1
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Weakly HMJ, Keller SL. Coupling liquid phases in 3D condensates and 2D membranes: Successes, challenges, and tools. Biophys J 2024; 123:1329-1341. [PMID: 38160256 PMCID: PMC11163299 DOI: 10.1016/j.bpj.2023.12.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/05/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024] Open
Abstract
This review describes the major experimental challenges researchers meet when attempting to couple phase separation between membranes and condensates. Although it is well known that phase separation in a 2D membrane could affect molecules capable of forming a 3D condensate (and vice versa), few researchers have quantified the effects to date. The scarcity of these measurements is not due to a lack of intense interest or effort in the field. Rather, it reflects significant experimental challenges in manipulating coupled membranes and condensates to yield quantitative values. These challenges transcend many molecular details, which means they impact a wide range of systems. This review highlights recent exciting successes in the field, and it lays out a comprehensive list of tools that address potential pitfalls for researchers who are considering coupling membranes with condensates.
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Affiliation(s)
- Heidi M J Weakly
- Department of Chemistry, University of Washington - Seattle, Seattle, Washington
| | - Sarah L Keller
- Department of Chemistry, University of Washington - Seattle, Seattle, Washington.
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2
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Reagle T, Xie Y, Li Z, Carnero W, Baumgart T. Methyl-β-cyclodextrin asymmetrically extracts phospholipid from bilayers, granting tunable control over differential stress in lipid vesicles. SOFT MATTER 2024; 20:4291-4307. [PMID: 38758097 PMCID: PMC11135146 DOI: 10.1039/d3sm01772a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 05/01/2024] [Indexed: 05/18/2024]
Abstract
Lipid asymmetry - that is, a nonuniform lipid distribution between the leaflets of a bilayer - is a ubiquitous feature of biomembranes and is implicated in several cellular phenomena. Differential tension - that is, unequal lateral monolayer tensions comparing the leaflets of a bilayer- is closely associated with lipid asymmetry underlying these varied roles. Because differential tension is not directly measurable in combination with the fact that common methods to adjust this quantity grant only semi-quantitative control over it, a detailed understanding of lipid asymmetry and differential tension are impeded. To overcome these challenges, we leveraged reversible complexation of phospholipid by methyl-β-cyclodextrin (mbCD) to tune the direction and magnitude of lipid asymmetry in synthetic vesicles. Lipid asymmetry generated in our study induced (i) vesicle shape changes and (ii) gel-liquid phase coexistence in 1-component vesicles. By applying mass-action considerations to interpret our findings, we discuss how this approach provides access to phospholipid thermodynamic potentials in bilayers containing lipid asymmetry (which are coupled to the differential tension of a bilayer). Because lipid asymmetry yielded by our approach is (i) tunable and (ii) maintained over minute to hour timescales, we anticipate that this approach will be a valuable addition to the experimental toolbox for systematic investigation into the biophysical role(s) of lipid asymmetry (and differential tension).
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Affiliation(s)
- Tyler Reagle
- University of Pennsylvania, Chemistry Department, 231 South 34th Street, Philadelphia, PA, 19104, USA.
| | - Yuxin Xie
- University of Pennsylvania, Chemistry Department, 231 South 34th Street, Philadelphia, PA, 19104, USA.
| | - Zheyuan Li
- University of Pennsylvania, Chemistry Department, 231 South 34th Street, Philadelphia, PA, 19104, USA.
| | - Warner Carnero
- University of Pennsylvania, Chemistry Department, 231 South 34th Street, Philadelphia, PA, 19104, USA.
| | - Tobias Baumgart
- University of Pennsylvania, Chemistry Department, 231 South 34th Street, Philadelphia, PA, 19104, USA.
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3
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Okada S, Shoji K. Microrail-assisted liposome trapping and aligning in microfluidic channels. RSC Adv 2024; 14:18003-18010. [PMID: 38841399 PMCID: PMC11152143 DOI: 10.1039/d4ra02094d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 05/28/2024] [Indexed: 06/07/2024] Open
Abstract
Liposome assemblies with a specific shape are potential cell tissue models for studying intercellular communication. Microfluidic channels that can trap liposomes have been constructed to achieve efficient and high-throughput manipulation and observation of liposomes. However, the trapping and alignment of multiple liposomes in a specific space are still challenging because the liposomes are soft and easily ruptured. In this study, we focused on a microrail-assisted technique for manipulating water-in-oil (w/o) emulsions. In this technique, w/o emulsions are trapped under the microrails through a surface energy gradient. First, we investigated whether the microrail channel can be applied for liposome trapping and alignment and found that the numerical simulations showed that drag forces in the direction of the microrail acted on the liposomes, thereby moving the liposomes from the main channel to the microrail. Next, we designed a microrail device based on the simulation results and trapped liposomes using the device. Resultantly, 24.7 ± 8.5 liposomes were aligned under the microrail within an hour, and the microrail was filled with liposomes for 3 hours. Finally, we prepared the microrail devices with y-shaped and ring-shaped microrails and demonstrated the construction of liposome assemblies with specific shapes, not only the straight shape. Our results indicate that the microrail-assisted technique is a valuable method for manipulating liposomes because it has the potential to provide various-shaped liposome assemblies. We believe the microrail channel will be a powerful tool for constructing liposome-based cell-cell interaction models.
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Affiliation(s)
- Shun Okada
- Department of Mechanical Engineering, Nagaoka University of Technology 1603-1 Kamitomioka Nagaoka Niigata 940-2188 Japan
| | - Kan Shoji
- Department of Mechanical Engineering, Nagaoka University of Technology 1603-1 Kamitomioka Nagaoka Niigata 940-2188 Japan
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4
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Hua L, Kaiser M, Carabadjac I, Meister A, Hause G, Heerklotz H. Vesicle budding caused by lysolipid-induced asymmetry stress. Biophys J 2023; 122:4011-4022. [PMID: 37649254 PMCID: PMC10598287 DOI: 10.1016/j.bpj.2023.08.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 08/10/2023] [Accepted: 08/28/2023] [Indexed: 09/01/2023] Open
Abstract
Lysolipids such as lauroyl, myristoyl, and palmitoyl lysophosphatidylcholine (LPC) insert into the outer leaflet of liposomes but do not flip to the inner leaflet over many hours. This way, they create asymmetry stress between the intrinsic areas of the two leaflets. We have studied how this stress is relaxed with particular emphasis on the budding and fission of small (diameter 20-30 nm) daughter vesicles (DVs). Asymmetric flow field-flow fractionation was utilized to quantify the extent of budding from large unilamellar vesicles after exposure to LPC. Budding starts at a low threshold of the order of 2 mol% LPC in the outer (and ≈0 mol% LPC in the inner) leaflet. We see reason to assume that the fractional fluorescence intensity from DVs is a good approximation for the fraction of membrane lipid, POPC, transferred into DVs. Accordingly, budding starts with a "budding power" of ≈6 POPC molecules budding off per LPC added, corresponding to a more than 10-fold accumulation of LPC in the outer leaflet of DVs to ≈24 mol%. As long as budding is possible, little strain is built up in the membranes, a claim supported by the lack of changes in limiting fluorescence anisotropy, rotational correlation time, and fluorescence lifetime of symmetrically and asymmetrically inserted TMA-DPH. At physiological osmolarity, budding is typically limited to 20-30% of budded fraction with some batch-to-batch variation, but independent of the LPC species. We hypothesize that the budding limit is determined by the excess area of the liposomes upon preparation, which is then used up upon budding given the larger area-to-volume ratio of smaller liposomes. As the mother vesicles approach ideal spheres, budding must stop. This is qualitatively supported by increased and decreased budding limits of osmotically predeflated and preinflated vesicles, respectively.
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Affiliation(s)
- Lisa Hua
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany.
| | - Michael Kaiser
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany
| | - Iulia Carabadjac
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany
| | - Annette Meister
- ZIK HALOmem and Institute of Biochemistry and Biotechnology, MLU Halle-Wittenberg, Halle, Germany
| | - Gerd Hause
- Biozentrum, MLU Halle-Wittenberg, Halle, Germany
| | - Heiko Heerklotz
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada; Signaling Research Center BIOSS, University of Freiburg, Freiburg, Germany.
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5
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Wubshet NH, Liu AP. Methods to mechanically perturb and characterize GUV-based minimal cell models. Comput Struct Biotechnol J 2022; 21:550-562. [PMID: 36659916 PMCID: PMC9816913 DOI: 10.1016/j.csbj.2022.12.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/15/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Cells shield organelles and the cytosol via an active boundary predominantly made of phospholipids and membrane proteins, yet allowing communication between the intracellular and extracellular environment. Micron-sized liposome compartments commonly known as giant unilamellar vesicles (GUVs) are used to model the cell membrane and encapsulate biological materials and processes in a cell-like confinement. In the field of bottom-up synthetic biology, many have utilized GUVs as substrates to study various biological processes such as protein-lipid interactions, cytoskeletal assembly, and dynamics of protein synthesis. Like cells, it is ideal that GUVs are also mechanically durable and able to stay intact when the inner and outer environment changes. As a result, studies have demonstrated approaches to tune the mechanical properties of GUVs by modulating membrane composition and lumenal material property. In this context, there have been many different methods developed to test the mechanical properties of GUVs. In this review, we will survey various perturbation techniques employed to mechanically characterize GUVs.
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Affiliation(s)
- Nadab H. Wubshet
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Allen P. Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
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6
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Avalos-Padilla Y, Georgiev VN, Ewins E, Robinson T, Orozco E, Lipowsky R, Dimova R. Stepwise remodeling and subcompartment formation in individual vesicles by three ESCRT-III proteins. iScience 2022; 26:105765. [PMID: 36590172 PMCID: PMC9800321 DOI: 10.1016/j.isci.2022.105765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 10/21/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
The endosomal sorting complex required for transport (ESCRT) is a multi-protein machinery involved in several membrane remodeling processes. Different approaches have been used to resolve how ESCRT proteins scission membranes. However, the underlying mechanisms generating membrane deformations are still a matter of debate. Here, giant unilamellar vesicles, microfluidic technology, and micropipette aspiration are combined to continuously follow the ESCRT-III-mediated membrane remodeling on the single-vesicle level for the first time. With this approach, we identify different mechanisms by which a minimal set of three ESCRT-III proteins from Entamoeba histolytica reshape the membrane. These proteins modulate the membrane stiffness and spontaneous curvature to regulate bud size and generate intraluminal vesicles even in the absence of ATP. We demonstrate that the bud stability depends on the protein concentration and membrane tension. The approaches introduced here should open the road to diverse applications in synthetic biology for establishing artificial cells with several membrane compartments.
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Affiliation(s)
- Yunuen Avalos-Padilla
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany,Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, ES-08028 Barcelona, Spain,Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, ES-08036 Barcelona, Spain
| | - Vasil N. Georgiev
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany
| | - Eleanor Ewins
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany
| | - Tom Robinson
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV IPN, 07360 Ciudad de México, México
| | - Reinhard Lipowsky
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476 Potsdam, Germany,Corresponding author
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7
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Wennerström H, Sparr E, Stenhammar J. Thermal fluctuations and osmotic stability of lipid vesicles. Phys Rev E 2022; 106:064607. [PMID: 36671149 DOI: 10.1103/physreve.106.064607] [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: 09/07/2022] [Accepted: 11/18/2022] [Indexed: 06/17/2023]
Abstract
Biological membranes constantly change their shape in response to external stimuli, and understanding the remodeling and stability of vesicles in heterogeneous environments is therefore of fundamental importance for a range of cellular processes. One crucial question is how vesicles respond to external osmotic stresses, imposed by differences in solute concentrations between the vesicle interior and exterior. Previous analyses of the membrane bending energy have predicted that micron-sized giant unilamellar vesicles (GUVs) should become globally deformed already for nanomolar concentration differences, in contrast to experimental findings that find deformations at much higher osmotic stresses. In this article, we analyze the mechanical stability of a spherical vesicle exposed to an external osmotic pressure in a statistical-mechanical model, including the effect of thermally excited membrane bending modes. We find that the inclusion of thermal fluctuations of the vesicle shape changes renders the vesicle deformation continuous, in contrast to the abrupt transition in the athermal picture. Crucially, however, the predicted critical pressure associated with global vesicle deformation remains the same as when thermal fluctuations are neglected, approximately six orders of magnitude smaller than the typical collapse pressure recently observed experimentally for GUVs. We conclude by discussing possible sources of this persisting dissonance between theory and experiments.
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Affiliation(s)
- Håkan Wennerström
- Division of Physical Chemistry, Lund University, P.O. Box 124, S-221 00 Lund, Sweden
| | - Emma Sparr
- Division of Physical Chemistry, Lund University, P.O. Box 124, S-221 00 Lund, Sweden
| | - Joakim Stenhammar
- Division of Physical Chemistry, Lund University, P.O. Box 124, S-221 00 Lund, Sweden
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8
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Abstract
Micromechanics techniques are playing an increasing role in characterization of biomembranes. The mechanical properties of membranes play an important role for a whole range of cellular processes. Lipid-protein biomembranes display lateral heterogeneity, domain formation, and morphological changes at mesoscopic and nanoscopic length scales. An attempt is made to introduce how membrane's material properties can be measured. Both fluctuation analysis and micro-pipette aspiration experiments have been used to quantify the micromechanics of membranes. The relationship between the structure and function of biomembranes is a critical concern in modern biology. This overview calls for a deeper understanding of how the cell complexity might be related to the mechanical properties of the lipid-protein membrane. Mechanical properties can influence cellular response to processes like adhesion, transport, differentiation, proliferation and migration.
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9
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Aleksanyan M, Faizi HA, Kirmpaki MA, Vlahovska PM, Riske KA, Dimova R. Assessing membrane material properties from the response of giant unilamellar vesicles to electric fields. ADVANCES IN PHYSICS: X 2022; 8:2125342. [PMID: 36211231 PMCID: PMC9536468 DOI: 10.1080/23746149.2022.2125342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023] Open
Abstract
Knowledge of the material properties of membranes is crucial to understanding cell viability and physiology. A number of methods have been developed to probe membranes in vitro, utilizing the response of minimal biomimetic membrane models to an external perturbation. In this review, we focus on techniques employing giant unilamellar vesicles (GUVs), model membrane systems, often referred to as minimal artificial cells because of the potential they offer to mimick certain cellular features. When exposed to electric fields, GUV deformation, dynamic response and poration can be used to deduce properties such as bending rigidity, pore edge tension, membrane capacitance, surface shear viscosity, excess area and membrane stability. We present a succinct overview of these techniques, which require only simple instrumentation, available in many labs, as well as reasonably facile experimental implementation and analysis.
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Affiliation(s)
- Mina Aleksanyan
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
- Institute for Chemistry and Biochemistry, Free University of Berlin, 14195 Berlin, Germany
| | - Hammad A. Faizi
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA
| | - Maria-Anna Kirmpaki
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
| | - Petia M. Vlahovska
- Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, IL, USA
| | - Karin A. Riske
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, 04039-032 Brazil
| | - Rumiana Dimova
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
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10
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Guindani C, Silva LC, Cao S, Ivanov T, Landfester K. Synthetic Cells: From Simple Bio‐Inspired Modules to Sophisticated Integrated Systems. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202110855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Camila Guindani
- Chemical Engineering Program COPPE Federal University of Rio de Janeiro, PEQ/COPPE/UFRJ, CEP 21941-972 Rio de Janeiro RJ Brazil
| | - Lucas Caire Silva
- Department of Physical Chemistry of Polymers Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Shoupeng Cao
- Department of Physical Chemistry of Polymers Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Tsvetomir Ivanov
- Department of Physical Chemistry of Polymers Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Katharina Landfester
- Department of Physical Chemistry of Polymers Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
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11
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Liu X, Stenhammar J, Wennerström H, Sparr E. Vesicles Balance Osmotic Stress with Bending Energy That Can Be Released to Form Daughter Vesicles. J Phys Chem Lett 2022; 13:498-507. [PMID: 35005979 PMCID: PMC8785185 DOI: 10.1021/acs.jpclett.1c03369] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
The bending energy of the lipid membrane is central to biological processes involving vesicles, such as endocytosis and exocytosis. To illustrate the role of bending energy in these processes, we study the response of single-component giant unilamellar vesicles (GUVs) subjected to external osmotic stress by glucose addition. For osmotic pressures exceeding 0.15 atm, an abrupt shape change from spherical to prolate occurs, showing that the osmotic pressure is balanced by the free energy of membrane bending. After equilibration, the external glucose solution was exchanged for pure water, yielding rapid formation of monodisperse daughter vesicles inside the GUVs through an endocytosis-like process. Our theoretical analysis shows that this process requires significant free energies stored in the deformed membrane to be kinetically allowed. The results indicate that bending energies stored in GUVs are much higher than previously implicated, with potential consequences for vesicle fusion/fission and the osmotic regulation in living cells.
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Affiliation(s)
- Xiaoyan Liu
- Physical Chemistry, Lund University, 221 00 Lund, Sweden
| | | | | | - Emma Sparr
- Physical Chemistry, Lund University, 221 00 Lund, Sweden
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12
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Zhao Z, Roy D, Steinkühler J, Robinson T, Lipowsky R, Dimova R. Super-Resolution Imaging of Highly Curved Membrane Structures in Giant Vesicles Encapsulating Molecular Condensates. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106633. [PMID: 34710248 DOI: 10.1002/adma.202106633] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/14/2021] [Indexed: 06/13/2023]
Abstract
Molecular crowding is an inherent feature of cell interiors. Synthetic cells as provided by giant unilamellar vesicles (GUVs) encapsulating macromolecules (poly(ethylene glycol) and dextran) represent an excellent mimetic system to study membrane transformations associated with molecular crowding and protein condensation. Similarly to cells, such GUVs exhibit highly curved structures like nanotubes. Upon liquid-liquid phase separation their membrane deforms into apparent kinks at the contact line of the interface between the two aqueous phases. These structures, nanotubes, and kinks, have dimensions below optical resolution. Here, these are studied with super-resolution stimulated emission depletion (STED) microscopy facilitated by immobilization in a microfluidic device. The cylindrical nature of the nanotubes based on the superior resolution of STED and automated data analysis is demonstrated. The deduced membrane spontaneous curvature is in excellent agreement with theoretical predictions. Furthermore, the membrane kink-like structure is resolved as a smoothly curved membrane demonstrating the existence of the intrinsic contact angle, which describes the wettability contrast of the encapsulated phases to the membrane. Resolving these highly curved membrane structures with STED imaging provides important insights in the membrane properties and interactions underlying cellular activities.
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Affiliation(s)
- Ziliang Zhao
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745, Jena, Germany
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743, Jena, Germany
| | - Debjit Roy
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
| | - Jan Steinkühler
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
| | - Tom Robinson
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
| | - Reinhard Lipowsky
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
| | - Rumiana Dimova
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424, Potsdam, Germany
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13
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Guindani C, Caire da Silva L, Cao S, Ivanov T, Landfester K. Synthetic Cells: From Simple Bio-Inspired Modules to Sophisticated Integrated Systems. Angew Chem Int Ed Engl 2021; 61:e202110855. [PMID: 34856047 PMCID: PMC9314110 DOI: 10.1002/anie.202110855] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 11/08/2021] [Indexed: 12/01/2022]
Abstract
Bottom‐up synthetic biology is the science of building systems that mimic the structure and function of living cells from scratch. To do this, researchers combine tools from chemistry, materials science, and biochemistry to develop functional and structural building blocks to construct synthetic cell‐like systems. The many strategies and materials that have been developed in recent decades have enabled scientists to engineer synthetic cells and organelles that mimic the essential functions and behaviors of natural cells. Examples include synthetic cells that can synthesize their own ATP using light, maintain metabolic reactions through enzymatic networks, perform gene replication, and even grow and divide. In this Review, we discuss recent developments in the design and construction of synthetic cells and organelles using the bottom‐up approach. Our goal is to present representative synthetic cells of increasing complexity as well as strategies for solving distinct challenges in bottom‐up synthetic biology.
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Affiliation(s)
- Camila Guindani
- Federal University of Rio de Janeiro: Universidade Federal do Rio de Janeiro, Chemical Engineering Program, COPPE, BRAZIL
| | - Lucas Caire da Silva
- Max Planck Institute for Polymer Research, Physical Chemistry of Polymers, Ackermannweg 10, 55128, Mainz, GERMANY
| | - Shoupeng Cao
- Max Planck Institute for Polymer Research: Max-Planck-Institut fur Polymerforschung, Physical Chemistry of Polymers, GERMANY
| | - Tsvetomir Ivanov
- Max Planck Institute for Polymer Research: Max-Planck-Institut fur Polymerforschung, Physical Chemistry of Polymers, GERMANY
| | - Katharina Landfester
- Max Planck Institute for Polymer Research: Max-Planck-Institut fur Polymerforschung, Physical Chemistry of Polymers, GERMANY
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14
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ESCRT-III induces phase separation in model membranes prior to budding and causes invagination of the liquid-ordered phase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183689. [PMID: 34224704 DOI: 10.1016/j.bbamem.2021.183689] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 06/05/2021] [Accepted: 06/27/2021] [Indexed: 11/21/2022]
Abstract
Membrane fission triggered by the endosomal sorting complex required for transport (ESCRT) is an important process observed in several pathogenic and non-pathogenic cellular events. From a synthetic-biology viewpoint, ESCRT proteins represent an interesting machinery for the construction of cell mimetic sub-compartments produced by fission. Since their discovery, the studies on ESCRT-III-mediated action, have mainly focused on protein dynamics, ignoring the role of lipid organization and membrane phase state. Recently, it has been suggested that membrane buds formed by the action of ESCRT-III are generated from transient microdomains in endosomal membranes. However, the interplay between membrane domain formation and ESCRT remodeling pathways has not been investigated. Here, giant unilamellar vesicles made of ternary lipid mixtures, either homogeneous in phase or exhibiting liquid-ordered/liquid-disordered phase coexistence, were employed as a model membrane system. These vesicles were incubated with purified recombinant ESCRT-III proteins from the parasite Entamoeba histolytica. In homogeneous membranes, we observe that EhVps32 can trigger domain formation while EhVps20 preferentially co-localizes in the liquid disordered phase. The addition of EhVps24 appears to induce the formation of intraluminal vesicles produced from the liquid-ordered phase. In phase separated membranes, the intraluminal vesicles are also generated from the liquid-ordered phase and presumably emerge from the phase boundary region. Our findings reinforce the hypothesis that ESCRT-mediated remodeling depends on the membrane phase state. Furthermore, the obtained results point to a potential synthetic biology approach for establishing eukaryotic mimics of artificial cells with microcompartments of specific membrane composition, which can also differ from that of the mother vesicle.
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15
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Sønder SL, Häger SC, Heitmann ASB, Frankel LB, Dias C, Simonsen AC, Nylandsted J. Restructuring of the plasma membrane upon damage by LC3-associated macropinocytosis. SCIENCE ADVANCES 2021; 7:eabg1969. [PMID: 34215587 PMCID: PMC11057704 DOI: 10.1126/sciadv.abg1969] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 05/19/2021] [Indexed: 06/13/2023]
Abstract
The plasma membrane shapes and protects the eukaryotic cell from its surroundings and is crucial for cell life. Although initial repair mechanisms to reseal injured membranes are well established, less is known about how cells restructure damaged membranes in the aftermath to restore homeostasis. Here, we show that cells respond to plasma membrane injury by activating proteins associated with macropinocytosis specifically at the damaged membrane. Subsequent to membrane resealing, cells form large macropinosomes originating from the repair site, which eventually become positive for autophagy-related LC3B protein. This process occurs independent of ULK1, ATG13, and WIPI2 but dependent on ATG7, p62, and Rubicon. Internalized macropinosomes shrink in the cytoplasm, likely by osmotic draining, and eventually fuse with lysosomes. We propose that a form of macropinocytosis coupled to noncanonical autophagy, which we term LC3-associated macropinocytosis (LAM) functions to remove damaged material from the plasma membrane and restore membrane integrity upon injury.
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Affiliation(s)
- Stine Lauritzen Sønder
- Membrane Integrity, Danish Cancer Society Research Center, Strandboulevarden 49, 2100, Copenhagen, Denmark
| | - Swantje Christin Häger
- Membrane Integrity, Danish Cancer Society Research Center, Strandboulevarden 49, 2100, Copenhagen, Denmark
| | - Anne Sofie Busk Heitmann
- Membrane Integrity, Danish Cancer Society Research Center, Strandboulevarden 49, 2100, Copenhagen, Denmark
| | - Lisa B Frankel
- RNA and Autophagy, Danish Cancer Society Research Center, Strandboulevarden 49, 2100, Copenhagen, Denmark
- Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Catarina Dias
- Membrane Integrity, Danish Cancer Society Research Center, Strandboulevarden 49, 2100, Copenhagen, Denmark
| | - Adam Cohen Simonsen
- Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Jesper Nylandsted
- Membrane Integrity, Danish Cancer Society Research Center, Strandboulevarden 49, 2100, Copenhagen, Denmark.
- Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3C, DK-2200 Copenhagen N, Denmark
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Bhatia T. Tubules, beads, discs and junctions - Morphologies and dynamics of dispersed multilamellar lipid phases in excess water. J Colloid Interface Sci 2021; 584:706-713. [PMID: 33317711 DOI: 10.1016/j.jcis.2020.08.126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 11/17/2022]
Abstract
In this paper, experimental results on the swelling, dispersion and disintegration of the lamellae composed of the lipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in contact with excess water are described. Multilamellar structures nucleate and grow at the interface between the pure solvent and the lipid. The system evolves slowly via flow and coalescence of lamellae through a variety of non-equilibrium morphologies demonstrating that their dynamics is complex and non-universal, with no unique kinetic pathway. The tubular structures disintegrate slowly into the bulk water phase, inside the sealed sample chamber.
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Affiliation(s)
- T Bhatia
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science-Park, Golm, 14424 Potsdam.
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