1
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Zhang Z, Ji J, Hossain MS, Bailey B, Nangia S, Mozhdehi D. Lipidation alters the phase-separation of resilin-like polypeptides. SOFT MATTER 2024; 20:4007-4014. [PMID: 38690757 PMCID: PMC11095499 DOI: 10.1039/d4sm00358f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 04/16/2024] [Indexed: 05/03/2024]
Abstract
Biology exploits biomacromolecular phase separation to form condensates, known as membraneless organelles. Despite significant advancements in deciphering sequence determinants for phase separation, modulating these features in vivo remains challenging. A promising approach inspired by biology is to use post-translational modifications (PTMs)-to modulate the amino acid physicochemistry instead of altering protein sequences-to control the formation and characteristics of condensates. However, despite the identification of more than 300 types of PTMs, the detailed understanding of how they influence the formation and material properties of protein condensates remains incomplete. In this study, we investigated how modification with myristoyl lipid alters the formation and characteristics of the resilin-like polypeptide (RLP) condensates, a prototypical disordered protein with upper critical solution temperature (UCST) phase behaviour. Using turbidimetry, dynamic light scattering, confocal and electron microscopy, we demonstrated that lipidation-in synergy with the sequence of the lipidation site-significantly influences RLPs' thermodynamic propensity for phase separation and their condensate properties. Molecular simulations suggested these effects result from an expanded hydrophobic region created by the interaction between the lipid and lipidation site rather than changes in peptide rigidity. These findings emphasize the role of "sequence context" in modifying the properties of PTMs, suggesting that variations in lipidation sequences could be strategically used to fine-tune the effect of these motifs. Our study advances understanding of lipidation's impact on UCST phase behaviour, relevant to proteins critical in biological processes and diseases, and opens avenues for designing lipidated resilins for biomedical applications like heat-mediated drug elution.
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Affiliation(s)
- Zhe Zhang
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, USA.
| | - Jingjing Ji
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, USA.
| | | | - Briah Bailey
- Department of Biomedical Engineering, Augusta University, Augusta, Georgia 30912, USA
| | - Shikha Nangia
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, USA.
| | - Davoud Mozhdehi
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, USA.
- BioInspired Syracuse: Institute for Material and Living Systems, Syracuse University, Syracuse, NY 13244, USA
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2
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Tiemann JKS, Szczuka M, Bouarroudj L, Oussaren M, Garcia S, Howard RJ, Delemotte L, Lindahl E, Baaden M, Lindorff-Larsen K, Chavent M, Poulain P. MDverse: Shedding Light on the Dark Matter of Molecular Dynamics Simulations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.02.538537. [PMID: 37205542 PMCID: PMC10187166 DOI: 10.1101/2023.05.02.538537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The rise of open science and the absence of a global dedicated data repository for molecular dynamics (MD) simulations has led to the accumulation of MD files in generalist data repositories, constituting the dark matter of MD - data that is technically accessible, but neither indexed, curated, or easily searchable. Leveraging an original search strategy, we found and indexed about 250,000 files and 2,000 datasets from Zenodo, Figshare and Open Science Framework. With a focus on files produced by the Gromacs MD software, we illustrate the potential offered by the mining of publicly available MD data. We identified systems with specific molecular composition and were able to characterize essential parameters of MD simulation such as temperature and simulation length, and could identify model resolution, such as all-atom and coarse-grain. Based on this analysis, we inferred metadata to propose a search engine prototype to explore the MD data. To continue in this direction, we call on the community to pursue the effort of sharing MD data, and to report and standardize metadata to reuse this valuable matter.
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3
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Thirumalai D, Kumar A, Chakraborty D, Straub JE, Mugnai ML. Conformational fluctuations and phases in fused in sarcoma (FUS) low-complexity domain. Biopolymers 2024; 115:e23558. [PMID: 37399327 PMCID: PMC10831756 DOI: 10.1002/bip.23558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/30/2023] [Accepted: 06/15/2023] [Indexed: 07/05/2023]
Abstract
The well-known phenomenon of phase separation in synthetic polymers and proteins has become a major topic in biophysics because it has been invoked as a mechanism of compartment formation in cells, without the need for membranes. Most of the coacervates (or condensates) are composed of Intrinsically Disordered Proteins (IDPs) or regions that are structureless, often in interaction with RNA and DNA. One of the more intriguing IDPs is the 526-residue RNA-binding protein, Fused in Sarcoma (FUS), whose monomer conformations and condensates exhibit unusual behavior that are sensitive to solution conditions. By focussing principally on the N-terminus low-complexity domain (FUS-LC comprising residues 1-214) and other truncations, we rationalize the findings of solid-state NMR experiments, which show that FUS-LC adopts a non-polymorphic fibril structure (core-1) involving residues 39-95, flanked by fuzzy coats on both the N- and C-terminal ends. An alternate structure (core-2), whose free energy is comparable to core-1, emerges only in the truncated construct (residues 110-214). Both core-1 and core-2 fibrils are stabilized by a Tyrosine ladder as well as hydrophilic interactions. The morphologies (gels, fibrils, and glass-like) adopted by FUS seem to vary greatly, depending on the experimental conditions. The effect of phosphorylation is site-specific. Simulations show that phosphorylation of residues within the fibril has a greater destabilization effect than residues that are outside the fibril region, which accords well with experiments. Many of the peculiarities associated with FUS may also be shared by other IDPs, such as TDP43 and hnRNPA2. We outline a number of problems for which there is no clear molecular explanation.
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Affiliation(s)
- D Thirumalai
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
- Department of Physics, The University of Texas at Austin, Austin, Texas, USA
| | - Abhinaw Kumar
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
| | - Debayan Chakraborty
- Department of Chemistry, The University of Texas at Austin, Austin, Texas, USA
| | - John E Straub
- Department of Chemistry, Boston University, Boston, Massachusetts, USA
| | - Mauro L Mugnai
- Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC, USA
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4
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Wei W, Liu Y, Shen Y, Yang T, Dong Y, Han Z, Wang Y, Liu Z, Chai Y, Zhang M, Wang H, Shen H, Shen Y, Chen M. In situ tissue profile of rat trigeminal nerve in trigeminal neuralgia using spatial transcriptome sequencing. Int J Surg 2024; 110:1463-1474. [PMID: 38270619 PMCID: PMC10942187 DOI: 10.1097/js9.0000000000001110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 01/08/2024] [Indexed: 01/26/2024]
Abstract
BACKGROUND Trigeminal neuralgia (TN) is the most common neuropathic disorder in the maxillofacial region. The etiology and pathogenesis of TN have not been clearly determined to date, although there are many hypotheses. OBJECTIVE The goal of this study was to investigate the interactions between different types of cells in TN, particularly the impact and intrinsic mechanism of demyelination on the trigeminal ganglion, and to identify new important target genes and regulatory pathways in TN. METHODS TN rat models were prepared by trigeminal root compression, and trigeminal nerve tissues were isolated for spatial transcriptome sequencing. The gene expression matrix was reduced dimensionally by PCA and presented by UMAP. Gene function annotation was analyzed by Metascape. The progression of certain clusters and the developmental pseudotime were analyzed using the Monocle package. Modules of the gene coexpression network between different groups were analyzed based on weighted gene coexpression network analysis and assigned AddModuleScore values. The intercellular communication of genes in these networks via ligand-receptor interactions was analyzed using CellPhoneDB analysis. RESULTS The results suggested that the trigeminal ganglion could affect Schwann cell demyelination and remyelination responses through many ligand-receptor interactions, while the effect of Schwann cells on the trigeminal ganglion was much weaker. Additionally, ferroptosis may be involved in the demyelination of Schwann cells. CONCLUSIONS This study provides spatial transcriptomics sequencing data on TN, reveals new markers, and redefines the relationship between the ganglion and myelin sheath, providing a theoretical basis and supporting data for future mechanistic research and drug development.
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Affiliation(s)
- Wenbin Wei
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | - Yuemin Liu
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | | | - Tao Yang
- Department of Medical Cosmetology, Suzhou, Jiangsu, People’s Republic of China
| | - Yabing Dong
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | - Zixiang Han
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | - Yiwen Wang
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | - Zhiyang Liu
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | - Ying Chai
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | - Mengjie Zhang
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | - Hanshao Wang
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
| | - Hao Shen
- Clinical Laboratory, Suzhou Ninth People’s Hospital
| | | | - Minjie Chen
- Department of Oral Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai
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5
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Mohanty P, Rizuan A, Kim YC, Fawzi NL, Mittal J. A complex network of interdomain interactions underlies the conformational ensemble of monomeric TDP-43 and modulates its phase behavior. Protein Sci 2024; 33:e4891. [PMID: 38160320 PMCID: PMC10804676 DOI: 10.1002/pro.4891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 12/07/2023] [Accepted: 12/28/2023] [Indexed: 01/03/2024]
Abstract
TAR DNA-binding protein 43 (TDP-43) is a multidomain protein involved in the regulation of RNA metabolism, and its aggregates have been observed in neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Numerous studies indicate TDP-43 can undergo liquid-liquid phase separation (LLPS) in vitro and is a component of biological condensates. Homo-oligomerization via the folded N-terminal domain (aa:1-77) and the conserved helical region (aa:319-341) of the disordered, C-terminal domain is found to be an important driver of TDP-43 phase separation. However, a comprehensive molecular view of TDP-43 phase separation, particularly regarding the nature of heterodomain interactions, is lacking due to the challenges associated with its stability and purification. Here, we utilize all-atom and coarse-grained (CG) molecular dynamics (MD) simulations to uncover the network of interdomain interactions implicated in TDP-43 phase separation. All-atom simulations uncovered the presence of transient, interdomain interactions involving flexible linkers, RNA-recognition motif (RRM) domains and a charged segment of disordered C-terminal domain (CTD). CG simulations indicate these inter-domain interactions which affect the conformational landscape of TDP-43 in the dilute phase are also prevalent in the condensed phase. Finally, sequence and surface charge distribution analysis coupled with all-atom simulations (at high salt) confirmed that the transient interdomain contacts are predominantly electrostatic in nature. Overall, our findings from multiscale simulations lead to a greater appreciation of the complex interaction network underlying the structural landscape and phase separation of TDP-43.
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Affiliation(s)
- Priyesh Mohanty
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTexasUSA
| | - Azamat Rizuan
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTexasUSA
| | - Young C. Kim
- Naval Research LaboratoryCenter for Materials Physics and TechnologyWashingtonDistrict of ColumbiaUSA
| | - Nicolas L. Fawzi
- Department of Molecular Biology, Cell Biology and BiochemistryProvidenceRhode IslandUSA
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTexasUSA
- Department of ChemistryTexas A&M UniversityCollege StationTexasUSA
- Interdisciplinary Graduate Program in Genetics and GenomicsTexas A&M UniversityCollege StationTexasUSA
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6
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Elena-Real CA, Mier P, Sibille N, Andrade-Navarro MA, Bernadó P. Structure-function relationships in protein homorepeats. Curr Opin Struct Biol 2023; 83:102726. [PMID: 37924569 DOI: 10.1016/j.sbi.2023.102726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 11/06/2023]
Abstract
Homorepeats (or polyX), protein segments containing repetitions of the same amino acid, are abundant in proteomes from all kingdoms of life and are involved in crucial biological functions as well as several neurodegenerative and developmental diseases. Mainly inserted in disordered segments of proteins, the structure/function relationships of homorepeats remain largely unexplored. In this review, we summarize present knowledge for the most abundant homorepeats, highlighting the role of the inherent structure and the conformational influence exerted by their flanking regions. Recent experimental and computational methods enable residue-specific investigations of these regions and promise novel structural and dynamic information for this elusive group of proteins. This information should increase our knowledge about the structural bases of phenomena such as liquid-liquid phase separation and trinucleotide repeat disorders.
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Affiliation(s)
- Carlos A Elena-Real
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS. 29 rue de Navacelles, 34090 Montpellier, France. https://twitter.com/carloselenareal
| | - Pablo Mier
- Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University Mainz. Hans-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Nathalie Sibille
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS. 29 rue de Navacelles, 34090 Montpellier, France
| | - Miguel A Andrade-Navarro
- Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University Mainz. Hans-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Pau Bernadó
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS. 29 rue de Navacelles, 34090 Montpellier, France.
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7
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O’Connell LC, Johnson V, Hutton AK, Otis JP, Murthy AC, Liang MC, Wang SH, Fawzi NL, Mowry KL. Intrinsically disordered regions and RNA binding domains contribute to protein enrichment in biomolecular condensates in Xenopus oocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.10.566489. [PMID: 37986933 PMCID: PMC10659413 DOI: 10.1101/2023.11.10.566489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Proteins containing both intrinsically disordered regions (IDRs) and RNA binding domains (RBDs) can phase separate in vitro, forming bodies similar to cellular biomolecular condensates. However, how IDR and RBD domains contribute to in vivo recruitment of proteins to biomolecular condensates remains poorly understood. Here, we analyzed the roles of IDRs and RBDs in L-bodies, biomolecular condensates present in Xenopus oocytes. We show that a cytoplasmic isoform of hnRNPAB, which contains two RBDs and an IDR, is highly enriched in L-bodies. While both of these domains contribute to hnRNPAB self-association and phase separation in vitro and mediate enrichment into L-bodies in oocytes, neither the RBDs nor the IDR replicate the localization of full-length hnRNPAB. Our results suggest a model where the additive effects of the IDR and RBDs regulate hnRNPAB partitioning into L-bodies. This model likely has widespread applications as proteins containing RBD and IDR domains are common biomolecular condensate residents.
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Affiliation(s)
- Liam C. O’Connell
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
| | - Victoria Johnson
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
| | - Anika K. Hutton
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
| | - Jessica P. Otis
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
| | - Anastasia C. Murthy
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
| | - Mark C. Liang
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
| | - Szu-Huan Wang
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
| | - Nicolas L. Fawzi
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
| | - Kimberly L. Mowry
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University Providence, RI 02912, USA
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8
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Oh C, Buckley PM, Choi J, Hierro A, DiMaio D. Sequence-independent activity of a predicted long disordered segment of the human papillomavirus type 16 L2 capsid protein during virus entry. Proc Natl Acad Sci U S A 2023; 120:e2307721120. [PMID: 37819982 PMCID: PMC10589650 DOI: 10.1073/pnas.2307721120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 08/28/2023] [Indexed: 10/13/2023] Open
Abstract
The activity of proteins is thought to be invariably determined by their amino acid sequence or composition, but we show that a long segment of a viral protein can support infection independent of its sequence or composition. During virus entry, the papillomavirus L2 capsid protein protrudes through the endosome membrane into the cytoplasm to bind cellular factors such as retromer required for intracellular virus trafficking. Here, we show that an ~110 amino acid segment of L2 is predicted to be disordered and that large deletions in this segment abolish infectivity of HPV16 pseudoviruses by inhibiting cytoplasmic protrusion of L2, association with retromer, and proper virus trafficking. The activity of these mutants can be restored by insertion of protein segments with diverse sequences, compositions, and chemical properties, including scrambled amino acid sequences, a tandem array of a short sequence, and the intrinsically disordered region of an unrelated cellular protein. The infectivity of mutants with small in-frame deletions in this segment directly correlates with the size of the segment. These results indicate that the length of the disordered segment, not its sequence or composition, determines its activity during HPV16 pseudovirus infection. We propose that a minimal length of L2 is required for it to protrude far enough into the cytoplasm to bind cytoplasmic trafficking factors, but the sequence of this segment is largely irrelevant. Thus, protein segments can carry out complex biological functions such as Human papillomavirus pseudovirus infection in a sequence-independent manner. This finding has important implications for protein function and evolution.
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Affiliation(s)
- Changin Oh
- Department of Genetics, Yale School of Medicine, New Haven, CT06520-8005
| | - Patrick M. Buckley
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT06536-0812
| | - Jeongjoon Choi
- Department of Genetics, Yale School of Medicine, New Haven, CT06520-8005
| | - Aitor Hierro
- Center for Cooperative Research in Biosciences, Bilbao, Derio48160, Spain
- Basque Foundation for Science, Bilbao48009, Spain
| | - Daniel DiMaio
- Department of Genetics, Yale School of Medicine, New Haven, CT06520-8005
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT06520-8040
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT06520-8024
- Yale Cancer Center, New Haven, CT06520-8028
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9
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Szała-Mendyk B, Phan TM, Mohanty P, Mittal J. Challenges in studying the liquid-to-solid phase transitions of proteins using computer simulations. Curr Opin Chem Biol 2023; 75:102333. [PMID: 37267850 PMCID: PMC10527940 DOI: 10.1016/j.cbpa.2023.102333] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/24/2023] [Accepted: 04/30/2023] [Indexed: 06/04/2023]
Abstract
"Membraneless organelles," also referred to as biomolecular condensates, perform a variety of cellular functions and their dysregulation is implicated in cancer and neurodegeneration. In the last two decades, liquid-liquid phase separation (LLPS) of intrinsically disordered and multidomain proteins has emerged as a plausible mechanism underlying the formation of various biomolecular condensates. Further, the occurrence of liquid-to-solid transitions within liquid-like condensates may give rise to amyloid structures, implying a biophysical link between phase separation and protein aggregation. Despite significant advances, uncovering the microscopic details of liquid-to-solid phase transitions using experiments remains a considerable challenge and presents an exciting opportunity for the development of computational models which provide valuable, complementary insights into the underlying phenomenon. In this review, we first highlight recent biophysical studies which provide new insights into the molecular mechanisms underlying liquid-to-solid (fibril) phase transitions of folded, disordered and multi-domain proteins. Next, we summarize the range of computational models used to study protein aggregation and phase separation. Finally, we discuss recent computational approaches which attempt to capture the underlying physics of liquid-to-solid transitions along with their merits and shortcomings.
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Affiliation(s)
- Beata Szała-Mendyk
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, TAMU 3127, College Station, 77843, Texas, United States.
| | - Tien Minh Phan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, TAMU 3127, College Station, 77843, Texas, United States.
| | - Priyesh Mohanty
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, TAMU 3127, College Station, 77843, Texas, United States.
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, TAMU 3127, College Station, 77843, Texas, United States; Department of Chemistry, Texas A&M University, TAMU 3255, College Station, 77843, Texas, United States; Interdisciplinary Graduate Program in Genetics and Genomics, Texas A&M University, TAMU 3255, College Station, 77843, Texas, United States.
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10
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Thirumalai D, Kumar A, Chakraborty D, Straub JE, Mugnai ML. Conformational Fluctuations and Phases in Fused in Sarcoma (FUS) Low-Complexity Domain. ARXIV 2023:arXiv:2303.04215v2. [PMID: 36945688 PMCID: PMC10029050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The well known phenomenon of phase separation in synthetic polymers and proteins has become a major topic in biophysics because it has been invoked as a mechanism of compartment formation in cells, without the need for membranes. Most of the coacervates (or condensates) are composed of Intrinsically Disordered Proteins (IDPs) or regions that are structureless, often in interaction with RNA and DNA. One of the more intriguing IDPs is the 526-residue RNA binding protein, Fused In Sarcoma (FUS), whose monomer conformations and condensates exhibit unusual behavior that are sensitive to solution conditions. By focussing principally on the N-terminus low complexity domain (FUS-LC comprising residues 1-214) and other truncations, we rationalize the findings of solid state NMR experiments, which show that FUS-LC adopts a non-polymorphic fibril (core-1) involving residues 39-95, flanked by fuzzy coats on both the N- and C- terminal ends. An alternate structure (core-2), whose free energy is comparable to core-1, emerges only in the truncated construct (residues 110-214). Both core-1 and core-2 fibrils are stabilized by a Tyrosine ladder as well as hydrophilic interactions. The morphologies (gels, fibrils, and glass-like behavior) adopted by FUS seem to vary greatly, depending on the experimental conditions. The effect of phosphorylation is site specific and affects the stability of the fibril depending on the sites that are phosphorylated. Many of the peculiarities associated with FUS may also be shared by other IDPs, such as TDP43 and hnRNPA2. We outline a number of problems for which there is no clear molecular understanding.
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Affiliation(s)
- D Thirumalai
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
- Department of Physics, The University of Texas at Austin, Austin, TX 78712
| | - Abhinaw Kumar
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - Debayan Chakraborty
- Department of Chemistry, The University of Texas at Austin, Austin, TX 78712
| | - John E Straub
- Department of Chemistry, Boston University, Boston, MA 78712
| | - Mauro L Mugnai
- Institute of Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC 20057
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11
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Guseva S, Schnapka V, Adamski W, Maurin D, Ruigrok RWH, Salvi N, Blackledge M. Liquid-Liquid Phase Separation Modifies the Dynamic Properties of Intrinsically Disordered Proteins. J Am Chem Soc 2023; 145:10548-10563. [PMID: 37146977 DOI: 10.1021/jacs.2c13647] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Liquid-liquid phase separation of flexible biomolecules has been identified as a ubiquitous phenomenon underlying the formation of membraneless organelles that harbor a multitude of essential cellular processes. We use nuclear magnetic resonance (NMR) spectroscopy to compare the dynamic properties of an intrinsically disordered protein (measles virus NTAIL) in the dilute and dense phases at atomic resolution. By measuring 15N NMR relaxation at different magnetic field strengths, we are able to characterize the dynamics of the protein in dilute and crowded conditions and to compare the amplitude and timescale of the different motional modes to those present in the membraneless organelle. Although the local backbone conformational sampling appears to be largely retained, dynamics occurring on all detectable timescales, including librational, backbone dihedral angle dynamics and segmental, chainlike motions, are considerably slowed down. Their relative amplitudes are also drastically modified, with slower, chain-like motions dominating the dynamic profile. In order to provide additional mechanistic insight, we performed extensive molecular dynamics simulations of the protein under self-crowding conditions at concentrations comparable to those found in the dense liquid phase. Simulation broadly reproduces the impact of formation of the condensed phase on both the free energy landscape and the kinetic interconversion between states. In particular, the experimentally observed reduction in the amplitude of the fastest component of backbone dynamics correlates with higher levels of intermolecular contacts or entanglement observed in simulations, reducing the conformational space available to this mode under strongly self-crowding conditions.
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Affiliation(s)
- Serafima Guseva
- Institut de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38000 Grenoble, France
| | - Vincent Schnapka
- Institut de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38000 Grenoble, France
| | - Wiktor Adamski
- Institut de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38000 Grenoble, France
| | - Damien Maurin
- Institut de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38000 Grenoble, France
| | - Rob W H Ruigrok
- Institut de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38000 Grenoble, France
| | - Nicola Salvi
- Institut de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38000 Grenoble, France
| | - Martin Blackledge
- Institut de Biologie Structurale, Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38000 Grenoble, France
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12
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Farshad M, DelloStritto MJ, Suma A, Carnevale V. Detecting Liquid-Liquid Phase Separations Using Molecular Dynamics Simulations and Spectral Clustering. J Phys Chem B 2023; 127:3682-3689. [PMID: 37053472 DOI: 10.1021/acs.jpcb.3c00805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
A stringent test of the accuracy of empirical force fields is reproducing the phase diagram of bulk phases and mixtures. Exploring the phase diagram of mixtures requires the detection of phase boundaries and critical points. In contrast to most solid-liquid transitions, in which a global order parameter (average density) can be used to discriminate between two phases, some demixing transitions entail relatively subtle changes in the local environment of each molecule. In such cases, finite sampling errors and finite-size effects make the identification of trends in local order parameters extremely challenging. Here we analyze one such example, namely a methanol/hexane mixture, and compute several local and global structural properties. We simulate the system at various temperatures and study the structural changes associated with demixing. We show that despite a seemingly continuous transformation between mixed and demixed states, the topological properties of the H-bond network change abruptly as the system crosses the demixing line. In particular, by using spectral clustering, we show that the distribution of cluster sizes develops a fat tail (as expected from percolation theory) in the vicinity of the critical point. We illustrate a simple criterion to identify this behavior, which results from the emergence of large system-spanning clusters from a collection of aggregates. We further tested the spectral clustering analysis on a Lennard-Jones system as a standard example of a system with no H-bonds, and also, in this case, we were able to detect the demixing transition.
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Affiliation(s)
- Mohsen Farshad
- Institute for Computational Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Mark J DelloStritto
- Institute for Computational Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Antonio Suma
- Institute for Computational Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
- Dipartimento di Fisica, Università di Bari, 70121 Bari, Italy
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, Pennsylvania 19122, United States
- Department of Biology, Temple University, Philadelphia, Pennsylvania 19122, United States
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13
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Zeng X, Pappu RV. Developments in describing equilibrium phase transitions of multivalent associative macromolecules. Curr Opin Struct Biol 2023; 79:102540. [PMID: 36804705 PMCID: PMC10732938 DOI: 10.1016/j.sbi.2023.102540] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/24/2022] [Accepted: 01/16/2023] [Indexed: 02/18/2023]
Abstract
Biomolecular condensates are distinct cellular bodies that form and dissolve reversibly to organize cellular matter and biochemical reactions in space and time. Condensates are thought to form and dissolve under the influence of spontaneous and driven phase transitions of multivalent associative macromolecules. These include phase separation, which is defined by segregation of macromolecules from the solvent or from one another, and percolation or gelation, which is an inclusive networking transition driven by reversible associations among multivalent macromolecules. Considerable progress has been made to model sequence-specific phase transitions, especially for intrinsically disordered proteins. Here, we summarize the state-of-the-art of theories and computations aimed at understanding and modeling sequence-specific, thermodynamically controlled, coupled associative and segregative phase transitions of archetypal multivalent macromolecules.
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Affiliation(s)
- Xiangze Zeng
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, 63130, USA. https://twitter.com/@xiangzezeng
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO, 63130, USA.
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14
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Oh C, Buckley PM, Choi J, Hierro A, DiMaio D. Sequence independent activity of a predicted long disordered segment of the human papillomavirus L2 capsid protein during virus entry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.21.533711. [PMID: 36993745 PMCID: PMC10055320 DOI: 10.1101/2023.03.21.533711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
The papillomavirus L2 capsid protein protrudes through the endosome membrane into the cytoplasm during virus entry to bind cellular factors required for intracellular virus trafficking. Cytoplasmic protrusion of HPV16 L2, virus trafficking, and infectivity are inhibited by large deletions in an ∼110 amino acid segment of L2 that is predicted to be disordered. The activity of these mutants can be restored by inserting protein segments with diverse compositions and chemical properties into this region, including scrambled sequences, a tandem array of a short sequence, and the intrinsically disordered region of a cellular protein. The infectivity of mutants with small in-frame insertions and deletions in this segment directly correlates with the size of the segment. These results indicate that the length of the disordered segment, not its sequence or its composition, determines its activity during virus entry. Sequence independent but length dependent activity has important implications for protein function and evolution.
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15
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Staples MI, Frazer C, Fawzi NL, Bennett RJ. Phase separation in fungi. Nat Microbiol 2023; 8:375-386. [PMID: 36782025 PMCID: PMC10081517 DOI: 10.1038/s41564-022-01314-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 12/16/2022] [Indexed: 02/15/2023]
Abstract
Phase separation, in which macromolecules partition into a concentrated phase that is immiscible with a dilute phase, is involved with fundamental cellular processes across the tree of life. We review the principles of phase separation and highlight how it impacts diverse processes in the fungal kingdom. These include the regulation of autophagy, cell signalling pathways, transcriptional circuits and the establishment of asymmetry in fungal cells. We describe examples of stable, phase-separated assemblies including membraneless organelles such as the nucleolus as well as transient condensates that also arise through phase separation and enable cells to rapidly and reversibly respond to important environmental cues. We showcase how research into phase separation in model yeasts, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe, in conjunction with that in plant and human fungal pathogens, such as Ashbya gossypii and Candida albicans, is continuing to enrich our understanding of fundamental molecular processes.
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Affiliation(s)
- Mae I Staples
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Corey Frazer
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Nicolas L Fawzi
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Richard J Bennett
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA.
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16
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Structural ensembles of disordered proteins from hierarchical chain growth and simulation. Curr Opin Struct Biol 2023; 78:102501. [PMID: 36463772 DOI: 10.1016/j.sbi.2022.102501] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 12/03/2022]
Abstract
Disordered proteins and nucleic acids play key roles in cellular function and disease. Here, we review recent advances in the computational exploration of the conformational dynamics of flexible biomolecules. While atomistic molecular dynamics (MD) simulation has seen a lot of improvement in recent years, large-scale computing resources and careful validation are required to simulate full-length disordered biopolymers in solution. As a computationally efficient alternative, hierarchical chain growth (HCG) combines pre-sampled chain fragments in a statistically reproducible manner into ensembles of full-length atomically detailed biomolecular structures. Experimental data can be integrated during and after chain assembly. Applications to the neurodegeneration-linked proteins α-synuclein, tau, and TDP-43, including as condensate, illustrate the use of HCG. We conclude by highlighting the emerging connections to AI-based structural modeling including AlphaFold2.
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17
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Baruch Leshem A, Sloan-Dennison S, Massarano T, Ben-David S, Graham D, Faulds K, Gottlieb HE, Chill JH, Lampel A. Biomolecular condensates formed by designer minimalistic peptides. Nat Commun 2023; 14:421. [PMID: 36702825 PMCID: PMC9879991 DOI: 10.1038/s41467-023-36060-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 01/13/2023] [Indexed: 01/27/2023] Open
Abstract
Inspired by the role of intracellular liquid-liquid phase separation (LLPS) in formation of membraneless organelles, there is great interest in developing dynamic compartments formed by LLPS of intrinsically disordered proteins (IDPs) or short peptides. However, the molecular mechanisms underlying the formation of biomolecular condensates have not been fully elucidated, rendering on-demand design of synthetic condensates with tailored physico-chemical functionalities a significant challenge. To address this need, here we design a library of LLPS-promoting peptide building blocks composed of various assembly domains. We show that the LLPS propensity, dynamics, and encapsulation efficiency of compartments can be tuned by changes to the peptide composition. Specifically, with the aid of Raman and NMR spectroscopy, we show that interactions between arginine and aromatic amino acids underlie droplet formation, and that both intra- and intermolecular interactions dictate droplet dynamics. The resulting sequence-structure-function correlation could support the future development of compartments for a variety of applications.
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Affiliation(s)
- Avigail Baruch Leshem
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Sian Sloan-Dennison
- Department of Pure and Applied Chemistry, Technology and Innovation Centre, University of Strathclyde, 99 George Street, Glasgow, G1 1RD, UK
| | - Tlalit Massarano
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Shavit Ben-David
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Duncan Graham
- Department of Pure and Applied Chemistry, Technology and Innovation Centre, University of Strathclyde, 99 George Street, Glasgow, G1 1RD, UK
| | - Karen Faulds
- Department of Pure and Applied Chemistry, Technology and Innovation Centre, University of Strathclyde, 99 George Street, Glasgow, G1 1RD, UK
| | - Hugo E Gottlieb
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Jordan H Chill
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, Ramat Gan, 52900, Israel.
| | - Ayala Lampel
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel. .,Center for Nanoscience and Nanotechnology Tel Aviv University, Tel Aviv, 69978, Israel. .,Sagol Center for Regenerative Biotechnology Tel Aviv University, Tel Aviv, 69978, Israel. .,Center for the Physics and Chemistry of Living Systems Tel Aviv University, Tel Aviv 69978, Israel, Tel Aviv, 69978, Israel.
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18
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Lyons H, Veettil RT, Pradhan P, Fornero C, De La Cruz N, Ito K, Eppert M, Roeder RG, Sabari BR. Functional partitioning of transcriptional regulators by patterned charge blocks. Cell 2023; 186:327-345.e28. [PMID: 36603581 PMCID: PMC9910284 DOI: 10.1016/j.cell.2022.12.013] [Citation(s) in RCA: 76] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 10/15/2022] [Accepted: 12/07/2022] [Indexed: 01/05/2023]
Abstract
Components of transcriptional machinery are selectively partitioned into specific condensates, often mediated by protein disorder, yet we know little about how this specificity is achieved. Here, we show that condensates composed of the intrinsically disordered region (IDR) of MED1 selectively partition RNA polymerase II together with its positive allosteric regulators while excluding negative regulators. This selective compartmentalization is sufficient to activate transcription and is required for gene activation during a cell-state transition. The IDRs of partitioned proteins are necessary and sufficient for selective compartmentalization and require alternating blocks of charged amino acids. Disrupting this charge pattern prevents partitioning, whereas adding the pattern to proteins promotes partitioning with functional consequences for gene activation. IDRs with similar patterned charge blocks show similar partitioning and function. These findings demonstrate that disorder-mediated interactions can selectively compartmentalize specific functionally related proteins from a complex mixture of biomolecules, leading to regulation of a biochemical pathway.
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Affiliation(s)
- Heankel Lyons
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Reshma T Veettil
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Prashant Pradhan
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Christy Fornero
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Nancy De La Cruz
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Keiichi Ito
- Laboratory of Biochemistry and Molecular Biology, the Rockefeller University, New York, NY 10065, USA
| | - Mikayla Eppert
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, the Rockefeller University, New York, NY 10065, USA
| | - Benjamin R Sabari
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, Division of Basic Research, Department of Obstetrics and Gynecology, Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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19
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Tesei G, Lindorff-Larsen K. Improved predictions of phase behaviour of intrinsically disordered proteins by tuning the interaction range. OPEN RESEARCH EUROPE 2023; 2:94. [PMID: 37645312 PMCID: PMC10450847 DOI: 10.12688/openreseurope.14967.2] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/16/2022] [Indexed: 08/31/2023]
Abstract
The formation and viscoelastic properties of condensates of intrinsically disordered proteins (IDPs) is dictated by amino acid sequence and solution conditions. Because of the involvement of biomolecular condensates in cell physiology and disease, advancing our understanding of the relationship between protein sequence and phase separation (PS) may have important implications in the formulation of new therapeutic hypotheses. Here, we present CALVADOS 2, a coarse-grained model of IDPs that accurately predicts conformational properties and propensities to undergo PS for diverse sequences and solution conditions. In particular, we systematically study the effect of varying the range of the nonionic interactions and use our findings to improve the temperature scale of the model. We further optimize the residue-specific model parameters against experimental data on the conformational properties of 55 proteins, while also leveraging 70 hydrophobicity scales from the literature to avoid overfitting the training data. Extensive testing shows that the model accurately predicts chain compaction and PS propensity for sequences of diverse length and charge patterning, as well as at different temperatures and salt concentrations.
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Affiliation(s)
- Giulio Tesei
- Structural Biology and NMR Laboratory & the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory & the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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20
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Tesei G, Lindorff-Larsen K. Improved predictions of phase behaviour of intrinsically disordered proteins by tuning the interaction range. OPEN RESEARCH EUROPE 2023; 2:94. [PMID: 37645312 PMCID: PMC10450847 DOI: 10.12688/openreseurope.14967.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/16/2022] [Indexed: 02/13/2024]
Abstract
The formation and viscoelastic properties of condensates of intrinsically disordered proteins (IDPs) is dictated by amino acid sequence and solution conditions. Because of the involvement of biomolecular condensates in cell physiology and disease, advancing our understanding of the relationship between protein sequence and phase separation (PS) may have important implications in the formulation of new therapeutic hypotheses. Here, we present CALVADOS 2, a coarse-grained model of IDPs that accurately predicts conformational properties and propensities to undergo PS for diverse sequences and solution conditions. In particular, we systematically study the effect of varying the range of the nonionic interactions and use our findings to improve the temperature scale of the model. We further optimize the residue-specific model parameters against experimental data on the conformational properties of 55 proteins, while also leveraging 70 hydrophobicity scales from the literature to avoid overfitting the training data. Extensive testing shows that the model accurately predicts chain compaction and PS propensity for sequences of diverse length and charge patterning, as well as at different temperatures and salt concentrations.
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Affiliation(s)
- Giulio Tesei
- Structural Biology and NMR Laboratory & the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory & the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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21
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Tibble RW, Gross JD. A call to order: Examining structured domains in biomolecular condensates. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 346:107318. [PMID: 36657879 PMCID: PMC10878105 DOI: 10.1016/j.jmr.2022.107318] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 09/20/2022] [Accepted: 10/13/2022] [Indexed: 06/17/2023]
Abstract
Diverse cellular processes have been observed or predicted to occur in biomolecular condensates, which are comprised of proteins and nucleic acids that undergo liquid-liquid phase separation (LLPS). Protein-driven LLPS often involves weak, multivalent interactions between intrinsically disordered regions (IDRs). Due to their inherent lack of defined tertiary structures, NMR has been a powerful resource for studying the behavior and interactions of IDRs in condensates. While IDRs in proteins are necessary for phase separation, core proteins enriched in condensates often contain structured domains that are essential for their function and contribute to phase separation. How phase separation can affect the structure and conformational dynamics of structured domains is critical for understanding how biochemical reactions can be effectively regulated in cellular condensates. In this perspective, we discuss the consequences phase separation can have on structured domains and outline NMR observables we believe are useful for assessing protein structure and dynamics in condensates.
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Affiliation(s)
- Ryan W Tibble
- Program in Chemistry and Chemical Biology, University of California, San Francisco, United States; Department of Pharmaceutical Chemistry, University of California, San Francisco, United States
| | - John D Gross
- Program in Chemistry and Chemical Biology, University of California, San Francisco, United States; Department of Pharmaceutical Chemistry, University of California, San Francisco, United States.
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22
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Her C, Phan TM, Jovic N, Kapoor U, Ackermann BE, Rizuan A, Kim Y, Mittal J, Debelouchina G. Molecular interactions underlying the phase separation of HP1α: role of phosphorylation, ligand and nucleic acid binding. Nucleic Acids Res 2022; 50:12702-12722. [PMID: 36537242 PMCID: PMC9825191 DOI: 10.1093/nar/gkac1194] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 11/04/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Heterochromatin protein 1α (HP1α) is a crucial element of chromatin organization. It has been proposed that HP1α functions through liquid-liquid phase separation (LLPS), which allows it to compact chromatin into transcriptionally repressed heterochromatin regions. In vitro, HP1α can undergo phase separation upon phosphorylation of its N-terminus extension (NTE) and/or through interactions with DNA and chromatin. Here, we combine computational and experimental approaches to elucidate the molecular interactions that drive these processes. In phosphorylation-driven LLPS, HP1α can exchange intradimer hinge-NTE interactions with interdimer contacts, which also leads to a structural change from a compacted to an extended HP1α dimer conformation. This process can be enhanced by the presence of positively charged HP1α peptide ligands and disrupted by the addition of negatively charged or neutral peptides. In DNA-driven LLPS, both positively and negatively charged peptide ligands can perturb phase separation. Our findings demonstrate the importance of electrostatic interactions in HP1α LLPS where binding partners can modulate the overall charge of the droplets and screen or enhance hinge region interactions through specific and non-specific effects. Our study illuminates the complex molecular framework that can fine-tune the properties of HP1α and that can contribute to heterochromatin regulation and function.
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Affiliation(s)
| | | | - Nina Jovic
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Utkarsh Kapoor
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Bryce E Ackermann
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA
| | - Azamat Rizuan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Young C Kim
- Center for Materials Physics and Technology, Naval Research Laboratory, WA, DC, USA
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23
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Unravelling the microscopic characteristics of intrinsically disordered proteins upon liquid–liquid phase separation. Essays Biochem 2022; 66:891-900. [DOI: 10.1042/ebc20220148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/13/2022] [Accepted: 11/14/2022] [Indexed: 12/23/2022]
Abstract
Abstract
Biomolecular condensate formation via liquid–liquid phase separation (LLPS) has emerged as a ubiquitous mechanism underlying the spatiotemporal organization of biomolecules in the cell. These membraneless condensates form and disperse dynamically in response to environmental stimuli. Growing evidence indicates that the liquid-like condensates not only play functional physiological roles but are also implicated in a wide range of human diseases. As a major component of biomolecular condensates, intrinsically disordered proteins (IDPs) are intimately involved in the LLPS process. During the last decade, great efforts have been made on the macroscopic characterization of the physicochemical properties and biological functions of liquid condensates both in vitro and in the cellular context. However, characterization of the conformations and interactions at the molecular level within phase-separated condensates is still at an early stage. In the present review, we summarize recent biophysical studies investigating the intramolecular conformational changes of IDPs upon LLPS and the intermolecular clustering of proteins undergoing LLPS, with a particular focus on single-molecule fluorescence detection. We also discuss how these microscopic features are linked to the macroscopic phase transitions that are relevant to the physiological and pathological roles of the condensates.
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24
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Mohanty P, Kapoor U, Sundaravadivelu Devarajan D, Phan TM, Rizuan A, Mittal J. Principles Governing the Phase Separation of Multidomain Proteins. Biochemistry 2022; 61:2443-2455. [PMID: 35802394 PMCID: PMC9669140 DOI: 10.1021/acs.biochem.2c00210] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A variety of membraneless organelles, often termed "biological condensates", play an important role in the regulation of cellular processes such as gene transcription, translation, and protein quality control. On the basis of experimental and theoretical investigations, liquid-liquid phase separation (LLPS) has been proposed as a possible mechanism for the origin of biological condensates. LLPS requires multivalent macromolecules that template the formation of long-range, intermolecular interaction networks and results in the formation of condensates with defined composition and material properties. Multivalent interactions driving LLPS exhibit a wide range of modes from highly stereospecific to nonspecific and involve both folded and disordered regions. Multidomain proteins serve as suitable macromolecules for promoting phase separation and achieving disparate functions due to their potential for multivalent interactions and regulation. Here, we aim to highlight the influence of the domain architecture and interdomain interactions on the phase separation of multidomain protein condensates. First, the general principles underlying these interactions are illustrated on the basis of examples of multidomain proteins that are predominantly associated with nucleic acid binding and protein quality control and contain both folded and disordered regions. Next, the examples showcase how LLPS properties of folded and disordered regions can be leveraged to engineer multidomain constructs that form condensates with the desired assembly and functional properties. Finally, we highlight the need for improvements in coarse-grained computational models that can provide molecular-level insights into multidomain protein condensates in conjunction with experimental efforts.
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Affiliation(s)
- Priyesh Mohanty
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Utkarsh Kapoor
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | | | - Tien Minh Phan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Azamat Rizuan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
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25
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Camacho-Zarco AR, Schnapka V, Guseva S, Abyzov A, Adamski W, Milles S, Jensen MR, Zidek L, Salvi N, Blackledge M. NMR Provides Unique Insight into the Functional Dynamics and Interactions of Intrinsically Disordered Proteins. Chem Rev 2022; 122:9331-9356. [PMID: 35446534 PMCID: PMC9136928 DOI: 10.1021/acs.chemrev.1c01023] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
![]()
Intrinsically disordered
proteins are ubiquitous throughout all
known proteomes, playing essential roles in all aspects of cellular
and extracellular biochemistry. To understand their function, it is
necessary to determine their structural and dynamic behavior and to
describe the physical chemistry of their interaction trajectories.
Nuclear magnetic resonance is perfectly adapted to this task, providing
ensemble averaged structural and dynamic parameters that report on
each assigned resonance in the molecule, unveiling otherwise inaccessible
insight into the reaction kinetics and thermodynamics that are essential
for function. In this review, we describe recent applications of NMR-based
approaches to understanding the conformational energy landscape, the
nature and time scales of local and long-range dynamics and how they
depend on the environment, even in the cell. Finally, we illustrate
the ability of NMR to uncover the mechanistic basis of functional
disordered molecular assemblies that are important for human health.
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Affiliation(s)
| | - Vincent Schnapka
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | - Serafima Guseva
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | - Anton Abyzov
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | - Wiktor Adamski
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | - Sigrid Milles
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
| | | | - Lukas Zidek
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 82500 Brno, Czech Republic.,Central European Institute of Technology, Masaryk University, Kamenice 5, 82500 Brno, Czech Republic
| | - Nicola Salvi
- Université Grenoble Alpes, CEA, CNRS, IBS, 38000 Grenoble, France
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26
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Najbauer EE, Ng SC, Griesinger C, Görlich D, Andreas LB. Atomic resolution dynamics of cohesive interactions in phase-separated Nup98 FG domains. Nat Commun 2022; 13:1494. [PMID: 35314668 PMCID: PMC8938434 DOI: 10.1038/s41467-022-28821-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/09/2022] [Indexed: 01/02/2023] Open
Abstract
Cohesive FG domains assemble into a condensed phase forming the selective permeability barrier of nuclear pore complexes. Nanoscopic insight into fundamental cohesive interactions has long been hampered by the sequence heterogeneity of native FG domains. We overcome this challenge by utilizing an engineered perfectly repetitive sequence and a combination of solution and magic angle spinning NMR spectroscopy. We map the dynamics of cohesive interactions in both phase-separated and soluble states at atomic resolution using TROSY for rotational correlation time (TRACT) measurements. We find that FG repeats exhibit nanosecond-range rotational correlation times and remain disordered in both states, although FRAP measurements show slow translation of phase-separated FG domains. NOESY measurements enable the direct detection of contacts involved in cohesive interactions. Finally, increasing salt concentration and temperature enhance phase separation and decrease local mobility of FG repeats. This lower critical solution temperature (LCST) behaviour indicates that cohesive interactions are driven by entropy. The permeability barrier of nuclear pores is formed by disordered and yet self-interacting FG repeat domains, whose sequence heterogeneity is a challenge for mechanistic insights. Here the authors overcome this challenge and characterize the protein’s dynamics by applying NMR techniques to an FG phase system that has been simplified to its essentials.
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27
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Abyzov A, Blackledge M, Zweckstetter M. Conformational Dynamics of Intrinsically Disordered Proteins Regulate Biomolecular Condensate Chemistry. Chem Rev 2022; 122:6719-6748. [PMID: 35179885 PMCID: PMC8949871 DOI: 10.1021/acs.chemrev.1c00774] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
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Motions in biomolecules
are critical for biochemical reactions.
In cells, many biochemical reactions are executed inside of biomolecular
condensates formed by ultradynamic intrinsically disordered proteins.
A deep understanding of the conformational dynamics of intrinsically
disordered proteins in biomolecular condensates is therefore of utmost
importance but is complicated by diverse obstacles. Here we review
emerging data on the motions of intrinsically disordered proteins
inside of liquidlike condensates. We discuss how liquid–liquid
phase separation modulates internal motions across a wide range of
time and length scales. We further highlight the importance of intermolecular
interactions that not only drive liquid–liquid phase separation
but appear as key determinants for changes in biomolecular motions
and the aging of condensates in human diseases. The review provides
a framework for future studies to reveal the conformational dynamics
of intrinsically disordered proteins in the regulation of biomolecular
condensate chemistry.
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Affiliation(s)
- Anton Abyzov
- Translational Structural Biology Group, German Center for Neurodegenerative Diseases (DZNE), 37075 Göttingen, Germany
| | - Martin Blackledge
- Université Grenoble Alpes, Institut de Biologie Structurale (IBS), 38044 Grenoble, France.,CEA, DSV, IBS, 38044 Grenoble, France.,CNRS, IBS, 38044 Grenoble, France
| | - Markus Zweckstetter
- Translational Structural Biology Group, German Center for Neurodegenerative Diseases (DZNE), 37075 Göttingen, Germany.,Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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28
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Pantoja CF, Zweckstetter M, Rezaei-Ghaleh N. Dynamical Component Exchange in a Model Phase Separating System: an NMR-based Approach. Phys Chem Chem Phys 2022; 24:6169-6175. [DOI: 10.1039/d2cp00042c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biomolecular phase separation plays a key role in spatial organization of cellular activities. Dynamic formation and rapid component exchange between phase separated cellular bodies and their environment are crucial for...
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29
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Regulation of spatially restricted gene expression: linking RNA localization and phase separation. Biochem Soc Trans 2021; 49:2591-2600. [PMID: 34821361 DOI: 10.1042/bst20210320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/17/2022]
Abstract
Subcellular restriction of gene expression is crucial to the functioning of a wide variety of cell types. The cellular machinery driving spatially restricted gene expression has been studied for many years, but recent advances have highlighted novel mechanisms by which cells can generate subcellular microenvironments with specialized gene expression profiles. Particularly intriguing are recent findings that phase separation plays a role in certain RNA localization pathways. The burgeoning field of phase separation has revolutionized how we view cellular compartmentalization, revealing that, in addition to membrane-bound organelles, phase-separated cytoplasmic microenvironments - termed biomolecular condensates - are compositionally and functionally distinct from the surrounding cytoplasm, without the need for a lipid membrane. The coupling of phase separation and RNA localization allows for precise subcellular targeting, robust translational repression and dynamic recruitment of accessory proteins. Despite the growing interest in the intersection between RNA localization and phase separation, it remains to be seen how exactly components of the localization machinery, particularly motor proteins, are able to associate with these biomolecular condensates. Further studies of the formation, function, and transport of biomolecular condensates promise to provide a new mechanistic understanding of how cells restrict gene expression at a subcellular level.
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30
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Ryu JK, Hwang DE, Choi JM. Current Understanding of Molecular Phase Separation in Chromosomes. Int J Mol Sci 2021; 22:10736. [PMID: 34639077 PMCID: PMC8509192 DOI: 10.3390/ijms221910736] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 12/12/2022] Open
Abstract
Biomolecular phase separation denotes the demixing of a specific set of intracellular components without membrane encapsulation. Recent studies have found that biomolecular phase separation is involved in a wide range of cellular processes. In particular, phase separation is involved in the formation and regulation of chromosome structures at various levels. Here, we review the current understanding of biomolecular phase separation related to chromosomes. First, we discuss the fundamental principles of phase separation and introduce several examples of nuclear/chromosomal biomolecular assemblies formed by phase separation. We also briefly explain the experimental and computational methods used to study phase separation in chromosomes. Finally, we discuss a recent phase separation model, termed bridging-induced phase separation (BIPS), which can explain the formation of local chromosome structures.
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Affiliation(s)
- Je-Kyung Ryu
- Department of Biological Sciences, KAIST, Daejeon 34141, Korea
| | - Da-Eun Hwang
- Department of Chemistry, Pusan National University, Busan 46241, Korea;
| | - Jeong-Mo Choi
- Department of Chemistry, Pusan National University, Busan 46241, Korea;
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