1
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Sakamoto R, Murrell MP. Composite branched and linear F-actin maximize myosin-induced membrane shape changes in a biomimetic cell model. Commun Biol 2024; 7:840. [PMID: 38987288 PMCID: PMC11236970 DOI: 10.1038/s42003-024-06528-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 07/01/2024] [Indexed: 07/12/2024] Open
Abstract
The architecture of the actin cortex determines the generation and transmission of stresses, during key events from cell division to migration. However, its impact on myosin-induced cell shape changes remains unclear. Here, we reconstitute a minimal model of the actomyosin cortex with branched or linear F-actin architecture within giant unilamellar vesicles (GUVs, liposomes). Upon light activation of myosin, neither the branched nor linear F-actin architecture alone induces significant liposome shape changes. The branched F-actin network forms an integrated, membrane-bound "no-slip boundary" -like cortex that attenuates actomyosin contractility. By contrast, the linear F-actin network forms an unintegrated "slip boundary" -like cortex, where actin asters form without inducing membrane deformations. Notably, liposomes undergo significant deformations at an optimized balance of branched and linear F-actin networks. Our findings highlight the pivotal roles of branched F-actin in force transmission and linear F-actin in force generation to yield membrane shape changes.
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Affiliation(s)
- Ryota Sakamoto
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA.
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA.
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, USA.
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2
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Mendoza-Soto P, Jara C, Torres-Arévalo Á, Oyarzún C, Mardones GA, Quezada-Monrás C, San Martín R. Pharmacological Blockade of the Adenosine A 2B Receptor Is Protective of Proteinuria in Diabetic Rats, through Affecting Focal Adhesion Kinase Activation and the Adhesion Dynamics of Podocytes. Cells 2024; 13:846. [PMID: 38786068 PMCID: PMC11119713 DOI: 10.3390/cells13100846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/24/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024] Open
Abstract
Induction of the adenosine receptor A2B (A2BAR) expression in diabetic glomeruli correlates with an increased abundance of its endogenous ligand adenosine and the progression of kidney dysfunction. Remarkably, A2BAR antagonism protects from proteinuria in experimental diabetic nephropathy. We found that A2BAR antagonism preserves the arrangement of podocytes on the glomerular filtration barrier, reduces diabetes-induced focal adhesion kinase (FAK) activation, and attenuates podocyte foot processes effacement. In spreading assays using human podocytes in vitro, adenosine enhanced the rate of cell body expansion on laminin-coated glass and promoted peripheral pY397-FAK subcellular distribution, while selective A2BAR antagonism impeded these effects and attenuated the migratory capability of podocytes. Increased phosphorylation of the Myosin2A light chain accompanied the effects of adenosine. Furthermore, when the A2BAR was stimulated, the cells expanded more broadly and more staining of pS19 myosin was detected which co-localized with actin cables, suggesting increased contractility potential in cells planted onto a matrix with a stiffness similar to of the glomerular basement membrane. We conclude that A2BAR is involved in adhesion dynamics and contractile actin bundle formation, leading to podocyte foot processes effacement. The antagonism of this receptor may be an alternative to the intervention of glomerular barrier deterioration and proteinuria in the diabetic kidney disease.
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Affiliation(s)
- Pablo Mendoza-Soto
- Molecular Pathology Laboratory, Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia 5110566, Chile; (P.M.-S.); (C.J.); (Á.T.-A.); (C.O.)
| | - Claudia Jara
- Molecular Pathology Laboratory, Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia 5110566, Chile; (P.M.-S.); (C.J.); (Á.T.-A.); (C.O.)
| | - Ángelo Torres-Arévalo
- Molecular Pathology Laboratory, Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia 5110566, Chile; (P.M.-S.); (C.J.); (Á.T.-A.); (C.O.)
| | - Carlos Oyarzún
- Molecular Pathology Laboratory, Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia 5110566, Chile; (P.M.-S.); (C.J.); (Á.T.-A.); (C.O.)
| | - Gonzalo A. Mardones
- Institute of Physiology, Medicine Faculty, Universidad Austral de Chile, Valdivia 5090000, Chile;
| | - Claudia Quezada-Monrás
- Tumor Biology Laboratory, Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia 5110566, Chile;
- Millennium Institute on Immunology and Immunotherapy, Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Rody San Martín
- Molecular Pathology Laboratory, Institute of Biochemistry and Microbiology, Science Faculty, Universidad Austral de Chile, Valdivia 5110566, Chile; (P.M.-S.); (C.J.); (Á.T.-A.); (C.O.)
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3
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Sakamoto R, Murrell MP. F-actin architecture determines the conversion of chemical energy into mechanical work. Nat Commun 2024; 15:3444. [PMID: 38658549 PMCID: PMC11043346 DOI: 10.1038/s41467-024-47593-x] [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: 10/13/2023] [Accepted: 04/03/2024] [Indexed: 04/26/2024] Open
Abstract
Mechanical work serves as the foundation for dynamic cellular processes, ranging from cell division to migration. A fundamental driver of cellular mechanical work is the actin cytoskeleton, composed of filamentous actin (F-actin) and myosin motors, where force generation relies on adenosine triphosphate (ATP) hydrolysis. F-actin architectures, whether bundled by crosslinkers or branched via nucleators, have emerged as pivotal regulators of myosin II force generation. However, it remains unclear how distinct F-actin architectures impact the conversion of chemical energy to mechanical work. Here, we employ in vitro reconstitution of distinct F-actin architectures with purified components to investigate their influence on myosin ATP hydrolysis (consumption). We find that F-actin bundles composed of mixed polarity F-actin hinder network contraction compared to non-crosslinked network and dramatically decelerate ATP consumption rates. Conversely, linear-nucleated networks allow network contraction despite reducing ATP consumption rates. Surprisingly, branched-nucleated networks facilitate high ATP consumption without significant network contraction, suggesting that the branched network dissipates energy without performing work. This study establishes a link between F-actin architecture and myosin energy consumption, elucidating the energetic principles underlying F-actin structure formation and the performance of mechanical work.
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Affiliation(s)
- Ryota Sakamoto
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA.
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA.
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, USA.
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4
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Waechtler BE, Jayasankar R, Morin EP, Robinson DN. Benefits and challenges of reconstituting the actin cortex. Cytoskeleton (Hoboken) 2024. [PMID: 38520148 DOI: 10.1002/cm.21855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/21/2024] [Accepted: 03/05/2024] [Indexed: 03/25/2024]
Abstract
The cell's ability to change shape is a central feature in many cellular processes, including cytokinesis, motility, migration, and tissue formation. The cell constructs a network of contractile proteins underneath the cell membrane to form the cortex, and the reorganization of these components directly contributes to cellular shape changes. The desire to mimic these cell shape changes to aid in the creation of a synthetic cell has been increasing. Therefore, membrane-based reconstitution experiments have flourished, furthering our understanding of the minimal components the cell uses throughout these processes. Although biochemical approaches increased our understanding of actin, myosin II, and actin-associated proteins, using membrane-based reconstituted systems has further expanded our understanding of actin structures and functions because membrane-cortex interactions can be analyzed. In this review, we highlight the recent developments in membrane-based reconstitution techniques. We examine the current findings on the minimal components needed to recapitulate distinct actin structures and functions and how they relate to the cortex's impact on cellular mechanical properties. We also explore how co-processing of computational models with wet-lab experiments enhances our understanding of these properties. Finally, we emphasize the benefits and challenges inherent to membrane-based, reconstitution assays, ranging from the advantage of precise control over the system to the difficulty of integrating these findings into the complex cellular environment.
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Affiliation(s)
- Brooke E Waechtler
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rajan Jayasankar
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Baltimore, Maryland, USA
| | - Emma P Morin
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Douglas N Robinson
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Baltimore, Maryland, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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5
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Kandiyoth FB, Michelot A. Reconstitution of actin-based cellular processes: Why encapsulation changes the rules. Eur J Cell Biol 2023; 102:151368. [PMID: 37922812 DOI: 10.1016/j.ejcb.2023.151368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/02/2023] [Accepted: 10/20/2023] [Indexed: 11/07/2023] Open
Abstract
While in vitro reconstitution of cellular processes is progressing rapidly, the encapsulation of biomimetic systems to reproduce the cellular environment is a major challenge. Here we review the difficulties, using reconstitution of processes dependent on actin polymerization as an example. Some of the problems are purely technical, due to the need for engineering strategies to encapsulate concentrated solutions in micrometer-sized compartments. However, other significant issues arise from the reduction of experimental volumes, which alters the chemical evolution of these non-equilibrium systems. Important parameters to consider for successful reconstitutions are the amount of each component, their consumption and renewal rates to guarantee their continuous availability.
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Affiliation(s)
| | - Alphée Michelot
- Aix Marseille Univ, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France.
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6
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Sakamoto R, Banerjee DS, Yadav V, Chen S, Gardel M, Sykes C, Banerjee S, Murrell MP. Membrane tension induces F-actin reorganization and flow in a biomimetic model cortex. Commun Biol 2023; 6:325. [PMID: 36973388 PMCID: PMC10043271 DOI: 10.1038/s42003-023-04684-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 03/07/2023] [Indexed: 03/28/2023] Open
Abstract
AbstractThe accumulation and transmission of mechanical stresses in the cell cortex and membrane determines the mechanics of cell shape and coordinates essential physical behaviors, from cell polarization to cell migration. However, the extent that the membrane and cytoskeleton each contribute to the transmission of mechanical stresses to coordinate diverse behaviors is unclear. Here, we reconstitute a minimal model of the actomyosin cortex within liposomes that adheres, spreads and ultimately ruptures on a surface. During spreading, accumulated adhesion-induced (passive) stresses within the membrane drive changes in the spatial assembly of actin. By contrast, during rupture, accumulated myosin-induced (active) stresses within the cortex determine the rate of pore opening. Thus, in the same system, devoid of biochemical regulation, the membrane and cortex can each play a passive or active role in the generation and transmission of mechanical stress, and their relative roles drive diverse biomimetic physical behaviors.
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7
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Baldauf L, Frey F, Arribas Perez M, Idema T, Koenderink GH. Branched actin cortices reconstituted in vesicles sense membrane curvature. Biophys J 2023:S0006-3495(23)00124-8. [PMID: 36806830 DOI: 10.1016/j.bpj.2023.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/16/2022] [Accepted: 02/14/2023] [Indexed: 02/19/2023] Open
Abstract
The actin cortex is a complex cytoskeletal machinery that drives and responds to changes in cell shape. It must generate or adapt to plasma membrane curvature to facilitate diverse functions such as cell division, migration, and phagocytosis. Due to the complex molecular makeup of the actin cortex, it remains unclear whether actin networks are inherently able to sense and generate membrane curvature, or whether they rely on their diverse binding partners to accomplish this. Here, we show that curvature sensing is an inherent capability of branched actin networks nucleated by Arp2/3 and VCA. We develop a robust method to encapsulate actin inside giant unilamellar vesicles (GUVs) and assemble an actin cortex at the inner surface of the GUV membrane. We show that actin forms a uniform and thin cortical layer when present at high concentration and distinct patches associated with negative membrane curvature at low concentration. Serendipitously, we find that the GUV production method also produces dumbbell-shaped GUVs, which we explain using mathematical modeling in terms of membrane hemifusion of nested GUVs. We find that branched actin networks preferentially assemble at the neck of the dumbbells, which possess a micrometer-range convex curvature comparable with the curvature of the actin patches found in spherical GUVs. Minimal branched actin networks can thus sense membrane curvature, which may help mammalian cells to robustly recruit actin to curved membranes to facilitate diverse cellular functions such as cytokinesis and migration.
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Affiliation(s)
- Lucia Baldauf
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Felix Frey
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Marcos Arribas Perez
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands
| | - Timon Idema
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands.
| | - Gijsje H Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, the Netherlands.
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8
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Lopes dos Santos R, Campillo C. Studying actin-induced cell shape changes using Giant Unilamellar Vesicles and reconstituted actin networks. Biochem Soc Trans 2022; 50:1527-1539. [PMID: 36111807 PMCID: PMC9704537 DOI: 10.1042/bst20220900] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/12/2022] [Accepted: 08/22/2022] [Indexed: 10/05/2023]
Abstract
Cell shape changes that are fuelled by the dynamics of the actomyosin cytoskeleton control cellular processes such as motility and division. However, the mechanisms of interplay between cell membranes and actomyosin are complicated to decipher in the complex environment of the cytoplasm. Using biomimetic systems offers an alternative approach to studying cell shape changes in assays with controlled biochemical composition. Biomimetic systems allow quantitative experiments that can help to build physical models describing the processes of cell shape changes. This article reviews works in which actin networks are reconstructed inside or outside cell-sized Giant Unilamellar Vesicles (GUVs), which are models of cell membranes. We show how various actin networks affect the shape and mechanics of GUVs and how some cell shape changes can be reproduced in vitro using these minimal systems.
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Affiliation(s)
- Rogério Lopes dos Santos
- LAMBE, Université d'Evry Val d'Essonne, CNRS, CEA, Université Paris-Saclay, 91025 Evry-Courcouronnes, France
| | - Clément Campillo
- LAMBE, Université d'Evry Val d'Essonne, CNRS, CEA, Université Paris-Saclay, 91025 Evry-Courcouronnes, France
- Institut Universitaire de France (IUF), Paris, France
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9
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Baldauf L, van Buren L, Fanalista F, Koenderink GH. Actomyosin-Driven Division of a Synthetic Cell. ACS Synth Biol 2022; 11:3120-3133. [PMID: 36164967 PMCID: PMC9594324 DOI: 10.1021/acssynbio.2c00287] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Indexed: 01/24/2023]
Abstract
One of the major challenges of bottom-up synthetic biology is rebuilding a minimal cell division machinery. From a reconstitution perspective, the animal cell division apparatus is mechanically the simplest and therefore attractive to rebuild. An actin-based ring produces contractile force to constrict the membrane. By contrast, microbes and plant cells have a cell wall, so division requires concerted membrane constriction and cell wall synthesis. Furthermore, reconstitution of the actin division machinery helps in understanding the physical and molecular mechanisms of cytokinesis in animal cells and thus our own cells. In this review, we describe the state-of-the-art research on reconstitution of minimal actin-mediated cytokinetic machineries. Based on the conceptual requirements that we obtained from the physics of the shape changes involved in cell division, we propose two major routes for building a minimal actin apparatus capable of division. Importantly, we acknowledge both the passive and active roles that the confining lipid membrane can play in synthetic cytokinesis. We conclude this review by identifying the most pressing challenges for future reconstitution work, thereby laying out a roadmap for building a synthetic cell equipped with a minimal actin division machinery.
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Affiliation(s)
| | | | - Federico Fanalista
- Department of Bionanoscience,
Kavli Institute of Nanoscience Delft, Delft
University of Technology, 2629 HZ Delft, The Netherlands
| | - Gijsje Hendrika Koenderink
- Department of Bionanoscience,
Kavli Institute of Nanoscience Delft, Delft
University of Technology, 2629 HZ Delft, The Netherlands
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10
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Systematic design of cell membrane coating to improve tumor targeting of nanoparticles. Nat Commun 2022; 13:6181. [PMID: 36261418 PMCID: PMC9580449 DOI: 10.1038/s41467-022-33889-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 10/06/2022] [Indexed: 12/24/2022] Open
Abstract
Cell membrane (CM) coating technology is increasingly being applied in nanomedicine, but the entire coating procedure including adsorption, rupture, and fusion is not completely understood. Previously, we showed that the majority of biomimetic nanoparticles (NPs) were only partially coated, but the mechanism underlying this partial coating remains unclear, which hinders the further improvement of the coating technique. Here, we show that partial coating is an intermediate state due to the adsorption of CM fragments or CM vesicles, the latter of which could eventually be ruptured under external force. Such partial coating is difficult to self-repair to achieve full coating due to the limited membrane fluidity. Building on our understanding of the detailed coating process, we develop a general approach for fixing the partial CM coating: external phospholipid is introduced as a helper to increase CM fluidity, promoting the final fusion of lipid patches. The NPs coated with this approach have a high ratio of full coating (~23%) and exhibit enhanced tumor targeting ability in comparison to the NPs coated traditionally (full coating ratio of ~6%). Our results provide a mechanistic basis for fixing partial CM coating towards enhancing tumor accumulation.
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11
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Geometric trade-off between contractile force and viscous drag determines the actomyosin-based motility of a cell-sized droplet. Proc Natl Acad Sci U S A 2022; 119:e2121147119. [PMID: 35857875 PMCID: PMC9335187 DOI: 10.1073/pnas.2121147119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cell migration in confined environments is fundamental for diverse biological processes from cancer invasion to leukocyte trafficking. The cell body is propelled by the contractile force of actomyosin networks transmitted from the cell membrane to the external substrates. However, physical determinants of actomyosin-based migration capacity in confined environments are not fully understood. Here, we develop an in vitro migratory cell model, where cytoplasmic actomyosin networks are encapsulated into droplets surrounded by a lipid monolayer membrane. We find that the droplet can move when the actomyosin networks are bound to the membrane, in which the physical interaction between the contracting actomyosin networks and the membrane generates a propulsive force. The droplet moves faster when it has a larger contact area with the substrates, while narrower confinement reduces the migration speed. By combining experimental observations and active gel theory, we propose a mechanism where the balance between sliding friction force, which is a reaction force of the contractile force, and viscous drag determines the migration speed, providing a physical basis of actomyosin-based motility in confined environments.
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12
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Yousafzai MS, Yadav V, Amiri S, Staddon MF, Errami Y, Jaspard G, Banerjee S, Murrell M. Cell-Matrix Elastocapillary Interactions Drive Pressure-based Wetting of Cell Aggregates. PHYSICAL REVIEW. X 2022; 12:031027. [PMID: 38009085 PMCID: PMC10673637 DOI: 10.1103/physrevx.12.031027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
Cell-matrix interfacial energies and the energies of matrix deformations may be comparable on cellular length-scales, yet how capillary effects influence tis sue shape and motion are unknown. In this work, we induce wetting (spreading and migration) of cell aggregates, as models of active droplets onto adhesive substrates of varying elasticity and correlate the dynamics of wetting to the balance of interfacial tensions. Upon wetting rigid substrates, cell-substrate tension drives outward expansion of the monolayer. By contrast, upon wetting compliant substrates, cell substrate tension is attenuated and aggregate capillary forces contribute to internal pressures that drive expansion. Thus, we show by experiments, data-driven modeling and computational simulations that myosin-driven 'active elasto-capillary' effects enable adaptation of wetting mechanisms to substrate rigidity and introduce a novel, pressure-based mechanism for guiding collective cell motion.
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Affiliation(s)
- M S Yousafzai
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
| | - V Yadav
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
| | - S Amiri
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
- Department of Mechanical Engineering and Material Science, Yale University, 10 Hillhouse Avenue, New Haven, Connecticut 06511, USA
| | - M F Staddon
- Center for Systems Biology Dresden, Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Y Errami
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
- Department of Genetics, Yale School of Medicine, Sterling Hall of Medicine, 333 Cedar Street, New Haven, 06510
- Center for Cancer Systems Biology, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
| | - G Jaspard
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
| | - S Banerjee
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA and
| | - M Murrell
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06511, USA
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13
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Beaune G, Sinkkonen L, Gonzalez-Rodriguez D, Timonen JVI, Brochard-Wyart F. Fusion Dynamics of Hybrid Cell-Microparticle Aggregates: A Jelly Pearl Model. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:5296-5306. [PMID: 35109658 DOI: 10.1021/acs.langmuir.1c02949] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We study the fusion of homogeneous cell aggregates and of hybrid aggregates combining cells and microparticles. In all cases, we find that the contact area does not vary linearly over time, as observed for liquid drops, but rather it follows a power law in t2/3. This result is interpreted by generalizing the fusion model of soft viscoelastic solid balls to viscoelastic liquid balls, akin to jelly pearls. We also explore the asymmetric fusion between a homogeneous aggregate and a hybrid aggregate. This latter experiment allows the determination of the self-diffusion coefficient of the cells in a tissue by following the spatial distribution of internalized particles in the cells.
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Affiliation(s)
- Grégory Beaune
- Department of Applied Physics, Aalto University School of Science, Puumiehenkuja 2, 02150 Espoo, Finland
| | - Laura Sinkkonen
- Department of Applied Physics, Aalto University School of Science, Puumiehenkuja 2, 02150 Espoo, Finland
| | | | - Jaakko V I Timonen
- Department of Applied Physics, Aalto University School of Science, Puumiehenkuja 2, 02150 Espoo, Finland
| | - Françoise Brochard-Wyart
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, 75005 Paris, France
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14
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Abstract
Giant unilamellar vesicles (GUVs) have gained great popularity as mimicries for cellular membranes. As their sizes are comfortably above the optical resolution limit, and their lipid composition is easily controlled, they are ideal for quantitative light microscopic investigation of dynamic processes in and on membranes. However, reconstitution of functional proteins into the lumen or the GUV membrane itself has proven technically challenging. In recent years, a selection of techniques has been introduced that tremendously improve GUV-assay development and enable the precise investigation of protein-membrane interactions under well-controlled conditions. Moreover, due to these methodological advances, GUVs are considered important candidates as protocells in bottom-up synthetic biology. In this review, we discuss the state of the art of the most important vesicle production and protein encapsulation methods and highlight some key protein systems whose functional reconstitution has advanced the field.
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Affiliation(s)
- Thomas Litschel
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; ,
| | - Petra Schwille
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; ,
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15
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Baschieri F, Porshneva K, Montagnac G. Frustrated clathrin-mediated endocytosis – causes and possible functions. J Cell Sci 2020; 133:133/11/jcs240861. [DOI: 10.1242/jcs.240861] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
ABSTRACT
Clathrin-mediated endocytosis is the main entry route for most cell surface receptors and their ligands. It is regulated by clathrin-coated structures that are endowed with the ability to cluster receptors and to locally bend the plasma membrane, resulting in the formation of receptor-containing vesicles that bud into the cytoplasm. This canonical role of clathrin-coated structures has been shown to play a fundamental part in many different aspects of cell physiology. However, it has recently become clear that the ability of clathrin-coated structures to deform membranes can be perturbed. In addition to chemical or genetic alterations, numerous environmental conditions can physically prevent or slow down membrane bending and/or budding at clathrin-coated structures. The resulting ‘frustrated endocytosis’ is emerging as not merely a passive consequence, but one that actually fulfils some very specific and important cellular functions. In this Review, we provide an historical and defining perspective on frustrated endocytosis in the clathrin pathway of mammalian cells, before discussing its causes and highlighting the possible functional consequences in physiology and diseases.
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Affiliation(s)
- Francesco Baschieri
- Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, Villejuif 94805, France
| | - Kseniia Porshneva
- Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, Villejuif 94805, France
| | - Guillaume Montagnac
- Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, Villejuif 94805, France
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16
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Oda A, Watanabe C, Aoki N, Yanagisawa M. Liposomal adhesion via electrostatic interactions and osmotic deflation increase membrane tension and lipid diffusion coefficient. SOFT MATTER 2020; 16:4549-4554. [PMID: 32364199 DOI: 10.1039/d0sm00416b] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Membrane adhesion is a ubiquitous phenomenon in cells and is related to various biological events such as migration, morphogenesis, and differentiation. To understand the physicochemical aspects of membrane adhesion, liposome-liposome adhesion and liposome-substrate adhesion have been studied. Although membrane adhesion has been shown to increase membrane tension and inhibit lipid diffusion, the relationship between these changes and the degree of membrane adhesion have not been quantified. Here, we analyzed the dependence of membrane tension and lipid diffusion on the degree of membrane adhesion, i.e., area fraction of the adherent region. For this purpose, we developed a simple method to prepare adhered liposomes by simple electrostatic interactions between the membranes and by osmotic deflation. We found that the membrane tension of the adhered liposomes increases slightly with an increase in the area fraction of the adherent region. In addition, the lipid diffusion coefficient of the adhered liposomes is larger than that of isolated liposomes, which is consistent with the theoretical prediction. The analysis provides a framework to understand the correlation between cell adhesion and bio-membrane properties such as membrane tension and molecular diffusion.
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Affiliation(s)
- Atsushi Oda
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Chiho Watanabe
- Komaba Institute for Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan.
| | - Natsumi Aoki
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Miho Yanagisawa
- Komaba Institute for Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan. and Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan
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17
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Mietke A, Jemseena V, Kumar KV, Sbalzarini IF, Jülicher F. Minimal Model of Cellular Symmetry Breaking. PHYSICAL REVIEW LETTERS 2019; 123:188101. [PMID: 31763902 DOI: 10.1103/physrevlett.123.188101] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Indexed: 06/10/2023]
Abstract
The cell cortex, a thin film of active material assembled below the cell membrane, plays a key role in cellular symmetry-breaking processes such as cell polarity establishment and cell division. Here, we present a minimal model of the self-organization of the cell cortex that is based on a hydrodynamic theory of curved active surfaces. Active stresses on this surface are regulated by a diffusing molecular species. We show that coupling of the active surface to a passive bulk fluid enables spontaneous polarization and the formation of a contractile ring on the surface via mechanochemical instabilities. We discuss the role of external fields in guiding such pattern formation. Our work reveals that key features of cellular symmetry breaking and cell division can emerge in a minimal model via general dynamic instabilities.
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Affiliation(s)
- Alexander Mietke
- Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
- Chair of Scientific Computing for Systems Biology, Faculty of Computer Science, TU Dresden, 01187 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - V Jemseena
- International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, 560 089 Bengaluru, India
| | - K Vijay Kumar
- International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, 560 089 Bengaluru, India
| | - Ivo F Sbalzarini
- Chair of Scientific Computing for Systems Biology, Faculty of Computer Science, TU Dresden, 01187 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01307 Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01307 Dresden, Germany
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18
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Omidvar R, Römer W. Glycan-decorated protocells: novel features for rebuilding cellular processes. Interface Focus 2019; 9:20180084. [PMID: 30842879 PMCID: PMC6388021 DOI: 10.1098/rsfs.2018.0084] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2019] [Indexed: 02/06/2023] Open
Abstract
In synthetic biology approaches, lipid vesicles are widely used as protocell models. While many compounds have been encapsulated in vesicles (e.g. DNA, cytoskeleton and enzymes), the incorporation of glycocalyx components in the lipid bilayer has attracted much less attention so far. In recent years, glycoconjugates have been integrated in the membrane of giant unilamellar vesicles (GUVs). These minimal membrane systems have largely contributed to shed light on the molecular mechanisms of cellular processes. In this review, we first introduce several preparation and biophysical characterization methods of GUVs. Then, we highlight specific applications of protocells investigating glycolipid-mediated endocytosis of toxins, viruses and bacteria. In addition, we delineate how prototissues have been assembled from glycan-decorated protocells by using lectin-mediated cross-linking of opposed glycoreceptors (e.g. glycolipids and glycopeptides). In future applications, glycan-decorated protocells might be useful for investigating cell-cell interactions (e.g. adhesion and communication). We also speculate about the implication of lectin-glycoreceptor interactions in membrane fusion processes.
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Affiliation(s)
- Ramin Omidvar
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technology (FIT), Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
| | - Winfried Römer
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technology (FIT), Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
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19
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Maan R, Loiseau E, Bausch AR. Adhesion of Active Cytoskeletal Vesicles. Biophys J 2018; 115:2395-2402. [PMID: 30455042 PMCID: PMC6301914 DOI: 10.1016/j.bpj.2018.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 10/08/2018] [Accepted: 10/12/2018] [Indexed: 11/08/2022] Open
Abstract
Regulation of adhesion is a ubiquitous feature of living cells, observed during processes such as motility, antigen recognition, or rigidity sensing. At the molecular scale, a myriad of mechanisms are necessary to recruit and activate the essential proteins, whereas at the cellular scale, efficient regulation of adhesion relies on the cell's ability to adapt its global shape. To understand the role of shape remodeling during adhesion, we use a synthetic biology approach to design a minimal experimental model, starting with a limited number of building blocks. We assemble cytoskeletal vesicles whose size, reduced volume, and cytoskeletal contractility can be independently tuned. We show that these cytoskeletal vesicles can sustain strong adhesion to solid substrates only if the actin cortex is actively remodeled significantly. When the cytoskeletal vesicles are deformed under hypertonic osmotic pressure, they develop a crumpled geometry with deformations. In the presence of molecular motors, these deformations are dynamic in nature, and the excess membrane area generated thereby can be used to gain adhesion energy. The cytoskeletal vesicles are able to attach to the rigid glass surfaces even under strong adhesive forces just like the cortex-free vesicles. The balance of deformability and adhesion strength is identified to be key to enable cytoskeletal vesicles to adhere to solid substrates.
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Affiliation(s)
- Renu Maan
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany; Department of Bionanoscience, Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Etienne Loiseau
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany; Aix-Marseille Université, CNRS, CINAM, Marseille, France
| | - Andreas R Bausch
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany.
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20
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Göpfrich K, Platzman I, Spatz JP. Mastering Complexity: Towards Bottom-up Construction of Multifunctional Eukaryotic Synthetic Cells. Trends Biotechnol 2018; 36:938-951. [PMID: 29685820 PMCID: PMC6100601 DOI: 10.1016/j.tibtech.2018.03.008] [Citation(s) in RCA: 156] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 12/11/2022]
Abstract
With the ultimate aim to construct a living cell, bottom-up synthetic biology strives to reconstitute cellular phenomena in vitro - disentangled from the complex environment of a cell. Recent work towards this ambitious goal has provided new insights into the mechanisms governing life. With the fast-growing library of functional modules for synthetic cells, their classification and integration become increasingly important. We discuss strategies to reverse-engineer and recombine functional parts for synthetic eukaryotes, mimicking the characteristics of nature's own prototype. Particularly, we focus on large outer compartments, complex endomembrane systems with organelles, and versatile cytoskeletons as hallmarks of eukaryotic life. Moreover, we identify microfluidics and DNA nanotechnology as two technologies that can integrate these functional modules into sophisticated multifunctional synthetic cells.
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Affiliation(s)
- Kerstin Göpfrich
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Jahnstraße 29, D 69120, Heidelberg, Germany; Department of Biophysical Chemistry, University of Heidelberg, Im Neuenheimer Feld 253, D 69120 Heidelberg, Germany.
| | - Ilia Platzman
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Jahnstraße 29, D 69120, Heidelberg, Germany; Department of Biophysical Chemistry, University of Heidelberg, Im Neuenheimer Feld 253, D 69120 Heidelberg, Germany.
| | - Joachim P Spatz
- Max Planck Institute for Medical Research, Department of Cellular Biophysics, Jahnstraße 29, D 69120, Heidelberg, Germany; Department of Biophysical Chemistry, University of Heidelberg, Im Neuenheimer Feld 253, D 69120 Heidelberg, Germany.
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21
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Chabanon M, Stachowiak JC, Rangamani P. Systems biology of cellular membranes: a convergence with biophysics. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2017; 9:10.1002/wsbm.1386. [PMID: 28475297 PMCID: PMC5561455 DOI: 10.1002/wsbm.1386] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/02/2017] [Accepted: 02/21/2017] [Indexed: 12/12/2022]
Abstract
Systems biology and systems medicine have played an important role in the last two decades in shaping our understanding of biological processes. While systems biology is synonymous with network maps and '-omics' approaches, it is not often associated with mechanical processes. Here, we make the case for considering the mechanical and geometrical aspects of biological membranes as a key step in pushing the frontiers of systems biology of cellular membranes forward. We begin by introducing the basic components of cellular membranes, and highlight their dynamical aspects. We then survey the functions of the plasma membrane and the endomembrane system in signaling, and discuss the role and origin of membrane curvature in these diverse cellular processes. We further give an overview of the experimental and modeling approaches to study membrane phenomena. We close with a perspective on the converging futures of systems biology and membrane biophysics, invoking the need to include physical variables such as location and geometry in the study of cellular membranes. WIREs Syst Biol Med 2017, 9:e1386. doi: 10.1002/wsbm.1386 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Morgan Chabanon
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
| | - Jeanne C. Stachowiak
- Department of Biomedical Engineering, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
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22
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Lemière J, Valentino F, Campillo C, Sykes C. How cellular membrane properties are affected by the actin cytoskeleton. Biochimie 2016; 130:33-40. [PMID: 27693515 DOI: 10.1016/j.biochi.2016.09.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/26/2016] [Indexed: 11/30/2022]
Abstract
Lipid membranes define the boundaries of living cells and intracellular compartments. The dynamic remodelling of these membranes by the cytoskeleton, a very dynamic structure made of active biopolymers, is crucial in many biological processes such as motility or division. In this review, we present some aspects of cellular membranes and how they are affected by the presence of the actin cytoskeleton. We show that, in parallel with the direct study of membranes and cytoskeleton in vivo, biomimetic in vitro systems allow reconstitution of biological processes in a controlled environment. In particular, we show that liposomes, or giant unilamellar vesicles, encapsulating a reconstituted actin network polymerizing at their membrane are suitable models of living cells and can be used to decipher the relative contributions of membrane and actin on the mechanical properties of the cellular interface.
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Affiliation(s)
- J Lemière
- Department of Molecular Biophysics and Biochemistry, Nanobiology Institute, Yale University, New Haven, CT, USA.
| | - F Valentino
- Institut Curie, PSL Research University, CNRS, UMR 168, 75005, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, 4 place Jussieu, 75005, Paris, France; Univ Paris Diderot, Sorbonne Paris Cité, 5 rue Thomas-Mann, 75205, Paris, France
| | - C Campillo
- Université Evry Val d'Essonne, LAMBE, Boulevard F Mitterrand, Evry, 91025, France
| | - C Sykes
- Institut Curie, PSL Research University, CNRS, UMR 168, 75005, Paris, France.
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23
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Mechanics of Biomimetic Liposomes Encapsulating an Actin Shell. Biophys J 2016; 109:2471-2479. [PMID: 26682806 PMCID: PMC4701011 DOI: 10.1016/j.bpj.2015.10.050] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 07/27/2015] [Accepted: 10/16/2015] [Indexed: 12/02/2022] Open
Abstract
Cell-shape changes are insured by a thin, dynamic, cortical layer of cytoskeleton underneath the plasma membrane. How this thin cortical structure impacts the mechanical properties of the whole cell is not fully understood. Here, we study the mechanics of liposomes or giant unilamellar vesicles, when a biomimetic actin cortex is grown at the inner layer of the lipid membrane via actin-nucleation-promoting factors. Using a hydrodynamic tube-pulling technique, we show that tube dynamics is clearly affected by the presence of an actin shell anchored to the lipid bilayer. The same force pulls much shorter tubes in the presence of the actin shell compared to bare membranes. However, in both cases, we observe that the dynamics of tube extrusion has two distinct features characteristic of viscoelastic materials: rapid elastic elongation, followed by a slower elongation phase at a constant rate. We interpret the initial elastic regime by an increase of membrane tension due to the loss of lipids into the tube. Tube length is considerably shorter for cortex liposomes at comparable pulling forces, resulting in a higher spring constant. The presence of the actin shell seems to restrict lipid mobility, as is observed in the corral effect in cells. The viscous regime for bare liposomes corresponds to a leakout of the internal liquid at constant membrane tension. The presence of the actin shell leads to a larger friction coefficient. As the tube is pulled from a patchy surface, membrane tension increases locally, leading to a Marangoni flow of lipids. As a conclusion, the presence of an actin shell is revealed by its action that alters membrane mechanics.
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24
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Denning D, Roos WH. Elucidating the molecular mechanisms underlying cellular response to biophysical cues using synthetic biology approaches. Cell Adh Migr 2016; 10:540-553. [PMID: 27266767 DOI: 10.1080/19336918.2016.1170259] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The use of synthetic surfaces and materials to influence and study cell behavior has vastly progressed our understanding of the underlying molecular mechanisms involved in cellular response to physicochemical and biophysical cues. Reconstituting cytoskeletal proteins and interfacing them with a defined microenvironment has also garnered deep insight into the engineering mechanisms existing within the cell. This review presents recent experimental findings on the influence of several parameters of the extracellular environment on cell behavior and fate, such as substrate topography, stiffness, chemistry and charge. In addition, the use of synthetic environments to measure physical properties of the reconstituted cytoskeleton and their interaction with intracellular proteins such as molecular motors is discussed, which is relevant for understanding cell migration, division and structural integrity, as well as intracellular transport. Insight is provided regarding the next steps to be taken in this interdisciplinary field, in order to achieve the global aim of artificially directing cellular response.
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Affiliation(s)
- Denise Denning
- a Moleculaire Biofysica , Zernike instituut, Rijksuniversiteit Groningen , Groningen , The Netherlands
| | - Wouter H Roos
- a Moleculaire Biofysica , Zernike instituut, Rijksuniversiteit Groningen , Groningen , The Netherlands
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25
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Loiseau E, Schneider JAM, Keber FC, Pelzl C, Massiera G, Salbreux G, Bausch AR. Shape remodeling and blebbing of active cytoskeletal vesicles. SCIENCE ADVANCES 2016; 2:e1500465. [PMID: 27152328 PMCID: PMC4846454 DOI: 10.1126/sciadv.1500465] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 03/22/2016] [Indexed: 05/21/2023]
Abstract
Morphological transformations of living cells, such as shape adaptation to external stimuli, blebbing, invagination, or tethering, result from an intricate interplay between the plasma membrane and its underlying cytoskeleton, where molecular motors generate forces. Cellular complexity defies a clear identification of the competing processes that lead to such a rich phenomenology. In a synthetic biology approach, designing a cell-like model assembled from a minimal set of purified building blocks would allow the control of all relevant parameters. We reconstruct actomyosin vesicles in which the coupling of the cytoskeleton to the membrane, the topology of the cytoskeletal network, and the contractile activity can all be precisely controlled and tuned. We demonstrate that tension generation of an encapsulated active actomyosin network suffices for global shape transformation of cell-sized lipid vesicles, which are reminiscent of morphological adaptations in living cells. The observed polymorphism of our cell-like model, such as blebbing, tether extrusion, or faceted shapes, can be qualitatively explained by the protein concentration dependencies and a force balance, taking into account the membrane tension, the density of anchoring points between the membrane and the actin network, and the forces exerted by molecular motors in the actin network. The identification of the physical mechanisms for shape transformations of active cytoskeletal vesicles sets a conceptual and quantitative benchmark for the further exploration of the adaptation mechanisms of cells.
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Affiliation(s)
- Etienne Loiseau
- Department of Physics, Technische Universität München, 85748 Garching, Germany
| | | | - Felix C. Keber
- Department of Physics, Technische Universität München, 85748 Garching, Germany
| | - Carina Pelzl
- Department of Physics, Technische Universität München, 85748 Garching, Germany
| | - Gladys Massiera
- Université de Montpellier, Laboratoire Charles Coulomb, UMR 5221, CNRS, F-34095 Montpellier, France
| | - Guillaume Salbreux
- Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
- The Francis Crick Institute, Lincoln’s Inn Fields Laboratories, London WC2A 3LY, UK
| | - Andreas R. Bausch
- Department of Physics, Technische Universität München, 85748 Garching, Germany
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26
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Siton-Mendelson O, Bernheim-Groswasser A. Toward the reconstitution of synthetic cell motility. Cell Adh Migr 2016; 10:461-474. [PMID: 27019160 DOI: 10.1080/19336918.2016.1170260] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cellular motility is a fundamental process essential for embryonic development, wound healing, immune responses, and tissues development. Cells are mostly moving by crawling on external, or inside, substrates which can differ in their surface composition, geometry, and dimensionality. Cells can adopt different migration phenotypes, e.g., bleb-based and protrusion-based, depending on myosin contractility, surface adhesion, and cell confinement. In the few past decades, research on cell motility has focused on uncovering the major molecular players and their order of events. Despite major progresses, our ability to infer on the collective behavior from the molecular properties remains a major challenge, especially because cell migration integrates numerous chemical and mechanical processes that are coupled via feedbacks that span over large range of time and length scales. For this reason, reconstituted model systems were developed. These systems allow for full control of the molecular constituents and various system parameters, thereby providing insight into their individual roles and functions. In this review we describe the various reconstituted model systems that were developed in the past decades. Because of the multiple steps involved in cell motility and the complexity of the overall process, most of the model systems focus on very specific aspects of the individual steps of cell motility. Here we describe the main advancement in cell motility reconstitution and discuss the main challenges toward the realization of a synthetic motile cell.
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Affiliation(s)
- Orit Siton-Mendelson
- a Department of Chemical Engineering and the Ilse Kats Institute for Nanoscale Science and Technology , Ben-Gurion University of the Negev , Beer-Sheva , Israel
| | - Anne Bernheim-Groswasser
- a Department of Chemical Engineering and the Ilse Kats Institute for Nanoscale Science and Technology , Ben-Gurion University of the Negev , Beer-Sheva , Israel
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27
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Chiba M, Miyazaki M, Ishiwata S. Quantitative analysis of the lamellarity of giant liposomes prepared by the inverted emulsion method. Biophys J 2015; 107:346-354. [PMID: 25028876 DOI: 10.1016/j.bpj.2014.05.039] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 05/29/2014] [Indexed: 11/26/2022] Open
Abstract
The inverted emulsion method is used to prepare giant liposomes by pushing water-in-oil droplets through the oil/water interface into an aqueous medium. Due to the high encapsulation efficiency of proteins under physiological conditions and the simplicity of the protocol, it has been widely used to prepare various cell models. However, the lamellarity of liposomes prepared by this method has not been evaluated quantitatively. Here, we prepared liposomes that were partially stained with a fluorescent dye, and analyzed their fluorescence intensity under an epifluorescence microscope. The fluorescence intensities of the membranes of individual liposomes were plotted against their diameter. The plots showed discrete distributions, which were classified into several groups. The group with the lowest fluorescence intensity was determined to be unilamellar by monitoring the exchangeability of the inner and the outer solutions of the liposomes in the presence of the pore-forming toxin α-hemolysin. Increasing the lipid concentration dissolved in oil increased the number of liposomes ∼100 times. However, almost all the liposomes were unilamellar even at saturating lipid concentrations. We also investigated the effects of lipid composition and liposome content, such as highly concentrated actin filaments and Xenopus egg extracts, on the lamellarity of the liposomes. Remarkably, over 90% of the liposomes were unilamellar under all conditions examined. We conclude that the inverted emulsion method can be used to efficiently prepare giant unilamellar liposomes and is useful for designing cell models.
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Affiliation(s)
- Masataka Chiba
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| | - Makito Miyazaki
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| | - Shin'ichi Ishiwata
- Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan; Waseda Bioscience Research Institute in Singapore (WABIOS), Singapore, Singapore.
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28
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Delabre U, Feld K, Crespo E, Whyte G, Sykes C, Seifert U, Guck J. Deformation of phospholipid vesicles in an optical stretcher. SOFT MATTER 2015; 11:6075-88. [PMID: 26135540 DOI: 10.1039/c5sm00562k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Phospholipid vesicles are common model systems for cell membranes. Important aspects of the membrane function relate to its mechanical properties. Here we have investigated the deformation behaviour of phospholipid vesicles in a dual-beam laser trap, also called an optical stretcher. This study explicitly makes use of the inherent heating present in such traps to investigate the dependence of vesicle deformation on temperature. By using lasers with different wavelengths, optically induced mechanical stresses and temperature increase can be tuned fairly independently with a single setup. The phase transition temperature of vesicles can be clearly identified by an increase in deformation. In the case of no heating effects, a minimal model for drop deformation in an optical stretcher and a more specific model for vesicle deformation that takes explicitly into account the angular dependence of the optical stress are presented to account for the experimental results. Elastic constants are extracted from the fitting procedures, which agree with literature data. This study demonstrates the utility of optical stretching, which is easily combined with microfluidic delivery, for the future serial, high-throughput study of the mechanical and thermodynamic properties of phospholipid vesicles.
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Affiliation(s)
- Ulysse Delabre
- Univ. Bordeaux, CNRS, Laboratoire Ondes et Matière d'Aquitaine, UMR 5798, F-33400 Talence, France.
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29
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Sens P, Plastino J. Membrane tension and cytoskeleton organization in cell motility. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:273103. [PMID: 26061624 DOI: 10.1088/0953-8984/27/27/273103] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Cell membrane shape changes are important for many aspects of normal biological function, such as tissue development, wound healing and cell division and motility. Various disease states are associated with deregulation of how cells move and change shape, including notably tumor initiation and cancer cell metastasis. Cell motility is powered, in large part, by the controlled assembly and disassembly of the actin cytoskeleton. Much of this dynamic happens in close proximity to the plasma membrane due to the fact that actin assembly factors are membrane-bound, and thus actin filaments are generally oriented such that their growth occurs against or near the membrane. For a long time, the membrane was viewed as a relatively passive scaffold for signaling. However, results from the last five years show that this is not the whole picture, and that the dynamics of the actin cytoskeleton are intimately linked to the mechanics of the cell membrane. In this review, we summarize recent findings concerning the role of plasma membrane mechanics in cell cytoskeleton dynamics and architecture, showing that the cell membrane is not just an envelope or a barrier for actin assembly, but is a master regulator controlling cytoskeleton dynamics and cell polarity.
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Affiliation(s)
- Pierre Sens
- Institut Curie, Centre de Recherche, Paris, F-75248 France. Centre National de la Recherche Scientifique, Unité Mixte de Recherche 168, Paris, F-75248 France. Université Pierre et Marie Curie, Paris F-75248, France
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30
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Dahl JB, Lin JMG, Muller SJ, Kumar S. Microfluidic Strategies for Understanding the Mechanics of Cells and Cell-Mimetic Systems. Annu Rev Chem Biomol Eng 2015; 6:293-317. [PMID: 26134738 PMCID: PMC5217707 DOI: 10.1146/annurev-chembioeng-061114-123407] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Microfluidic systems are attracting increasing interest for the high-throughput measurement of cellular biophysical properties and for the creation of engineered cellular microenvironments. Here we review recent applications of microfluidic technologies to the mechanics of living cells and synthetic cell-mimetic systems. We begin by discussing the use of microfluidic devices to dissect the mechanics of cellular mimics, such as capsules and vesicles. We then explore applications to circulating cells, including erythrocytes and other normal blood cells, and rare populations with potential disease diagnostic value, such as circulating tumor cells. We conclude by discussing how microfluidic devices have been used to investigate the mechanics, chemotaxis, and invasive migration of adherent cells. In these ways, microfluidic technologies represent an increasingly important toolbox for investigating cellular mechanics and motility at high throughput and in a format that lends itself to clinical translation.
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Affiliation(s)
- Joanna B. Dahl
- Department of Chemical and Biomolecular Engineering, UC-Berkeley, Berkeley, CA 94720
| | - Jung-Ming G. Lin
- Department of Bioengineering, UC-Berkeley, Berkeley, CA 94720
- The UC Berkeley/UCSF Graduate Program in Bioengineering, Berkeley, CA 94720
| | - Susan J. Muller
- Department of Chemical and Biomolecular Engineering, UC-Berkeley, Berkeley, CA 94720
| | - Sanjay Kumar
- Department of Bioengineering, UC-Berkeley, Berkeley, CA 94720
- The UC Berkeley/UCSF Graduate Program in Bioengineering, Berkeley, CA 94720
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31
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Abstract
Actomyosin-mediated contractility is a highly conserved mechanism for generating mechanical stress in animal cells and underlies muscle contraction, cell migration, cell division and tissue morphogenesis. Whereas actomyosin-mediated contractility in striated muscle is well understood, the regulation of such contractility in non-muscle and smooth muscle cells is less certain. Our increased understanding of the mechanics of actomyosin arrays that lack sarcomeric organization has revealed novel modes of regulation and force transmission. This work also provides an example of how diverse mechanical behaviours at cellular scales can arise from common molecular components, underscoring the need for experiments and theories to bridge the molecular to cellular length scales.
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32
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Schäfer E, Vache M, Kliesch TT, Janshoff A. Mechanical response of adherent giant liposomes to indentation with a conical AFM-tip. SOFT MATTER 2015; 11:4487-95. [PMID: 25946988 DOI: 10.1039/c5sm00191a] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Indentation of giant liposomes with a conical indenter is described by means of a tension-based membrane model. We found that nonlinear membrane theory neglecting the impact of bending sufficiently describes the mechanical response of liposomes to indentation as measured by atomic force microscopy. Giant vesicles are gently adsorbed on glassy surfaces via avidin-biotin linkages and indented centrally using an atomic force microscope equipped with conventional sharp tips mounted on top of an inverted microscope. Force indentation curves display a nonlinear response that allows to extract pre-stress of the bilayer T0 and the area compressibility modulus KA by computing the contour of the vesicle at a given force. The values for KA of fluid membranes correspond well to what is known from micropipet suction experiments and inferred from membrane undulation monitoring. Assembly of actin shells inside the liposome considerably stiffens the vesicles resulting in significantly larger area compressibility modules. The analysis can be easily extended to different indenter geometries with rotational symmetry.
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Affiliation(s)
- Edith Schäfer
- Department of Chemistry, University of Goettingen, Goettingen, Germany.
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33
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Brüggemann D, Frohnmayer JP, Spatz JP. Model systems for studying cell adhesion and biomimetic actin networks. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2014; 5:1193-202. [PMID: 25161853 PMCID: PMC4142981 DOI: 10.3762/bjnano.5.131] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 06/25/2014] [Indexed: 05/28/2023]
Abstract
Many cellular processes, such as migration, proliferation, wound healing and tumor progression are based on cell adhesion. Amongst different cell adhesion molecules, the integrin receptors play a very significant role. Over the past decades the function and signalling of various such integrins have been studied by incorporating the proteins into lipid membranes. These proteolipid structures lay the foundation for the development of artificial cells, which are able to adhere to substrates. To build biomimetic models for studying cell shape and spreading, actin networks can be incorporated into lipid vesicles, too. We here review the mechanisms of integrin-mediated cell adhesion and recent advances in the field of minimal cells towards synthetic adhesion. We focus on reconstituting integrins into lipid structures for mimicking cell adhesion and on the incorporation of actin networks and talin into model cells.
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Affiliation(s)
- Dorothea Brüggemann
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- Department of Biophysical Chemistry, University of Heidelberg, INF 253, D-69120 Heidelberg, Germany
| | - Johannes P Frohnmayer
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- Department of Biophysical Chemistry, University of Heidelberg, INF 253, D-69120 Heidelberg, Germany
| | - Joachim P Spatz
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- Department of Biophysical Chemistry, University of Heidelberg, INF 253, D-69120 Heidelberg, Germany
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34
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Wang J, Lü D, Mao D, Long M. Mechanomics: an emerging field between biology and biomechanics. Protein Cell 2014; 5:518-31. [PMID: 24756566 PMCID: PMC4085284 DOI: 10.1007/s13238-014-0057-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/10/2014] [Indexed: 12/31/2022] Open
Abstract
Cells sense various in vivo mechanical stimuli, which initiate downstream signaling to mechanical forces. While a body of evidences is presented on the impact of limited mechanical regulators in past decades, the mechanisms how biomechanical responses globally affect cell function need to be addressed. Complexity and diversity of in vivo mechanical clues present distinct patterns of shear flow, tensile stretch, or mechanical compression with various parametric combination of its magnitude, duration, or frequency. Thus, it is required to understand, from the viewpoint of mechanobiology, what mechanical features of cells are, why mechanical properties are different among distinct cell types, and how forces are transduced to downstream biochemical signals. Meanwhile, those in vitro isolated mechanical stimuli are usually coupled together in vivo, suggesting that the different factors that are in effect individually could be canceled out or orchestrated with each other. Evidently, omics analysis, a powerful tool in the field of system biology, is advantageous to combine with mechanobiology and then to map the full-set of mechanically sensitive proteins and transcripts encoded by its genome. This new emerging field, namely mechanomics, makes it possible to elucidate the global responses under systematically-varied mechanical stimuli. This review discusses the current advances in the related fields of mechanomics and elaborates how cells sense external forces and activate the biological responses.
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Affiliation(s)
- Jiawen Wang
- Center for Biomechanics and Bioengineering and Key Laboratory of Microgravity, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, China
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35
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Luo T, Srivastava V, Ren Y, Robinson DN. Mimicking the mechanical properties of the cell cortex by the self-assembly of an actin cortex in vesicles. APPLIED PHYSICS LETTERS 2014; 104:153701. [PMID: 24803681 PMCID: PMC4000382 DOI: 10.1063/1.4871861] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 03/30/2014] [Indexed: 05/07/2023]
Abstract
The composite of the actin cytoskeleton and plasma membrane plays important roles in many biological events. Here, we employed the emulsion method to synthesize artificial cells with biomimetic actin cortex in vesicles and characterized their mechanical properties. We demonstrated that the emulsion method provides the flexibility to adjust the lipid composition and protein concentrations in artificial cells to achieve the desired size distribution, internal microstructure, and mechanical properties. Moreover, comparison of the cortical elasticity measured for reconstituted artificial cells to that of real cells, including those manipulated using genetic depletion and pharmacological inhibition, strongly supports that actin cytoskeletal proteins are dominant over lipid molecules in cortical mechanics. Our study indicates that the assembly of biological systems in artificial cells with purified cellular components provides a powerful way to answer biological questions.
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Affiliation(s)
- Tianzhi Luo
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Vasudha Srivastava
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA ; Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Yixin Ren
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Douglas N Robinson
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA ; Department of Pharmacology and Molecular Science, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA ; Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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36
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McCann CP, Rericha EC, Wang C, Losert W, Parent CA. Dictyostelium cells migrate similarly on surfaces of varying chemical composition. PLoS One 2014; 9:e87981. [PMID: 24516575 PMCID: PMC3916393 DOI: 10.1371/journal.pone.0087981] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 01/01/2014] [Indexed: 11/18/2022] Open
Abstract
During cell migration, cell-substrate binding is required for pseudopod anchoring to move the cell forward, yet the interactions with the substrate must be sufficiently weak to allow parts of the cell to de-adhere in a controlled manner during typical protrusion/retraction cycles. Mammalian cells actively control cell-substrate binding and respond to extracellular conditions with localized integrin-containing focal adhesions mediating mechanotransduction. We asked whether mechanotransduction also occurs during non-integrin mediated migration by examining the motion of the social amoeba Dictyostelium discoideum, which is thought to bind non-specifically to surfaces. We discovered that Dictyostelium cells are able to regulate forces generated by the actomyosin cortex to maintain optimal cell-surface contact area and adhesion on surfaces of various chemical composition and that individual cells migrate with similar speed and contact area on the different surfaces. In contrast, during collective migration, as observed in wound healing and metastasis, the balance between surface forces and protrusive forces is altered. We found that Dictyostelium collective migration dynamics are strongly affected when cells are plated on different surfaces. These results suggest that the presence of cell-cell contacts, which appear as Dictyostelium cells enter development, alter the mechanism cells use to migrate on surfaces of varying composition.
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Affiliation(s)
- Colin P. McCann
- Department of Physics, University of Maryland College Park, College Park, Maryland, United States of America
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America
| | - Erin C. Rericha
- Department of Physics, University of Maryland College Park, College Park, Maryland, United States of America
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America
| | - Chenlu Wang
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America
- Biophysics Graduate Program, University of Maryland, College Park, Maryland, United States of America
| | - Wolfgang Losert
- Department of Physics, University of Maryland College Park, College Park, Maryland, United States of America
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, United States of America
| | - Carole A. Parent
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, United States of America
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37
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Luo T, Mohan K, Iglesias PA, Robinson DN. Molecular mechanisms of cellular mechanosensing. NATURE MATERIALS 2013; 12:1064-71. [PMID: 24141449 PMCID: PMC3838893 DOI: 10.1038/nmat3772] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 09/04/2013] [Indexed: 05/03/2023]
Abstract
Mechanical forces direct a host of cellular and tissue processes. Although much emphasis has been placed on cell-adhesion complexes as force sensors, the forces must nevertheless be transmitted through the cortical cytoskeleton. Yet how the actin cortex senses and transmits forces and how cytoskeletal proteins interact in response to the forces is poorly understood. Here, by combining molecular and mechanical experimental perturbations with theoretical multiscale modelling, we decipher cortical mechanosensing from molecular to cellular scales. We show that forces are shared between myosin II and different actin crosslinkers, with myosin having potentiating or inhibitory effects on certain crosslinkers. Different types of cell deformation elicit distinct responses, with myosin and α-actinin responding to dilation, and filamin mainly reacting to shear. Our observations show that the accumulation kinetics of each protein may be explained by its molecular mechanisms, and that protein accumulation and the cell's viscoelastic state can explain cell contraction against mechanical load.
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Affiliation(s)
- Tianzhi Luo
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
- Correspondence to or
| | - Krithika Mohan
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Pablo A. Iglesias
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Douglas N. Robinson
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Pharmacology and Molecular Science, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
- Correspondence to or
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38
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Golde T, Schuldt C, Schnauß J, Strehle D, Glaser M, Käs J. Fluorescent beads disintegrate actin networks. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:044601. [PMID: 24229308 DOI: 10.1103/physreve.88.044601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Indexed: 06/02/2023]
Abstract
We studied the influence of fluorescent polystyrene beads on both entangled and cross-linked actin networks. Thermal bead fluctuations were observed via video particle tracking and analyzed with one-point microrheology. Illumination of fluorescent beads with their appropriate excitation wavelength leads to a drastic softening of actin gels. Other wavelengths and bright field microscopy do not increase thermal bead fluctuations. This effect cannot be significantly reduced by adding common oxygen scavengers. We conclude that the usage of fluorescent beads impairs results when studying the microrheology of actin networks.
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Affiliation(s)
- Tom Golde
- Soft Matter Physics, Institute for Experimental Physics I, University of Leipzig, 04103 Leipzig, Germany
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39
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Cell-sized liposomes reveal how actomyosin cortical tension drives shape change. Proc Natl Acad Sci U S A 2013; 110:16456-61. [PMID: 24065829 DOI: 10.1073/pnas.1221524110] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Animal cells actively generate contractile stress in the actin cortex, a thin actin network beneath the cell membrane, to facilitate shape changes during processes like cytokinesis and motility. On the microscopic scale, this stress is generated by myosin molecular motors, which bind to actin cytoskeletal filaments and use chemical energy to exert pulling forces. To decipher the physical basis for the regulation of cell shape changes, here, we use a cell-like system with a cortex anchored to the outside or inside of a liposome membrane. This system enables us to dissect the interplay between motor pulling forces, cortex-membrane anchoring, and network connectivity. We show that cortices on the outside of liposomes either spontaneously rupture and relax built-up mechanical stress by peeling away around the liposome or actively compress and crush the liposome. The decision between peeling and crushing depends on the cortical tension determined by the amount of motors and also on the connectivity of the cortex and its attachment to the membrane. Membrane anchoring strongly affects the morphology of cortex contraction inside liposomes: cortices contract inward when weakly attached, whereas they contract toward the membrane when strongly attached. We propose a physical model based on a balance of active tension and mechanical resistance to rupture. Our findings show how membrane attachment and network connectivity are able to regulate actin cortex remodeling and membrane-shape changes for cell polarization.
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40
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Schäfer E, Kliesch TT, Janshoff A. Mechanical properties of giant liposomes compressed between two parallel plates: impact of artificial actin shells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:10463-10474. [PMID: 23869855 DOI: 10.1021/la401969t] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The mechanical response of giant liposomes to compression between two parallel plates is investigated in the context of an artificial actin cortex adjacent to the inner leaflet of the bilayer. We found that nonlinear membrane theory neglecting the impact of bending sufficiently describes the mechanical response of liposomes consisting of fluid lipids to compression whereas the formation of an actin cortex or the use of gel-phase lipids generally leads to substantial stiffening of the shell. Giant vesicles are gently adsorbed on glassy surfaces and are compressed with tipless cantilevers using an atomic force microscope. Force-compression curves display a nonlinear response that allows us to determine the membrane tension σ0 and the area compressibility modulus K(A) by computing the contour of the vesicle as a function of the compression depth. The values for KA of fluid membranes correspond well to what is known from micropipet-suction experiments and computed from monitoring membrane undulations. The presence of a thick actin shell adjacent to the inner leaflet of the liposome membrane stiffens the system considerably, as mirrored in a significantly higher apparent area compressibility modulus.
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Affiliation(s)
- Edith Schäfer
- Institute of Physical Chemistry, Georg-August-University of Goettingen, Tammannstr. 6, 37077 Goettingen
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41
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Campillo C, Sens P, Köster D, Pontani LL, Lévy D, Bassereau P, Nassoy P, Sykes C. Unexpected membrane dynamics unveiled by membrane nanotube extrusion. Biophys J 2013; 104:1248-56. [PMID: 23528084 DOI: 10.1016/j.bpj.2013.01.051] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 11/20/2012] [Accepted: 01/08/2013] [Indexed: 11/17/2022] Open
Abstract
In cell mechanics, distinguishing the respective roles of the plasma membrane and of the cytoskeleton is a challenge. The difference in the behavior of cellular and pure lipid membranes is usually attributed to the presence of the cytoskeleton as explored by membrane nanotube extrusion. Here we revisit this prevalent picture by unveiling unexpected force responses of plasma membrane spheres devoid of cytoskeleton and synthetic liposomes. We show that a tiny variation in the content of synthetic membranes does not affect their static mechanical properties, but is enough to reproduce the dynamic behavior of their cellular counterparts. This effect is attributed to an amplified intramembrane friction. Reconstituted actin cortices inside liposomes induce an additional, but not dominant, contribution to the effective membrane friction. Our work underlines the necessity of a careful consideration of the role of membrane proteins on cell membrane rheology in addition to the role of the cytoskeleton.
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Affiliation(s)
- Clément Campillo
- Institut Curie, Centre de Recherche, Laboratoire Physico-Chimie, Paris, France.
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42
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Mullins RD, Hansen SD. In vitro studies of actin filament and network dynamics. Curr Opin Cell Biol 2012; 25:6-13. [PMID: 23267766 DOI: 10.1016/j.ceb.2012.11.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 11/26/2012] [Indexed: 11/30/2022]
Abstract
Now that many genomes have been sequenced, a central concern of cell biology is to understand how the proteins they encode work together to create living matter. In vitro studies form an essential part of this program because understanding cellular functions of biological molecules often requires isolating them and reconstituting their activities. In particular, many elements of the actin cytoskeleton were first discovered by biochemical methods and their cellular functions deduced from in vitro experiments. We highlight recent advances that have come from in vitro studies, beginning with studies of actin filaments, and ending with multi-component reconstitutions of complex actin-based processes, including force-generation and cell spreading. We describe both scientific results and the technical innovations that made them possible.
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Affiliation(s)
- R Dyche Mullins
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, 600 16th Street, San Francisco, CA 94110, United States.
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43
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Hamada T, Yoshikawa K. Cell-Sized Liposomes and Droplets: Real-World Modeling of Living Cells. MATERIALS 2012. [PMCID: PMC5449011 DOI: 10.3390/ma5112292] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent developments in studies concerning cell-sized vesicles, such as liposomes with a lipid bilayer and water-in-oil droplets covered by a lipid monolayer, aim to realize the real-world modeling of living cells. Compartmentalization with a membrane boundary is essential for the organization of living systems. Due to the relatively large surface/volume ratio in microconfinement, the membrane interface influences phenomena related to biological functions. In this article, we mainly focus on the following subjects: (i) conformational transition of biopolymers in a confined space; (ii) molecular association on the membrane surface; and (iii) remote control of cell-sized membrane morphology.
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Affiliation(s)
- Tsutomu Hamada
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1, Asahidai, Nomi, Ishikawa 923-1292, Japan
- Authors to whom correspondence should be addressed; E-Mails: (T.H.); (K.Y.); Tel./Fax: +81-761-51-1670 (T.H.); +81-774-65-6243 (K.Y.)
| | - Kenichi Yoshikawa
- Faculty of Life and Medical Sciences, Doshisha University, 1-3, Tatara Miyakodani, Kyotanabe, Kyoto 610-0394, Japan
- Authors to whom correspondence should be addressed; E-Mails: (T.H.); (K.Y.); Tel./Fax: +81-761-51-1670 (T.H.); +81-774-65-6243 (K.Y.)
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44
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A mean field Ising model for cortical rotation in amphibian one-cell stage embryos. Biosystems 2012; 109:381-9. [DOI: 10.1016/j.biosystems.2012.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/11/2012] [Accepted: 05/14/2012] [Indexed: 12/12/2022]
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45
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Abstract
Tremendous progress has been made in recent years in understanding the working of the living cell, including its micro-anatomy, signalling networks, and regulation of genes. However, an understanding of cellular phenomena using fundamental laws starting from first principles is still very far away. Part of the reason is that a cell is an active and exquisitely complex system where every part is linked to the other. Thus, it is difficult or even impossible to design experiments that selectively and exclusively probe a chosen aspect of the cell. Various kinds of idealised systems and cell models have been used to circumvent this problem. An important example is a giant unilamellar vesicle (GUV, also called giant liposome), which provides a cell-sized confined volume to study biochemical reactions as well as self-assembly processes that occur on the membrane. The GUV membrane can be designed suitably to present selected, correctly-oriented cell-membrane proteins, whose mobility is confined to two dimensions. Here, we present recent advances in GUV design and the use of GUVs as cell models that enable quantitative testing leading to insight into the working of real cells. We briefly recapitulate important classical concepts in membrane biophysics emphasising the advantages and limitations of GUVs. We then present results obtained over the last decades using GUVs, choosing the formation of membrane domains and cell adhesion as examples for in-depth treatment. Insight into cell adhesion obtained using micro-interferometry is treated in detail. We conclude by summarising the open questions and possible future directions.
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Affiliation(s)
- Susanne F Fenz
- Leiden Institute of Physics: Physics of Life Processes, Leiden University, The Netherlands
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46
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Miyoshi H, Adachi T. Spatiotemporal coordinated hierarchical properties of cellular protrusion revealed by multiscale analysis. Integr Biol (Camb) 2012; 4:875-88. [PMID: 22689105 DOI: 10.1039/c2ib20013a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We present a methodology for integrative multiscale analysis to highlight hierarchical properties of cellular protrusion and mechanochemical interactions in cellular protrusion based on live cell imaging data with high spatiotemporal resolution. As an appropriate experimental system, we selected non-polarized full-moon-shaped keratocytes that present balanced protrusion around the entire cell periphery at the cellular scale simultaneously with active protrusion and retraction at the subcellular scale. We achieved the observation of a whole cell with sub-micrometer spatial precision and sub-second time resolution for three minutes or more. The multiscale characteristics of cell peripheral activity and those of the cell peripheral shape were extracted from an identical image sequence by estimating the cell protrusion rates and the cell peripheral curvatures at various differential intervals. The spatiotemporal maps of the cell protrusion rates demonstrated a spatiotemporally nested structure of travelling waves of active protruding regions at the cellular and subcellular scales. Moreover, correlation analysis demonstrated the relationship between the cell protrusion rate and peripheral curvature at the subcellular scale. The novel integrative methodology presented here well highlighted the hierarchical properties of organized cellular protrusion, and further provided insight about the underlying mechanochemical interactions between the cell membrane and the actin filaments under the membrane.
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Affiliation(s)
- Hiromi Miyoshi
- Ultrahigh Precision Fabrication Team, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
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47
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Vogel SK, Schwille P. Minimal systems to study membrane-cytoskeleton interactions. Curr Opin Biotechnol 2012; 23:758-65. [PMID: 22503237 DOI: 10.1016/j.copbio.2012.03.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 03/21/2012] [Accepted: 03/22/2012] [Indexed: 11/16/2022]
Abstract
In the context of minimal systems design, there are two areas in which the reductionist approach has been particularly successful: studies of molecular motors on cytoskeletal filaments, and of protein-lipid interactions in model membranes. However, a minimal cortex, that is, the interface between membrane and cytoskeleton, has just begun to be functionally reconstituted. A key property of living cells is their ability to change their shape in response to extracellular and intracellular stimuli. Although studied in live cells since decades, the mutual dependence between cytoskeleton and membrane dynamics in these large-scale transformations is still poorly understood. Here we report on inspiring recent in vitro work in this direction, and the promises it holds for a better understanding of key cellular processes.
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Affiliation(s)
- Sven K Vogel
- Max Planck Institute of Biochemistry, Department of Cellular and Molecular Biophysics, Am Klopferspitz 18, D-82152 Martinsried, Germany
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48
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Takiguchi K, Negishi M, Tanaka-Takiguchi Y, Homma M, Yoshikawa K. Transformation of actoHMM assembly confined in cell-sized liposome. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:11528-35. [PMID: 21819144 PMCID: PMC3171996 DOI: 10.1021/la2016287] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
To construct a simple model of a cellular system equipped with motor proteins, cell-sized giant liposomes encapsulating various amounts of actoHMM, the complexes of actin filaments (F-actin) and heavy meromyosin (HMM, an actin-related molecular motor), with a depletion reagent to mimic the crowding effect of inside of living cell, were prepared. We adapted the methodology of the spontaneous transfer of water-in-oil (W/O) droplets through a phospholipid monolayer into the bulk aqueous phase and successfully prepared stable giant liposomes encapsulating the solution with a physiological salt concentration containing the desired concentrations of actoHMM, which had been almost impossible to obtain using currently adapted methodologies such as natural swelling and electro-formation on an electrode. We then examined the effect of ATP on the cytoskeleton components confined in those cell-sized liposomes, because ATP is known to drive the sliding motion for actoHMM. We added α-hemolysin, a bacterial membrane pore-forming toxin, to the bathing solution and obtained liposomes with the protein pores embedded on the bilayer membrane to allow the transfer of ATP inside the liposomes. We show that, by the ATP supply, the actoHMM bundles inside the liposomes exhibit specific changes in spatial distribution, caused by the active sliding between F-actin and HMM. Interestingly, all F-actins localized around the inner periphery of liposomes smaller than a critical size, whereas in the bulk solution and also in larger liposomes, the actin bundles formed aster-like structures under the same conditions.
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Affiliation(s)
- Kingo Takiguchi
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
- Phone: +81-52-789-2993 (K.T.); +81-75-753-3812 (K.Y.). Fax: +81-52-789-3001 (K.T.); +81-75-753-3779 (K.Y.). E-mail: (K.T.); (K.Y.)
| | - Makiko Negishi
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yohko Tanaka-Takiguchi
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Kenichi Yoshikawa
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
- Phone: +81-52-789-2993 (K.T.); +81-75-753-3812 (K.Y.). Fax: +81-52-789-3001 (K.T.); +81-75-753-3779 (K.Y.). E-mail: (K.T.); (K.Y.)
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Tsai FC, Stuhrmann B, Koenderink GH. Encapsulation of active cytoskeletal protein networks in cell-sized liposomes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:10061-10071. [PMID: 21707043 DOI: 10.1021/la201604z] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate that cytoskeletal actin-myosin networks can be encapsulated with high efficiency in giant liposomes by hydration of lipids in an agarose hydrogel. The liposomes have cell-sized diameters of 10-20 μm and a uniform actin content. We show by measurements of membrane fluorescence intensity and bending rigidity that the majority of liposomes are unilamellar. We further demonstrate that the actin network can be specifically anchored to the membrane by biotin-streptavidin linkages. These protein-filled liposomes are useful model systems for quantitative studies of the physical mechanisms by which the cytoskeleton actively controls cell shape and mechanics. In a broader context, this new preparation method should be widely applicable to encapsulation of proteins and polymers, for instance, to create polymer-reinforced liposomes for drug delivery.
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Affiliation(s)
- Feng-Ching Tsai
- Biological Soft Matter Group, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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