101
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Balka KR, De Nardo D. Molecular and spatial mechanisms governing STING signalling. FEBS J 2020; 288:5504-5529. [PMID: 33237620 DOI: 10.1111/febs.15640] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/12/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022]
Abstract
Detection of microbial nucleic acids via innate immune receptors is critical for establishing host defence against pathogens. The DNA-sensing cGAS-STING pathway has gained increasing attention in the last decade as a key pathway for combating viral and bacterial infections. cGAS-STING activation primarily promotes the secretion of antiviral type I IFNs via the key transcription factor, IRF3. In addition, cGAS-STING signalling also elicits proinflammatory cytokines through NF-κB activity. Activation of IRF3 and NF-κB is mediated by the chief signalling receptor protein STING. Interestingly, STING undergoes significant trafficking events across multiple subcellular locations, which regulates both the activation of downstream signalling pathways, as well as appropriate termination of the responses. Studies to date have provided a comprehensive view of the regulation and role of the IRF3-IFN pathway downstream of STING. However, many aspects of STING signalling remain relatively poorly defined. This review will explore the current understanding of the mechanisms through which STING elicits inflammatory and antimicrobial responses, focusing on the precise signalling and intracellular trafficking events that occur. We will also discuss exciting and emerging concepts in the field, including the importance of IFN-independent STING responses for host defence and during STING-related disease.
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Affiliation(s)
- Katherine R Balka
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Vic., Australia
| | - Dominic De Nardo
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Vic., Australia
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102
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Armaos A, Zacco E, Sanchez de Groot N, Tartaglia GG. RNA-protein interactions: Central players in coordination of regulatory networks. Bioessays 2020; 43:e2000118. [PMID: 33284474 DOI: 10.1002/bies.202000118] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022]
Abstract
Changes in the abundance of protein and RNA molecules can impair the formation of complexes in the cell leading to toxicity and death. Here we exploit the information contained in protein, RNA and DNA interaction networks to provide a comprehensive view of the regulation layers controlling the concentration-dependent formation of assemblies in the cell. We present the emerging concept that RNAs can act as scaffolds to promote the formation ribonucleoprotein complexes and coordinate the post-transcriptional layer of gene regulation. We describe the structural and interaction network properties that characterize the ability of protein and RNA molecules to interact and phase separate in liquid-like compartments. Finally, we show that presence of structurally disordered regions in proteins correlate with the propensity to undergo liquid-to-solid phase transitions and cause human diseases. Also see the video abstract here https://youtu.be/kfpqibsNfS0.
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Affiliation(s)
- Alexandros Armaos
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Center for Human Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Elsa Zacco
- Center for Human Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Natalia Sanchez de Groot
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Gian Gaetano Tartaglia
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Center for Human Technologies, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Biology 'Charles Darwin', Sapienza University of Rome, Rome, Italy.,Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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103
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Tarczewska A, Wycisk K, Orłowski M, Waligórska A, Dobrucki J, Drewniak-Świtalska M, Berlicki Ł, Ożyhar A. Nuclear immunophilin FKBP39 from Drosophila melanogaster drives spontaneous liquid-liquid phase separation. Int J Biol Macromol 2020; 163:108-119. [PMID: 32615218 DOI: 10.1016/j.ijbiomac.2020.06.255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 11/27/2022]
Abstract
The FKBP39 from Drosophila melanogaster is a multifunctional regulatory immunophilin. It contains two globular domains linked by a highly charged disordered region. The N-terminal domain shows homology to the nucleoplasmin core domain, and the C-terminal domain is characteristic for the family of the FKBP immunophilin ligand binding domain. The specific partially disordered structure of the protein inspired us to investigate whether FKBP39 can drive spontaneous liquid-liquid phase separation (LLPS). Preliminary analyses using CatGranule and Pi-Pi contact predictors suggested a propensity for LLPS. Microscopy observations revealed that FKBP39 can self-concentrate to form liquid condensates. We also found that FKBP39 can lead to LLPS in the presence of RNA and peptides containing Arg-rich linear motifs derived from selected nuclear and nucleolar proteins. These heterotypic interactions have a stronger propensity for driving LLPS when compared to the interactions mediated by self-associating FKBP39 molecules. To investigate whether FKBP39 can drive LLPS in the cellular environment, we analysed it in fusion with YFP in COS-7 cells. The specific distribution and diffusion kinetics of FKBP39 examined by FRAP experiments provided evidence that immunophilin is an important driver of phase separation. The ability of FKBP39 to go into heterotypic interaction may be fundamental for ribosome subunits assembly.
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Affiliation(s)
- Aneta Tarczewska
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland.
| | - Krzysztof Wycisk
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Marek Orłowski
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Agnieszka Waligórska
- Department of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Jurek Dobrucki
- Department of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland
| | - Magda Drewniak-Świtalska
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Łukasz Berlicki
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Andrzej Ożyhar
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland
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104
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A framework for understanding the functions of biomolecular condensates across scales. Nat Rev Mol Cell Biol 2020; 22:215-235. [PMID: 33169001 DOI: 10.1038/s41580-020-00303-z] [Citation(s) in RCA: 412] [Impact Index Per Article: 103.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2020] [Indexed: 02/07/2023]
Abstract
Biomolecular condensates are found throughout eukaryotic cells, including in the nucleus, in the cytoplasm and on membranes. They are also implicated in a wide range of cellular functions, organizing molecules that act in processes ranging from RNA metabolism to signalling to gene regulation. Early work in the field focused on identifying condensates and understanding how their physical properties and regulation arise from molecular constituents. Recent years have brought a focus on understanding condensate functions. Studies have revealed functions that span different length scales: from molecular (modulating the rates of chemical reactions) to mesoscale (organizing large structures within cells) to cellular (facilitating localization of cellular materials and homeostatic responses). In this Roadmap, we discuss representative examples of biochemical and cellular functions of biomolecular condensates from the recent literature and organize these functions into a series of non-exclusive classes across the different length scales. We conclude with a discussion of areas of current interest and challenges in the field, and thoughts about how progress may be made to further our understanding of the widespread roles of condensates in cell biology.
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105
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Garaizar A, Sanchez-Burgos I, Collepardo-Guevara R, Espinosa JR. Expansion of Intrinsically Disordered Proteins Increases the Range of Stability of Liquid-Liquid Phase Separation. Molecules 2020; 25:E4705. [PMID: 33076213 PMCID: PMC7587599 DOI: 10.3390/molecules25204705] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/25/2020] [Accepted: 10/01/2020] [Indexed: 12/23/2022] Open
Abstract
Proteins containing intrinsically disordered regions (IDRs) are ubiquitous within biomolecular condensates, which are liquid-like compartments within cells formed through liquid-liquid phase separation (LLPS). The sequence of amino acids of a protein encodes its phase behaviour, not only by establishing the patterning and chemical nature (e.g., hydrophobic, polar, charged) of the various binding sites that facilitate multivalent interactions, but also by dictating the protein conformational dynamics. Besides behaving as random coils, IDRs can exhibit a wide-range of structural behaviours, including conformational switching, where they transition between alternate conformational ensembles. Using Molecular Dynamics simulations of a minimal coarse-grained model for IDRs, we show that the role of protein conformation has a non-trivial effect in the liquid-liquid phase behaviour of IDRs. When an IDR transitions to a conformational ensemble enriched in disordered extended states, LLPS is enhanced. In contrast, IDRs that switch to ensembles that preferentially sample more compact and structured states show inhibited LLPS. This occurs because extended and disordered protein conformations facilitate LLPS-stabilising multivalent protein-protein interactions by reducing steric hindrance; thereby, such conformations maximize the molecular connectivity of the condensed liquid network. Extended protein configurations promote phase separation regardless of whether LLPS is driven by homotypic and/or heterotypic protein-protein interactions. This study sheds light on the link between the dynamic conformational plasticity of IDRs and their liquid-liquid phase behaviour.
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Affiliation(s)
- Adiran Garaizar
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK; (A.G.); (I.S.-B.); (R.C.-G.)
| | - Ignacio Sanchez-Burgos
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK; (A.G.); (I.S.-B.); (R.C.-G.)
| | - Rosana Collepardo-Guevara
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK; (A.G.); (I.S.-B.); (R.C.-G.)
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
- Department of Genetics, University of Cambridge, Downing Site, Cambridge CB2 3EJ, UK
| | - Jorge R. Espinosa
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK; (A.G.); (I.S.-B.); (R.C.-G.)
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106
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Emenecker RJ, Holehouse AS, Strader LC. Emerging Roles for Phase Separation in Plants. Dev Cell 2020; 55:69-83. [PMID: 33049212 PMCID: PMC7577370 DOI: 10.1016/j.devcel.2020.09.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/19/2020] [Accepted: 09/02/2020] [Indexed: 12/12/2022]
Abstract
The plant cell internal environment is a dynamic, intricate landscape composed of many intracellular compartments. Cells organize some cellular components through formation of biomolecular condensates-non-stoichiometric assemblies of protein and/or nucleic acids. In many cases, phase separation appears to either underly or contribute to the formation of biomolecular condensates. Many canonical membraneless compartments within animal cells form in a manner that is at least consistent with phase separation, including nucleoli, stress granules, Cajal bodies, and numerous additional bodies, regulated by developmental and environmental stimuli. In this Review, we examine the emerging roles for phase separation in plants. Further, drawing on studies carried out in other organisms, we identify cellular phenomenon in plants that might also arise via phase separation. We propose that plants make use of phase separation to a much greater extent than has been previously appreciated, implicating phase separation as an evolutionarily ancient mechanism for cellular organization.
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Affiliation(s)
- Ryan J Emenecker
- Department of Biology, Washington University, St. Louis, MO 63130, USA; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Science and Engineering Living Systems (CSELS), Washington University, St. Louis, MO 63130, USA; Center for Engineering Mechanobiology, Washington University, St. Louis, MO 63130, USA
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Science and Engineering Living Systems (CSELS), Washington University, St. Louis, MO 63130, USA.
| | - Lucia C Strader
- Center for Science and Engineering Living Systems (CSELS), Washington University, St. Louis, MO 63130, USA; Center for Engineering Mechanobiology, Washington University, St. Louis, MO 63130, USA; Department of Biology, Duke University, Durham, NC 27708, USA.
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107
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Sukhanova MV, Singatulina AS, Pastré D, Lavrik OI. Fused in Sarcoma (FUS) in DNA Repair: Tango with Poly(ADP-ribose) Polymerase 1 and Compartmentalisation of Damaged DNA. Int J Mol Sci 2020; 21:E7020. [PMID: 32987654 PMCID: PMC7582374 DOI: 10.3390/ijms21197020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 12/18/2022] Open
Abstract
The fused in sarcoma (FUS) protein combines prion-like properties with a multifunctional DNA/RNA-binding domain and has functions spanning the regulation of RNA metabolism, including transcription, pre-mRNA splicing, mRNA transport and translation. In addition to its roles in RNA metabolism, FUS is implicated in the maintenance of DNA integrity. In this review, we examine the participation of FUS in major DNA repair pathways, focusing on DNA repair associated with poly(ADP-ribosyl)ation events and on how the interaction of FUS with poly(ADP-ribose) may orchestrate transient compartmentalisation of DNA strand breaks. Unravelling how prion-like RNA-binding proteins control DNA repair pathways will deepen our understanding of the pathogenesis of some neurological diseases and cancer as well as provide the basis for the development of relevant innovative therapeutic technologies. This knowledge may also extend the range of applications of poly(ADP-ribose) polymerase inhibitors to the treatment of neurodegenerative diseases related to RNA-binding proteins in the cell, e.g., amyotrophic lateral sclerosis and frontotemporal lobar degeneration.
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Affiliation(s)
- Maria V. Sukhanova
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, 630090 Novosibirsk, Russia; (A.S.S.); (O.I.L.)
| | - Anastasia S. Singatulina
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, 630090 Novosibirsk, Russia; (A.S.S.); (O.I.L.)
| | - David Pastré
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, INSERM U1204, Université Paris-Saclay, 91025 Evry, France;
| | - Olga I. Lavrik
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, 630090 Novosibirsk, Russia; (A.S.S.); (O.I.L.)
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108
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Masser AE, Ciccarelli M, Andréasson C. Hsf1 on a leash - controlling the heat shock response by chaperone titration. Exp Cell Res 2020; 396:112246. [PMID: 32861670 DOI: 10.1016/j.yexcr.2020.112246] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/14/2020] [Accepted: 08/22/2020] [Indexed: 01/06/2023]
Abstract
Heat shock factor 1 (Hsf1) is an ancient transcription factor that monitors protein homeostasis (proteostasis) and counteracts disturbances by triggering a transcriptional programme known as the heat shock response (HSR). The HSR is transiently activated and upregulates the expression of core proteostasis genes, including chaperones. Dysregulation of Hsf1 and its target genes are associated with disease; cancer cells rely on a constitutively active Hsf1 to promote rapid growth and malignancy, whereas Hsf1 hypoactivation in neurodegenerative disorders results in formation of toxic aggregates. These central but opposing roles highlight the importance of understanding the underlying molecular mechanisms that control Hsf1 activity. According to current understanding, Hsf1 is maintained latent by chaperone interactions but proteostasis perturbations titrate chaperone availability as a result of chaperone sequestration by misfolded proteins. Liberated and activated Hsf1 triggers a negative feedback loop by inducing the expression of key chaperones. Until recently, Hsp90 has been highlighted as the central negative regulator of Hsf1 activity. In this review, we focus on recent advances regarding how the Hsp70 chaperone controls Hsf1 activity and in addition summarise several additional layers of activity control.
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Affiliation(s)
- Anna E Masser
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-106 91, Stockholm, Sweden
| | - Michela Ciccarelli
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-106 91, Stockholm, Sweden
| | - Claes Andréasson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-106 91, Stockholm, Sweden.
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109
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Linsenmeier M, Kopp MRG, Stavrakis S, de Mello A, Arosio P. Analysis of biomolecular condensates and protein phase separation with microfluidic technology. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118823. [PMID: 32800925 DOI: 10.1016/j.bbamcr.2020.118823] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 12/17/2022]
Abstract
An increasing body of evidence shows that membraneless organelles are key components in cellular organization. These observations open a variety of outstanding questions about the physico-chemical rules underlying their assembly, disassembly and functions. Some molecular determinants of biomolecular condensates are challenging to probe and understand in complex in vivo systems. Minimalistic in vitro reconstitution approaches can fill this gap, mimicking key biological features, while maintaining sufficient simplicity to enable the analysis of fundamental aspects of biomolecular condensates. In this context, microfluidic technologies are highly attractive tools for the analysis of biomolecular phase transitions. In addition to enabling high-throughput measurements on small sample volumes, microfluidic tools provide for exquisite control of self-assembly in both time and space, leading to accurate quantitative analysis of biomolecular phase transitions. Here, with a specific focus on droplet-based microfluidics, we describe the advantages of microfluidic technology for the analysis of several aspects of phase separation. These include phase diagrams, dynamics of assembly and disassembly, rheological and surface properties, exchange of materials with the surrounding environment and the coupling between compartmentalization and biochemical reactions. We illustrate these concepts with selected examples, ranging from simple solutions of individual proteins to more complex mixtures of proteins and RNA, which represent synthetic models of biological membraneless organelles. Finally, we discuss how this technology may impact the bottom-up fabrication of synthetic artificial cells and for the development of synthetic protein materials in biotechnology.
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Affiliation(s)
- Miriam Linsenmeier
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Marie R G Kopp
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Stavros Stavrakis
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Andrew de Mello
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Paolo Arosio
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland.
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110
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Triandafillou CG, Katanski CD, Dinner AR, Drummond DA. Transient intracellular acidification regulates the core transcriptional heat shock response. eLife 2020; 9:e54880. [PMID: 32762843 PMCID: PMC7449696 DOI: 10.7554/elife.54880] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 08/07/2020] [Indexed: 01/18/2023] Open
Abstract
Heat shock induces a conserved transcriptional program regulated by heat shock factor 1 (Hsf1) in eukaryotic cells. Activation of this heat shock response is triggered by heat-induced misfolding of newly synthesized polypeptides, and so has been thought to depend on ongoing protein synthesis. Here, using the budding yeast Saccharomyces cerevisiae, we report the discovery that Hsf1 can be robustly activated when protein synthesis is inhibited, so long as cells undergo cytosolic acidification. Heat shock has long been known to cause transient intracellular acidification which, for reasons which have remained unclear, is associated with increased stress resistance in eukaryotes. We demonstrate that acidification is required for heat shock response induction in translationally inhibited cells, and specifically affects Hsf1 activation. Physiological heat-triggered acidification also increases population fitness and promotes cell cycle reentry following heat shock. Our results uncover a previously unknown adaptive dimension of the well-studied eukaryotic heat shock response.
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Affiliation(s)
| | - Christopher D Katanski
- Department of Biochemistry and Molecular Biology and Department of Medicine, Section of Genetic Medicine, The University of ChicagoChicagoUnited States
| | - Aaron R Dinner
- Department of Chemistry and the James Franck Institute, The University of ChicagoChicagoUnited States
| | - D Allan Drummond
- Department of Biochemistry and Molecular Biology and Department of Medicine, Section of Genetic Medicine, The University of ChicagoChicagoUnited States
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111
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Clusters of bacterial RNA polymerase are biomolecular condensates that assemble through liquid-liquid phase separation. Proc Natl Acad Sci U S A 2020; 117:18540-18549. [PMID: 32675239 PMCID: PMC7414142 DOI: 10.1073/pnas.2005019117] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacterial cells are small and were long thought to have little to no internal structure. However, advances in microscopy have revealed that bacteria do indeed contain subcellular compartments. But how these compartments form has remained a mystery. Recent progress in larger, more complex eukaryotic cells has identified a novel mechanism for intracellular organization known as liquid–liquid phase separation. This process causes certain types of molecules to concentrate within distinct compartments inside the cell. Here, we demonstrate that the same process also occurs in bacteria. This work, together with a growing body of literature, suggests that liquid–liquid phase separation is a common mechanism for intracellular organization in both eukaryotic and prokaryotic cells. Once described as mere “bags of enzymes,” bacterial cells are in fact highly organized, with many macromolecules exhibiting nonuniform localization patterns. Yet the physical and biochemical mechanisms that govern this spatial heterogeneity remain largely unknown. Here, we identify liquid–liquid phase separation (LLPS) as a mechanism for organizing clusters of RNA polymerase (RNAP) in Escherichia coli. Using fluorescence imaging, we show that RNAP quickly transitions from a dispersed to clustered localization pattern as cells enter log phase in nutrient-rich media. RNAP clusters are sensitive to hexanediol, a chemical that dissolves liquid-like compartments in eukaryotic cells. In addition, we find that the transcription antitermination factor NusA forms droplets in vitro and in vivo, suggesting that it may nucleate RNAP clusters. Finally, we use single-molecule tracking to characterize the dynamics of cluster components. Our results indicate that RNAP and NusA molecules move inside clusters, with mobilities faster than a DNA locus but slower than bulk diffusion through the nucleoid. We conclude that RNAP clusters are biomolecular condensates that assemble through LLPS. This work provides direct evidence for LLPS in bacteria and demonstrates that this process can serve as a mechanism for intracellular organization in prokaryotes and eukaryotes alike.
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112
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Zheng C, Liu M, Fan H. Targeting complexes of super-enhancers is a promising strategy for cancer therapy. Oncol Lett 2020; 20:2557-2566. [PMID: 32782573 PMCID: PMC7400756 DOI: 10.3892/ol.2020.11855] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 05/27/2020] [Indexed: 12/16/2022] Open
Abstract
The hyperactivation and overexpression of critical oncogenes is a common occurrence in multiple types of malignant tumors. Recently, the abnormal activation mechanism of an oncogene by a super-enhancer (SE) has attracted significant attention. A series of changes (insertion, deletion, translocation and rearrangement) in the genome occurring in cancer cells may generate new SEs, leading to the overexpression of SE-driven oncogenes. SEs are composed of typical enhancers densely loaded with mediator complexes, transcription factors, and chromatin regulators, and drive the overexpression of oncogenes associated with cellular identity and disease. Cyclin-dependent kinase 7 (CDK7) and bromodomain protein 4 (BRD4) are critical mediator complexes associated with SE-mediated transcription. Clinical trials have shown that emerging small-molecule inhibitors (CDK7 and BRD4 inhibitor), targeting the SE exert a notable effect on cancer treatment. Increasing evidences has illustrated that the SE and its associated complexes play a critical role in the development of various types of cancer. The present review discusses the composition, function and regulation of SEs and their contribution to oncogenic transcription. In addition, creative therapeutic approaches that target SE, their advantages and disadvantages, as well as the problems with their clinical application are discussed. It was found that targeting SE may be used in conventional treatment and establish more access for patients with cancer.
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Affiliation(s)
- Chuqian Zheng
- Department of Medical Genetics and Developmental Biology, School of Medicine, The Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, P.R. China
| | - Min Liu
- Department of Medical Genetics and Developmental Biology, School of Medicine, The Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, P.R. China.,School of Life Science and Technology, Southeast University, Nanjing, Jiangsu 210018, P.R. China
| | - Hong Fan
- Department of Medical Genetics and Developmental Biology, School of Medicine, The Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, P.R. China
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113
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Carl PL, Fried HM, Cohen PL. Proteins in assemblages formed by phase separation possess properties that promote their transformation to autoantigens: Implications for autoimmunity. J Autoimmun 2020; 111:102471. [DOI: 10.1016/j.jaut.2020.102471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/14/2020] [Accepted: 04/22/2020] [Indexed: 10/24/2022]
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114
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Frank L, Rippe K. Repetitive RNAs as Regulators of Chromatin-Associated Subcompartment Formation by Phase Separation. J Mol Biol 2020; 432:4270-4286. [DOI: 10.1016/j.jmb.2020.04.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 04/14/2020] [Accepted: 04/14/2020] [Indexed: 12/21/2022]
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115
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Espinosa JR, Joseph JA, Sanchez-Burgos I, Garaizar A, Frenkel D, Collepardo-Guevara R. Liquid network connectivity regulates the stability and composition of biomolecular condensates with many components. Proc Natl Acad Sci U S A 2020; 117:13238-13247. [PMID: 32482873 PMCID: PMC7306995 DOI: 10.1073/pnas.1917569117] [Citation(s) in RCA: 125] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
One of the key mechanisms used by cells to control the spatiotemporal organization of their many components is the formation and dissolution of biomolecular condensates through liquid-liquid phase separation (LLPS). Using a minimal coarse-grained model that allows us to simulate thousands of interacting multivalent proteins, we investigate the physical parameters dictating the stability and composition of multicomponent biomolecular condensates. We demonstrate that the molecular connectivity of the condensed-liquid network-i.e., the number of weak attractive protein-protein interactions per unit of volume-determines the stability (e.g., in temperature, pH, salt concentration) of multicomponent condensates, where stability is positively correlated with connectivity. While the connectivity of scaffolds (biomolecules essential for LLPS) dominates the phase landscape, introduction of clients (species recruited via scaffold-client interactions) fine-tunes it by transforming the scaffold-scaffold bond network. Whereas low-valency clients that compete for scaffold-scaffold binding sites decrease connectivity and stability, those that bind to alternate scaffold sites not required for LLPS or that have higher-than-scaffold valencies form additional scaffold-client-scaffold bridges increasing stability. Proteins that establish more connections (via increased valencies, promiscuous binding, and topologies that enable multivalent interactions) support the stability of and are enriched within multicomponent condensates. Importantly, proteins that increase the connectivity of multicomponent condensates have higher critical points as pure systems or, if pure LLPS is unfeasible, as binary scaffold-client mixtures. Hence, critical points of accessible systems (i.e., with just a few components) might serve as a unified thermodynamic parameter to predict the composition of multicomponent condensates.
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Affiliation(s)
- Jorge R Espinosa
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kindgdom
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
| | - Jerelle A Joseph
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kindgdom
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
| | - Ignacio Sanchez-Burgos
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kindgdom
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
| | - Adiran Garaizar
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kindgdom
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
| | - Daan Frenkel
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Rosana Collepardo-Guevara
- Maxwell Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kindgdom;
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
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116
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Mészáros B, Erdős G, Szabó B, Schád É, Tantos Á, Abukhairan R, Horváth T, Murvai N, Kovács OP, Kovács M, Tosatto SCE, Tompa P, Dosztányi Z, Pancsa R. PhaSePro: the database of proteins driving liquid-liquid phase separation. Nucleic Acids Res 2020; 48:D360-D367. [PMID: 31612960 PMCID: PMC7145634 DOI: 10.1093/nar/gkz848] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/11/2019] [Accepted: 10/07/2019] [Indexed: 11/13/2022] Open
Abstract
Membraneless organelles (MOs) are dynamic liquid condensates that host a variety of specific cellular processes, such as ribosome biogenesis or RNA degradation. MOs form through liquid-liquid phase separation (LLPS), a process that relies on multivalent weak interactions of the constituent proteins and other macromolecules. Since the first discoveries of certain proteins being able to drive LLPS, it emerged as a general mechanism for the effective organization of cellular space that is exploited in all kingdoms of life. While numerous experimental studies report novel cases, the computational identification of LLPS drivers is lagging behind, and many open questions remain about the sequence determinants, composition, regulation and biological relevance of the resulting condensates. Our limited ability to overcome these issues is largely due to the lack of a dedicated LLPS database. Therefore, here we introduce PhaSePro (https://phasepro.elte.hu), an openly accessible, comprehensive, manually curated database of experimentally validated LLPS driver proteins/protein regions. It not only provides a wealth of information on such systems, but improves the standardization of data by introducing novel LLPS-specific controlled vocabularies. PhaSePro can be accessed through an appealing, user-friendly interface and thus has definite potential to become the central resource in this dynamically developing field.
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Affiliation(s)
- Bálint Mészáros
- MTA-ELTE Momentum Bioinformatics Research Group, Department of Biochemistry, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Gábor Erdős
- MTA-ELTE Momentum Bioinformatics Research Group, Department of Biochemistry, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Beáta Szabó
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
| | - Éva Schád
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
| | - Ágnes Tantos
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
| | - Rawan Abukhairan
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
| | - Tamás Horváth
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
| | - Nikoletta Murvai
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
| | - Orsolya P Kovács
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
| | - Márton Kovács
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
| | - Silvio C E Tosatto
- Department of Biomedical Sciences, University of Padova CNR Institute of Neuroscience, Padova, Italy
| | - Péter Tompa
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary.,Structural Biology (CSB), Brussels, Belgium; Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), Brussels 1050, Belgium
| | - Zsuzsanna Dosztányi
- MTA-ELTE Momentum Bioinformatics Research Group, Department of Biochemistry, Eötvös Loránd University, Budapest H-1117, Hungary
| | - Rita Pancsa
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest H-1117, Hungary
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117
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Lau Y, Oamen HP, Caudron F. Protein Phase Separation during Stress Adaptation and Cellular Memory. Cells 2020; 9:cells9051302. [PMID: 32456195 PMCID: PMC7291175 DOI: 10.3390/cells9051302] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/14/2020] [Accepted: 05/21/2020] [Indexed: 12/13/2022] Open
Abstract
Cells need to organise and regulate their biochemical processes both in space and time in order to adapt to their surrounding environment. Spatial organisation of cellular components is facilitated by a complex network of membrane bound organelles. Both the membrane composition and the intra-organellar content of these organelles can be specifically and temporally controlled by imposing gates, much like bouncers controlling entry into night-clubs. In addition, a new level of compartmentalisation has recently emerged as a fundamental principle of cellular organisation, the formation of membrane-less organelles. Many of these structures are dynamic, rapidly condensing or dissolving and are therefore ideally suited to be involved in emergency cellular adaptation to stresses. Remarkably, the same proteins have also the propensity to adopt self-perpetuating assemblies which properties fit the needs to encode cellular memory. Here, we review some of the principles of phase separation and the function of membrane-less organelles focusing particularly on their roles during stress response and cellular memory.
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118
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Capasso Palmiero U, Küffner AM, Krumeich F, Faltova L, Arosio P. Adaptive Chemoenzymatic Microreactors Composed of Inorganic Nanoparticles and Bioinspired Intrinsically Disordered Proteins. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Umberto Capasso Palmiero
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
| | - Andreas M. Küffner
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
| | - Frank Krumeich
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
| | - Lenka Faltova
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
| | - Paolo Arosio
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
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119
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Abstract
Many biomolecular condensates appear to form via spontaneous or driven processes that have the hallmarks of intracellular phase transitions. This suggests that a common underlying physical framework might govern the formation of functionally and compositionally unrelated biomolecular condensates. In this review, we summarize recent work that leverages a stickers-and-spacers framework adapted from the field of associative polymers for understanding how multivalent protein and RNA molecules drive phase transitions that give rise to biomolecular condensates. We discuss how the valence of stickers impacts the driving forces for condensate formation and elaborate on how stickers can be distinguished from spacers in different contexts. We touch on the impact of sticker- and spacer-mediated interactions on the rheological properties of condensates and show how the model can be mapped to known drivers of different types of biomolecular condensates.
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Affiliation(s)
- Jeong-Mo Choi
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, USA; , ,
- Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri, 63130, USA
- Natural Science Research Institute, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Alex S Holehouse
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, USA; , ,
- Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri, 63130, USA
| | - Rohit V Pappu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, USA; , ,
- Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri, 63130, USA
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120
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Pla‐Martín D, Schatton D, Wiederstein JL, Marx M, Khiati S, Krüger M, Rugarli EI. CLUH granules coordinate translation of mitochondrial proteins with mTORC1 signaling and mitophagy. EMBO J 2020; 39:e102731. [PMID: 32149416 PMCID: PMC7196838 DOI: 10.15252/embj.2019102731] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 11/09/2022] Open
Abstract
Mitochondria house anabolic and catabolic processes that must be balanced and adjusted to meet cellular demands. The RNA-binding protein CLUH (clustered mitochondria homolog) binds mRNAs of nuclear-encoded mitochondrial proteins and is highly expressed in the liver, where it regulates metabolic plasticity. Here, we show that in primary hepatocytes, CLUH coalesces in specific ribonucleoprotein particles that define the translational fate of target mRNAs, such as Pcx, Hadha, and Hmgcs2, to match nutrient availability. Moreover, CLUH granules play signaling roles, by recruiting mTOR kinase and the RNA-binding proteins G3BP1 and G3BP2. Upon starvation, CLUH regulates translation of Hmgcs2, involved in ketogenesis, inhibits mTORC1 activation and mitochondrial anabolic pathways, and promotes mitochondrial turnover, thus allowing efficient reprograming of metabolic function. In the absence of CLUH, a mitophagy block causes mitochondrial clustering that is rescued by rapamycin treatment or depletion of G3BP1 and G3BP2. Our data demonstrate that metabolic adaptation of liver mitochondria to nutrient availability depends on a compartmentalized CLUH-dependent post-transcriptional mechanism that controls both mTORC1 and G3BP signaling and ensures survival.
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Affiliation(s)
- David Pla‐Martín
- Institute for GeneticsUniversity of CologneCologneGermany
- Institute for Vegetative PhysiologyUniversity of CologneCologneGermany
| | - Désirée Schatton
- Institute for GeneticsUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Janica L Wiederstein
- Institute for GeneticsUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Marie‐Charlotte Marx
- Institute for GeneticsUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Salim Khiati
- MitoLab TeamInstitut MitoVascUMR CNRS 6015INSERM U1083Université d'AngersAngersFrance
| | - Marcus Krüger
- Institute for GeneticsUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
- Center for Molecular Medicine (CMMC)University of CologneCologneGermany
| | - Elena I Rugarli
- Institute for GeneticsUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
- Center for Molecular Medicine (CMMC)University of CologneCologneGermany
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121
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Capasso Palmiero U, Küffner AM, Krumeich F, Faltova L, Arosio P. Adaptive Chemoenzymatic Microreactors Composed of Inorganic Nanoparticles and Bioinspired Intrinsically Disordered Proteins. Angew Chem Int Ed Engl 2020; 59:8138-8142. [DOI: 10.1002/anie.202000835] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/28/2020] [Indexed: 02/03/2023]
Affiliation(s)
- Umberto Capasso Palmiero
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
| | - Andreas M. Küffner
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
| | - Frank Krumeich
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
| | - Lenka Faltova
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
| | - Paolo Arosio
- Department of Chemistry and Applied BiosciencesInstitute for Chemical and BioengineeringETH Zurich 8093 Zurich Switzerland
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122
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Boncella AE, Shattuck JE, Cascarina SM, Paul KR, Baer MH, Fomicheva A, Lamb AK, Ross ED. Composition-based prediction and rational manipulation of prion-like domain recruitment to stress granules. Proc Natl Acad Sci U S A 2020; 117:5826-5835. [PMID: 32127480 PMCID: PMC7084078 DOI: 10.1073/pnas.1912723117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mutations in a number of stress granule-associated proteins have been linked to various neurodegenerative diseases. Several of these mutations are found in aggregation-prone prion-like domains (PrLDs) within these proteins. In this work, we examine the sequence features governing PrLD localization to stress granules upon stress. We demonstrate that many yeast PrLDs are sufficient for stress-induced assembly into microscopically visible foci that colocalize with stress granule markers. Additionally, compositional biases exist among PrLDs that assemble upon stress, and these biases are consistent across different stressors. Using these biases, we have developed a composition-based prediction method that accurately predicts PrLD assembly into foci upon heat shock. We show that compositional changes alter PrLD assembly behavior in a predictable manner, while scrambling primary sequence has little effect on PrLD assembly and recruitment to stress granules. Furthermore, we were able to design synthetic PrLDs that were efficiently recruited to stress granules, and found that aromatic amino acids, which have previously been linked to PrLD phase separation, were dispensable for this recruitment. These results highlight the flexible sequence requirements for stress granule recruitment and suggest that PrLD localization to stress granules is driven primarily by amino acid composition, rather than primary sequence.
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Affiliation(s)
- Amy E Boncella
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Jenifer E Shattuck
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Sean M Cascarina
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Kacy R Paul
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Matthew H Baer
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Anastasia Fomicheva
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Andrew K Lamb
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
| | - Eric D Ross
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523
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123
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Bratek-Skicki A, Pancsa R, Meszaros B, Van Lindt J, Tompa P. A guide to regulation of the formation of biomolecular condensates. FEBS J 2020; 287:1924-1935. [PMID: 32080961 DOI: 10.1111/febs.15254] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/15/2020] [Accepted: 02/18/2020] [Indexed: 12/18/2022]
Abstract
Cellular organelles that lack a surrounding lipid bilayer, such as the nucleolus and stress granule, represent a newly recognized, general paradigm of cellular organization. The formation of such biomolecular condensates that include 'membraneless organelles' (MLOs) by liquid-liquid phase separation (LLPS) has been in the focus of a surge of recent studies. Through a combination of in vitro and in vivo approaches, thousands of potential phase-separating proteins have been identified, and it was found that different cellular MLOs share many common components. These perplexing observations raise the question of how cells regulate the timing and specificity of LLPS, and ensure that different MLOs form and disperse at the right moment and cellular location and can preserve their identity and physical separation. This guide gives an overview of basic regulatory mechanisms, which manifest through the action of intrinsic regulatory elements, alternative splicing, post-translational modifications, and a broad range of phase-separating partners. We also elaborate on the cellular integration of these different mechanisms and highlight how complex regulation can orchestrate the parallel functioning of a dozen or so different MLOs in the cell.
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Affiliation(s)
| | - Rita Pancsa
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Balint Meszaros
- Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary
| | - Joris Van Lindt
- VIB-VUB Center for Structural Biology (CSB), Brussels, Belgium
| | - Peter Tompa
- VIB-VUB Center for Structural Biology (CSB), Brussels, Belgium.,Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary.,Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), Brussels, Belgium
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124
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Affiliation(s)
- Arpan Rai
- Department of Molecular Life Sciences, Ernst Hadorn Chair, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Lucas Pelkmans
- Department of Molecular Life Sciences, Ernst Hadorn Chair, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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125
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Titus AR, Ferreira LA, Belgovskiy AI, Kooijman EE, Mann EK, Mann JA, Meyer WV, Smart AE, Uversky VN, Zaslavsky BY. Interfacial tension and mechanism of liquid-liquid phase separation in aqueous media. Phys Chem Chem Phys 2020; 22:4574-4580. [PMID: 32048659 DOI: 10.1039/c9cp05810a] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The organization of multiple subcellular compartments is controlled by liquid-liquid phase separation. Phase separation of this type occurs with the emergence of interfacial tension. Aqueous two-phase systems formed by two non-ionic polymers can be used to separate and analyze biological macromolecules, cells and viruses. Phase separation in these systems may serve as the simple model of phase separation in cells also occurring in aqueous media. To better understand liquid-liquid phase separation mechanisms, interfacial tension was measured in aqueous two-phase systems formed by dextran and polyethylene glycol and by polyethylene glycol and sodium sulfate in the presence of different additives. Interfacial tension values depend on differences between the solvent properties of the coexisting phases, estimated experimentally by parameters representing dipole-dipole, ion-dipole, ion-ion, and hydrogen bonding interactions. Based on both current and literature data, we propose a mechanism for phase separation in aqueous two-phase systems. This mechanism is based on the fundamental role of intermolecular forces. Although it remains to be confirmed, it is possible that these may underlie all liquid-liquid phase separation processes in biology.
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Affiliation(s)
- Amber R Titus
- Department of Biological Sciences, Kent State University, OH, Kent, USA
| | | | | | - Edgar E Kooijman
- Department of Biological Sciences, Kent State University, OH, Kent, USA
| | | | - J Adin Mann
- Department of Chemical and Biomolecular Engineering, Case Western Reserve University, Cleveland, OH, USA
| | | | | | - Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA and Institute for Biological Instrumentation of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Pushchino, Moscow region, Russia
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126
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Holehouse AS, Sukenik S. Controlling Structural Bias in Intrinsically Disordered Proteins Using Solution Space Scanning. J Chem Theory Comput 2020; 16:1794-1805. [DOI: 10.1021/acs.jctc.9b00604] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Shahar Sukenik
- Department of Chemistry and Chemical Biology, UC Merced, Merced, California 95340, United States
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127
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Driving Forces of Liquid-Liquid Phase Separation in Biological Systems. Biomolecules 2019; 9:biom9090473. [PMID: 31510097 PMCID: PMC6770153 DOI: 10.3390/biom9090473] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 09/02/2019] [Indexed: 12/03/2022] Open
Abstract
Analysis of liquid–liquid phase separation in biological systems shows that this process is similar to the phase separation observed in aqueous two-phase systems formed by nonionic polymers, proteins, and polysaccharides. The emergence of interfacial tension is a necessary condition of phase separation. The situation in this regard is similar to that of phase separation in mixtures of partially miscible solvents. It is suggested that the evaluation of the effects of biological macromolecules on the solvent properties of aqueous media and the measurement of the interfacial tension as a function of these solvent properties may be more productive for gaining insights into the mechanism of liquid–liquid phase separation than the study of structural details of proteins and RNAs engaged in the process.
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128
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Shorter J. Phase separation of RNA-binding proteins in physiology and disease: An introduction to the JBC Reviews thematic series. J Biol Chem 2019; 294:7113-7114. [PMID: 30948513 DOI: 10.1074/jbc.rev119.007944] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In recent years, there has been a jarring awakening that liquid-liquid phase separation (LLPS) of key protein and nucleic acid scaffolds underpins the biogenesis of diverse membraneless organelles, including P granules and stress granules in the cytoplasm and nucleoli and paraspeckles in the nucleus. These biomolecular condensates are proposed to be critical organizers of subcellular biochemistry and to control the flow of information from genotype to phenotype. Despite clear biological utility, LLPS can also have deleterious outcomes. Phase-separated compartments can concentrate specific RNA-binding proteins (RBPs), such as TDP-43 and fused in sarcoma (FUS), that through low-complexity, prion-like domains have an intrinsic tendency to form self-templating fibrils that are closely tied to fatal neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. This series of reviews illuminates the molecular language underlying membraneless organelle biogenesis, how prion-like domains and post-translational modifications regulate phase behavior, how cells exploit the phase-separation process for adaptive modalities, and how phase separation is corrupted in neurodegenerative diseases. Collectively, these pieces provide a cutting-edge view of our functional and mechanistic understanding of phase separation in physiology and disease.
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Affiliation(s)
- James Shorter
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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