1
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Kaurin D, Bal PK, Arroyo M. Peeling dynamics of fluid membranes bridged by molecular bonds: moving or breaking. JOURNAL OF THE ROYAL SOCIETY, INTERFACE 2022; 19:20220183. [PMID: 35765808 PMCID: PMC9240675 DOI: 10.1098/rsif.2022.0183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biological adhesion is a critical mechanical function of complex organisms. At the scale of cell–cell contacts, adhesion is remarkably tunable to enable both cohesion and malleability during development, homeostasis and disease. It is physically supported by transient and laterally mobile molecular bonds embedded in fluid membranes. Thus, unlike specific adhesion at solid–solid or solid–fluid interfaces, peeling at fluid–fluid interfaces can proceed by breaking bonds, by moving bonds or by a combination of both. How the additional degree of freedom provided by bond mobility changes the mechanics of peeling is not understood. To address this, we develop a theoretical model coupling diffusion, reactions and mechanics. Mobility and reaction rates determine distinct peeling regimes. In a diffusion-dominated Stefan-like regime, bond motion establishes self-stabilizing dynamics that increase the effective fracture energy. In a reaction-dominated regime, peeling proceeds by travelling fronts where marginal diffusion and unbinding control peeling speed. In a mixed reaction–diffusion regime, strengthening by bond motion competes with weakening by bond breaking in a force-dependent manner, defining the strength of the adhesion patch. In turn, patch strength depends on molecular properties such as bond stiffness, force sensitivity or crowding. We thus establish the physical rules enabling tunable cohesion in cellular tissues and in engineered biomimetic systems.
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Affiliation(s)
- Dimitri Kaurin
- Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
| | - Pradeep K Bal
- Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
| | - Marino Arroyo
- Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain.,Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08034 Barcelona, Spain.,CIMNE, 08034 Barcelona, Spain
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2
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Li L, Kamal MA, Stumpf BH, Thibaudau F, Sengupta K, Smith AS. Biomechanics as driver of aggregation of tethers in adherent membranes. SOFT MATTER 2021; 17:10101-10107. [PMID: 34723306 DOI: 10.1039/d1sm00921d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cell adhesion is an important cellular process and is mediated by adhesion proteins residing on the cell membrane. Sometimes, two types of linker proteins are involved in adhesion, and they can segregate to form domains through a poorly understood size-exclusion process. We present an experimental and theoretical study of adhesion via linkers of two different sizes, realised in a mimetic model-system, based on giant unilamellar vesicles interacting with supported lipid bilayers. Here, adhesion is mediated by DNA linkers with two different lengths, but with the same binding enthalpy. We study the organisation of these linkers into domains as a function of relative fraction of long and short DNA constructs. Experimentally, we find that, irrespective of the composition, the adhesion domains are uniform with coexisting DNA bridge types, despite their relative difference in length of 9 nm. However, simulations suggest formation of nanodomains of the minority fraction at short length scales, which is below the optical resolution of the microscope. The nano-aggregation is more significant for long bridges, which are also more stable.
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Affiliation(s)
- Long Li
- PULS Group, Institut for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, Erlangen, 91058, Germany.
- Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu, 730000, China
| | - Mohammad Arif Kamal
- Aix Marseille Univ, CNRS, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), 13009 Marseille, France.
| | - Bernd Henning Stumpf
- PULS Group, Institut for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, Erlangen, 91058, Germany.
| | - Franck Thibaudau
- Aix Marseille Univ, CNRS, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), 13009 Marseille, France.
| | - Kheya Sengupta
- Aix Marseille Univ, CNRS, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), 13009 Marseille, France.
| | - Ana-Sunčana Smith
- PULS Group, Institut for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, Erlangen, 91058, Germany.
- Group for Computational Life Sciences, Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
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3
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Arslan FN, Eckert J, Schmidt T, Heisenberg CP. Holding it together: when cadherin meets cadherin. Biophys J 2021; 120:4182-4192. [PMID: 33794149 PMCID: PMC8516678 DOI: 10.1016/j.bpj.2021.03.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/12/2021] [Accepted: 03/17/2021] [Indexed: 12/21/2022] Open
Abstract
Intercellular adhesion is the key to multicellularity, and its malfunction plays an important role in various developmental and disease-related processes. Although it has been intensively studied by both biologists and physicists, a commonly accepted definition of cell-cell adhesion is still being debated. Cell-cell adhesion has been described at the molecular scale as a function of adhesion receptors controlling binding affinity, at the cellular scale as resistance to detachment forces or modulation of surface tension, and at the tissue scale as a regulator of cellular rearrangements and morphogenesis. In this review, we aim to summarize and discuss recent advances in the molecular, cellular, and theoretical description of cell-cell adhesion, ranging from biomimetic models to the complexity of cells and tissues in an organismal context. In particular, we will focus on cadherin-mediated cell-cell adhesion and the role of adhesion signaling and mechanosensation therein, two processes central for understanding the biological and physical basis of cell-cell adhesion.
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Affiliation(s)
- Feyza Nur Arslan
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Julia Eckert
- Physics of Life Processes, Leiden Institute of Physics, Leiden University, Leiden, the Netherlands
| | - Thomas Schmidt
- Physics of Life Processes, Leiden Institute of Physics, Leiden University, Leiden, the Netherlands
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4
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Li L, Stumpf BH, Smith AS. Molecular Biomechanics Controls Protein Mixing and Segregation in Adherent Membranes. Int J Mol Sci 2021; 22:3699. [PMID: 33918167 PMCID: PMC8037219 DOI: 10.3390/ijms22073699] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 03/22/2021] [Accepted: 03/25/2021] [Indexed: 01/28/2023] Open
Abstract
Cells interact with their environment by forming complex structures involving a multitude of proteins within assemblies in the plasma membrane. Despite the omnipresence of these assemblies, a number of questions about the correlations between the organisation of domains and the biomechanical properties of the involved proteins, namely their length, flexibility and affinity, as well as about the coupling to the elastic, fluctuating membrane, remain open. Here we address these issues by developing an effective Kinetic Monte Carlo simulation to model membrane adhesion. We apply this model to a typical experiment in which a cell binds to a functionalized solid supported bilayer and use two ligand-receptor pairs to study these couplings. We find that differences in affinity and length of proteins forming adhesive contacts result in several characteristic features in the calculated phase diagrams. One such feature is mixed states occurring even with proteins with length differences of 10 nm. Another feature are stable nanodomains with segregated proteins appearing on time scales of cell experiments, and for biologically relevant parameters. Furthermore, we show that macroscopic ring-like patterns can spontaneously form as a consequence of emergent protein fluxes. The capacity to form domains is captured by an order parameter that is founded on the virial coefficients for the membrane mediated interactions between bonds, which allow us to collapse all the data. These findings show that taking into account the role of the membrane allows us to recover a number of experimentally observed patterns. This is an important perspective in the context of explicit biological systems, which can now be studied in significant detail.
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Affiliation(s)
- Long Li
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany; (L.L.); (B.H.S.)
- Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China
| | - Bernd Henning Stumpf
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany; (L.L.); (B.H.S.)
| | - Ana-Sunčana Smith
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-University Erlangen-Nürnberg, Cauerstrasse 3, 91058 Erlangen, Germany; (L.L.); (B.H.S.)
- Group for Computational Life Sciences, Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička cesta, 10000 Zagreb, Croatia
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5
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Henning Stumpf B, Ambriović-Ristov A, Radenovic A, Smith AS. Recent Advances and Prospects in the Research of Nascent Adhesions. Front Physiol 2020; 11:574371. [PMID: 33343382 PMCID: PMC7746844 DOI: 10.3389/fphys.2020.574371] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 11/09/2020] [Indexed: 01/08/2023] Open
Abstract
Nascent adhesions are submicron transient structures promoting the early adhesion of cells to the extracellular matrix. Nascent adhesions typically consist of several tens of integrins, and serve as platforms for the recruitment and activation of proteins to build mature focal adhesions. They are also associated with early stage signaling and the mechanoresponse. Despite their crucial role in sampling the local extracellular matrix, very little is known about the mechanism of their formation. Consequently, there is a strong scientific activity focused on elucidating the physical and biochemical foundation of their development and function. Precisely the results of this effort will be summarized in this article.
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Affiliation(s)
- Bernd Henning Stumpf
- PULS Group, Institute for Theoretical Physics, Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Andreja Ambriović-Ristov
- Laboratory for Cell Biology and Signalling, Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Aleksandra Radenovic
- Laboratory of Nanoscale Biology, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ana-Sunčana Smith
- PULS Group, Institute for Theoretical Physics, Interdisciplinary Center for Nanostructured Films, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Group for Computational Life Sciences, Division of Physical Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
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6
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Sivaram AJ, Wardiana A, Alcantara S, Sonderegger SE, Fletcher NL, Houston ZH, Howard CB, Mahler SM, Alexander C, Kent SJ, Bell CA, Thurecht KJ. Controlling the Biological Fate of Micellar Nanoparticles: Balancing Stealth and Targeting. ACS NANO 2020; 14:13739-13753. [PMID: 32936613 DOI: 10.1021/acsnano.0c06033] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Integrating nanomaterials with biological entities has led to the development of diagnostic tools and biotechnology-derived therapeutic products. However, to optimize the design of these hybrid bionanomaterials, it is essential to understand how controlling the biological interactions will influence desired outcomes. Ultimately, this knowledge will allow more rapid translation from the bench to the clinic. In this paper, we developed a micellar system that was assembled using modular antibody-polymer amphiphilic materials. The amphiphilic nature was established using either poly(ethylene glycol) (PEG) or a single-chain variable fragment (scFv) from an antibody as the hydrophile and a thermoresponsive polymer (poly(oligoethylene glycol) methyl ether methacrylate) as the hydrophobe. By varying the ratios of these components, a series of nanoparticles with different antibody content was self-assembled, where the surface presentation of targeting ligand was carefully controlled. In vitro and in vivo analysis of these systems identified a mismatch between the optimal targeting ligand density to achieve maximum cell association in vitro compared to tumor accumulation in vivo. For this system, we determined an optimum antibody density for both longer circulation and enhanced targeting to tumors that balanced stealthiness of the particle (to evade immune recognition as determined in both mouse models and in whole human blood) with enhanced accumulation achieved through receptor binding on tumor cells in solid tumors. This approach provides fundamental insights into how different antibody densities affect the interaction of designed nanoparticles with both target cells and immune cells, thereby offering a method to probe the intricate interplay between increased targeting efficiency and the subsequent immune response to nanoparticles.
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Affiliation(s)
- Amal J Sivaram
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD 4072, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Andri Wardiana
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Sheilajen Alcantara
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Parkville, Victoria 3010, Australia
| | - Stefan E Sonderegger
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Nicholas L Fletcher
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD 4072, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zachary H Houston
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD 4072, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Christopher B Howard
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- ARC Training Centre for Biopharmaceutical Innovation, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Stephen M Mahler
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- ARC Training Centre for Biopharmaceutical Innovation, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Cameron Alexander
- School of Pharmacy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Stephen J Kent
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Parkville, Victoria 3010, Australia
| | - Craig A Bell
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD 4072, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Kristofer J Thurecht
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD 4072, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and ARC Training Centre for Innovation in Biomedical Imaging Technology, The University of Queensland, St Lucia, QLD 4072, Australia
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7
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Abstract
Many critical biological events, including biochemical signaling, membrane traffic, and cell motility, originate at membrane surfaces. Each such event requires that members of a specific group of proteins and lipids rapidly assemble together at a specific site on the membrane surface. Understanding the biophysical mechanisms that stabilize these assemblies is critical to decoding and controlling cellular functions. In this article, we review progress toward a quantitative biophysical understanding of the mechanisms that drive membrane heterogeneity and organization. We begin from a physical perspective, reviewing the fundamental principles and key experimental evidence behind each proposed mechanism. We then shift to a biological perspective, presenting key examples of the role of heterogeneity in biology and asking which physical mechanisms may be responsible. We close with an applied perspective, noting that membrane heterogeneity provides a novel therapeutic target that is being exploited by a growing number of studies at the interface of biology, physics, and engineering.
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Affiliation(s)
- Wade F Zeno
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA;
| | - Kasey J Day
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA;
| | - Vernita D Gordon
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA;
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
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8
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Zhu M, Zernicka-Goetz M. Building an apical domain in the early mouse embryo: Lessons, challenges and perspectives. Curr Opin Cell Biol 2019; 62:144-149. [PMID: 31869760 DOI: 10.1016/j.ceb.2019.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 11/21/2019] [Indexed: 01/09/2023]
Abstract
Cell polarization is critical for lineage segregation and morphogenesis during mammalian embryogenesis. However, the processes and mechanisms that establish cell polarity in the mammalian embryo are not well understood. Recent studies suggest that unique regulatory mechanisms are deployed by the mouse embryo to establish cell polarization. In this review, we discuss the current understanding of cell polarity establishment, focusing on the formation of the apical domain in the mouse embryo. We will also discuss outstanding questions and possible directions for future study.
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Affiliation(s)
- Meng Zhu
- Mammalian Embryo and Stem Cell Group, University of Cambridge, Department of Physiology, Development and Neuroscience, Downing Street, Cambridge, CB2 3DY, UK
| | - Magdalena Zernicka-Goetz
- Mammalian Embryo and Stem Cell Group, University of Cambridge, Department of Physiology, Development and Neuroscience, Downing Street, Cambridge, CB2 3DY, UK.
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9
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Kaurin D, Arroyo M. Surface Tension Controls the Hydraulic Fracture of Adhesive Interfaces Bridged by Molecular Bonds. PHYSICAL REVIEW LETTERS 2019; 123:228102. [PMID: 31868410 DOI: 10.1103/physrevlett.123.228102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Biological function requires cell-cell adhesions to tune their cohesiveness; for instance, during the opening of new fluid-filled cavities under hydraulic pressure. To understand the physical mechanisms supporting this adaptability, we develop a stochastic model for the hydraulic fracture of adhesive interfaces bridged by molecular bonds. We find that surface tension strongly enhances the stability of these interfaces by controlling flaw sensitivity, lifetime, and optimal architecture in terms of bond clustering. We also show that bond mobility embrittles adhesions and changes the mechanism of decohesion. Our study provides a mechanistic background to understand the biological regulation of cell-cell cohesion and fracture.
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Affiliation(s)
- Dimitri Kaurin
- Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
| | - Marino Arroyo
- Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
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10
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Knežević M, Jiang H, Wang S. Active Tuning of Synaptic Patterns Enhances Immune Discrimination. PHYSICAL REVIEW LETTERS 2018; 121:238101. [PMID: 30576186 DOI: 10.1103/physrevlett.121.238101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 07/07/2018] [Indexed: 06/09/2023]
Abstract
Immune cells learn about their antigenic targets using tactile sense: a self-organized motif named immunological synapse forms between an immune cell and an antigen-presenting cell (APC) during recognition. Via synapses, immune cells apply mechanical pulling forces to selectively extract antigen (Ag) from APCs. Curiously, depending on its stage of development, a B lymphocyte exhibits distinct synaptic patterns and uses force at different strength and timing, which appears to strongly impact its ability to distinguish Ag affinities. We use a statistical-mechanical model to study how the experimentally observed synaptic architectures can originate from normal cytoskeletal forces coupled to the lateral organization of mobile receptors, and show how this active regulation scheme, collective in nature, may enhance the efficiency and capacity of discrimination.
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Affiliation(s)
- Miloš Knežević
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Hongda Jiang
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Shenshen Wang
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
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11
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Shindell O, Mica N, Cheng KH, Wang E, Gordon VD. Dynamic Fingering in Adhered Lipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:4673-4680. [PMID: 29363972 DOI: 10.1021/acs.langmuir.7b03708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Artificial lipid membranes incorporating proteins have frequently been used as models for the dynamic organization of biological structures in living cells as well as in the development of biology-inspired technologies. We report here on the experimental demonstration and characterization of a pattern-forming process that occurs in a lipid bilayer membrane adhered via biotin-avidin binding to a second lipid membrane that is supported by a solid substrate. Adhesion regions are roughly circular with a diameter of about 25 μm. Using confocal fluorescence microscopy, we record time series of dynamic fingering patterns that grow in the upper lipid membrane and intermembrane biotin-avidin bonds. The fingers are micrometer-scale elongated pores that grow from the edge of an already-stabilized hole. Finger growth is saltatory on the scale of tens of seconds. We find that as the fingers grow and the density of adhesion proteins increases, the rate of finger growth decreases exponentially and the width of newly formed fingers decreases linearly. We show that these findings are consistent with a thermodynamic description of dynamic pore formation and stabilization.
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Affiliation(s)
- Orrin Shindell
- Center for Nonlinear Dynamics and Department of Physics , University of Texas at Austin , Austin 78712 , United States
- Department of Physics and Astronomy , Trinity University , San Antonio , Texas 78212 , United States
| | - Natalie Mica
- Center for Nonlinear Dynamics and Department of Physics , University of Texas at Austin , Austin 78712 , United States
- School of Physics and Astronomy , University of St. Andrews , Saint Andrews , Scotland KY16 9AJ , U.K
| | - Kwan H Cheng
- Department of Physics and Astronomy , Trinity University , San Antonio , Texas 78212 , United States
| | - Exing Wang
- Department of Cell Systems & Anatomy , University of Texas Health Science Center San Antonio , San Antonio , Texas 78229 , United States
| | - Vernita D Gordon
- Center for Nonlinear Dynamics and Department of Physics , University of Texas at Austin , Austin 78712 , United States
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12
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Ge Y, Lin YH, Lautscham LA, Goldmann WH, Fabry B, Naumann CA. N-cadherin-functionalized polymer-tethered multi-bilayer: a cell surface-mimicking substrate to probe cellular mechanosensitivity. SOFT MATTER 2016; 12:8274-8284. [PMID: 27731476 DOI: 10.1039/c6sm01673a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Fate and function of anchorage-dependent cells depend on a variety of environmental cues, including those of mechanical nature. Previous progress in the understanding of cellular mechanosensitivity has been closely linked to the availability of artificial cell substrates of adjustable viscoelasticity, allowing for a direct correlation between substrate stiffness and cell response. Exemplary, polymeric gel substrates with polymer-conjugated cell-substrate linkers provided valuable insight into the role of mechanical signals during cell migration in an extracellular matrix environment. In contrast, less is known about the role of external mechanical signals across cell-cell interfaces, in part, due to the limitations of traditional polymeric substrates to mimic the remarkable dynamics of cell-cell linkages. To overcome this shortcoming, we introduce a cell surface-mimicking cell substrate of adjustable stiffness, which is comprised of a polymer-tethered lipid multi-bilayer stack with N-cadherin linkers. Unlike traditional polymeric cell substrates with polymer-conjugated linkers, this novel artificial cell substrate is able to replicate the dynamic assembly/disassembly of cadherin linkers into linker clusters and the long-range movements of cadherin-based cell-substrate linkages observed at cell-cell interfaces. Moreover, substrate stiffness can be changed by adjusting the number of bilayers in the multi-bilayer stack, thus enabling the analysis of cellular mechanosensitivity in the presence of artificial cell-cell linkages. The presented biomembrane-mimicking cell substrate provides a valuable tool to explore the functional role of mechanical cues from neighboring cells.
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Affiliation(s)
- Y Ge
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
| | - Y H Lin
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
| | - L A Lautscham
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - W H Goldmann
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - B Fabry
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - C A Naumann
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
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13
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Weikl TR, Hu J, Xu GK, Lipowsky R. Binding equilibrium and kinetics of membrane-anchored receptors and ligands in cell adhesion: Insights from computational model systems and theory. Cell Adh Migr 2016; 10:576-589. [PMID: 27294442 PMCID: PMC5079412 DOI: 10.1080/19336918.2016.1180487] [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: 02/02/2016] [Accepted: 04/13/2016] [Indexed: 10/21/2022] Open
Abstract
The adhesion of cell membranes is mediated by the binding of membrane-anchored receptor and ligand proteins. In this article, we review recent results from simulations and theory that lead to novel insights on how the binding equilibrium and kinetics of these proteins is affected by the membranes and by the membrane anchoring and molecular properties of the proteins. Simulations and theory both indicate that the binding equilibrium constant [Formula: see text] and the on- and off-rate constants of anchored receptors and ligands in their 2-dimensional (2D) membrane environment strongly depend on the membrane roughness from thermally excited shape fluctuations on nanoscales. Recent theory corroborated by simulations provides a general relation between [Formula: see text] and the binding constant [Formula: see text] of soluble variants of the receptors and ligands that lack the membrane anchors and are free to diffuse in 3 dimensions (3D).
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Affiliation(s)
- Thomas R. Weikl
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, Potsdam, Germany
| | - Jinglei Hu
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, Potsdam, Germany
- Kuang Yaming Honors School, Nanjing University, Nanjing, China
| | - Guang-Kui Xu
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, Potsdam, Germany
- International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, China
| | - Reinhard Lipowsky
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, Potsdam, Germany
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