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Acharya BR, Nestor-Bergmann A, Liang X, Gupta S, Duszyc K, Gauquelin E, Gomez GA, Budnar S, Marcq P, Jensen OE, Bryant Z, Yap AS. A Mechanosensitive RhoA Pathway that Protects Epithelia against Acute Tensile Stress. Dev Cell 2018; 47:439-452.e6. [PMID: 30318244 DOI: 10.1016/j.devcel.2018.09.016] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/16/2018] [Accepted: 09/15/2018] [Indexed: 12/22/2022]
Abstract
Adherens junctions are tensile structures that couple epithelial cells together. Junctional tension can arise from cell-intrinsic application of contractility or from the cell-extrinsic forces of tissue movement. Here, we report a mechanosensitive signaling pathway that activates RhoA at adherens junctions to preserve epithelial integrity in response to acute tensile stress. We identify Myosin VI as the force sensor, whose association with E-cadherin is enhanced when junctional tension is increased by mechanical monolayer stress. Myosin VI promotes recruitment of the heterotrimeric Gα12 protein to E-cadherin, where it signals for p114 RhoGEF to activate RhoA. Despite its potential to stimulate junctional actomyosin and further increase contractility, tension-activated RhoA signaling is necessary to preserve epithelial integrity. This is explained by an increase in tensile strength, especially at the multicellular vertices of junctions, that is due to mDia1-mediated actin assembly.
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Affiliation(s)
- Bipul R Acharya
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Alexander Nestor-Bergmann
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Xuan Liang
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Shafali Gupta
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Kinga Duszyc
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Estelle Gauquelin
- Institut Jacques Monod, CNRS, UMR 7592, Universite Paris Diderot, Sorbonne Paris Cité, Paris 75205, France
| | - Guillermo A Gomez
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Srikanth Budnar
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Philippe Marcq
- Physico Chimie Curie, Institut Curie, Sorbonne Universite, PSL Research University, Paris and CNRS UMR 168, Paris 75005, France
| | - Oliver E Jensen
- School of Mathematics, University of Manchester, Manchester M13 9PL, UK
| | - Zev Bryant
- Department of Bioengineering, Stanford University and Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alpha S Yap
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
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52
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Adhikari S, Moran J, Weddle C, Hinczewski M. Unraveling the mechanism of the cadherin-catenin-actin catch bond. PLoS Comput Biol 2018; 14:e1006399. [PMID: 30118477 PMCID: PMC6114904 DOI: 10.1371/journal.pcbi.1006399] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/29/2018] [Accepted: 07/24/2018] [Indexed: 11/19/2022] Open
Abstract
The adherens junctions between epithelial cells involve a protein complex formed by E-cadherin, β-catenin, α-catenin and F-actin. The stability of this complex was a puzzle for many years, since in vitro studies could reconstitute various stable subsets of the individual proteins, but never the entirety. The missing ingredient turned out to be mechanical tension: a recent experiment that applied physiological forces to the complex with an optical tweezer dramatically increased its lifetime, a phenomenon known as catch bonding. However, in the absence of a crystal structure for the full complex, the microscopic details of the catch bond mechanism remain mysterious. Building on structural clues that point to α-catenin as the force transducer, we present a quantitative theoretical model for how the catch bond arises, fully accounting for the experimental lifetime distributions. The underlying hypothesis is that force induces a rotational transition between two conformations of α-catenin, overcoming a significant energy barrier due to a network of salt bridges. This transition allosterically regulates the energies at the interface between α-catenin and F-actin. The model allows us to predict these energetic changes, as well as highlighting the importance of the salt bridge rotational barrier. By stabilizing one of the α-catenin states, this barrier could play a role in how the complex responds to additional in vivo binding partners like vinculin. Since significant conformational energy barriers are a common feature of other adhesion systems that exhibit catch bonds, our model can be adapted into a general theoretical framework for integrating structure and function in a variety of force-regulated protein complexes.
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Affiliation(s)
- Shishir Adhikari
- Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jacob Moran
- Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Christopher Weddle
- Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Michael Hinczewski
- Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States of America
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53
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Sibener LV, Fernandes RA, Kolawole EM, Carbone CB, Liu F, McAffee D, Birnbaum ME, Yang X, Su LF, Yu W, Dong S, Gee MH, Jude KM, Davis MM, Groves JT, Goddard WA, Heath JR, Evavold BD, Vale RD, Garcia KC. Isolation of a Structural Mechanism for Uncoupling T Cell Receptor Signaling from Peptide-MHC Binding. Cell 2018; 174:672-687.e27. [PMID: 30053426 PMCID: PMC6140336 DOI: 10.1016/j.cell.2018.06.017] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/13/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022]
Abstract
TCR-signaling strength generally correlates with peptide-MHC binding affinity; however, exceptions exist. We find high-affinity, yet non-stimulatory, interactions occur with high frequency in the human T cell repertoire. Here, we studied human TCRs that are refractory to activation by pMHC ligands despite robust binding. Analysis of 3D affinity, 2D dwell time, and crystal structures of stimulatory versus non-stimulatory TCR-pMHC interactions failed to account for their different signaling outcomes. Using yeast pMHC display, we identified peptide agonists of a formerly non-responsive TCR. Single-molecule force measurements demonstrated the emergence of catch bonds in the activating TCR-pMHC interactions, correlating with exclusion of CD45 from the TCR-APC contact site. Molecular dynamics simulations of TCR-pMHC disengagement distinguished agonist from non-agonist ligands based on the acquisition of catch bonds within the TCR-pMHC interface. The isolation of catch bonds as a parameter mediating the coupling of TCR binding and signaling has important implications for TCR and antigen engineering for immunotherapy.
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Affiliation(s)
- Leah V Sibener
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Immunology Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ricardo A Fernandes
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elizabeth M Kolawole
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Catherine B Carbone
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Fan Liu
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA; Institute for Systems Biology, Seattle, WA 98109, USA
| | - Darren McAffee
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Michael E Birnbaum
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Immunology Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Xinbo Yang
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Laura F Su
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wong Yu
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Shen Dong
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marvin H Gee
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Immunology Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin M Jude
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mark M Davis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - William A Goddard
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - James R Heath
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Brian D Evavold
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Ronald D Vale
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - K Christopher Garcia
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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54
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Atomic force microscopy for imaging and nanomechanical characterisation of live nematode epicuticle: A comparative Caenorhabditis elegans and Turbatrix aceti study. Ultramicroscopy 2018; 194:40-47. [PMID: 30071372 DOI: 10.1016/j.ultramic.2018.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 06/28/2018] [Accepted: 07/22/2018] [Indexed: 11/24/2022]
Abstract
Atomic force microscopy (AFM), a powerful tool in interdisciplinary biomedical research, has been applied here to investigate the surface of live nematodes epicuticle. We have used AFM in PeakForce Tapping non-resonant imaging and nanomechanical characterisation mode to investigate and compare the surface features of epicuticle of two free-living microscopic nematodes, Caenorhabditis elegans and Turbatrix aceti. We have successfully immobilised live anesthetized adult nematodes on glass supports using either layer-by-layer-deposited polyelectrolyte films or bioadhesive coatings, which allowed for imaging the living nematodes in native environment. We have obtained AFM images and corresponding nanomechanical maps of annular rings and furrows, demonstrating the differences in topography and structure between the species. Our results demonstrate that AFM in PeakForce Tapping mode can be used to image and characterise surfaces of relatively-large live immobilised multicellular organisms, which can be further applied to a number of invertebrates.
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55
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Shafraz O, Rübsam M, Stahley SN, Caldara AL, Kowalczyk AP, Niessen CM, Sivasankar S. E-cadherin binds to desmoglein to facilitate desmosome assembly. eLife 2018; 7:37629. [PMID: 29999492 PMCID: PMC6066328 DOI: 10.7554/elife.37629] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/10/2018] [Indexed: 02/04/2023] Open
Abstract
Desmosomes are adhesive junctions composed of two desmosomal cadherins: desmocollin (Dsc) and desmoglein (Dsg). Previous studies demonstrate that E-cadherin (Ecad), an adhesive protein that interacts in both trans (between opposing cells) and cis (on the same cell surface) conformations, facilitates desmosome assembly via an unknown mechanism. Here we use structure-function analysis to resolve the mechanistic roles of Ecad in desmosome formation. Using AFM force measurements, we demonstrate that Ecad interacts with isoform 2 of Dsg via a conserved Leu-175 on the Ecad cis binding interface. Super-resolution imaging reveals that Ecad is enriched in nascent desmosomes, supporting a role for Ecad in early desmosome assembly. Finally, confocal imaging demonstrates that desmosome assembly is initiated at sites of Ecad mediated adhesion, and that Ecad-L175 is required for efficient Dsg2 and desmoplakin recruitment to intercellular contacts. We propose that Ecad trans interactions at nascent cell-cell contacts initiate the recruitment of Dsg through direct cis interactions with Ecad which facilitates desmosome assembly.
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Affiliation(s)
- Omer Shafraz
- Department of Physics and Astronomy, Iowa State University, Ames, United States
| | - Matthias Rübsam
- Department of Dermatology, Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sara N Stahley
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Amber L Caldara
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Andrew P Kowalczyk
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Carien M Niessen
- Department of Dermatology, Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sanjeevi Sivasankar
- Department of Physics and Astronomy, Iowa State University, Ames, United States
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56
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Oakes PW. Balancing forces in migration. Curr Opin Cell Biol 2018; 54:43-49. [PMID: 29723736 DOI: 10.1016/j.ceb.2018.04.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/06/2018] [Accepted: 04/12/2018] [Indexed: 01/13/2023]
Abstract
The integrated molecular interactions of proteins can create active biological networks whose material properties and actions can impact a variety of physiological processes. Chief among these is the ability to generate and respond to physical forces. The cytoskeleton plays a key role in this behavior, characterized by active self-reorganization to control a cell's shape and mediate its physical interactions. This review discusses our current understanding of how the material properties of the cytoskeleton and its physical interactions with the extracellular environment impact cell migration.
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Affiliation(s)
- Patrick W Oakes
- Department of Physics & Astronomy, University of Rochester, Rochester, NY 14627, United States; Department of Biology, University of Rochester, Rochester, NY 14627, United States.
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57
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Yang R, Broussard JA, Green KJ, Espinosa HD. Techniques to stimulate and interrogate cell-cell adhesion mechanics. EXTREME MECHANICS LETTERS 2018; 20:125-139. [PMID: 30320194 PMCID: PMC6181239 DOI: 10.1016/j.eml.2017.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cell-cell adhesions maintain the mechanical integrity of multicellular tissues and have recently been found to act as mechanotransducers, translating mechanical cues into biochemical signals. Mechanotransduction studies have primarily focused on focal adhesions, sites of cell-substrate attachment. These studies leverage technical advances in devices and systems interfacing with living cells through cell-extracellular matrix adhesions. As reports of aberrant signal transduction originating from mutations in cell-cell adhesion molecules are being increasingly associated with disease states, growing attention is being paid to this intercellular signaling hub. Along with this renewed focus, new requirements arise for the interrogation and stimulation of cell-cell adhesive junctions. This review covers established experimental techniques for stimulation and interrogation of cell-cell adhesion from cell pairs to monolayers.
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Affiliation(s)
- Ruiguo Yang
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
- Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
| | - Joshua A. Broussard
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
- Department of Dermatology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Kathleen J. Green
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
- Department of Dermatology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Horacio D. Espinosa
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, United States
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL 60208, United States
- Institute for Cellular Engineering Technologies, Northwestern University, Evanston, IL 60208, United States
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58
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Catch Bonds at T Cell Interfaces: Impact of Surface Reorganization and Membrane Fluctuations. Biophys J 2017; 113:120-131. [PMID: 28700910 DOI: 10.1016/j.bpj.2017.05.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/07/2017] [Accepted: 05/19/2017] [Indexed: 01/30/2023] Open
Abstract
Catch bonds are characterized by average lifetimes that initially increase with increasing tensile force. Recently, they have been implicated in T cell activation, where small numbers of antigenic receptor-ligand bonds at a cell-cell interface can stimulate a T cell. Here, we use computational methods to investigate small numbers of bonds at the interface between two membranes. We characterize the time-dependent forces on the bonds in response to changes in the membrane shape and the organization of other surface molecules. We then determine the distributions of bond lifetimes using recent force-dependent lifetime data for T cell receptors bound to various ligands. Strong agonists, which exhibit catch bond behavior, are markedly more likely to remain intact than an antagonist whose average lifetime decreases with increasing force. Thermal fluctuations of the membrane shape enhance the decay of the average force on a bond, but also lead to fluctuations of the force. These fluctuations promote bond rupture, but the effect is buffered by catch bonds. When more than one bond is present, the bonds experience reduced average forces that depend on their relative positions, leading to changes in bond lifetimes. Our results highlight the importance of force-dependent binding kinetics when bonds experience time-dependent and fluctuating forces, as well as potential consequences of collective bond behavior relevant to T cell activation.
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59
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Bachir AI, Horwitz AR, Nelson WJ, Bianchini JM. Actin-Based Adhesion Modules Mediate Cell Interactions with the Extracellular Matrix and Neighboring Cells. Cold Spring Harb Perspect Biol 2017; 9:9/7/a023234. [PMID: 28679638 DOI: 10.1101/cshperspect.a023234] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cell adhesions link cells to the extracellular matrix (ECM) and to each other and depend on interactions with the actin cytoskeleton. Both cell-ECM and cell-cell adhesion sites contain discrete, yet overlapping, functional modules. These modules establish physical associations with the actin cytoskeleton, locally modulate actin organization and dynamics, and trigger intracellular signaling pathways. Interplay between these modules generates distinct actin architectures that underlie different stages, types, and functions of cell-ECM and cell-cell adhesions. Actomyosin contractility is required to generate mature, stable adhesions, as well as to sense and translate the mechanical properties of the cellular environment into changes in cell organization and behavior. Here, we review the organization and function of different adhesion modules and how they interact with the actin cytoskeleton. We highlight the molecular mechanisms of mechanotransduction in adhesions and how adhesion molecules mediate cross talk between cell-ECM and cell-cell adhesion sites.
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Affiliation(s)
- Alexia I Bachir
- Protein and Cell Analysis, Biosciences Division, Thermo Fisher Scientific, Eugene, Oregon 97402
| | - Alan Rick Horwitz
- Protein and Cell Analysis, Biosciences Division, Thermo Fisher Scientific, Eugene, Oregon 97402
| | - W James Nelson
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22903
| | - Julie M Bianchini
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22903
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60
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61
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Tehrani M, Sarvestani AS. Force-driven growth of intercellular junctions. J Theor Biol 2017; 421:101-111. [PMID: 28377302 DOI: 10.1016/j.jtbi.2017.03.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 10/19/2022]
Abstract
Mechanical force regulates the formation and growth of cell-cell junctions. Cadherin is a prominent homotypic cell adhesion molecule that plays a crucial role in establishment of intercellular adhesion. It is known that the transmitted force through the cadherin-mediated junctions directly correlates with the growth and enlargement of the junctions. In this paper, we propose a physical model for the structural evolution of cell-cell junctions subjected to pulling tractions, using the Bell-Dembo-Bongard thermodynamic model. Cadherins have multiple adhesive states and may establish slip or catch bonds depending on the Ca2+ concentration. We conducted a comparative study between the force-dependent behavior of clusters of slip and catch bonds. The results show that the clusters of catch bonds feature some hallmarks of cell mechanotransduction in response to the pulling traction. This is a passive thermodynamic response and is entirely controlled by the effect of mechanical work of the pulling force on the free energy landscape of the junction.
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Affiliation(s)
- Mohammad Tehrani
- Department of Mechanical Engineering, Ohio University, Athens, OH 45701, United States
| | - Alireza S Sarvestani
- Department of Mechanical Engineering, Ohio University, Athens, OH 45701, United States.
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62
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Priest AV, Shafraz O, Sivasankar S. Biophysical basis of cadherin mediated cell-cell adhesion. Exp Cell Res 2017; 358:10-13. [PMID: 28300566 DOI: 10.1016/j.yexcr.2017.03.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 03/09/2017] [Indexed: 10/20/2022]
Abstract
Classical cadherin transmembrane cell-cell adhesion proteins play essential roles in tissue morphogenesis and in mediating tissue integrity. Cadherin ectodomains from opposing cells interact to form load-bearing trans dimers that mechanically couple cells. Cell-cell adhesion is believed to be strengthened by cis clustering of cadherins on the same cell surface. This review summarizes biophysical studies of the structure, interaction kinetics and biomechanics of classical cadherin ectodomains. We first discuss the structure and equilibrium binding kinetics of classical cadherin trans and cis dimers. We then discuss how mechanical stimuli alters the kinetics of cadherin interaction and tunes adhesion. Finally, we highlight open questions on the role of mechanical forces in influencing cadherin structure, function and organization on the cell surface.
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Affiliation(s)
- Andrew Vae Priest
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
| | - Omer Shafraz
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
| | - Sanjeevi Sivasankar
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA.
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63
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Powers RE, Gaudet R, Sotomayor M. A Partial Calcium-Free Linker Confers Flexibility to Inner-Ear Protocadherin-15. Structure 2017; 25:482-495. [PMID: 28238533 DOI: 10.1016/j.str.2017.01.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/16/2017] [Accepted: 01/30/2017] [Indexed: 12/30/2022]
Abstract
Tip links of the inner ear are protein filaments essential for hearing and balance. Two atypical cadherins, cadherin-23 and protocadherin-15, interact in a Ca2+-dependent manner to form tip links. The largely unknown structure and mechanics of these proteins are integral to understanding how tip links pull on ion channels to initiate sensory perception. Protocadherin-15 has 11 extracellular cadherin (EC) repeats. Its EC3-4 linker lacks several of the canonical Ca2+-binding residues, and contains an aspartate-to-alanine polymorphism (D414A) under positive selection in East Asian populations. We present structures of protocadherin-15 EC3-5 featuring two Ca2+-binding linker regions: canonical EC4-5 linker binding three Ca2+ ions, and non-canonical EC3-4 linker binding only two Ca2+ ions. Our structures and biochemical assays reveal little difference between the D414 and D414A variants. Simulations predict that the partial Ca2+-free EC3-4 linker exhibits increased flexural flexibility without compromised mechanical strength, providing insight into the dynamics of tip links and other atypical cadherins.
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Affiliation(s)
- Robert E Powers
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA; Biophysics Graduate Program, Harvard University, Boston, MA 02115, USA
| | - Rachelle Gaudet
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA.
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12(th) Avenue, Columbus, OH 43210, USA.
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64
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Biswas KH, Zaidel-Bar R. Early events in the assembly of E-cadherin adhesions. Exp Cell Res 2017; 358:14-19. [PMID: 28237244 DOI: 10.1016/j.yexcr.2017.02.037] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 02/20/2017] [Indexed: 12/30/2022]
Abstract
E-cadherin is a calcium dependent cell adhesion molecule that is key to the organization of cells in the epithelial tissue. It is a multidomain, trans-membrane protein in which the extracellular domain forms the homotypic, adhesive interaction while the intracellular domain interacts with the actin cytoskeleton through the catenin family of adaptor proteins. A number of recent studies have provided novel insights into the mechanism of adhesion formation by this class of adhesion proteins. Here, we describe an updated view of the process of E-cadherin adhesion formation with an emphasis on the role of molecular mobility, clustering, and active cellular processes.
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Affiliation(s)
- Kabir H Biswas
- Mechanobiology Institute, National University of Singapore, Singapore.
| | - Ronen Zaidel-Bar
- Mechanobiology Institute, National University of Singapore, Singapore; Department of Biomedical Engineering, National University of Singapore, Singapore.
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65
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Chakrabarti S, Hinczewski M, Thirumalai D. Phenomenological and microscopic theories for catch bonds. J Struct Biol 2017; 197:50-56. [PMID: 27046010 PMCID: PMC5580263 DOI: 10.1016/j.jsb.2016.03.022] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/18/2016] [Accepted: 03/30/2016] [Indexed: 12/15/2022]
Abstract
Lifetimes of bound states of protein complexes or biomolecule folded states typically decrease when subject to mechanical force. However, a plethora of biological systems exhibit the counter-intuitive phenomenon of catch bonding, where non-covalent bonds become stronger under externally applied forces. The quest to understand the origin of catch-bond behavior has led to the development of phenomenological and microscopic theories that can quantitatively recapitulate experimental data. Here, we assess the successes and limitations of such theories in explaining experimental data. The most widely applied approach is a phenomenological two-state model, which fits all of the available data on a variety of complexes: actomyosin, kinetochore-microtubule, selectin-ligand, and cadherin-catenin binding to filamentous actin. With a primary focus on the selectin family of cell-adhesion complexes, we discuss the positives and negatives of phenomenological models and the importance of evaluating the physical relevance of fitting parameters. We describe a microscopic theory for selectins, which provides a structural basis for catch bonds and predicts a crucial allosteric role for residues Asn82-Glu88. We emphasize the need for new theories and simulations that can mimic experimental conditions, given the complex response of cell adhesion complexes to force and their potential role in a variety of biological contexts.
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Affiliation(s)
- Shaon Chakrabarti
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, United States; Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA 02215, United States.
| | - Michael Hinczewski
- Department of Physics, Case Western Reserve University, OH 44106, United States
| | - D Thirumalai
- Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, United States
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66
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Araya-Secchi R, Neel BL, Sotomayor M. An elastic element in the protocadherin-15 tip link of the inner ear. Nat Commun 2016; 7:13458. [PMID: 27857071 PMCID: PMC5120219 DOI: 10.1038/ncomms13458] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 10/03/2016] [Indexed: 01/16/2023] Open
Abstract
Tip link filaments convey force and gate inner-ear hair-cell transduction channels to mediate perception of sound and head movements. Cadherin-23 and protocadherin-15 form tip links through a calcium-dependent interaction of their extracellular domains made of multiple extracellular cadherin (EC) repeats. These repeats are structurally similar, but not identical in sequence, often featuring linkers with conserved calcium-binding sites that confer mechanical strength to them. Here we present the X-ray crystal structures of human protocadherin-15 EC8-EC10 and mouse EC9-EC10, which show an EC8-9 canonical-like calcium-binding linker, and an EC9-10 calcium-free linker that alters the linear arrangement of EC repeats. Molecular dynamics simulations and small-angle X-ray scattering experiments support this non-linear conformation. Simulations also suggest that unbending of EC9-10 confers some elasticity to otherwise rigid tip links. The new structure provides a first view of protocadherin-15's non-canonical EC linkers and suggests how they may function in inner-ear mechanotransduction, with implications for other cadherins.
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Affiliation(s)
- Raul Araya-Secchi
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W 12th Avenue, Columbus, Ohio 43210, USA
| | - Brandon L. Neel
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W 12th Avenue, Columbus, Ohio 43210, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W 12th Avenue, Columbus, Ohio 43210, USA
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67
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Manibog K, Yen CF, Sivasankar S. Measuring Force-Induced Dissociation Kinetics of Protein Complexes Using Single-Molecule Atomic Force Microscopy. Methods Enzymol 2016; 582:297-320. [PMID: 28062039 DOI: 10.1016/bs.mie.2016.08.009] [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: 01/02/2023]
Abstract
Proteins respond to mechanical force by undergoing conformational changes and altering the kinetics of their interactions. However, the biophysical relationship between mechanical force and the lifetime of protein complexes is not completely understood. In this chapter, we provide a step-by-step tutorial on characterizing the force-dependent regulation of protein interactions using in vitro and in vivo single-molecule force clamp measurements with an atomic force microscope (AFM). While we focus on the force-induced dissociation of E-cadherins, a critical cell-cell adhesion protein, the approaches described here can be readily adapted to study other protein complexes. We begin this chapter by providing a brief overview of theoretical models that describe force-dependent kinetics of biomolecular interactions. Next, we present step-by-step methods for measuring the response of single receptor-ligand bonds to tensile force in vitro. Finally, we describe methods for quantifying the mechanical response of single protein complexes on the surface of living cells. We describe general protocols for conducting such measurements, including sample preparation, AFM force clamp measurements, and data analysis. We also highlight critical limitations in current technologies and discuss solutions to these challenges.
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Affiliation(s)
- K Manibog
- Iowa State University, Ames, IA, United States; Ames Laboratory, U.S. Department of Energy, Ames, IA, United States
| | - C F Yen
- Iowa State University, Ames, IA, United States; Ames Laboratory, U.S. Department of Energy, Ames, IA, United States
| | - S Sivasankar
- Iowa State University, Ames, IA, United States; Ames Laboratory, U.S. Department of Energy, Ames, IA, United States.
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68
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Makarov DE. Perspective: Mechanochemistry of biological and synthetic molecules. J Chem Phys 2016; 144:030901. [PMID: 26801011 DOI: 10.1063/1.4939791] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Coupling of mechanical forces and chemical transformations is central to the biophysics of molecular machines, polymer chemistry, fracture mechanics, tribology, and other disciplines. As a consequence, the same physical principles and theoretical models should be applicable in all of those fields; in fact, similar models have been invoked (and often repeatedly reinvented) to describe, for example, cell adhesion, dry and wet friction, propagation of cracks, and action of molecular motors. This perspective offers a unified view of these phenomena, described in terms of chemical kinetics with rates of elementary steps that are force dependent. The central question is then to describe how the rate of a chemical transformation (and its other measurable properties such as the transition path) depends on the applied force. I will describe physical models used to answer this question and compare them with experimental measurements, which employ single-molecule force spectroscopy and which become increasingly common. Multidimensionality of the underlying molecular energy landscapes and the ensuing frequent misalignment between chemical and mechanical coordinates result in a number of distinct scenarios, each showing a nontrivial force dependence of the reaction rate. I will discuss these scenarios, their commonness (or its lack), and the prospects for their experimental validation. Finally, I will discuss open issues in the field.
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Affiliation(s)
- Dmitrii E Makarov
- Department of Chemistry and Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas 78712, USA
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69
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Li Z, Lee H, Zhu C. Molecular mechanisms of mechanotransduction in integrin-mediated cell-matrix adhesion. Exp Cell Res 2016; 349:85-94. [PMID: 27720950 DOI: 10.1016/j.yexcr.2016.10.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/30/2016] [Accepted: 10/03/2016] [Indexed: 01/09/2023]
Abstract
Cell-matrix adhesion complexes are multi-protein structures linking the extracellular matrix (ECM) to the cytoskeleton. They are essential to both cell motility and function by bidirectionally sensing and transmitting mechanical and biochemical stimulations. Several types of cell-matrix adhesions have been identified and they share many key molecular components, such as integrins and actin-integrin linkers. Mechanochemical coupling between ECM molecules and the actin cytoskeleton has been observed from the single cell to the single molecule level and from immune cells to neuronal cells. However, the mechanisms underlying force regulation of integrin-mediated mechanotransduction still need to be elucidated. In this review article, we focus on integrin-mediated adhesions and discuss force regulation of cell-matrix adhesions and key adaptor molecules, three different force-dependent behaviors, and molecular mechanisms for mechanochemical coupling in force regulation.
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Affiliation(s)
- Zhenhai Li
- Molecular Modeling and Simulation Group, National Institutes for Quantum and Radiological Science and Technology, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan
| | - Hyunjung Lee
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Cheng Zhu
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; George W Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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70
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Manibog K, Sankar K, Kim SA, Zhang Y, Jernigan RL, Sivasankar S. Molecular determinants of cadherin ideal bond formation: Conformation-dependent unbinding on a multidimensional landscape. Proc Natl Acad Sci U S A 2016; 113:E5711-20. [PMID: 27621473 PMCID: PMC5047164 DOI: 10.1073/pnas.1604012113] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Classical cadherin cell-cell adhesion proteins are essential for the formation and maintenance of tissue structures; their primary function is to physically couple neighboring cells and withstand mechanical force. Cadherins from opposing cells bind in two distinct trans conformations: strand-swap dimers and X-dimers. As cadherins convert between these conformations, they form ideal bonds (i.e., adhesive interactions that are insensitive to force). However, the biophysical mechanism for ideal bond formation is unknown. Here, we integrate single-molecule force measurements with coarse-grained and atomistic simulations to resolve the mechanistic basis for cadherin ideal bond formation. Using simulations, we predict the energy landscape for cadherin adhesion, the transition pathways for interconversion between X-dimers and strand-swap dimers, and the cadherin structures that form ideal bonds. Based on these predictions, we engineer cadherin mutants that promote or inhibit ideal bond formation and measure their force-dependent kinetics using single-molecule force-clamp measurements with an atomic force microscope. Our data establish that cadherins adopt an intermediate conformation as they shuttle between X-dimers and strand-swap dimers; pulling on this conformation induces a torsional motion perpendicular to the pulling direction that unbinds the proteins and forms force-independent ideal bonds. Torsional motion is blocked when cadherins associate laterally in a cis orientation, suggesting that ideal bonds may play a role in mechanically regulating cadherin clustering on cell surfaces.
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Affiliation(s)
- Kristine Manibog
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011; Ames Laboratory, US Department of Energy, Ames, IA 50011
| | - Kannan Sankar
- Bioinformatics and Computational Biology Interdepartmental Program, Iowa State University, Ames, IA 50011; Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011
| | - Sun-Ae Kim
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011; Ames Laboratory, US Department of Energy, Ames, IA 50011
| | - Yunxiang Zhang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Robert L Jernigan
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011; Bioinformatics and Computational Biology Interdepartmental Program, Iowa State University, Ames, IA 50011; Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011; L. H. Baker Center for Bioinformatics and Computational Biology, Iowa State University, Ames, IA 50011
| | - Sanjeevi Sivasankar
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011; Ames Laboratory, US Department of Energy, Ames, IA 50011;
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71
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Chen Y, Lee H, Tong H, Schwartz M, Zhu C. Force regulated conformational change of integrin α Vβ 3. Matrix Biol 2016; 60-61:70-85. [PMID: 27423389 DOI: 10.1016/j.matbio.2016.07.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 06/18/2016] [Accepted: 07/08/2016] [Indexed: 11/28/2022]
Abstract
Integrins mediate cell adhesion to extracellular matrix and transduce signals bidirectionally across the membrane. Integrin αVβ3 has been shown to play an essential role in tumor metastasis, angiogenesis, hemostasis and phagocytosis. Integrins can take several conformations, including the bent and extended conformations of the ectodomain, which regulate integrin functions. Using a biomembrane force probe, we characterized the bending and unbending conformational changes of single αVβ3 integrins on living cell surfaces in real-time. We measured the probabilities of conformational changes, rates and speeds of conformational transitions, and the dynamic equilibrium between the two conformations, which were regulated by tensile force, dependent on the ligand, and altered by point mutations. These findings provide insights into how αVβ3 acts as a molecular machine and how its physiological function and molecular structure are coupled at the single-molecule level.
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Affiliation(s)
- Yunfeng Chen
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hyunjung Lee
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Haibin Tong
- Yale Cardiovascular Research Center, Departments of Internal Medicine (Section of Cardiovascular Medicine), Cell Biology and Biomedical Engineering, Yale University, New Haven, CT 06511, USA; Current address: Life Science Research Center, Beihua University, Jilin 132013, China
| | - Martin Schwartz
- Yale Cardiovascular Research Center, Departments of Internal Medicine (Section of Cardiovascular Medicine), Cell Biology and Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Cheng Zhu
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA; Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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72
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Yen CF, Harischandra DS, Kanthasamy A, Sivasankar S. Copper-induced structural conversion templates prion protein oligomerization and neurotoxicity. SCIENCE ADVANCES 2016; 2:e1600014. [PMID: 27419232 PMCID: PMC4942324 DOI: 10.1126/sciadv.1600014] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 05/27/2016] [Indexed: 05/26/2023]
Abstract
Prion protein (PrP) misfolding and oligomerization are key pathogenic events in prion disease. Copper exposure has been linked to prion pathogenesis; however, its mechanistic basis is unknown. We resolve, with single-molecule precision, the molecular mechanism of Cu(2+)-induced misfolding of PrP under physiological conditions. We also demonstrate that misfolded PrPs serve as seeds for templated formation of aggregates, which mediate inflammation and degeneration of neuronal tissue. Using a single-molecule fluorescence assay, we demonstrate that Cu(2+) induces PrP monomers to misfold before oligomer assembly; the disordered amino-terminal region mediates this structural change. Single-molecule force spectroscopy measurements show that the misfolded monomers have a 900-fold higher binding affinity compared to the native isoform, which promotes their oligomerization. Real-time quaking-induced conversion demonstrates that misfolded PrPs serve as seeds that template amyloid formation. Finally, organotypic slice cultures show that misfolded PrPs mediate inflammation and degeneration of neuronal tissue. Our study establishes a direct link, at the molecular level, between copper exposure and PrP neurotoxicity.
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Affiliation(s)
- Chi-Fu Yen
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA
| | - Dilshan S. Harischandra
- Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Anumantha Kanthasamy
- Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| | - Sanjeevi Sivasankar
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
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73
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Interlandi G, Thomas WE. Mechanism of allosteric propagation across a β-sheet structure investigated by molecular dynamics simulations. Proteins 2016; 84:990-1008. [PMID: 27090060 PMCID: PMC5084802 DOI: 10.1002/prot.25050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 03/24/2016] [Accepted: 04/08/2016] [Indexed: 12/21/2022]
Abstract
The bacterial adhesin FimH consists of an allosterically regulated mannose-binding lectin domain and a covalently linked inhibitory pilin domain. Under normal conditions, the two domains are bound to each other, and FimH interacts weakly with mannose. However, under tensile force, the domains separate and the lectin domain undergoes conformational changes that strengthen its bond with mannose. Comparison of the crystallographic structures of the low and the high affinity state of the lectin domain reveals conformational changes mainly in the regulatory inter-domain region, the mannose binding site and a large β sheet that connects the two distally located regions. Here, molecular dynamics simulations investigated how conformational changes are propagated within and between different regions of the lectin domain. It was found that the inter-domain region moves towards the high affinity conformation as it becomes more compact and buries exposed hydrophobic surface after separation of the pilin domain. The mannose binding site was more rigid in the high affinity state, which prevented water penetration into the pocket. The large central β sheet demonstrated a soft spring-like twisting. Its twisting motion was moderately correlated to fluctuations in both the regulatory and the binding region, whereas a weak correlation was seen in a direct comparison of these two distal sites. The results suggest a so called "population shift" model whereby binding of the lectin domain to either the pilin domain or mannose locks the β sheet in a rather twisted or flat conformation, stabilizing the low or the high affinity state, respectively. Proteins 2016; 84:990-1008. © 2016 The Authors. Proteins: Structure, Function, and Bioinformatics Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Gianluca Interlandi
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195
| | - Wendy E Thomas
- Department of Bioengineering, University of Washington, Seattle, Washington, 98195
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74
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Sauer MM, Jakob RP, Eras J, Baday S, Eriş D, Navarra G, Bernèche S, Ernst B, Maier T, Glockshuber R. Catch-bond mechanism of the bacterial adhesin FimH. Nat Commun 2016; 7:10738. [PMID: 26948702 PMCID: PMC4786642 DOI: 10.1038/ncomms10738] [Citation(s) in RCA: 144] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 01/13/2016] [Indexed: 01/12/2023] Open
Abstract
Ligand–receptor interactions that are reinforced by mechanical stress, so-called catch-bonds, play a major role in cell–cell adhesion. They critically contribute to widespread urinary tract infections by pathogenic Escherichia coli strains. These pathogens attach to host epithelia via the adhesin FimH, a two-domain protein at the tip of type I pili recognizing terminal mannoses on epithelial glycoproteins. Here we establish peptide-complemented FimH as a model system for fimbrial FimH function. We reveal a three-state mechanism of FimH catch-bond formation based on crystal structures of all states, kinetic analysis of ligand interaction and molecular dynamics simulations. In the absence of tensile force, the FimH pilin domain allosterically accelerates spontaneous ligand dissociation from the FimH lectin domain by 100,000-fold, resulting in weak affinity. Separation of the FimH domains under stress abolishes allosteric interplay and increases the affinity of the lectin domain. Cell tracking demonstrates that rapid ligand dissociation from FimH supports motility of piliated E. coli on mannosylated surfaces in the absence of shear force. Catch bonds have a role in bacterial adhesion and infection by uropathogenic E. coli. Here, the authors report crystal structures, molecular dynamics simulations, ligand binding analysis and cell tracking to characterise the catch bond interaction between the adhesin FimH and carbohydrate receptors.
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Affiliation(s)
- Maximilian M Sauer
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH, Zurich, Otto-Stern-Weg 5, 8093 Zurich, Switzerland
| | - Roman P Jakob
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Jonathan Eras
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH, Zurich, Otto-Stern-Weg 5, 8093 Zurich, Switzerland
| | - Sefer Baday
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.,SIB Swiss Institute of Bioinformatics, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Deniz Eriş
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Giulio Navarra
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Simon Bernèche
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.,SIB Swiss Institute of Bioinformatics, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Beat Ernst
- Institute of Molecular Pharmacy, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Timm Maier
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Rudi Glockshuber
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH, Zurich, Otto-Stern-Weg 5, 8093 Zurich, Switzerland
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75
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Przekwas A, Somayaji MR, Gupta RK. Synaptic Mechanisms of Blast-Induced Brain Injury. Front Neurol 2016; 7:2. [PMID: 26834697 PMCID: PMC4720734 DOI: 10.3389/fneur.2016.00002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 01/04/2016] [Indexed: 01/08/2023] Open
Abstract
Blast wave-induced traumatic brain injury (TBI) is one of the most common injuries to military personnel. Brain tissue compression/tension due to blast-induced cranial deformations and shear waves due to head rotation may generate diffuse micro-damage to neuro-axonal structures and trigger a cascade of neurobiological events culminating in cognitive and neurodegenerative disorders. Although diffuse axonal injury is regarded as a signature wound of mild TBI (mTBI), blast loads may also cause synaptic injury wherein neuronal synapses are stretched and sheared. This synaptic injury may result in temporary disconnect of the neural circuitry and transient loss in neuronal communication. We hypothesize that mTBI symptoms such as loss of consciousness or dizziness, which start immediately after the insult, could be attributed to synaptic injury. Although empirical evidence is beginning to emerge; the detailed mechanisms underlying synaptic injury are still elusive. Coordinated in vitro-in vivo experiments and mathematical modeling studies can shed light into the synaptic injury mechanisms and their role in the potentiation of mTBI symptoms.
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Affiliation(s)
- Andrzej Przekwas
- Computational Medicine and Biology Division, CFD Research Corporation, Huntsville, AL, USA
| | | | - Raj K. Gupta
- Department of Defense Blast Injury Research Program Coordinating Office, U.S. Army Medical Research and Materiel Command, Fort Detrick, MD, USA
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76
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Hoffman BD, Yap AS. Towards a Dynamic Understanding of Cadherin-Based Mechanobiology. Trends Cell Biol 2015; 25:803-814. [DOI: 10.1016/j.tcb.2015.09.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/21/2015] [Accepted: 09/21/2015] [Indexed: 01/23/2023]
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77
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Homophilic interaction and deformation of E-cadherin and cadherin 7 probed by single molecule force spectroscopy. Arch Biochem Biophys 2015; 587:38-47. [PMID: 26476343 DOI: 10.1016/j.abb.2015.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 10/08/2015] [Accepted: 10/09/2015] [Indexed: 01/18/2023]
Abstract
Cadherin-mediated adhesion plays a crucial role in multicellular organisms. Dysfunction within this adhesion system has major consequences in many pathologies, including cancer invasion and metastasis. However, mechanisms controlling cadherin recognition and adhesive strengthening are only partially understood. Here, we investigated the homophilic interactions and mechanical stability of the extracellular (EC) domains of E-cadherin and cadherin 7 using atomic force microscopy and magnetic tweezers. Besides exhibiting stronger interactions, E-cadherin also showed more efficient force-induced self-strengthening of interactions than cadherin 7. In addition, the distributions of the unbinding forces for both cadherins partially overlap with those of the unfolding forces, indicating that partial unfolding/deformation of the cadherin EC domains may take place during their homophilic interactions. These conformational changes may be involved in cadherins physiology function and contribute to the significant differences in adhesive strength mediated by type I and type II cadherins.
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78
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Adherens Junctions Revisualized: Organizing Cadherins as Nanoassemblies. Dev Cell 2015; 35:12-20. [DOI: 10.1016/j.devcel.2015.09.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 08/27/2015] [Accepted: 09/17/2015] [Indexed: 01/31/2023]
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79
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Nucleotides regulate the mechanical hierarchy between subdomains of the nucleotide binding domain of the Hsp70 chaperone DnaK. Proc Natl Acad Sci U S A 2015; 112:10389-94. [PMID: 26240360 DOI: 10.1073/pnas.1504625112] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The regulation of protein function through ligand-induced conformational changes is crucial for many signal transduction processes. The binding of a ligand alters the delicate energy balance within the protein structure, eventually leading to such conformational changes. In this study, we elucidate the energetic and mechanical changes within the subdomains of the nucleotide binding domain (NBD) of the heat shock protein of 70 kDa (Hsp70) chaperone DnaK upon nucleotide binding. In an integrated approach using single molecule optical tweezer experiments, loop insertions, and steered coarse-grained molecular simulations, we find that the C-terminal helix of the NBD is the major determinant of mechanical stability, acting as a glue between the two lobes. After helix unraveling, the relative stability of the two separated lobes is regulated by ATP/ADP binding. We find that the nucleotide stays strongly bound to lobe II, thus reversing the mechanical hierarchy between the two lobes. Our results offer general insights into the nucleotide-induced signal transduction within members of the actin/sugar kinase superfamily.
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80
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E-cadherin junctions as active mechanical integrators in tissue dynamics. Nat Cell Biol 2015; 17:533-9. [PMID: 25925582 DOI: 10.1038/ncb3136] [Citation(s) in RCA: 369] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
During epithelial morphogenesis, E-cadherin adhesive junctions play an important part in mechanically coupling the contractile cortices of cells together, thereby distributing the stresses that drive cell rearrangements at both local and tissue levels. Here we discuss the concept that cellular contractility and E-cadherin-based adhesion are functionally integrated by biomechanical feedback pathways that operate on molecular, cellular and tissue scales.
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81
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Study of protein structural deformations under external mechanical perturbations by a coarse-grained simulation method. Biomech Model Mechanobiol 2015; 15:317-29. [DOI: 10.1007/s10237-015-0690-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 05/30/2015] [Indexed: 01/14/2023]
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82
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Radtke M, Netz RR. Shear-enhanced adsorption of a homopolymeric globule mediated by surface catch bonds. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2015; 38:69. [PMID: 26123772 DOI: 10.1140/epje/i2015-15069-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/19/2015] [Accepted: 05/27/2015] [Indexed: 06/04/2023]
Abstract
The adsorption of a single collapsed homopolymer onto a planar smooth surface in shear flow is investigated by means of Brownian hydrodynamics simulation. While cohesive intra-polymer forces are modeled by Lennard-Jones potentials, surface-monomer interactions are described by stochastic bonds whose two-state kinetics is characterized by three parameters: bond formation rate, bond dissociation rate and an effective catch bond parameter that describes how the force acting on a surface-monomer bond influences the dissociation rate. We construct adsorption state diagrams as a function of shear rate and all three surface-monomer bond parameters. We find shear-induced adsorption in a small range of parameters for low dissociation and association rates and only when the surface-monomer bond is near the transition between slip and catch bond behavior. By mapping on a simple surface-monomer interaction model with conservative pair potentials we try to estimate the conservative potential parameters necessary to observe shear-induced surface adsorption phenomena.
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Affiliation(s)
- Matthias Radtke
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
| | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
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83
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Molecular Mechanoneurobiology: An Emerging Angle to Explore Neural Synaptic Functions. BIOMED RESEARCH INTERNATIONAL 2015; 2015:486827. [PMID: 26106609 PMCID: PMC4461725 DOI: 10.1155/2015/486827] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 03/17/2015] [Indexed: 12/28/2022]
Abstract
Neural synapses are intercellular asymmetrical junctions that transmit biochemical and biophysical information between a neuron and a target cell. They are very tight, dynamic, and well organized by many synaptic adhesion molecules, signaling receptors, ion channels, and their associated cytoskeleton that bear forces. Mechanical forces have been an emerging factor in regulating axon guidance and growth, synapse formation and plasticity in physiological and pathological brain activity. Therefore, mechanical forces are undoubtedly exerted on those synaptic molecules and modulate their functions. Here we review current progress on how mechanical forces regulate receptor-ligand interactions, protein conformations, ion channels activation, and cytoskeleton dynamics and discuss how these regulations potentially affect synapse formation, stabilization, and plasticity.
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84
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Abstract
Molecular force spectroscopy has become a powerful tool to study how mechanics regulates biology, especially the mechanical regulation of molecular interactions and its impact on cellular functions. This force-driven methodology has uncovered a wealth of new information of the physical chemistry of molecular bonds for various biological systems. The new concepts, qualitative and quantitative measures describing bond behavior under force, and structural bases underlying these phenomena have substantially advanced our fundamental understanding of the inner workings of biological systems from the nanoscale (molecule) to the microscale (cell), elucidated basic molecular mechanisms of a wide range of important biological processes, and provided opportunities for engineering applications. Here, we review major force spectroscopic assays, conceptual developments of mechanically regulated kinetics of molecular interactions, and their biological relevance. We also present current challenges and highlight future directions.
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Affiliation(s)
- Baoyu Liu
- Coulter Department of Biomedical Engineering
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85
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Chen Y, Radford SE, Brockwell DJ. Force-induced remodelling of proteins and their complexes. Curr Opin Struct Biol 2015; 30:89-99. [PMID: 25710390 PMCID: PMC4499843 DOI: 10.1016/j.sbi.2015.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/29/2015] [Accepted: 02/02/2015] [Indexed: 11/23/2022]
Abstract
Force can drive conformational changes in proteins, as well as modulate their stability and the affinity of their complexes, allowing a mechanical input to be converted into a biochemical output. These properties have been utilised by nature and force is now recognised to be widely used at the cellular level. The effects of force on the biophysical properties of biological systems can be large and varied. As these effects are only apparent in the presence of force, studies on the same proteins using traditional ensemble biophysical methods can yield apparently conflicting results. Where appropriate, therefore, force measurements should be integrated with other experimental approaches to understand the physiological context of the system under study.
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Affiliation(s)
- Yun Chen
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK.
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86
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Friedman LG, Benson DL, Huntley GW. Cadherin-based transsynaptic networks in establishing and modifying neural connectivity. Curr Top Dev Biol 2015; 112:415-65. [PMID: 25733148 DOI: 10.1016/bs.ctdb.2014.11.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
It is tacitly understood that cell adhesion molecules (CAMs) are critically important for the development of cells, circuits, and synapses in the brain. What is less clear is what CAMs continue to contribute to brain structure and function after the early period of development. Here, we focus on the cadherin family of CAMs to first briefly recap their multidimensional roles in neural development and then to highlight emerging data showing that with maturity, cadherins become largely dispensible for maintaining neuronal and synaptic structure, instead displaying new and narrower roles at mature synapses where they critically regulate dynamic aspects of synaptic signaling, structural plasticity, and cognitive function. At mature synapses, cadherins are an integral component of multiprotein networks, modifying synaptic signaling, morphology, and plasticity through collaborative interactions with other CAM family members as well as a variety of neurotransmitter receptors, scaffolding proteins, and other effector molecules. Such recognition of the ever-evolving functions of synaptic cadherins may yield insight into the pathophysiology of brain disorders in which cadherins have been implicated and that manifest at different times of life.
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Affiliation(s)
- Lauren G Friedman
- Fishberg Department of Neuroscience, Friedman Brain Institute and the Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Deanna L Benson
- Fishberg Department of Neuroscience, Friedman Brain Institute and the Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, USA
| | - George W Huntley
- Fishberg Department of Neuroscience, Friedman Brain Institute and the Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, USA.
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87
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Aschenbrenner D, Pippig DA, Klamecka K, Limmer K, Leonhardt H, Gaub HE. Parallel force assay for protein-protein interactions. PLoS One 2014; 9:e115049. [PMID: 25546146 PMCID: PMC4278885 DOI: 10.1371/journal.pone.0115049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 11/18/2014] [Indexed: 11/20/2022] Open
Abstract
Quantitative proteome research is greatly promoted by high-resolution parallel format assays. A characterization of protein complexes based on binding forces offers an unparalleled dynamic range and allows for the effective discrimination of non-specific interactions. Here we present a DNA-based Molecular Force Assay to quantify protein-protein interactions, namely the bond between different variants of GFP and GFP-binding nanobodies. We present different strategies to adjust the maximum sensitivity window of the assay by influencing the binding strength of the DNA reference duplexes. The binding of the nanobody Enhancer to the different GFP constructs is compared at high sensitivity of the assay. Whereas the binding strength to wild type and enhanced GFP are equal within experimental error, stronger binding to superfolder GFP is observed. This difference in binding strength is attributed to alterations in the amino acids that form contacts according to the crystal structure of the initial wild type GFP-Enhancer complex. Moreover, we outline the potential for large-scale parallelization of the assay.
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Affiliation(s)
- Daniela Aschenbrenner
- Lehrstuhl für Angewandte Physik and Center for Nanoscience (CeNS), Ludwig-Maximilians-
- Munich Center for Integrated Protein Science (CIPSM), Butenandtstr. 5–13, 81377 Munich, Germany
| | - Diana A. Pippig
- Lehrstuhl für Angewandte Physik and Center for Nanoscience (CeNS), Ludwig-Maximilians-
| | - Kamila Klamecka
- Lehrstuhl für Angewandte Physik and Center for Nanoscience (CeNS), Ludwig-Maximilians-
- Department of Biology II and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität, Großhadernerstr. 2, 82152 Planegg-Martinsried, Germany
| | - Katja Limmer
- Lehrstuhl für Angewandte Physik and Center for Nanoscience (CeNS), Ludwig-Maximilians-
| | - Heinrich Leonhardt
- Department of Biology II and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universität, Großhadernerstr. 2, 82152 Planegg-Martinsried, Germany
- Munich Center for Integrated Protein Science (CIPSM), Butenandtstr. 5–13, 81377 Munich, Germany
| | - Hermann E. Gaub
- Lehrstuhl für Angewandte Physik and Center for Nanoscience (CeNS), Ludwig-Maximilians-
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88
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Buckley CD, Tan J, Anderson KL, Hanein D, Volkmann N, Weis WI, Nelson WJ, Dunn AR. Cell adhesion. The minimal cadherin-catenin complex binds to actin filaments under force. Science 2014; 346:1254211. [PMID: 25359979 DOI: 10.1126/science.1254211] [Citation(s) in RCA: 431] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Linkage between the adherens junction (AJ) and the actin cytoskeleton is required for tissue development and homeostasis. In vivo findings indicated that the AJ proteins E-cadherin, β-catenin, and the filamentous (F)-actin binding protein αE-catenin form a minimal cadherin-catenin complex that binds directly to F-actin. Biochemical studies challenged this model because the purified cadherin-catenin complex does not bind F-actin in solution. Here, we reconciled this difference. Using an optical trap-based assay, we showed that the minimal cadherin-catenin complex formed stable bonds with an actin filament under force. Bond dissociation kinetics can be explained by a catch-bond model in which force shifts the bond from a weakly to a strongly bound state. These results may explain how the cadherin-catenin complex transduces mechanical forces at cell-cell junctions.
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Affiliation(s)
- Craig D Buckley
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Jiongyi Tan
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Karen L Anderson
- Bioinformatics and Structural Systems Biology Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037
| | - Dorit Hanein
- Bioinformatics and Structural Systems Biology Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037
| | - Niels Volkmann
- Bioinformatics and Structural Systems Biology Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037
| | - William I Weis
- Biophysics Program, Stanford University, Stanford, CA 94305, USA.,Department of Structural Biology, Stanford University, Stanford, CA 94305, USA.,Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - W James Nelson
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.,Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.,Biophysics Program, Stanford University, Stanford, CA 94305, USA.,Stanford Cardiovascular Institute, Stanford University, Stanford, CA 94305, USA
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