(s)
- Elliot Dine
- Department of Molecular Biology, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Agnieszka A Gil
- Department of Molecular Biology, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Giselle Uribe
- Department of Molecular Biology, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Washington Road, Princeton, NJ 08544, USA.
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45
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Berry J, Brangwynne CP, Haataja M. Physical principles of intracellular organization via active and passive phase transitions. Rep Prog Phys 2018; 81:046601. [PMID: 29313527 DOI: 10.1088/1361-6633/aaa61e] [Citation(s) in RCA: 222] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Exciting recent developments suggest that phase transitions represent an important and ubiquitous mechanism underlying intracellular organization. We describe key experimental findings in this area of study, as well as the application of classical theoretical approaches for quantitatively understanding these data. We also discuss the way in which equilibrium thermodynamic driving forces may interface with the fundamentally out-of-equilibrium nature of living cells. In particular, time and/or space-dependent concentration profiles may modulate the phase behavior of biomolecules in living cells. We suggest future directions for both theoretical and experimental work that will shed light on the way in which biological activity modulates the assembly, properties, and function of viscoelastic states of living matter.
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Affiliation(s)
- Joel Berry
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, United States of America. Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, United States of America
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46
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Abstract
Phase transitions are ubiquitous in nonliving matter, and recent discoveries have shown that they also play a key role within living cells. Intracellular liquid-liquid phase separation is thought to drive the formation of condensed liquid-like droplets of protein, RNA, and other biomolecules, which form in the absence of a delimiting membrane. Recent studies have elucidated many aspects of the molecular interactions underlying the formation of these remarkable and ubiquitous droplets and the way in which such interactions dictate their material properties, composition, and phase behavior. Here, we review these exciting developments and highlight key remaining challenges, particularly the ability of liquid condensates to both facilitate and respond to biological function and how their metastability may underlie devastating protein aggregation diseases.
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Affiliation(s)
- Yongdae Shin
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
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47
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Affiliation(s)
- David W Sanders
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, 08540, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, 08540, USA
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48
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Shin Y, Berry J, Pannucci N, Haataja MP, Toettcher JE, Brangwynne CP. Spatiotemporal Control of Intracellular Phase Transitions Using Light-Activated optoDroplets. Cell 2016; 168:159-171.e14. [PMID: 28041848 DOI: 10.1016/j.cell.2016.11.054] [Citation(s) in RCA: 531] [Impact Index Per Article: 66.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/20/2016] [Accepted: 11/28/2016] [Indexed: 11/28/2022]
Abstract
Phase transitions driven by intrinsically disordered protein regions (IDRs) have emerged as a ubiquitous mechanism for assembling liquid-like RNA/protein (RNP) bodies and other membrane-less organelles. However, a lack of tools to control intracellular phase transitions limits our ability to understand their role in cell physiology and disease. Here, we introduce an optogenetic platform that uses light to activate IDR-mediated phase transitions in living cells. We use this "optoDroplet" system to study condensed phases driven by the IDRs of various RNP body proteins, including FUS, DDX4, and HNRNPA1. Above a concentration threshold, these constructs undergo light-activated phase separation, forming spatiotemporally definable liquid optoDroplets. FUS optoDroplet assembly is fully reversible even after multiple activation cycles. However, cells driven deep within the phase boundary form solid-like gels that undergo aging into irreversible aggregates. This system can thus elucidate not only physiological phase transitions but also their link to pathological aggregates.
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Affiliation(s)
- Yongdae Shin
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Joel Berry
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Nicole Pannucci
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Mikko P Haataja
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.
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Taylor N, Elbaum-Garfinkle S, Vaidya N, Zhang H, Stone HA, Brangwynne CP. Biophysical characterization of organelle-based RNA/protein liquid phases using microfluidics. Soft Matter 2016; 12:9142-9150. [PMID: 27791212 PMCID: PMC6724727 DOI: 10.1039/c6sm01087c] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Living cells contain numerous membrane-less RNA/protein (RNP) bodies that assemble by intracellular liquid-liquid phase separation. The properties of these condensed phase droplets are increasingly recognized as important in their physiological function within living cells, and also through the link to protein aggregation pathologies. However, techniques such as droplet coalescence analysis or standard microrheology do not always enable robust property measurements of model RNA/protein droplets in vitro. Here, we introduce a microfluidic platform that drives protein droplets into a single large phase, which facilitates viscosity measurements using passive microrheology and/or active two-phase flow analysis. We use this technique to study various phase separating proteins from structures including P granules, nucleoli, and Whi3 droplets. In each case, droplets exhibit simple liquid behavior, with shear rate-independent viscosities, over observed timescales. Interestingly, we find that a reported order of magnitude difference between the timescale of Whi3 and LAF-1 droplet coalescence is driven by large differences in surface tension rather than viscosity, with implications for droplet assembly and function. The ability to simultaneously perform active and passive microrheological measurements enables studying the impact of ATP-dependent biological activity on RNP droplets, which is a key area for future research.
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Affiliation(s)
- Nicole Taylor
- Department of Chemical and Biological Engineering, Princeton University, USA.
| | | | - Nilesh Vaidya
- Department of Chemical and Biological Engineering, Princeton University, USA.
| | - Huaiying Zhang
- Department of Chemical and Biological Engineering, Princeton University, USA.
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, USA
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