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Norrild RK, Mason TO, Boyens-Thiele L, Ray S, Mortensen JB, Fritsch AW, Iglesias-Artola JM, Klausen LK, Stender EGP, Jensen H, Buell AK. Taylor Dispersion-Induced Phase Separation for the Efficient Characterisation of Protein Condensate Formation. Angew Chem Int Ed Engl 2024; 63:e202404018. [PMID: 38593269 DOI: 10.1002/anie.202404018] [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: 02/27/2024] [Revised: 04/08/2024] [Accepted: 04/08/2024] [Indexed: 04/11/2024]
Abstract
Biomolecular condensates have emerged as important structures in cellular function and disease, and are thought to form through liquid-liquid phase separation (LLPS). Thorough and efficient in vitro experiments are therefore needed to elucidate the driving forces of protein LLPS and the possibility to modulate it with drugs. Here we present Taylor dispersion-induced phase separation (TDIPS), a method to robustly measure condensation phenomena using a commercially available microfluidic platform. It uses only nanoliters of sample, does not require extrinsic fluorescent labels, and is straightforward to implement. We demonstrate TDIPS by screening the phase behaviour of two proteins that form biomolecular condensates in vivo, PGL-3 and Ddx4. Uniquely accessible to this method, we find an unexpected re-entrant behaviour at very low ionic strength, where LLPS is inhibited for both proteins. TDIPS can also probe the reversibility of assemblies, which was shown for both α-synuclein and for lysozyme, relevant for health and biotechnology, respectively. Finally, we highlight how effective inhibition concentrations and partitioning of LLPS-modifying compounds can be screened highly efficiently.
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Affiliation(s)
- Rasmus K Norrild
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 227, 2800, Kgs. Lyngby, Denmark
| | - Thomas O Mason
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 227, 2800, Kgs. Lyngby, Denmark
| | - Lars Boyens-Thiele
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 227, 2800, Kgs. Lyngby, Denmark
| | - Soumik Ray
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 227, 2800, Kgs. Lyngby, Denmark
| | - Joachim B Mortensen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 227, 2800, Kgs. Lyngby, Denmark
| | - Anatol W Fritsch
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - Juan M Iglesias-Artola
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - Louise K Klausen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 227, 2800, Kgs. Lyngby, Denmark
| | | | - Henrik Jensen
- FIDA Biosystems Aps, Generatorvej 6 A+B, 2860, Søborg, Denmark
| | - Alexander K Buell
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 227, 2800, Kgs. Lyngby, Denmark
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2
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Ibrahim KA, Naidu AS, Miljkovic H, Radenovic A, Yang W. Label-Free Techniques for Probing Biomolecular Condensates. ACS NANO 2024; 18:10738-10757. [PMID: 38609349 DOI: 10.1021/acsnano.4c01534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2024]
Abstract
Biomolecular condensates play important roles in a wide array of fundamental biological processes, such as cellular compartmentalization, cellular regulation, and other biochemical reactions. Since their discovery and first observations, an extensive and expansive library of tools has been developed to investigate various aspects and properties, encompassing structural and compositional information, material properties, and their evolution throughout the life cycle from formation to eventual dissolution. This Review presents an overview of the expanded set of tools and methods that researchers use to probe the properties of biomolecular condensates across diverse scales of length, concentration, stiffness, and time. In particular, we review recent years' exciting development of label-free techniques and methodologies. We broadly organize the set of tools into 3 categories: (1) imaging-based techniques, such as transmitted-light microscopy (TLM) and Brillouin microscopy (BM), (2) force spectroscopy techniques, such as atomic force microscopy (AFM) and the optical tweezer (OT), and (3) microfluidic platforms and emerging technologies. We point out the tools' key opportunities, challenges, and future perspectives and analyze their correlative potential as well as compatibility with other techniques. Additionally, we review emerging techniques, namely, differential dynamic microscopy (DDM) and interferometric scattering microscopy (iSCAT), that have huge potential for future applications in studying biomolecular condensates. Finally, we highlight how some of these techniques can be translated for diagnostics and therapy purposes. We hope this Review serves as a useful guide for new researchers in this field and aids in advancing the development of new biophysical tools to study biomolecular condensates.
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3
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Ray S, Buell AK. Emerging experimental methods to study the thermodynamics of biomolecular condensate formation. J Chem Phys 2024; 160:091001. [PMID: 38445729 DOI: 10.1063/5.0190160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/15/2024] [Indexed: 03/07/2024] Open
Abstract
The formation of biomolecular condensates in vivo is increasingly recognized to underlie a multitude of crucial cellular functions. Furthermore, the evolution of highly dynamic protein condensates into progressively less reversible assemblies is thought to be involved in a variety of disorders, from cancer over neurodegeneration to rare genetic disorders. There is an increasing need for efficient experimental methods to characterize the thermodynamics of condensate formation and that can be used in screening campaigns to identify and rationally design condensate modifying compounds. Theoretical advances in the field are also identifying the key parameters that need to be measured in order to obtain a comprehensive understanding of the underlying interactions and driving forces. Here, we review recent progress in the development of efficient and quantitative experimental methods to study the driving forces behind and the temporal evolution of biomolecular condensates.
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Affiliation(s)
- Soumik Ray
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Alexander K Buell
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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4
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Seo S, Kim T. Gas transport mechanisms through gas-permeable membranes in microfluidics: A perspective. BIOMICROFLUIDICS 2023; 17:061301. [PMID: 38025658 PMCID: PMC10656118 DOI: 10.1063/5.0169555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023]
Abstract
Gas-permeable membranes (GPMs) and membrane-like micro-/nanostructures offer precise control over the transport of liquids, gases, and small molecules on microchips, which has led to the possibility of diverse applications, such as gas sensors, solution concentrators, and mixture separators. With the escalating demand for GPMs in microfluidics, this Perspective article aims to comprehensively categorize the transport mechanisms of gases through GPMs based on the penetrant type and the transport direction. We also provide a comprehensive review of recent advancements in GPM-integrated microfluidic devices, provide an overview of the fundamental mechanisms underlying gas transport through GPMs, and present future perspectives on the integration of GPMs in microfluidics. Furthermore, we address the current challenges associated with GPMs and GPM-integrated microfluidic devices, taking into consideration the intrinsic material properties and capabilities of GPMs. By tackling these challenges head-on, we believe that our perspectives can catalyze innovative advancements and help meet the evolving demands of microfluidic applications.
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Affiliation(s)
- Sangjin Seo
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea
| | - Taesung Kim
- Author to whom correspondence should be addressed:. Tel.: +82-52-217-2313. Fax: +82-52-217-2409
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5
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Biomolecular condensate phase diagrams with a combinatorial microdroplet platform. Nat Commun 2022; 13:7845. [PMID: 36543777 PMCID: PMC9768726 DOI: 10.1038/s41467-022-35265-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022] Open
Abstract
The assembly of biomolecules into condensates is a fundamental process underlying the organisation of the intracellular space and the regulation of many cellular functions. Mapping and characterising phase behaviour of biomolecules is essential to understand the mechanisms of condensate assembly, and to develop therapeutic strategies targeting biomolecular condensate systems. A central concept for characterising phase-separating systems is the phase diagram. Phase diagrams are typically built from numerous individual measurements sampling different parts of the parameter space. However, even when performed in microwell plate format, this process is slow, low throughput and requires significant sample consumption. To address this challenge, we present here a combinatorial droplet microfluidic platform, termed PhaseScan, for rapid and high-resolution acquisition of multidimensional biomolecular phase diagrams. Using this platform, we characterise the phase behaviour of a wide range of systems under a variety of conditions and demonstrate that this approach allows the quantitative characterisation of the effect of small molecules on biomolecular phase transitions.
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6
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Erkamp NA, Qi R, Welsh TJ, Knowles TPJ. Microfluidics for multiscale studies of biomolecular condensates. LAB ON A CHIP 2022; 23:9-24. [PMID: 36269080 PMCID: PMC9764808 DOI: 10.1039/d2lc00622g] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/04/2022] [Indexed: 05/12/2023]
Abstract
Membraneless organelles formed through condensation of biomolecules in living cells have become the focus of sustained efforts to elucidate their mechanisms of formation and function. These condensates perform a range of vital functions in cells and are closely connected to key processes in functional and aberrant biology. Since these systems occupy a size scale intermediate between single proteins and conventional protein complexes on the one hand, and cellular length scales on the other hand, they have proved challenging to probe using conventional approaches from either protein science or cell biology. Additionally, condensate can form, solidify and perform functions on various time-scales. From a physical point of view, biomolecular condensates are colloidal soft matter systems, and microfluidic approaches, which originated in soft condensed matter research, have successfully been used to study biomolecular condensates. This review explores how microfluidics have aided condensate research into the thermodynamics, kinetics and other properties of condensates, by offering high-throughput and novel experimental setups.
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Affiliation(s)
- Nadia A Erkamp
- Yusuf Hamied Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Runzhang Qi
- Yusuf Hamied Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Timothy J Welsh
- Yusuf Hamied Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
| | - Tuomas P J Knowles
- Yusuf Hamied Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Ave, Cambridge, CB3 0HE, UK
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7
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Jeyhani M, Navi M, Chan KWY, Kieda J, Tsai SSH. Water-in-water droplet microfluidics: A design manual. BIOMICROFLUIDICS 2022; 16:061503. [PMID: 36406338 PMCID: PMC9674389 DOI: 10.1063/5.0119316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Droplet microfluidics is utilized in a wide range of applications in biomedicine and biology. Applications include rapid biochemical analysis, materials generation, biochemical assays, and point-of-care medicine. The integration of aqueous two-phase systems (ATPSs) into droplet microfluidic platforms has potential utility in oil-free biological and biomedical applications, namely, reducing cytotoxicity and preserving the native form and function of costly biomolecular reagents. In this review, we present a design manual for the chemist, biologist, and engineer to design experiments in the context of their biological applications using all-in-water droplet microfluidic systems. We describe the studies achievable using these systems and the corresponding fabrication and stabilization methods. With this information, readers may apply the fundamental principles and recent advancements in ATPS droplet microfluidics to their research. Finally, we propose a development roadmap of opportunities to utilize ATPS droplet microfluidics in applications that remain underexplored.
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8
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Villois A, Capasso Palmiero U, Mathur P, Perone G, Schneider T, Li L, Salvalaglio M, deMello A, Stavrakis S, Arosio P. Droplet Microfluidics for the Label-Free Extraction of Complete Phase Diagrams and Kinetics of Liquid-Liquid Phase Separation in Finite Volumes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2202606. [PMID: 36180409 DOI: 10.1002/smll.202202606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Liquid-liquid phase separation of polymer and protein solutions is central in many areas of biology and material sciences. Here, an experimental and theoretical framework is provided to investigate the thermodynamics and kinetics of liquid-liquid phase separation in volumes comparable to cells. The strategy leverages droplet microfluidics to accurately measure the volume of the dense phase generated by liquid-liquid phase separation of solutions confined in micro-sized compartments. It is shown that the measurement of the volume fraction of the dense phase at different temperatures allows the evaluation of the binodal lines that determine the coexistence region of the two phases in the temperature-concentration phase diagram. By applying a thermodynamic model of phase separation in finite volumes, it is further shown that the platform can predict and validate kinetic barriers associated with the formation of a dense droplet in a parent dilute phase, therefore connecting thermodynamics and kinetics of liquid-liquid phase separation.
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Affiliation(s)
- Alessia Villois
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Umberto Capasso Palmiero
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Prerit Mathur
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Gaia Perone
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Timo Schneider
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Lunna Li
- Thomas Young Centre and Department of Chemical Engineering, University College London, London, WC1E 7JE, UK
| | - Matteo Salvalaglio
- Thomas Young Centre and Department of Chemical Engineering, University College London, London, WC1E 7JE, UK
| | - Andrew deMello
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Stavros Stavrakis
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Paolo Arosio
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
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9
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Bergmann AM, Donau C, Späth F, Jahnke K, Göpfrich K, Boekhoven J. Evolution and Single‐Droplet Analysis of Fuel‐Driven Compartments by Droplet‐Based Microfluidics. Angew Chem Int Ed Engl 2022; 61:e202203928. [PMID: 35657164 PMCID: PMC9400878 DOI: 10.1002/anie.202203928] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Alexander M. Bergmann
- Department of Chemistry Technical University of Munich Lichtenbergstrasse 4 85748 Garching Germany
| | - Carsten Donau
- Department of Chemistry Technical University of Munich Lichtenbergstrasse 4 85748 Garching Germany
| | - Fabian Späth
- Department of Chemistry Technical University of Munich Lichtenbergstrasse 4 85748 Garching Germany
| | - Kevin Jahnke
- Biophysical Engineering Group Max Planck Institute for Medical Research Jahnstraße 29 69120 Heidelberg Germany
- Department of Physics and Astronomy Heidelberg University 69120 Heidelberg Germany
| | - Kerstin Göpfrich
- Biophysical Engineering Group Max Planck Institute for Medical Research Jahnstraße 29 69120 Heidelberg Germany
- Department of Physics and Astronomy Heidelberg University 69120 Heidelberg Germany
| | - Job Boekhoven
- Department of Chemistry Technical University of Munich Lichtenbergstrasse 4 85748 Garching Germany
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10
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Chan KWY, Navi M, Kieda J, Moran T, Hammers D, Lee S, Tsai SSH. Phase transition modulation and biophysical characterization of biomolecular condensates using microfluidics. LAB ON A CHIP 2022; 22:2647-2656. [PMID: 35616128 DOI: 10.1039/d2lc00037g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Membraneless organelles (MLOs) formed through liquid-liquid phase separation (LLPS) are becoming increasingly relevant to understanding viral-host interactions, neurodegenerative disease, and cancer. The modulation of LLPS involves many parameters and components. To describe these modulators, typical in vitro studies require laborious, manual sample preparation of different concentrations and costly biological reagents. Here, we introduce a minimal reagent, microfluidic platform to systematically generate samples of different concentrations and trigger phase separation. We demonstrate the platform's utility by constructing phase diagrams describing the modulation of LLPS using an aqueous two-phase system (ATPS) and an MLO-based phase separating system. We also show on-chip biophysical characterization typical of in vitro studies. We expect that this platform will be utilized by scientists to study the growing number of MLOs and inform clinical treatments for pathology related to LLPS.
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Affiliation(s)
- Katherine W Y Chan
- Graduate Program in Biomedical Engineering, Ryerson University, Toronto M5B 2K3, Canada.
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto M5B 2K3, Canada
- Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Ryerson University and St. Michael's Hospital, Toronto M5B 1W8, Canada
| | - Maryam Navi
- Graduate Program in Biomedical Engineering, Ryerson University, Toronto M5B 2K3, Canada.
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto M5B 2K3, Canada
- Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Ryerson University and St. Michael's Hospital, Toronto M5B 1W8, Canada
| | - Jennifer Kieda
- Graduate Program in Biomedical Engineering, Ryerson University, Toronto M5B 2K3, Canada.
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto M5B 2K3, Canada
- Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Ryerson University and St. Michael's Hospital, Toronto M5B 1W8, Canada
| | - Thomas Moran
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Daniel Hammers
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Shaun Lee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana 46556, USA
- Institution for Precision Health, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Scott S H Tsai
- Graduate Program in Biomedical Engineering, Ryerson University, Toronto M5B 2K3, Canada.
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto M5B 2K3, Canada
- Institute for Biomedical Engineering, Science, and Technology (iBEST) - A partnership between Ryerson University and St. Michael's Hospital, Toronto M5B 1W8, Canada
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto M5B 2K3, Canada
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11
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Bergmann AM, Donau C, Späth F, Jahnke K, Göpfrich K, Boekhoven J. Evolution and Single‐Droplet Analysis of Fuel‐Driven Compartments by Droplet‐Based Microfluidics. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Carsten Donau
- Technische Universität München: Technische Universitat Munchen Chemistry GERMANY
| | - Fabian Späth
- TU München: Technische Universitat Munchen Chemistry GERMANY
| | - Kevin Jahnke
- Max-Planck-Institute for Medical Research: Max-Planck-Institut fur medizinische Forschung Medical Research GERMANY
| | - Kerstin Göpfrich
- Max-Planck-Institute for Medical Research: Max-Planck-Institut fur medizinische Forschung Medical Research GERMANY
| | - Job Boekhoven
- Technical University of Munchen Chemistry Lichtenbergstrasse 485748Germany 85748 Garching GERMANY
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12
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Wang Z, Lou J, Zhang H. Essence determines phenomenon: Assaying the material properties of biological condensates. J Biol Chem 2022; 298:101782. [PMID: 35245500 PMCID: PMC8958544 DOI: 10.1016/j.jbc.2022.101782] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 01/02/2023] Open
Abstract
Intracellular spaces are partitioned into separate compartments to ensure that numerous biochemical reactions and cellular functions take place in a spatiotemporally controlled manner. Biomacromolecules including proteins and RNAs undergo liquid–liquid phase separation and subsequent phase transition to form biological condensates with diverse material states. The material/physical properties of biological condensates are crucial for fulfilling their distinct physiological functions, and abnormal material properties can cause deleterious effects under pathological conditions. Here, we review recent studies showing the role of the material properties of biological condensates in their physiological functions. We also summarize several classic methods as well as newly emerging techniques for characterization and/or measurement of the material properties of biological condensates.
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Affiliation(s)
- Zheng Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
| | - Jizhong Lou
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.
| | - Hong Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
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13
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Currie SL, Rosen MK. Using quantitative reconstitution to investigate multicomponent condensates. RNA (NEW YORK, N.Y.) 2022; 28:27-35. [PMID: 34772789 PMCID: PMC8675290 DOI: 10.1261/rna.079008.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Many biomolecular condensates are thought to form via liquid-liquid phase separation (LLPS) of multivalent macromolecules. For those that form through this mechanism, our understanding has benefitted significantly from biochemical reconstitutions of key components and activities. Reconstitutions of RNA-based condensates to date have mostly been based on relatively simple collections of molecules. However, proteomics and sequencing data indicate that natural RNA-based condensates are enriched in hundreds to thousands of different components, and genetic data suggest multiple interactions can contribute to condensate formation to varying degrees. In this Perspective, we describe recent progress in understanding RNA-based condensates through different levels of biochemical reconstitutions as a means to bridge the gap between simple in vitro reconstitution and cellular analyses. Complex reconstitutions provide insight into the formation, regulation, and functions of multicomponent condensates. We focus on two RNA-protein condensate case studies: stress granules and RNA processing bodies (P bodies), and examine the evidence for cooperative interactions among multiple components promoting LLPS. An important concept emerging from these studies is that composition and stoichiometry regulate biochemical activities within condensates. Based on the lessons learned from stress granules and P bodies, we discuss forward-looking approaches to understand the thermodynamic relationships between condensate components, with the goal of developing predictive models of composition and material properties, and their effects on biochemical activities. We anticipate that quantitative reconstitutions will facilitate understanding of the complex thermodynamics and functions of diverse RNA-protein condensates.
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Affiliation(s)
- Simon L Currie
- Department of Biophysics and Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, Texas 75390, USA
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14
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Li P, Zeng X, Li S, Xiang X, Chen P, Li Y, Liu BF. Rapid Determination of Phase Diagrams for Biomolecular Liquid-Liquid Phase Separation with Microfluidics. Anal Chem 2021; 94:687-694. [PMID: 34936324 DOI: 10.1021/acs.analchem.1c02700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Biomolecular phase separation is currently emerging in both the medical and life science fields. Meanwhile, the application of liquid-liquid phase separation has been extended to many fields including drug discovery, fibrous material fabrication, 3D printing, and polymer design. Although more than 8600 proteins and other synthetic macromolecules are capable of phase separation as recently reported, there is still a lack of a high-throughput approach to quantitatively characterize its phase behaviors. To meet this requirement, here, we proposed fast and high-resolution acquisition of biomolecular phase diagrams using microfluidic chips. Using this platform, we demonstrated the phase behavior of polyU/RRASLRRASLRRASL in a quantitative manner. Up to 1750 concentration conditions can be generated in 140 min. The detection limitation of our device to capture the saturation concentration for phase separation is about 5 times lower than that of the traditional turbidity method. Thus, our results provide a basis for the rapid acquisition of phase diagrams with high-throughput and pave the way for its wide application.
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Affiliation(s)
- Pengjie Li
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xuemei Zeng
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shunji Li
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xufu Xiang
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Peng Chen
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yiwei Li
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Bi-Feng Liu
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics and Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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15
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Capillary flow experiments for thermodynamic and kinetic characterization of protein liquid-liquid phase separation. Nat Commun 2021; 12:7289. [PMID: 34911929 PMCID: PMC8674230 DOI: 10.1038/s41467-021-27433-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 11/22/2021] [Indexed: 12/13/2022] Open
Abstract
Liquid-liquid phase separation or LLPS of proteins is a field of mounting importance and the value of quantitative kinetic and thermodynamic characterization of LLPS is increasingly recognized. We present a method, Capflex, which allows rapid and accurate quantification of key parameters for LLPS: Dilute phase concentration, relative droplet size distributions, and the kinetics of droplet formation and maturation into amyloid fibrils. The binding affinity between the polypeptide undergoing LLPS and LLPS-modulating compounds can also be determined. We apply Capflex to characterize the LLPS of Human DEAD-box helicase-4 and the coacervate system ssDNA/RP3. Furthermore, we study LLPS and the aberrant liquid-to-solid phase transition of α-synuclein. We quantitatively measure the decrease in dilute phase concentration as the LLPS of α-synuclein is followed by the formation of Thioflavin-T positive amyloid aggregates. The high information content, throughput and the versatility of Capflex makes it a valuable tool for characterizing biomolecular LLPS.
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16
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Bacchin P, Leng J, Salmon JB. Microfluidic Evaporation, Pervaporation, and Osmosis: From Passive Pumping to Solute Concentration. Chem Rev 2021; 122:6938-6985. [PMID: 34882390 DOI: 10.1021/acs.chemrev.1c00459] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Evaporation, pervaporation, and forward osmosis are processes leading to a mass transfer of solvent across an interface: gas/liquid for evaporation and solid/liquid (membrane) for pervaporation and osmosis. This Review provides comprehensive insight into the use of these processes at the microfluidic scales for applications ranging from passive pumping to the screening of phase diagrams and micromaterials engineering. Indeed, for a fixed interface relative to the microfluidic chip, these processes passively induce flows driven only by gradients of chemical potential. As a consequence, these passive-transport phenomena lead to an accumulation of solutes that cannot cross the interface and thus concentrate solutions in the microfluidic chip up to high concentration regimes, possibly up to solidification. The purpose of this Review is to provide a unified description of these processes and associated microfluidic applications to highlight the differences and similarities between these three passive-transport phenomena.
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Affiliation(s)
- Patrice Bacchin
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, 31000 Toulouse, France
| | - Jacques Leng
- CNRS, Solvay, LOF, UMR 5258, Université de Bordeaux, 33600 Pessac, France
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17
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Kar M, Posey AE, Dar F, Hyman AA, Pappu RV. Glycine-Rich Peptides from FUS Have an Intrinsic Ability to Self-Assemble into Fibers and Networked Fibrils. Biochemistry 2021; 60:3213-3222. [PMID: 34648275 PMCID: PMC10715152 DOI: 10.1021/acs.biochem.1c00501] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Glycine-rich regions feature prominently in intrinsically disordered regions (IDRs) of proteins that drive phase separation and the regulated formation of membraneless biomolecular condensates. Interestingly, the Gly-rich IDRs seldom feature poly-Gly tracts. The protein fused in sarcoma (FUS) is an exception. This protein includes two 10-residue poly-Gly tracts within the prion-like domain (PLD) and at the interface between the PLD and the RNA binding domain. Poly-Gly tracts are known to be highly insoluble, being potent drivers of self-assembly into solid-like fibrils. Given that the internal concentrations of FUS and FUS-like molecules cross the high micromolar and even millimolar range within condensates, we reasoned that the intrinsic insolubility of poly-Gly tracts might be germane to emergent fluid-to-solid transitions within condensates. To assess this possibility, we characterized the concentration-dependent self-assembly for three non-overlapping 25-residue Gly-rich peptides derived from FUS. Two of the three peptides feature 10-residue poly-Gly tracts. These peptides form either long fibrils based on twisted ribbon-like structures or self-supporting gels based on physical cross-links of fibrils. Conversely, the peptide with similar Gly contents but lacking a poly-Gly tract does not form fibrils or gels. Instead, it remains soluble across a wide range of concentrations. Our findings highlight the ability of poly-Gly tracts within IDRs that drive phase separation to undergo self-assembly. We propose that these tracts are likely to contribute to nucleation of fibrillar solids within dense condensates formed by FUS.
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Affiliation(s)
- Mrityunjoy Kar
- Max Planck Institute of Cell Biology and Genetics (MPI-CBG), 01307 Dresden, Germany
| | - Ammon E. Posey
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Furqan Dar
- Department of Physics, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Anthony A. Hyman
- Max Planck Institute of Cell Biology and Genetics (MPI-CBG), 01307 Dresden, Germany
| | - Rohit V. Pappu
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO 63130, USA
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18
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Spegg V, Altmeyer M. Biomolecular condensates at sites of DNA damage: More than just a phase. DNA Repair (Amst) 2021; 106:103179. [PMID: 34311273 PMCID: PMC7612016 DOI: 10.1016/j.dnarep.2021.103179] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 12/12/2022]
Abstract
Protein recruitment to DNA break sites is an integral part of the DNA damage response (DDR). Elucidation of the hierarchy and temporal order with which DNA damage sensors as well as repair and signaling factors assemble around chromosome breaks has painted a complex picture of tightly regulated macromolecular interactions that build specialized compartments to facilitate repair and maintenance of genome integrity. While many of the underlying interactions, e.g. between repair factors and damage-induced histone marks, can be explained by lock-and-key or induced fit binding models assuming fixed stoichiometries, structurally less well defined interactions, such as the highly dynamic multivalent interactions implicated in phase separation, also participate in the formation of multi-protein assemblies in response to genotoxic stress. Although much remains to be learned about these types of cooperative and highly dynamic interactions and their functional roles, the rapidly growing interest in material properties of biomolecular condensates and in concepts from polymer chemistry and soft matter physics to understand biological processes at different scales holds great promises. Here, we discuss nuclear condensates in the context of genome integrity maintenance, highlighting the cooperative potential between clustered stoichiometric binding and phase separation. Rather than viewing them as opposing scenarios, their combined effects can balance structural specificity with favorable physicochemical properties relevant for the regulation and function of multilayered nuclear condensates.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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19
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Ruff KM, Dar F, Pappu RV. Polyphasic linkage and the impact of ligand binding on the regulation of biomolecular condensates. BIOPHYSICS REVIEWS 2021; 2:021302. [PMID: 34179888 PMCID: PMC8211317 DOI: 10.1063/5.0050059] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/11/2021] [Indexed: 12/30/2022]
Abstract
Cellular matter can be spatially and temporally organized into membraneless biomolecular condensates. The current thinking is that these condensates form and dissolve via phase transitions driven by one or more condensate-specific multivalent macromolecules known as scaffolds. Cells likely regulate condensate formation and dissolution by exerting control over the concentrations of regulatory molecules, which we refer to as ligands. Wyman and Gill introduced the framework of polyphasic linkage to explain how ligands can exert thermodynamic control over phase transitions. This review focuses on describing the concepts of polyphasic linkage and the relevance of such a mechanism for controlling condensate formation and dissolution. We describe how ligand-mediated control over scaffold phase behavior can be quantified experimentally. Further, we build on recent studies to highlight features of ligands that make them suppressors vs drivers of phase separation. Finally, we highlight areas where advances are needed to further understand ligand-mediated control of condensates in complex cellular environments. These advances include understanding the effects of networks of ligands on condensate behavior and how ligands modulate phase transitions controlled by different combinations of homotypic and heterotypic interactions among scaffold macromolecules. Insights gained from the application of polyphasic linkage concepts should be useful for designing novel pharmaceutical ligands to regulate condensates.
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Affiliation(s)
- Kiersten M. Ruff
- Department of Biomedical Engineering and Center for Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Furqan Dar
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Rohit V. Pappu
- Department of Biomedical Engineering and Center for Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri 63130, USA
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