1
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Tavasoli M, McMaster CR. Defects in integrin complex formation promote CHKB-mediated muscular dystrophy. Life Sci Alliance 2024; 7:e202301956. [PMID: 38749543 PMCID: PMC11096732 DOI: 10.26508/lsa.202301956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/03/2024] [Accepted: 05/07/2024] [Indexed: 05/18/2024] Open
Abstract
Phosphatidylcholine (PC) is the major membrane phospholipid in most eukaryotic cells. Bi-allelic loss of function variants in CHKB, encoding the first step in the synthesis of PC, is the cause of a rostrocaudal muscular dystrophy in both humans and mice. Loss of sarcolemma integrity is a hallmark of muscular dystrophies; however, how this occurs in the absence of choline kinase function is not known. We determine that in Chkb -/- mice there is a failure of the α7β1 integrin complex that is specific to affected muscle. We observed that in Chkb -/- hindlimb muscles there is a decrease in sarcolemma association/abundance of the PI(4,5)P2 binding integrin complex proteins vinculin, and α-actinin, and a decrease in actin association with the sarcolemma. In cells, pharmacological inhibition of choline kinase activity results in internalization of a fluorescent PI(4,5)P2 reporter from discrete plasma membrane clusters at the cell surface membrane to cytosol, this corresponds with a decreased vinculin localization at plasma membrane focal adhesions that was rescued by overexpression of CHKB.
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Affiliation(s)
- Mahtab Tavasoli
- https://ror.org/01e6qks80 Department of Pharmacology, Dalhousie University, Halifax, Canada
| | - Christopher R McMaster
- https://ror.org/01e6qks80 Department of Pharmacology, Dalhousie University, Halifax, Canada
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2
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Cocom-Chan B, Khakzad H, Konate M, Aguilar DI, Bello C, Valencia-Gallardo C, Zarrouk Y, Fattaccioli J, Mauviel A, Javelaud D, Tran Van Nhieu G. IpaA reveals distinct modes of vinculin activation during Shigella invasion and cell-matrix adhesion. Life Sci Alliance 2024; 7:e202302418. [PMID: 38834194 PMCID: PMC11150655 DOI: 10.26508/lsa.202302418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/06/2024] Open
Abstract
Vinculin is a cytoskeletal linker strengthening cell adhesion. The Shigella IpaA invasion effector binds to vinculin to promote vinculin supra-activation associated with head-domain-mediated oligomerization. Our study investigates the impact of mutations of vinculin D1D2 subdomains' residues predicted to interact with IpaA VBS3. These mutations affected the rate of D1D2 trimer formation with distinct effects on monomer disappearance, consistent with structural modeling of a closed and open D1D2 conformer induced by IpaA. Notably, mutations targeting the closed D1D2 conformer significantly reduced Shigella invasion of host cells as opposed to mutations targeting the open D1D2 conformer and later stages of vinculin head-domain oligomerization. In contrast, all mutations affected the formation of focal adhesions (FAs), supporting the involvement of vinculin supra-activation in this process. Our findings suggest that IpaA-induced vinculin supra-activation primarily reinforces matrix adhesion in infected cells, rather than promoting bacterial invasion. Consistently, shear stress studies pointed to a key role for IpaA-induced vinculin supra-activation in accelerating and strengthening cell-matrix adhesion.
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Affiliation(s)
- Benjamin Cocom-Chan
- Team "Ca2+ Signaling and Microbial Infections", I2BC, Gif-sur-Yvette, France
- Institut National de la Santé et de la Recherche Médicale U1280, Gif-sur-Yvette, France
- Centre National de la Recherche Scientifique UMR9198, Gif-sur-Yvette, France
| | - Hamed Khakzad
- Team "Ca2+ Signaling and Microbial Infections", I2BC, Gif-sur-Yvette, France
- Institut National de la Santé et de la Recherche Médicale U1280, Gif-sur-Yvette, France
- Centre National de la Recherche Scientifique UMR9198, Gif-sur-Yvette, France
- Université de Lorraine, CNRS, Inria, LORIA, Nancy, France
| | - Mahamadou Konate
- Team "Ca2+ Signaling and Microbial Infections", I2BC, Gif-sur-Yvette, France
- Institut National de la Santé et de la Recherche Médicale U1280, Gif-sur-Yvette, France
- Centre National de la Recherche Scientifique UMR9198, Gif-sur-Yvette, France
| | - Daniel Isui Aguilar
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
- Institut National de la Santé et de la Recherche Médicale U1050, Paris, France
- Centre National de la Recherche Scientifique UMR7241, Paris, France
- MEMOLIFE Laboratory of Excellence and Paris Science Lettre, Paris, France
| | - Chakir Bello
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
- Institut National de la Santé et de la Recherche Médicale U1050, Paris, France
- Centre National de la Recherche Scientifique UMR7241, Paris, France
- MEMOLIFE Laboratory of Excellence and Paris Science Lettre, Paris, France
| | - Cesar Valencia-Gallardo
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
- Institut National de la Santé et de la Recherche Médicale U1050, Paris, France
- Centre National de la Recherche Scientifique UMR7241, Paris, France
- MEMOLIFE Laboratory of Excellence and Paris Science Lettre, Paris, France
| | - Yosra Zarrouk
- Team "Ca2+ Signaling and Microbial Infections", I2BC, Gif-sur-Yvette, France
- Institut National de la Santé et de la Recherche Médicale U1280, Gif-sur-Yvette, France
- Centre National de la Recherche Scientifique UMR9198, Gif-sur-Yvette, France
| | - Jacques Fattaccioli
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, Paris, France
- Institut Pierre-Gilles de Gennes pour la Microfluidique, Paris, France
| | - Alain Mauviel
- Institut Curie, PSL Research University, INSERM U1021, CNRS UMR3347, Team "TGF-ß and Oncogenesis", Equipe Labellisée LIGUE 2016, Orsay, France
- Université Paris-Sud, Orsay, France
- Centre National de la Recherche Scientifique UMR 3347, Orsay, France
| | - Delphine Javelaud
- Institut Curie, PSL Research University, INSERM U1021, CNRS UMR3347, Team "TGF-ß and Oncogenesis", Equipe Labellisée LIGUE 2016, Orsay, France
- Université Paris-Sud, Orsay, France
- Centre National de la Recherche Scientifique UMR 3347, Orsay, France
| | - Guy Tran Van Nhieu
- Team "Ca2+ Signaling and Microbial Infections", I2BC, Gif-sur-Yvette, France
- Institut National de la Santé et de la Recherche Médicale U1280, Gif-sur-Yvette, France
- Centre National de la Recherche Scientifique UMR9198, Gif-sur-Yvette, France
- Equipe Communication Intercellulaire et Infections Microbiennes, Centre de Recherche Interdisciplinaire en Biologie (CIRB), Collège de France, Paris, France
- Institut National de la Santé et de la Recherche Médicale U1050, Paris, France
- Centre National de la Recherche Scientifique UMR7241, Paris, France
- MEMOLIFE Laboratory of Excellence and Paris Science Lettre, Paris, France
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3
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Quinn JM, Wang Y, Wood M, Flozak AS, Le PM, Yemelyanov A, Oakes PW, Gottardi CJ. α-catenin middle- and actin-binding domain unfolding mutants differentially impact epithelial strength and sheet migration. Mol Biol Cell 2024; 35:ar65. [PMID: 38507238 PMCID: PMC11151094 DOI: 10.1091/mbc.e23-01-0036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/23/2024] [Accepted: 03/15/2024] [Indexed: 03/22/2024] Open
Abstract
α-catenin (α-cat) displays force-dependent unfolding and binding to actin filaments through direct and indirect means, but features of adherens junction structure and function most vulnerable to loss of these allosteric mechanisms have not been directly compared. By reconstituting an α-cat F-actin-binding domain unfolding mutant known to exhibit enhanced binding to actin (α-cat-H0-FABD+) into α-cat knockout Madin Darby Canine Kidney (MDCK) cells, we show that partial loss of the α-cat catch bond mechanism (via an altered H0 α-helix) leads to stronger epithelial sheet integrity with greater colocalization between the α-cat-H0-FABD+ mutant and actin. α-cat-H0-FABD+ -expressing cells are less efficient at closing scratch-wounds, suggesting reduced capacity for more dynamic cell-cell coordination. Evidence that α-cat-H0-FABD+ is equally accessible to the conformationally sensitive α18 antibody epitope as WT α-cat and shows similar vinculin recruitment suggests this mutant engages lower tension cortical actin networks, as its M-domain is not persistently open. Conversely, α-cat-M-domain salt-bridge mutants with persistent recruitment of vinculin and phosphorylated myosin light chain show only intermediate monolayer adhesive strengths, but display less directionally coordinated and thereby slower migration speeds during wound-repair. These data show α-cat M- and FABD-unfolding mutants differentially impact cell-cell cohesion and migration properties, and suggest signals favoring α-cat-cortical actin interaction without persistent M-domain opening may improve epithelial monolayer strength through enhanced coupling to lower tension actin networks.
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Affiliation(s)
- Jeanne M. Quinn
- Department of Pulmonary Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
| | - Yuou Wang
- Department of Pulmonary Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
| | - Megan Wood
- Department of Pulmonary Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
| | - Annette S. Flozak
- Department of Pulmonary Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
| | - Phuong M. Le
- Department of Pulmonary Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
| | - Alex Yemelyanov
- Department of Pulmonary Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
| | - Patrick W. Oakes
- Department of Cell & Molecular Physiology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153
| | - Cara J. Gottardi
- Department of Pulmonary Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
- Cell & Developmental Biology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611
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4
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Chirasani VR, Khan MAI, Malavade JN, Dokholyan NV, Hoffman BD, Campbell SL. Molecular basis and cellular functions of vinculin-actin directional catch bonding. Nat Commun 2023; 14:8300. [PMID: 38097542 PMCID: PMC10721916 DOI: 10.1038/s41467-023-43779-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023] Open
Abstract
The ability of cells and tissues to respond differentially to mechanical forces applied in distinct directions is mediated by the ability of load-bearing proteins to preferentially maintain physical linkages in certain directions. However, the molecular basis and biological consequences of directional force-sensitive binding remain unclear. Vinculin (Vcn) is a load-bearing linker protein that exhibits directional catch bonding due to interactions between the Vcn tail domain (Vt) and filamentous (F)-actin. We developed a computational approach to predict Vcn residues involved in directional catch bonding and produced a set of associated Vcn variants with unaltered Vt structure, actin binding, or phospholipid interactions. Incorporation of the variants did not affect Vcn activation but reduced Vcn loading and altered exchange dynamics, consistent with the loss of directional catch bonding. Expression of Vcn variants perturbed the coordination of subcellular structures and cell migration, establishing key cellular functions for Vcn directional catch bonding.
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Affiliation(s)
- Venkat R Chirasani
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Mohammad Ashhar I Khan
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Juilee N Malavade
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Nikolay V Dokholyan
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, USA.
- Department of Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, USA.
- Department of Chemistry, Penn State College of Medicine, Hershey, PA, USA.
| | - Brenton D Hoffman
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
- Department of Cell Biology, Duke University, Durham, NC, USA.
| | - Sharon L Campbell
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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5
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Franz F, Tapia-Rojo R, Winograd-Katz S, Boujemaa-Paterski R, Li W, Unger T, Albeck S, Aponte-Santamaria C, Garcia-Manyes S, Medalia O, Geiger B, Gräter F. Allosteric activation of vinculin by talin. Nat Commun 2023; 14:4311. [PMID: 37463895 DOI: 10.1038/s41467-023-39646-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 06/22/2023] [Indexed: 07/20/2023] Open
Abstract
The talin-vinculin axis is a key mechanosensing component of cellular focal adhesions. How talin and vinculin respond to forces and regulate one another remains unclear. By combining single-molecule magnetic tweezers experiments, Molecular Dynamics simulations, actin-bundling assays, and adhesion assembly experiments in live cells, we here describe a two-ways allosteric network within vinculin as a regulator of the talin-vinculin interaction. We directly observe a maturation process of vinculin upon talin binding, which reinforces the binding to talin at a rate of 0.03 s-1. This allosteric transition can compete with force-induced dissociation of vinculin from talin only at forces up to 10 pN. Mimicking the allosteric activation by mutation yields a vinculin molecule that bundles actin and localizes to focal adhesions in a force-independent manner. Hence, the allosteric switch confines talin-vinculin interactions and focal adhesion build-up to intermediate force levels. The 'allosteric vinculin mutant' is a valuable molecular tool to further dissect the mechanical and biochemical signalling circuits at focal adhesions and elsewhere.
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Affiliation(s)
- Florian Franz
- Heidelberg Institute for Theoretical Studies (HITS), Schloß-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Mathematikon, INF 205, 69120, Heidelberg, Germany
| | - Rafael Tapia-Rojo
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, Strand, WC2R 2LS London, UK.
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, London, UK.
| | - Sabina Winograd-Katz
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot, Israel
| | | | - Wenhong Li
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Unger
- The Dana and Yossie Hollander Center for Structural Proteomics, Weizmann Institute of Science, Rehovot, Israel
| | - Shira Albeck
- The Dana and Yossie Hollander Center for Structural Proteomics, Weizmann Institute of Science, Rehovot, Israel
| | - Camilo Aponte-Santamaria
- Heidelberg Institute for Theoretical Studies (HITS), Schloß-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Mathematikon, INF 205, 69120, Heidelberg, Germany
| | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, Strand, WC2R 2LS London, UK
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, London, UK
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland.
| | - Benjamin Geiger
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot, Israel.
| | - Frauke Gräter
- Heidelberg Institute for Theoretical Studies (HITS), Schloß-Wolfsbrunnenweg 35, 69118, Heidelberg, Germany.
- Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Mathematikon, INF 205, 69120, Heidelberg, Germany.
- IMSEAM, Heidelberg University, INF 225, 69120, Heidelberg, Germany.
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6
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Bachmann M, Su B, Rahikainen R, Hytönen VP, Wu J, Wehrle-Haller B. ConFERMing the role of talin in integrin activation and mechanosignaling. J Cell Sci 2023; 136:jcs260576. [PMID: 37078342 PMCID: PMC10198623 DOI: 10.1242/jcs.260576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023] Open
Abstract
Talin (herein referring to the talin-1 form), is a cytoskeletal adapter protein that binds integrin receptors and F-actin, and is a key factor in the formation and regulation of integrin-dependent cell-matrix adhesions. Talin forms the mechanical link between the cytoplasmic domain of integrins and the actin cytoskeleton. Through this linkage, talin is at the origin of mechanosignaling occurring at the plasma membrane-cytoskeleton interface. Despite its central position, talin is not able to fulfill its tasks alone, but requires help from kindlin and paxillin to detect and transform the mechanical tension along the integrin-talin-F-actin axis into intracellular signaling. The talin head forms a classical FERM domain, which is required to bind and regulate the conformation of the integrin receptor, as well as to induce intracellular force sensing. The FERM domain allows the strategic positioning of protein-protein and protein-lipid interfaces, including the membrane-binding and integrin affinity-regulating F1 loop, as well as the interaction with lipid-anchored Rap1 (Rap1a and Rap1b in mammals) GTPase. Here, we summarize the structural and regulatory features of talin and explain how it regulates cell adhesion and force transmission, as well as intracellular signaling at integrin-containing cell-matrix attachment sites.
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Affiliation(s)
- Michael Bachmann
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, 1211 Geneva 4, Switzerland
| | - Baihao Su
- Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA 19111, USA
| | - Rolle Rahikainen
- Faculty of Medicine and Health Technology, Arvo Ylpön katu 34, Tampere University, FI-33520 Tampere, Finland
| | - Vesa P. Hytönen
- Faculty of Medicine and Health Technology, Arvo Ylpön katu 34, Tampere University, FI-33520 Tampere, Finland
- Fimlab Laboratories, Biokatu 4, FI-33520 Tampere, Finland
| | - Jinhua Wu
- Molecular Therapeutics Program, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA 19111, USA
| | - Bernhard Wehrle-Haller
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, 1211 Geneva 4, Switzerland
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7
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Braun L, Schoen I, Vogel V. PIP 2-induced membrane binding of the vinculin tail competes with its other binding partners. Biophys J 2021; 120:4608-4622. [PMID: 34411575 DOI: 10.1016/j.bpj.2021.08.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 06/14/2021] [Accepted: 08/11/2021] [Indexed: 01/09/2023] Open
Abstract
Vinculin plays a key role during the first phase of focal adhesion formation and interacts with the plasma membrane through specific binding of its tail domain to the lipid phosphatidylinositol 4,5-bisphosphate (PIP2). Our understanding of the PIP2-vinculin interaction has been hampered by contradictory biochemical and structural data. Here, we used a multiscale molecular dynamics simulation approach, in which unbiased coarse-grained molecular dynamics were used to generate starting structures for subsequent microsecond-long all-atom simulations. This allowed us to map the interaction of the vinculin tail with PIP2-enriched membranes in atomistic detail. In agreement with experimental data, we have shown that membrane binding is sterically incompatible with the intramolecular interaction between vinculin's head and tail domain. Our simulations further confirmed biochemical and structural results, which identified two positively charged surfaces, the basic collar and the basic ladder, as the main PIP2 interaction sites. By introducing a valency-disaggregated binding network analysis, we were able to map the protein-lipid interactions in unprecedented detail. In contrast to the basic collar, in which PIP2 is specifically recognized by an up to hexavalent binding pocket, the basic ladder forms a series of low-valency binding sites. Importantly, many of these PIP2 binding residues are also involved in maintaining vinculin in a closed, autoinhibited conformation. These findings led us to propose a molecular mechanism for the coupling between vinculin activation and membrane binding. Finally, our refined binding site suggests an allosteric relationship between PIP2 and F-actin binding that disfavors simultaneous interaction with both ligands, despite nonoverlapping binding sites.
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Affiliation(s)
- Lukas Braun
- Laboratory of Applied Mechanobiology, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
| | - Ingmar Schoen
- School of Pharmacy and Biomolecular Sciences, Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Viola Vogel
- Laboratory of Applied Mechanobiology, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
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8
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Rangarajan ES, Izard T. The Cryogenic Electron Microscopy Structure of the Cell Adhesion Regulator Metavinculin Reveals an Isoform-Specific Kinked Helix in Its Cytoskeleton Binding Domain. Int J Mol Sci 2021; 22:E645. [PMID: 33440717 PMCID: PMC7827843 DOI: 10.3390/ijms22020645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/08/2021] [Accepted: 01/08/2021] [Indexed: 11/16/2022] Open
Abstract
Vinculin and its heart-specific splice variant metavinculin are key regulators of cell adhesion processes. These membrane-bound cytoskeletal proteins regulate the cell shape by binding to several other proteins at cell-cell and cell-matrix junctions. Vinculin and metavinculin link integrin adhesion molecules to the filamentous actin network. Loss of both proteins prevents cell adhesion and cell spreading and reduces the formation of stress fibers, focal adhesions, or lamellipodia extensions. The binding of talin at cell-matrix junctions or of α-catenin at cell-cell junctions activates vinculin and metavinculin by releasing their autoinhibitory head-tail interaction. Once activated, vinculin and metavinculin bind F-actin via their five-helix bundle tail domains. Unlike vinculin, metavinculin has a 68-amino-acid insertion before the second α-helix of this five-helix F-actin-binding domain. Here, we present the full-length cryogenic electron microscopy structure of metavinculin that captures the dynamics of its individual domains and unveiled a hallmark structural feature, namely a kinked isoform-specific α-helix in its F-actin-binding domain. Our identified conformational landscape of metavinculin suggests a structural priming mechanism that is consistent with the cell adhesion functions of metavinculin in response to mechanical and cellular cues. Our findings expand our understanding of metavinculin function in the heart with implications for the etiologies of cardiomyopathies.
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Affiliation(s)
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL 33458, USA;
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9
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Mei L, Espinosa de Los Reyes S, Reynolds MJ, Leicher R, Liu S, Alushin GM. Molecular mechanism for direct actin force-sensing by α-catenin. eLife 2020; 9:62514. [PMID: 32969337 PMCID: PMC7588232 DOI: 10.7554/elife.62514] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 09/21/2020] [Indexed: 12/13/2022] Open
Abstract
The actin cytoskeleton mediates mechanical coupling between cells and their tissue microenvironments. The architecture and composition of actin networks are modulated by force; however, it is unclear how interactions between actin filaments (F-actin) and associated proteins are mechanically regulated. Here we employ both optical trapping and biochemical reconstitution with myosin motor proteins to show single piconewton forces applied solely to F-actin enhance binding by the human version of the essential cell-cell adhesion protein αE-catenin but not its homolog vinculin. Cryo-electron microscopy structures of both proteins bound to F-actin reveal unique rearrangements that facilitate their flexible C-termini refolding to engage distinct interfaces. Truncating α-catenin’s C-terminus eliminates force-activated F-actin binding, and addition of this motif to vinculin confers force-activated binding, demonstrating that α-catenin’s C-terminus is a modular detector of F-actin tension. Our studies establish that piconewton force on F-actin can enhance partner binding, which we propose mechanically regulates cellular adhesion through α-catenin. All of the cells in our bodies rely on cues from their surrounding environment to alter their behavior. As well sending each other chemical signals, such as hormones, cells can also detect pressure and physical forces applied by the cells around them. These physical interactions are coordinated by a network of proteins called the cytoskeleton, which provide the internal scaffold that maintains a cell’s shape. However, it is not well understood how forces transmitted through the cytoskeleton are converted into mechanical signals that control cell behavior. The cytoskeleton is primarily made up protein filaments called actin, which are frequently under tension from external and internal forces that push and pull on the cell. Many proteins bind directly to actin, including adhesion proteins that allow the cell to ‘stick’ to its surroundings. One possibility is that when actin filaments feel tension, they convert this into a mechanical signal by altering how they bind to other proteins. To test this theory, Mei et al. isolated and studied an adhesion protein called α-catenin which is known to interact with actin. This revealed that when tiny forces – similar to the amount cells experience in the body – were applied to actin filaments, this caused α-catenin and actin to bind together more strongly. However, applying the same level of physical force did not alter how well actin bound to a similar adhesion protein called vinculin. Further experiments showed that this was due to differences in a small, flexible region found on both proteins. Manipulating this region revealed that it helps α-catenin attach to actin when a force is present, and was thus named a ‘force detector’. Proteins that bind to actin are essential in all animals, making it likely that force detectors are a common mechanism. Scientists can now use this discovery to identify and manipulate force detectors in other proteins across different cells and animals. This may help to develop drugs that target the mechanical signaling process, although this will require further understanding of how force detectors work at the molecular level.
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Affiliation(s)
- Lin Mei
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, United States.,Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, United States
| | | | - Matthew J Reynolds
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, United States
| | - Rachel Leicher
- Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, United States.,Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, United States
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, United States
| | - Gregory M Alushin
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, United States
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10
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Xu XP, Pokutta S, Torres M, Swift MF, Hanein D, Volkmann N, Weis WI. Structural basis of αE-catenin-F-actin catch bond behavior. eLife 2020; 9:e60878. [PMID: 32915141 PMCID: PMC7588230 DOI: 10.7554/elife.60878] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/09/2020] [Indexed: 11/13/2022] Open
Abstract
Cell-cell and cell-matrix junctions transmit mechanical forces during tissue morphogenesis and homeostasis. α-Catenin links cell-cell adhesion complexes to the actin cytoskeleton, and mechanical load strengthens its binding to F-actin in a direction-sensitive manner. Specifically, optical trap experiments revealed that force promotes a transition between weak and strong actin-bound states. Here, we describe the cryo-electron microscopy structure of the F-actin-bound αE-catenin actin-binding domain, which in solution forms a five-helix bundle. In the actin-bound structure, the first helix of the bundle dissociates and the remaining four helices and connecting loops rearrange to form the interface with actin. Deletion of the first helix produces strong actin binding in the absence of force, suggesting that the actin-bound structure corresponds to the strong state. Our analysis explains how mechanical force applied to αE-catenin or its homolog vinculin favors the strongly bound state, and the dependence of catch bond strength on the direction of applied force.
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Affiliation(s)
| | - Sabine Pokutta
- Departments of Structural Biology and Molecular & Cellular Physiology, Stanford University School of MedicineStanfordUnited States
| | - Megan Torres
- Departments of Structural Biology and Molecular & Cellular Physiology, Stanford University School of MedicineStanfordUnited States
| | | | - Dorit Hanein
- Scintillon InstituteSan DiegoUnited States
- Department of Structural Biology and Chemistry, Pasteur InstituteParisFrance
| | - Niels Volkmann
- Scintillon InstituteSan DiegoUnited States
- Department of Structural Biology and Chemistry, Pasteur InstituteParisFrance
| | - William I Weis
- Departments of Structural Biology and Molecular & Cellular Physiology, Stanford University School of MedicineStanfordUnited States
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11
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Kelley CF, Litschel T, Schumacher S, Dedden D, Schwille P, Mizuno N. Phosphoinositides regulate force-independent interactions between talin, vinculin, and actin. eLife 2020; 9:e56110. [PMID: 32657269 PMCID: PMC7384861 DOI: 10.7554/elife.56110] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/10/2020] [Indexed: 12/25/2022] Open
Abstract
Focal adhesions (FA) are large macromolecular assemblies which help transmit mechanical forces and regulatory signals between the extracellular matrix and an interacting cell. Two key proteins talin and vinculin connecting integrin to actomyosin networks in the cell. Both proteins bind to F-actin and each other, providing a foundation for network formation within FAs. However, the underlying mechanisms regulating their engagement remain unclear. Here, we report on the results of in vitro reconstitution of talin-vinculin-actin assemblies using synthetic membrane systems. We find that neither talin nor vinculin alone recruit actin filaments to the membrane. In contrast, phosphoinositide-rich membranes recruit and activate talin, and the membrane-bound talin then activates vinculin. Together, the two proteins then link actin to the membrane. Encapsulation of these components within vesicles reorganized actin into higher-order networks. Notably, these observations were made in the absence of applied force, whereby we infer that the initial assembly stage of FAs is force independent. Our findings demonstrate that the local membrane composition plays a key role in controlling the stepwise recruitment, activation, and engagement of proteins within FAs.
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Affiliation(s)
- Charlotte F Kelley
- Max Planck Institute of Biochemistry, Department of Structural Cell BiologyMartinsriedGermany
| | - Thomas Litschel
- Max Planck Institute of Biochemistry, Department of Cellular and Molecular BiophysicsMartinsriedGermany
| | - Stephanie Schumacher
- Max Planck Institute of Biochemistry, Department of Structural Cell BiologyMartinsriedGermany
| | - Dirk Dedden
- Max Planck Institute of Biochemistry, Department of Structural Cell BiologyMartinsriedGermany
| | - Petra Schwille
- Max Planck Institute of Biochemistry, Department of Cellular and Molecular BiophysicsMartinsriedGermany
| | - Naoko Mizuno
- Max Planck Institute of Biochemistry, Department of Structural Cell BiologyMartinsriedGermany
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of HealthBethesdaUnited States
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of HealthBethesdaUnited States
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12
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Torres-Gomez A, Cabañas C, Lafuente EM. Phagocytic Integrins: Activation and Signaling. Front Immunol 2020; 11:738. [PMID: 32425937 PMCID: PMC7203660 DOI: 10.3389/fimmu.2020.00738] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/31/2020] [Indexed: 01/06/2023] Open
Abstract
Phagocytic integrins are endowed with the ability to engulf and dispose of particles of different natures. Evolutionarily conserved from worms to humans, they are involved in pathogen elimination and apoptotic and tumoral cell clearance. Research in the field of integrin-mediated phagocytosis has shed light on the molecular events controlling integrin activation and their effector functions. However, there are still some aspects of the regulation of the phagocytic process that need to be clarified. Here, we have revised the molecular events controlling phagocytic integrin activation and the downstream signaling driving particle engulfment, and we have focused particularly on αMβ2/CR3, αXβ2/CR4, and a brief mention of αVβ5/αVβ3integrins.
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Affiliation(s)
- Alvaro Torres-Gomez
- Department of Immunology, Ophthalmology and Otorhinolaryngology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Carlos Cabañas
- Department of Immunology, Ophthalmology and Otorhinolaryngology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12), Madrid, Spain.,Severo Ochoa Center for Molecular Biology (CSIC-UAM), Madrid, Spain
| | - Esther M Lafuente
- Department of Immunology, Ophthalmology and Otorhinolaryngology, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12), Madrid, Spain
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13
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Spatial arrangement of LD motif-interacting residues on focal adhesion targeting domain of Focal Adhesion Kinase determine domain-motif interaction affinity and specificity. Biochim Biophys Acta Gen Subj 2019; 1864:129450. [PMID: 31676296 DOI: 10.1016/j.bbagen.2019.129450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 08/22/2019] [Accepted: 09/18/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND Leucine rich Aspartate motifs (LD motifs) are molecular recognition motifs on Paxillin that recognize LD-motif binding domains (LDBD) of a number of focal adhesion proteins in order to carry out downstream signaling and actin cytoskeleton remodeling. In this study, we identified structural features within LDBDs that influence their binding affinity with Paxillin LD motifs. METHODS Various point mutants of focal adhesion targeting (FAT) domain of Focal Adhesion Kinase (FAK) were created by moving a key Lysine residue two and three helical turns in order to match the unique conformations as observed in LDBDs of two other focal adhesion proteins, Vinculin and CCM3. RESULTS This led to identify a mutant of FAT domain of FAK, named as FAT(NV) (Asn992 of FAT domain was replaced by Val), with remarkable high affinity for LD1 (Kd = 1.5 μM vs no-binding with wild type) and LD2 peptides (Kd = 7.2 μM vs 63 μM with wild type). Consistently, the focal adhesions of MCF7 cells expressing FAK(NV) were highly stable (turnover rate = 1.25 × 10-5 μm2/s) as compared to wild type FAK transfected cells (turnover rate = 1.5 × 10-3 μm2/s). CONCLUSIONS We observed that the relative disposition of key LD binding amino-acids at LDBD surface, hydrophobic burial of long Leucine side chains of LD-motifs and complementarity of charged surfaces are the key factors determining the binding affinities of LD motifs with LDBDs. GENERAL SIGNIFICANCE Our study will help in protein engineering of FAT domain of FAK by modulating FAK-LD motif interactions which have implications in cellular focal adhesions and cell migration.
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14
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Krokhotin A, Sarker M, Sevilla EA, Costantini LM, Griffith JD, Campbell SL, Dokholyan NV. Distinct Binding Modes of Vinculin Isoforms Underlie Their Functional Differences. Structure 2019; 27:1527-1536.e3. [PMID: 31422909 PMCID: PMC6774862 DOI: 10.1016/j.str.2019.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 05/23/2019] [Accepted: 07/23/2019] [Indexed: 12/11/2022]
Abstract
Vinculin and its splice isoform metavinculin play key roles in regulating cellular morphology, motility, and force transduction. Vinculin is distinct from metavinculin in its ability to bundle filamentous actin (F-actin). To elucidate the molecular basis for these differences, we employed computational and experimental approaches. Results from these analyses suggest that the C terminus of both vinculin and metavinculin form stable interactions with the F-actin surface. However, the metavinculin tail (MVt) domain contains a 68 amino acid insert, with helix 1 (H1) sequestered into a globular subdomain, which protrudes from the F-actin surface and prevents actin bundling by sterically occluding actin filaments. Consistent with our model, deletion and selective point mutations within the MVt H1 disrupt this protruding structure, and facilitate actin bundling similar to vinculin tail (Vt) domain.
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Affiliation(s)
- Andrey Krokhotin
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Departments of Pathology, Genetics and Developmental Biology, Howard Hughes Medical Institute, Stanford Medical School, Palo Alto, CA 94305, USA
| | - Muzaddid Sarker
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Ernesto Alva Sevilla
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Lindsey M Costantini
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jack D Griffith
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sharon L Campbell
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Nikolay V Dokholyan
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Departments of Pharmacology and Departments of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA 17033, USA.
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15
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Miller PW, Pokutta S, Mitchell JM, Chodaparambil JV, Clarke DN, Nelson WJ, Weis WI, Nichols SA. Analysis of a vinculin homolog in a sponge (phylum Porifera) reveals that vertebrate-like cell adhesions emerged early in animal evolution. J Biol Chem 2018; 293:11674-11686. [PMID: 29880641 PMCID: PMC6066325 DOI: 10.1074/jbc.ra117.001325] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/21/2018] [Indexed: 01/27/2023] Open
Abstract
The evolution of cell-adhesion mechanisms in animals facilitated the assembly of organized multicellular tissues. Studies in traditional animal models have revealed two predominant adhesion structures, the adherens junction (AJ) and focal adhesions (FAs), which are involved in the attachment of neighboring cells to each other and to the secreted extracellular matrix (ECM), respectively. The AJ (containing cadherins and catenins) and FAs (comprising integrins, talin, and paxillin) differ in protein composition, but both junctions contain the actin-binding protein vinculin. The near ubiquity of these structures in animals suggests that AJ and FAs evolved early, possibly coincident with multicellularity. However, a challenge to this perspective is that previous studies of sponges-a divergent animal lineage-indicate that their tissues are organized primarily by an alternative, sponge-specific cell-adhesion mechanism called "aggregation factor." In this study, we examined the structure, biochemical properties, and tissue localization of a vinculin ortholog in the sponge Oscarella pearsei (Op). Our results indicate that Op vinculin localizes to both cell-cell and cell-ECM contacts and has biochemical and structural properties similar to those of vertebrate vinculin. We propose that Op vinculin played a role in cell adhesion and tissue organization in the last common ancestor of sponges and other animals. These findings provide compelling evidence that sponge tissues are indeed organized like epithelia in other animals and support the notion that AJ- and FA-like structures extend to the earliest periods of animal evolution.
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Affiliation(s)
| | - Sabine Pokutta
- From the Departments of Molecular and Cellular Physiology and
- Structural Biology, School of Medicine and
| | - Jennyfer M Mitchell
- the Department of Biological Sciences, University of Denver, Denver, Colorado 80208
| | - Jayanth V Chodaparambil
- From the Departments of Molecular and Cellular Physiology and
- Structural Biology, School of Medicine and
| | - D Nathaniel Clarke
- the Department of Biology, Stanford University, Stanford, California 94305 and
| | - W James Nelson
- From the Departments of Molecular and Cellular Physiology and
- the Department of Biology, Stanford University, Stanford, California 94305 and
| | - William I Weis
- From the Departments of Molecular and Cellular Physiology and
- Structural Biology, School of Medicine and
| | - Scott A Nichols
- the Department of Biological Sciences, University of Denver, Denver, Colorado 80208
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16
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Dwivedi M, Winter R. Binding of Vinculin to Lipid Membranes in Its Inhibited and Activated States. Biophys J 2017; 111:1444-1453. [PMID: 27705767 DOI: 10.1016/j.bpj.2016.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 10/20/2022] Open
Abstract
Phosphoinositols are an important class of phospholipids that are involved in a myriad of cellular processes, from cell signaling to motility and adhesion. Vinculin (Vn) is a major adaptor protein that regulates focal adhesions in conjunction with PIP2 in lipid membranes and other cytoskeletal components. The binding and unbinding transitions of Vn at the membrane interface are an important link to understanding the coordination of cell signaling and motility. Using different biophysical tools, including atomic force microscopy combined with confocal fluorescence microscopy and Fourier transform infrared spectroscopy, we studied the nanoscopic interactions of activated and autoinhibited states of Vn with lipid membranes. We hypothesize that a weak interaction occurs between Vn and lipid membranes, which leads to binding of autoinhibited Vn to supported lipid bilayers, and to unbinding in freestanding lipid vesicles. Likely driving forces may include tethering of the C-terminus to the lipid membrane, as well as hydrophobic helix-membrane interactions. Conversely, activated Vn binds strongly to membranes through specific interactions with clusters of PIP2 embedded in lipid membranes. Activated Vn harbored on PIP2 clusters may form small oligomeric interaction platforms for further interaction partners, which is necessary for the proper function of focal adhesion points.
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Affiliation(s)
- Mridula Dwivedi
- Physical Chemistry I, Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany.
| | - Roland Winter
- Physical Chemistry I, Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany.
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17
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Bays JL, DeMali KA. Vinculin in cell-cell and cell-matrix adhesions. Cell Mol Life Sci 2017; 74:2999-3009. [PMID: 28401269 PMCID: PMC5501900 DOI: 10.1007/s00018-017-2511-3] [Citation(s) in RCA: 273] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 03/17/2017] [Accepted: 03/20/2017] [Indexed: 02/07/2023]
Abstract
Vinculin was identified as a component of focal adhesions and adherens junctions nearly 40 years ago. Since that time, remarkable progress has been made in understanding its activation, regulation and function. Here we discuss the current understanding of the roles of vinculin in cell–cell and cell–matrix adhesions. Emphasis is placed on the how vinculin is recruited, activated and regulated. We also highlight the recent understanding of how vinculin responds to and transmits force at integrin- and cadherin-containing adhesion complexes to the cytoskeleton. Furthermore, we discuss roles of vinculin in binding to and rearranging the actin cytoskeleton.
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Affiliation(s)
- Jennifer L Bays
- Department of Biochemistry, University of Iowa, Iowa City, IA, 52242, USA
| | - Kris A DeMali
- Department of Biochemistry, University of Iowa, Iowa City, IA, 52242, USA.
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18
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Thompson PM, Ramachandran S, Case LB, Tolbert CE, Tandon A, Pershad M, Dokholyan NV, Waterman CM, Campbell SL. A Structural Model for Vinculin Insertion into PIP 2-Containing Membranes and the Effect of Insertion on Vinculin Activation and Localization. Structure 2017; 25:264-275. [PMID: 28089450 DOI: 10.1016/j.str.2016.12.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 11/10/2016] [Accepted: 12/12/2016] [Indexed: 12/20/2022]
Abstract
Vinculin, a scaffolding protein that localizes to focal adhesions (FAs) and adherens junctions, links the actin cytoskeleton to the adhesive super-structure. While vinculin binds to a number of cytoskeletal proteins, it can also associate with phosphatidylinositol 4,5-bisphosphate (PIP2) to drive membrane association. To generate a structural model for PIP2-dependent interaction of vinculin with the lipid bilayer, we conducted lipid-association, nuclear magnetic resonance, and computational modeling experiments. We find that two basic patches on the vinculin tail drive membrane association: the basic collar specifically recognizes PIP2, while the basic ladder drives association with the lipid bilayer. Vinculin mutants with defects in PIP2-dependent liposome association were then expressed in vinculin knockout murine embryonic fibroblasts. Results from these analyses indicate that PIP2 binding is not required for localization of vinculin to FAs or FA strengthening, but is required for vinculin activation and turnover at FAs to promote its association with the force transduction FA nanodomain.
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Affiliation(s)
- Peter M Thompson
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Srinivas Ramachandran
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Lindsay B Case
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Caitlin E Tolbert
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Arpit Tandon
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mihir Pershad
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nikolay V Dokholyan
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Clare M Waterman
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sharon L Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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19
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Calkins S, Youssef NH. Insights into the Utility of the Focal Adhesion Scaffolding Proteins in the Anaerobic Fungus Orpinomyces sp. C1A. PLoS One 2016; 11:e0163553. [PMID: 27685796 PMCID: PMC5042518 DOI: 10.1371/journal.pone.0163553] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/11/2016] [Indexed: 12/30/2022] Open
Abstract
Focal adhesions (FAs) are large eukaryotic multiprotein complexes that are present in all metazoan cells and function as stable sites of tight adhesion between the extracellular matrix (ECM) and the cell's cytoskeleton. FAs consist of anchor membrane protein (integrins), scaffolding proteins (e.g. α-actinin, talin, paxillin, and vinculin), signaling proteins of the IPP complex (e.g. integrin-linked kinase, α-parvin, and PINCH), and signaling kinases (e.g. focal adhesion kinase (FAK) and Src kinase). While genes encoding complete focal adhesion machineries are present in genomes of all multicellular Metazoa; incomplete machineries were identified in the genomes of multiple non-metazoan unicellular Holozoa, basal fungal lineages, and amoebozoan representatives. Since a complete FA machinery is required for functioning, the putative role, if any, of these incomplete FA machineries is currently unclear. We sought to examine the expression patterns of FA-associated genes in the anaerobic basal fungal isolate Orpinomyces sp. strain C1A under different growth conditions and at different developmental stages. Strain C1A lacks clear homologues of integrin, and the two signaling kinases FAK and Src, but encodes for all scaffolding proteins, and the IPP complex proteins. We developed a protocol for synchronizing growth of C1A cultures, allowing for the collection and mRNA extraction from flagellated spores, encysted germinating spores, active zoosporangia, and late inactive sporangia of strain C1A. We demonstrate that the genes encoding the FA scaffolding proteins α-actinin, talin, paxillin, and vinculin are indeed transcribed under all growth conditions, and at all developmental stages of growth. Further, analysis of the observed transcriptional patterns suggests the putative involvement of these components in alternative non-adhesion-specific functions, such as hyphal tip growth during germination and flagellar assembly during zoosporogenesis. Based on these results, we propose putative alternative functions for such proteins in the anaerobic gut fungi. Our results highlight the presumed diverse functionalities of FA scaffolding proteins in basal fungi.
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Affiliation(s)
- Shelby Calkins
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, United States of America
| | - Noha H. Youssef
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, United States of America
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20
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Differential lipid binding of vinculin isoforms promotes quasi-equivalent dimerization. Proc Natl Acad Sci U S A 2016; 113:9539-44. [PMID: 27503891 DOI: 10.1073/pnas.1600702113] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The main cause of death globally remains debilitating heart conditions, such as dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM), which are often due to mutations of specific components of adhesion complexes. Vinculin regulates these complexes and plays essential roles in intercalated discs that are necessary for muscle cell function and coordinated movement and in the development and function of the heart. Humans bearing familial or sporadic mutations in vinculin suffer from chronic, progressively debilitating DCM that ultimately leads to cardiac failure and death, whereas autosomal dominant mutations in vinculin can also provoke HCM, causing acute cardiac failure. The DCM/HCM-associated mutants of vinculin occur in the 68-residue insert unique to the muscle-specific, alternatively spliced isoform of vinculin, termed metavinculin (MV). Contrary to studies that suggested that phosphoinositol-4,5-bisphosphate (PIP2) only induces vinculin homodimers, which are asymmetric, we show that phospholipid binding results in a domain-swapped symmetric MV dimer via a quasi-equivalent interface compared with vinculin involving R975. Although one of the two PIP2 binding sites is preserved, the symmetric MV dimer that bridges two PIP2 molecules differs from the asymmetric vinculin dimer that bridges only one PIP2 Unlike vinculin, wild-type MV and the DCM/HCM-associated R975W mutant bind PIP2 in their inactive conformations, and R975W MV fails to dimerize. Mutating selective vinculin residues to their corresponding MV residues, or vice versa, switches the isoform's dimeric constellation and lipid binding site. Collectively, our data suggest that MV homodimerization modulates microfilament attachment at muscular adhesion sites and furthers our understanding of MV-mediated cardiac remodeling.
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21
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Izard T, Brown DT. Mechanisms and Functions of Vinculin Interactions with Phospholipids at Cell Adhesion Sites. J Biol Chem 2016; 291:2548-55. [PMID: 26728462 DOI: 10.1074/jbc.r115.686493] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The cytoskeletal protein vinculin is a major regulator of cell adhesion and attaches to the cell surface by binding to specific phospholipids. Structural, biochemical, and biological studies provided much insight into how vinculin binds to membranes, what components it recognizes, and how lipid binding is regulated. Here we discuss the roles and mechanisms of phospholipids in regulating the structure and function of vinculin and of its muscle-specific metavinculin splice variant. A full appreciation of these processes is necessary for understanding how vinculin regulates cell motility, migration, and wound healing, and for understanding of its role in cancer and cardiovascular diseases.
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Affiliation(s)
- Tina Izard
- From the Cell Adhesion Laboratory, Department of Cancer Biology and Department of Immunology and Microbial Sciences, The Scripps Research Institute, Jupiter, Florida 33458 and
| | - David T Brown
- the Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi 39216
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22
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Goldmann WH. Role of vinculin in cellular mechanotransduction. Cell Biol Int 2016; 40:241-56. [DOI: 10.1002/cbin.10563] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/14/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Wolfgang H. Goldmann
- Department of Biophysics; Friedrich-Alexander-University of Erlangen-Nuremberg; Erlangen Germany
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23
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Mechanosensitive components of integrin adhesions: Role of vinculin. Exp Cell Res 2015; 343:21-27. [PMID: 26607713 PMCID: PMC4856733 DOI: 10.1016/j.yexcr.2015.11.017] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 11/18/2015] [Indexed: 12/14/2022]
Abstract
External forces play a key role in shaping development and normal physiology. Aberrant responses to forces, or changes in the nature of such forces, are implicated in a variety of diseases. Cells contain several types of adhesions, linking them to their external environment. It is through these adhesions that forces are both sensed (from the outside inwards) and applied (from inside to out). Furthermore, several adhesion-based proteins are sensitive to changes in intracellular forces, utilising them for activation and regulation. Here, we outline how vinculin, a key component of integrin-mediated adhesions linking the actin cytoskeleton to the extracellular matrix (ECM), is regulated by force and acts as force transducing protein. We discuss the role of vinculin in vivo and its place in health and disease; summarise the proposed mechanisms by which vinculin is recruited to and activated at integrin-ECM adhesions; and discuss recent findings that place vinculin as the major force sensing and transmitting component of cell–matrix adhesion complexes. Finally, we discuss the role of vinculin in regulating the cellular responses to both the physical properties of the external environment and to externally applied physical stimuli.
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24
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Kim LY, Thompson PM, Lee HT, Pershad M, Campbell SL, Alushin GM. The Structural Basis of Actin Organization by Vinculin and Metavinculin. J Mol Biol 2015; 428:10-25. [PMID: 26493222 DOI: 10.1016/j.jmb.2015.09.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/23/2015] [Accepted: 09/25/2015] [Indexed: 11/30/2022]
Abstract
Vinculin is an essential adhesion protein that links membrane-bound integrin and cadherin receptors through their intracellular binding partners to filamentous actin, facilitating mechanotransduction. Here we present an 8.5-Å-resolution cryo-electron microscopy reconstruction and pseudo-atomic model of the vinculin tail (Vt) domain bound to F-actin. Upon actin engagement, the N-terminal "strap" and helix 1 are displaced from the Vt helical bundle to mediate actin bundling. We find that an analogous conformational change also occurs in the H1' helix of the tail domain of metavinculin (MVt) upon actin binding, a muscle-specific splice isoform that suppresses actin bundling by Vt. These data support a model in which metavinculin tunes the actin bundling activity of vinculin in a tissue-specific manner, providing a mechanistic framework for understanding metavinculin mutations associated with hereditary cardiomyopathies.
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Affiliation(s)
- Laura Y Kim
- Laboratory of Macromolecular Interactions, Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter M Thompson
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hyunna T Lee
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mihir Pershad
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sharon L Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Gregory M Alushin
- Laboratory of Macromolecular Interactions, Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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25
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Oztug Durer ZA, McGillivary RM, Kang H, Elam WA, Vizcarra CL, Hanein D, De La Cruz EM, Reisler E, Quinlan ME. Metavinculin Tunes the Flexibility and the Architecture of Vinculin-Induced Bundles of Actin Filaments. J Mol Biol 2015; 427:2782-98. [PMID: 26168869 DOI: 10.1016/j.jmb.2015.07.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 11/19/2022]
Abstract
Vinculin is an abundant protein found at cell-cell and cell-extracellular matrix junctions. In muscles, a longer splice isoform of vinculin, metavinculin, is also expressed. The metavinculin-specific insert is part of the C-terminal tail domain, the actin-binding site of both isoforms. Mutations in the metavinculin-specific insert are linked to heart disease such as dilated cardiomyopathies. Vinculin tail domain (VT) both binds and bundles actin filaments. Metavinculin tail domain (MVT) binds actin filaments in a similar orientation but does not bundle filaments. Recently, MVT was reported to sever actin filaments. In this work, we asked how MVT influences F-actin alone or in combination with VT. Cosedimentation and limited proteolysis experiments indicated a similar actin binding affinity and mode for both VT and MVT. In real-time total internal reflection fluorescence microscopy experiments, MVT's severing activity was negligible. Instead, we found that MVT binding caused a 2-fold reduction in F-actin's bending persistence length and increased susceptibility to breakage. Using mutagenesis and site-directed labeling with fluorescence probes, we determined that MVT alters actin interprotomer contacts and dynamics, which presumably reflect the observed changes in bending persistence length. Finally, we found that MVT decreases the density and thickness of actin filament bundles generated by VT. Altogether, our data suggest that MVT alters actin filament flexibility and tunes filament organization in the presence of VT. Both of these activities are potentially important for muscle cell function. Perhaps MVT allows the load of muscle contraction to act as a signal to reorganize actin filaments.
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Affiliation(s)
- Zeynep A Oztug Durer
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-1569, USA
| | - Rebecca M McGillivary
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-1569, USA
| | - Hyeran Kang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - W Austin Elam
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Christina L Vizcarra
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-1569, USA
| | - Dorit Hanein
- Bioinformatics and Structural Biology Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095-1570, USA
| | - Margot E Quinlan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095-1570, USA.
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26
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Chinthalapudi K, Patil DN, Rangarajan ES, Rader C, Izard T. Lipid-directed vinculin dimerization. Biochemistry 2015; 54:2758-68. [PMID: 25880222 DOI: 10.1021/acs.biochem.5b00015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Vinculin localizes to cellular adhesions where it regulates motility, migration, development, wound healing, and response to force. Importantly, vinculin loss results in cancer phenotypes, cardiovascular disease, and embryonic lethality. At the plasma cell membrane, the most abundant phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PIP2), binds the vinculin tail domain, Vt, and triggers homotypic and heterotypic interactions that amplify binding of vinculin to the actin network. Binding of PIP2 to Vt is necessary for maintaining optimal focal adhesions, for organizing stress fibers, for cell migration and spreading, and for the control of vinculin dynamics and turnover of focal adhesions. While the recently determined Vt/PIP2 crystal structure revealed the conformational changes occurring upon lipid binding and oligomerization, characterization of PIP2-induced vinculin oligomerization has been challenging in the adhesion biology field. Here, via a series of novel biochemical assays not performed in previous studies that relied on chemical cross-linking, we characterize the PIP2-induced vinculin oligomerization. Our results show that Vt/PIP2 forms a tight dimer with Vt or with the muscle-specific vinculin isoform, metavinculin, at sites of adhesion at the cell membrane. Insight into how PIP2 regulates clustering and into mechanisms that regulate cell adhesion allows the development for a more definite sensor for PIP2, and our developed techniques can be applied generally and thus open the door for the characterization of many other protein/PIP2 complexes under physiological conditions.
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Affiliation(s)
- Krishna Chinthalapudi
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Dipak N Patil
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Erumbi S Rangarajan
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Christoph Rader
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Tina Izard
- †Cell Adhesion Laboratory, ‡Department of Cancer Biology, and §Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, United States
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27
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Vinculin-dependent actin bundling regulates cell migration and traction forces. Biochem J 2015; 465:383-93. [PMID: 25358683 DOI: 10.1042/bj20140872] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Vinculin binding to actin filaments is thought to be critical for force transduction within a cell, but direct experimental evidence to support this conclusion has been limited. In the present study, we found mutation (R1049E) of the vinculin tail impairs its ability to bind F-actin, stimulate actin polymerization, and bundle F-actin in vitro. Further, mutant (R1049E) vinculin expressing cells are altered in cell migration, which is accompanied by changes in cell adhesion, cell spreading and cell generation of traction forces, providing direct evidence for the critical role of vinculin in mechanotransduction at adhesion sites. Lastly, we discuss the viability of models detailing the F-actin-binding surface on vinculin in the context of our mutational analysis.
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28
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Lewinski MK, Jafari M, Zhang H, Opella SJ, Guatelli J. Membrane Anchoring by a C-terminal Tryptophan Enables HIV-1 Vpu to Displace Bone Marrow Stromal Antigen 2 (BST2) from Sites of Viral Assembly. J Biol Chem 2015; 290:10919-33. [PMID: 25759385 DOI: 10.1074/jbc.m114.630095] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 12/28/2022] Open
Abstract
The restriction factor BST2 (tetherin) prevents the release of enveloped viruses from the host cell and is counteracted by HIV-1 Vpu. Vpu and BST2 interact directly via their transmembrane domains. This interaction enables Vpu to induce the surface down-regulation and the degradation of BST2, but neither of these activities fully accounts for the ability of Vpu to enhance virion release. During a study of naturally occurring Vpu proteins, we found that a tryptophan residue near the Vpu C terminus is particularly important for enhancing virion release. Vpu proteins with a W76G polymorphism degraded and down-regulated BST2 from the cell surface, yet they inefficiently stimulated virion release. Here we explore the mechanism of this anomaly. We find that Trp-76 is critical for the ability of Vpu to displace BST2 from sites of viral assembly in the plane of the plasma membrane. This effect does not appear to involve a general reorganization of the membrane microdomains associated with virion assembly, but rather is a specific effect of Vpu on BST2. Using NMR spectroscopy, we find that the cytoplasmic domain of Vpu and Trp-76 specifically interact with lipids. Moreover, paramagnetic relaxation enhancement studies show that Trp-76 inserts into the lipid. These data are consistent with a model whereby Trp-76 anchors the C terminus of the cytoplasmic tail of Vpu to the plasma membrane, enabling the movement of Vpu-bound BST2 away from viral assembly sites.
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Affiliation(s)
- Mary K Lewinski
- From the Departments of Medicine and the Veterans Affairs San Diego Healthcare System, San Diego, California 92161
| | | | - Hua Zhang
- Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0679 and
| | - Stanley J Opella
- Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0679 and
| | - John Guatelli
- From the Departments of Medicine and the Veterans Affairs San Diego Healthcare System, San Diego, California 92161
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29
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Chinthalapudi K, Rangarajan ES, Patil DN, George EM, Brown DT, Izard T. Lipid binding promotes oligomerization and focal adhesion activity of vinculin. ACTA ACUST UNITED AC 2015; 207:643-56. [PMID: 25488920 PMCID: PMC4259812 DOI: 10.1083/jcb.201404128] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PIP2 binds vinculin and directs its oligomerization, which promotes proper focal adhesion structure and function. Adherens junctions (AJs) and focal adhesion (FA) complexes are necessary for cell migration and morphogenesis, and for the development, growth, and survival of all metazoans. Vinculin is an essential regulator of both AJs and FAs, where it provides links to the actin cytoskeleton. Phosphatidylinositol 4,5-bisphosphate (PIP2) affects the functions of many targets, including vinculin. Here we report the crystal structure of vinculin in complex with PIP2, which revealed that PIP2 binding alters vinculin structure to direct higher-order oligomerization and suggests that PIP2 and F-actin binding to vinculin are mutually permissive. Forced expression of PIP2-binding–deficient mutants of vinculin in vinculin-null mouse embryonic fibroblasts revealed that PIP2 binding is necessary for maintaining optimal FAs, for organization of actin stress fibers, and for cell migration and spreading. Finally, photobleaching experiments indicated that PIP2 binding is required for the control of vinculin dynamics and turnover in FAs. Thus, through oligomerization, PIP2 directs a transient vinculin sequestration at FAs that is necessary for proper FA function.
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Affiliation(s)
- Krishna Chinthalapudi
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458
| | - Erumbi S Rangarajan
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458
| | - Dipak N Patil
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458
| | - Eric M George
- Department of Biochemistry and Department of Physiology, University of Mississippi Medical Center, Jackson, MS 39216 Department of Biochemistry and Department of Physiology, University of Mississippi Medical Center, Jackson, MS 39216
| | - David T Brown
- Department of Biochemistry and Department of Physiology, University of Mississippi Medical Center, Jackson, MS 39216
| | - Tina Izard
- Cell Adhesion Laboratory, Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458
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30
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Nanda SY, Hoang T, Patel P, Zhang H. Vinculin regulates assembly of talin: β3 integrin complexes. J Cell Biochem 2014; 115:1206-16. [PMID: 24446374 DOI: 10.1002/jcb.24772] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 01/17/2014] [Indexed: 11/09/2022]
Abstract
Vinculin is a talin-binding protein that promotes integrin-mediated cell adhesion, but the mechanisms are not understood. Because talin is a direct activator of integrins, we asked whether and how vinculin regulates the formation of integrin: talin complexes. We report that VD1 (aa 1-258) and its talin-binding mutant, VD1A50I, bind directly and equally to several β integrin cytoplasmic tails (βCT). Results from competition assays show that VD1, but not VD1A50I, inhibits the interaction of talin (Tn) and talin rod (TnR), but not talin head (TnH) with β3CT. The inhibition observed could be the result of VD1 binding to one or more of the 11 vinculin binding sites (VBSs) in the TnR domain. Our studies demonstrate that VD1 binding to amino acids 482-911, a VBS rich region, in TnR perturbs the interaction of rod with β3CT. The integrin activation assays done using CHOA5 cells show that activated vinculin enhances αIIbβ3 integrin activation and that the effect is dependent on talin. The TnR domain however shows no integrin activation unlike TnH that shows enhanced integrin activation. The overall results indicate that activated vinculin promotes talin-mediated integrin activation by binding to accessible VBSs in TnR and thus displacing the TnR from the β3 subunit. The study presented, defines a novel direct interaction of VD1 with β3CT and provides an attractive explanation for vinculin's ability to potentiate integrin-mediated cell adhesion through directly binding to both TnR and the integrin cytoplasmic tail.
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Affiliation(s)
- Suman Yadav Nanda
- Department of Biological Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
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31
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Auernheimer V, Goldmann WH. Vinculin E29R mutation changes cellular mechanics. Biochem Biophys Res Commun 2014; 452:661-4. [DOI: 10.1016/j.bbrc.2014.08.133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 08/25/2014] [Indexed: 10/24/2022]
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32
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Tolbert CE, Thompson PM, Superfine R, Burridge K, Campbell SL. Phosphorylation at Y1065 in vinculin mediates actin bundling, cell spreading, and mechanical responses to force. Biochemistry 2014; 53:5526-36. [PMID: 25115937 PMCID: PMC4151700 DOI: 10.1021/bi500678x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
![]()
Vinculin
is an essential structural adaptor protein that localizes
to sites of adhesion and is involved in a number of cell processes
including adhesion, spreading, motility, force transduction, and cell
survival. The C-terminal vinculin tail domain (Vt) contains the necessary
structural components to bind and cross-link actin filaments. Actin
binding to Vt induces a conformational change that promotes dimerization
through the C-terminal hairpin of Vt and enables actin filament cross-linking.
Here we show that Src phosphorylation of Y1065 within the C-terminal
hairpin regulates Vt-mediated actin bundling and provide a detailed
characterization of Y1065 mutations. Furthermore, we show that phosphorylation
at Y1065 plays a role in cell spreading and the response to the application
of mechanical force.
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Affiliation(s)
- Caitlin E Tolbert
- Department of Cell Biology and Physiology, ‡Department of Biochemistry and Biophysics, §Graduate Molecular and Cellular Biophysics Program, ∥Department of Physics and Astronomy, and ⊥the Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
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33
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How to find a leucine in a haystack? Structure, ligand recognition and regulation of leucine-aspartic acid (LD) motifs. Biochem J 2014; 460:317-29. [PMID: 24870021 DOI: 10.1042/bj20140298] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
LD motifs (leucine-aspartic acid motifs) are short helical protein-protein interaction motifs that have emerged as key players in connecting cell adhesion with cell motility and survival. LD motifs are required for embryogenesis, wound healing and the evolution of multicellularity. LD motifs also play roles in disease, such as in cancer metastasis or viral infection. First described in the paxillin family of scaffolding proteins, LD motifs and similar acidic LXXLL interaction motifs have been discovered in several other proteins, whereas 16 proteins have been reported to contain LDBDs (LD motif-binding domains). Collectively, structural and functional analyses have revealed a surprising multivalency in LD motif interactions and a wide diversity in LDBD architectures. In the present review, we summarize the molecular basis for function, regulation and selectivity of LD motif interactions that has emerged from more than a decade of research. This overview highlights the intricate multi-level regulation and the inherently noisy and heterogeneous nature of signalling through short protein-protein interaction motifs.
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34
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Liang Q, Han Q, Huang W, Nan G, Xu BQ, Jiang JL, Chen ZN. HAb18G/CD147 regulates vinculin-mediated focal adhesion and cytoskeleton organization in cultured human hepatocellular carcinoma cells. PLoS One 2014; 9:e102496. [PMID: 25033086 PMCID: PMC4102505 DOI: 10.1371/journal.pone.0102496] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 06/18/2014] [Indexed: 11/19/2022] Open
Abstract
Focal adhesions (FAs), integrin-mediated macromolecular complexes located at the cell membrane extracellular interface, have been shown to regulate cell adhesion and migration. Our previous studies have indicated that HAb18G/CD147 (CD147) is involved in cytoskeleton reorganization and FA formation in human hepatocellular carcinoma (HCC) cells. However, the precise mechanisms underlying these processes remain unclear. In the current study, we determined that CD147 was involved in vinculin-mediated FA focal adhesion formation in HCC cells. We also found that deletion of CD147 led to reduced vinculin-mediated FA areas (P<0.0001), length/width ratios (P<0.0001), and mean intensities (P<0.0001). CD147 promoted lamellipodia formation by localizing Arp2/3 to the leading edge of the cell. Deletion of CD147 significantly reduced the fluorescence (t1/2) recovery times (22.7±3.3 s) of vinculin-mediated focal adhesions (P<0.0001). In cell-spreading assays, CD147 was found to be essential for dynamic focal adhesion enlargement and disassembly. Furthermore, the current data showed that CD147 reduced tyrosine phosphorylation in vinculin-mediated focal adhesions, and enhanced the accumulation of the acidic phospholipid phosphatidylinositol-4, 5-bisphosphate (PIP2). Together, these results revealed that CD147 is involved in vinculin-mediated focal adhesion formation, which subsequently promotes cytoskeleton reorganization to facilitate invasion and migration of human HCC cells.
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Affiliation(s)
- Qiang Liang
- Cell Engineering Research Centre and Department of Cell Biology, State Key Discipline of Cell Biology, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Qing Han
- Department of Clinical Immunology, Xijing Hospital, Fourth Military Medical University, Xi’ an, Shaanxi, China
| | - Wan Huang
- Cell Engineering Research Centre and Department of Cell Biology, State Key Discipline of Cell Biology, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Gang Nan
- Cell Engineering Research Centre and Department of Cell Biology, State Key Discipline of Cell Biology, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Bao-Qing Xu
- Cell Engineering Research Centre and Department of Cell Biology, State Key Discipline of Cell Biology, Fourth Military Medical University, Xi’an, Shaanxi, China
| | - Jian-Li Jiang
- Cell Engineering Research Centre and Department of Cell Biology, State Key Discipline of Cell Biology, Fourth Military Medical University, Xi’an, Shaanxi, China
- * E-mail: (JLJ); (ZNC)
| | - Zhi-Nan Chen
- Cell Engineering Research Centre and Department of Cell Biology, State Key Discipline of Cell Biology, Fourth Military Medical University, Xi’an, Shaanxi, China
- * E-mail: (JLJ); (ZNC)
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35
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Thompson PM, Tolbert CE, Shen K, Kota P, Palmer SM, Plevock KM, Orlova A, Galkin VE, Burridge K, Egelman EH, Dokholyan NV, Superfine R, Campbell SL. Identification of an actin binding surface on vinculin that mediates mechanical cell and focal adhesion properties. Structure 2014; 22:697-706. [PMID: 24685146 DOI: 10.1016/j.str.2014.03.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/04/2014] [Accepted: 03/04/2014] [Indexed: 11/30/2022]
Abstract
Vinculin, a cytoskeletal scaffold protein essential for embryogenesis and cardiovascular function, localizes to focal adhesions and adherens junctions, connecting cell surface receptors to the actin cytoskeleton. While vinculin interacts with many adhesion proteins, its interaction with filamentous actin regulates cell morphology, motility, and mechanotransduction. Disruption of this interaction lowers cell traction forces and enhances actin flow rates. Although a model for the vinculin:actin complex exists, we recently identified actin-binding deficient mutants of vinculin outside sites predicted to bind actin and developed an alternative model to better define this actin-binding surface, using negative-stain electron microscopy (EM), discrete molecular dynamics, and mutagenesis. Actin-binding deficient vinculin variants expressed in vinculin knockout fibroblasts fail to rescue cell-spreading defects and reduce cellular response to external force. These findings highlight the importance of this actin-binding surface and provide the molecular basis for elucidating additional roles of this interaction, including actin-induced conformational changes that promote actin bundling.
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Affiliation(s)
- Peter M Thompson
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Molecular and Cellular Biophysics Program, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Caitlin E Tolbert
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kai Shen
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pradeep Kota
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Molecular and Cellular Biophysics Program, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sean M Palmer
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Molecular and Cellular Biophysics Program, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Karen M Plevock
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Molecular and Cellular Biophysics Program, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Albina Orlova
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA
| | - Vitold E Galkin
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA
| | - Keith Burridge
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA
| | - Nikolay V Dokholyan
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Richard Superfine
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sharon L Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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36
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Jahed Z, Shams H, Mehrbod M, Mofrad MRK. Mechanotransduction pathways linking the extracellular matrix to the nucleus. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 310:171-220. [PMID: 24725427 DOI: 10.1016/b978-0-12-800180-6.00005-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cells contain several mechanosensing components that transduce mechanical signals into biochemical cascades. During cell-ECM adhesion, a complex network of molecules mechanically couples the extracellular matrix (ECM), cytoskeleton, and nucleoskeleton. The network comprises transmembrane receptor proteins and focal adhesions, which link the ECM and cytoskeleton. Additionally, recently identified protein complexes extend this linkage to the nucleus by linking the cytoskeleton and the nucleoskeleton. Despite numerous studies in this field, due to the complexity of this network, our knowledge of the mechanisms of cell-ECM adhesion at the molecular level remains remarkably incomplete. Herein, we present a review of the structures of key molecules involved in cell-ECM adhesion, along with an evaluation of their predicted roles in mechanical sensing. Additionally, specific binding events prompted by force-induced conformational changes of each molecule are discussed. Finally, we propose a model for the biomechanical events prominent in cell-ECM adhesion.
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Affiliation(s)
- Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Hengameh Shams
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Mehrdad Mehrbod
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA.
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Hansen SD, Kwiatkowski AV, Ouyang CY, Liu H, Pokutta S, Watkins SC, Volkmann N, Hanein D, Weis WI, Mullins RD, Nelson WJ. αE-catenin actin-binding domain alters actin filament conformation and regulates binding of nucleation and disassembly factors. Mol Biol Cell 2013; 24:3710-20. [PMID: 24068324 PMCID: PMC3842997 DOI: 10.1091/mbc.e13-07-0388] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
αE-catenin regulates transitions in actin organization between cell migration and cell–cell adhesion by controlling barbed-end polymerization of unbranched actin filaments and inhibiting Arp2/3 complex and cofilin regulation of actin filament branching and disassembly. The actin-binding protein αE-catenin may contribute to transitions between cell migration and cell–cell adhesion that depend on remodeling the actin cytoskeleton, but the underlying mechanisms are unknown. We show that the αE-catenin actin-binding domain (ABD) binds cooperatively to individual actin filaments and that binding is accompanied by a conformational change in the actin protomer that affects filament structure. αE-catenin ABD binding limits barbed-end growth, especially in actin filament bundles. αE-catenin ABD inhibits actin filament branching by the Arp2/3 complex and severing by cofilin, both of which contact regions of the actin protomer that are structurally altered by αE-catenin ABD binding. In epithelial cells, there is little correlation between the distribution of αE-catenin and the Arp2/3 complex at developing cell–cell contacts. Our results indicate that αE-catenin binding to filamentous actin favors assembly of unbranched filament bundles that are protected from severing over more dynamic, branched filament arrays.
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Affiliation(s)
- Scott D Hansen
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, School of Medicine, San Francisco, CA 94158 Department of Biology, Stanford University, Stanford, CA 94305 Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 Bioinformatics and Systems Biology Program, Sanford Burnham Medical Research Institute, La Jolla, CA 92037 Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305 Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
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Ishiyama N, Tanaka N, Abe K, Yang YJ, Abbas YM, Umitsu M, Nagar B, Bueler SA, Rubinstein JL, Takeichi M, Ikura M. An autoinhibited structure of α-catenin and its implications for vinculin recruitment to adherens junctions. J Biol Chem 2013; 288:15913-25. [PMID: 23589308 PMCID: PMC3668747 DOI: 10.1074/jbc.m113.453928] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 03/18/2013] [Indexed: 11/06/2022] Open
Abstract
α-Catenin is an actin- and vinculin-binding protein that regulates cell-cell adhesion by interacting with cadherin adhesion receptors through β-catenin, but the mechanisms by which it anchors the cadherin-catenin complex to the actin cytoskeleton at adherens junctions remain unclear. Here we determined crystal structures of αE-catenin in the autoinhibited state and the actin-binding domain of αN-catenin. Together with the small-angle x-ray scattering analysis of full-length αN-catenin, we deduced an elongated multidomain assembly of monomeric α-catenin that structurally and functionally couples the vinculin- and actin-binding mechanisms. Cellular and biochemical studies of αE- and αN-catenins show that αE-catenin recruits vinculin to adherens junctions more effectively than αN-catenin, partly because of its higher affinity for actin filaments. We propose a molecular switch mechanism involving multistate conformational changes of α-catenin. This would be driven by actomyosin-generated tension to dynamically regulate the vinculin-assisted linkage between adherens junctions and the actin cytoskeleton.
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Affiliation(s)
- Noboru Ishiyama
- From the Campbell Family Cancer Research Institute, Ontario Cancer Institute and
| | - Nobutoshi Tanaka
- the Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
- the RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Kentaro Abe
- the Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Yoo Jeong Yang
- From the Campbell Family Cancer Research Institute, Ontario Cancer Institute and
| | - Yazan M. Abbas
- the Department of Biochemistry and Groupe de Recherche Axe sur la Structure des Proteines, McGill University, Montreal, Quebec H3G 0B1, Canada, and
| | - Masataka Umitsu
- From the Campbell Family Cancer Research Institute, Ontario Cancer Institute and
| | - Bhushan Nagar
- the Department of Biochemistry and Groupe de Recherche Axe sur la Structure des Proteines, McGill University, Montreal, Quebec H3G 0B1, Canada, and
| | - Stephanie A. Bueler
- the Molecular Structure and Function Program, The Hospital for Sick Children Research Institute and
| | - John L. Rubinstein
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
- the Molecular Structure and Function Program, The Hospital for Sick Children Research Institute and
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | | | - Mitsuhiko Ikura
- From the Campbell Family Cancer Research Institute, Ontario Cancer Institute and
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
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Vinculin and metavinculin: Oligomerization and interactions with F-actin. FEBS Lett 2013; 587:1220-9. [DOI: 10.1016/j.febslet.2013.02.042] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 02/20/2013] [Accepted: 02/20/2013] [Indexed: 01/09/2023]
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Prasad Gajula MNV, Vogel KP, Rai A, Dietrich F, Steinhoff HJ. How far in-silico computing meets real experiments. A study on the structure and dynamics of spin labeled vinculin tail protein by molecular dynamics simulations and EPR spectroscopy. BMC Genomics 2013; 14 Suppl 2:S4. [PMID: 23445506 PMCID: PMC3582443 DOI: 10.1186/1471-2164-14-s2-s4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background Investigation of conformational changes in a protein is a prerequisite to understand its biological function. To explore these conformational changes in proteins we developed a strategy with the combination of molecular dynamics (MD) simulations and electron paramagnetic resonance (EPR) spectroscopy. The major goal of this work is to investigate how far computer simulations can meet the experiments. Methods Vinculin tail protein is chosen as a model system as conformational changes within the vinculin protein are believed to be important for its biological function at the sites of cell adhesion. MD simulations were performed on vinculin tail protein both in water and in vacuo environments. EPR experimental data is compared with those of the simulated data for corresponding spin label positions. Results The calculated EPR spectra from MD simulations trajectories of selected spin labelled positions are comparable to experimental EPR spectra. The results show that the information contained in the spin label mobility provides a powerful means of mapping protein folds and their conformational changes. Conclusions The results suggest the localization of dynamic and flexible regions of the vinculin tail protein. This study shows MD simulations can be used as a complementary tool to interpret experimental EPR data.
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Affiliation(s)
- M N V Prasad Gajula
- CABin division, DST Ramanujan Fellow, Indian Agricultural Statistics Research Institute, PUSA campus, New Delhi-110012, India.
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41
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Tolbert CE, Burridge K, Campbell SL. Vinculin regulation of F-actin bundle formation: what does it mean for the cell? Cell Adh Migr 2013; 7:219-25. [PMID: 23307141 DOI: 10.4161/cam.23184] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Vinculin is an essential cell adhesion protein, found at both focal adhesions and adherens junctions, where it couples transmembrane proteins to the actin cytoskeleton. Vinculin is involved in controlling cell shape, motility and cell survival, and has more recently been shown to play a role in force transduction. The tail domain of vinculin (Vt) has the ability to both bind and bundle actin filaments. Binding to actin induces a conformational change in Vt believed to promote formation of a Vt dimer that is able to crosslink actin filaments. We have recently provided additional evidence for the actin-induced Vt dimer and have shown that the vinculin carboxyl (C)-terminal hairpin is critical for both the formation of the Vt dimer and for bundling F-actin. We have also demonstrated the importance of the C-terminal hairpin in cells as deletion of this region impacts both adhesion properties and force transduction. Intriguingly, we have identified bundling deficient variants of vinculin that show different cellular phenotypes. These results suggest additional role(s) for the C-terminal hairpin, distinct from its bundling function. In this commentary, we will expand on our previous findings and further investigate these actin bundling deficient vinculin variants.
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Affiliation(s)
- Caitlin E Tolbert
- Department of Cell Biology and Physiology, University of North Carolina School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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42
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Hansen MDH, Kwiatkowski AV. Control of actin dynamics by allosteric regulation of actin binding proteins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 303:1-25. [PMID: 23445807 DOI: 10.1016/b978-0-12-407697-6.00001-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The regulated assembly and organization of actin filaments allows the cell to construct a large diversity of actin-based structures specifically suited to a range of cellular processes. A vast array of actin regulatory proteins must work in concert to form specific actin networks within cells, and spatial and temporal requirements for actin assembly necessitate rapid regulation of protein activity. This chapter explores a common mechanism of controlling the activity of actin binding proteins: allosteric autoinhibition by interdomain head-tail interactions. Intramolecular interactions maintain these proteins in a closed conformation that masks protein domains needed to regulate actin dynamics. Autoinhibition is typically relieved by two or more ligand binding and/or posttranslational modification events that expose key protein domains. Regulation through multiple inputs permits precise temporal and spatial control of protein activity to guide actin network formation.
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Affiliation(s)
- Marc D H Hansen
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, USA.
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Miller PW, Clarke DN, Weis WI, Lowe CJ, Nelson WJ. The evolutionary origin of epithelial cell-cell adhesion mechanisms. CURRENT TOPICS IN MEMBRANES 2013; 72:267-311. [PMID: 24210433 PMCID: PMC4118598 DOI: 10.1016/b978-0-12-417027-8.00008-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A simple epithelium forms a barrier between the outside and the inside of an organism, and is the first organized multicellular tissue found in evolution. We examine the relationship between the evolution of epithelia and specialized cell-cell adhesion proteins comprising the classical cadherin/β-catenin/α-catenin complex (CCC). A review of the divergent functional properties of the CCC in metazoans and non-metazoans, and an updated phylogenetic coverage of the CCC using recent genomic data reveal: (1) The core CCC likely originated before the last common ancestor of unikonts and their closest bikont sister taxa. (2) Formation of the CCC may have constrained sequence evolution of the classical cadherin cytoplasmic domain and β-catenin in metazoa. (3) The α-catenin-binding domain in β-catenin appears to be the favored mutation site for disrupting β-catenin function in the CCC. (4) The ancestral function of the α/β-catenin heterodimer appears to be an actin-binding module. In some metazoan groups, more complex functions of α-catenin were gained by sequence divergence in the non-actin-binding (N-, M-) domains. (5) Allosteric regulation of α-catenin may have evolved for more complex regulation of the actin cytoskeleton.
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Affiliation(s)
- Phillip W. Miller
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | | | - William I. Weis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | | | - W. James Nelson
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biology, Stanford University, Stanford, CA 94305
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Maiden SL, Harrison N, Keegan J, Cain B, Lynch AM, Pettitt J, Hardin J. Specific conserved C-terminal amino acids of Caenorhabditis elegans HMP-1/α-catenin modulate F-actin binding independently of vinculin. J Biol Chem 2012; 288:5694-706. [PMID: 23271732 DOI: 10.1074/jbc.m112.438093] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Stable intercellular adhesions formed through the cadherin-catenin complex are important determinants of proper tissue architecture and help maintain tissue integrity during morphogenetic movements in developing embryos. A key regulator of this stability is α-catenin, which connects the cadherin-catenin complex to the actin cytoskeleton. Although the C-terminal F-actin-binding domain of α-catenin has been shown to be crucial for its function, a more detailed in vivo analysis of discrete regions and residues required for actin binding has not been performed. Using Caenorhabditis elegans as a model system, we have characterized mutations in hmp-1/α-catenin that identify HMP-1 residues 687-742 and 826-927, as well as amino acid 802, as critical to the localization of junctional proximal actin during epidermal morphogenesis. We also find that the S823F transition in a hypomorphic allele, hmp-1(fe4), decreases actin binding in vitro. Using hmp-1(fe4) animals in a mutagenesis screen, we were then able to identify 11 intragenic suppressors of hmp-1(fe4) that revert actin binding to wild-type levels. Using homology modeling, we show that these amino acids are positioned at key conserved sites within predicted α-helices in the C terminus. Through the use of transgenic animals, we also demonstrate that HMP-1 residues 315-494, which correspond to a putative mechanotransduction domain that binds vinculin in vertebrate αE-catenin, are not required during epidermal morphogenesis but may aid efficient recruitment of HMP-1 to the junction. Our studies are the first to identify key conserved amino acids in the C terminus of α-catenin that modulate F-actin binding in living embryos of a simple metazoan.
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Affiliation(s)
- Stephanie L Maiden
- Department of Zoology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Thoss F, Dietrich F, Punkt K, Illenberger S, Rottner K, Himmel M, Ziegler WH. Metavinculin: New insights into functional properties of a muscle adhesion protein. Biochem Biophys Res Commun 2012; 430:7-13. [PMID: 23159629 DOI: 10.1016/j.bbrc.2012.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 11/04/2012] [Indexed: 11/16/2022]
Abstract
Metavinculin is a muscle-specific splice variant of the ubiquitously expressed cytoskeletal adaptor protein vinculin. Both proteins are thought to be co-expressed in all muscle types where they co-localize to microfilament-associated adhesion sites. It has been shown that a metavinculin-specific insertion of 68 amino acids alters the biochemical properties of the five-helix bundle in the tail domain. Here, we demonstrate that the metavinculin-specific helix H1' plays an important role for protein stability of the tail domain, since a point mutation in this helix, R975W, which is associated with the occurrence of dilated cardiomyopathy in man, further decreases thermal stability of the metavinculin tail domain. In striated muscle progenitor cells (myoblasts), both, metavinculin and the R975W mutant show significantly reduced, albeit distinctive residency and exchange rates in adhesion sites as compared to vinculin. In contrast to previous studies, we show that metavinculin is localized in a muscle fiber type-dependent fashion to the costameres of striated muscle, reflecting the individual metabolic and physiological status of a given muscle fiber. Metavinculin expression is highest in fast, glycolytic muscle fibers and virtually absent in M. diaphragmaticus, a skeletal muscle entirely lacking fast, glycolytic fibers. In summary, our data suggest that metavinculin enrichment in attachment sites of muscle cells leads to higher mechanical stability of adhesion complexes allowing for greater shear force resistance.
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Affiliation(s)
- Florian Thoss
- Interdisciplinary Center for Clinical Research (IZKF) Leipzig, Faculty of Medicine, University of Leipzig, D-04103 Leipzig, Germany
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Abstract
The cadherin-containing intercellular junctions, adherens junctions and desmosomes share an overall logical organization in which the extracellular regions of the cadherins on opposing cells interact, while their cytoplasmic domains are linked to the cytoskeleton through protein assemblies. In adherens junctions, beta-catenin binds to the cytoplasmic domain of cadherins and to alpha-catenin, which links the cadherin/beta-catenin complex to the actin cytoskeleton. In desmosomes, the beta-catenin homolog plakoglobin binds to desmosomal cadherins. The desmosomal cadherin/plakoglobin complex is linked to the intermediate filament system by the protein desmoplakin. In the past decade, components of these systems have been purified to homogeneity and studied biochemically and structurally, providing the beginnings of a mechanistic description of junction architecture and dynamics.
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Affiliation(s)
- H-J Choi
- Department of Structural Biology, Stanford University School of Medicine, 299 Campus Drive, West Stanford, CA, 94305-5126, USA
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47
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Huber RJ, O'Day DH. EGF-like peptide-enhanced cell movement in Dictyostelium is mediated by protein kinases and the activity of several cytoskeletal proteins. Cell Signal 2012; 24:1770-80. [PMID: 22588127 DOI: 10.1016/j.cellsig.2012.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 05/07/2012] [Accepted: 05/07/2012] [Indexed: 12/19/2022]
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48
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Janssen MEW, Liu H, Volkmann N, Hanein D. The C-terminal tail domain of metavinculin, vinculin's splice variant, severs actin filaments. ACTA ACUST UNITED AC 2012; 197:585-93. [PMID: 22613835 PMCID: PMC3365496 DOI: 10.1083/jcb.201111046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Relative to vinculin, a unique 68-residue insert in the C-terminal tail of metavinculin results in a loss of actin filament-bundling activity but gain of actin filament-severing activity. Vinculin and its splice variant, metavinculin (MV), are key elements of multiple protein assemblies linking the extracellular matrix to the actin cytoskeleton. Vinculin is expressed ubiquitously, whereas MV is mainly expressed in smooth and cardiac muscle tissue. The only difference in amino acid sequence between the isoforms is a 68-residue insert in the C-terminal tail domain of MV (MVt). Although the functional role of this insert remains elusive, its importance is exemplified by point mutations that are associated with dilated and hypertrophic cardiomyopathy. In vinculin, the actin binding site resides in the tail domain. In this paper, we show that MVt binds actin filaments similarly to the vinculin tail domain. Unlike its splice variant, MVt did not bundle actin filaments. Instead, MVt promoted severing of actin filaments, most efficiently at substoichiometric concentrations. This surprising and seemingly contradictory alteration of vinculin function by the 68-residue insert may be essential for modulating compliance of vinculin-induced actin bundles when exposed to rapidly increasing external forces.
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Affiliation(s)
- Mandy E W Janssen
- Bioinformatics and Systems Biology Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
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49
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Abé C, Dietrich F, Gajula P, Benz M, Vogel KP, van Gastel M, Illenberger S, Ziegler WH, Steinhoff HJ. Monomeric and dimeric conformation of the vinculin tail five-helix bundle in solution studied by EPR spectroscopy. Biophys J 2012; 101:1772-80. [PMID: 21961604 DOI: 10.1016/j.bpj.2011.08.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 08/03/2011] [Accepted: 08/31/2011] [Indexed: 11/28/2022] Open
Abstract
The cytoskeletal adaptor protein vinculin plays an important role in the control of cell adhesion and migration, linking the actin cytoskeleton to adhesion receptor complexes in cell adhesion sites. The conformation of the vinculin tail dimer, which is crucial for protein function, was analyzed using site-directed spin labeling in electron paramagnetic resonance spectroscopy. Interspin distances for a set of six singly and four doubly spin-labeled mutants of the tail domain of vinculin were determined and used as constraints for modeling of the vinculin tail dimer. A comparison of the results obtained by molecular dynamic simulations and a rotamer library approach reveals that the crystal structure of the vinculin tail monomer is essentially preserved in aqueous solution. The orientation of monomers within the dimer observed previously by x-ray crystallography agrees with the solution electron paramagnetic resonance data. Furthermore, the distance between positions 1033 is shown to increase by >3 nm upon interaction of the vinculin tail domain with F-actin.
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Affiliation(s)
- Christoph Abé
- Department of Physics, University of Osnabrück, Osnabrück, Germany
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50
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Abstract
Classical cadherins are a family of transmembrane proteins that mediate cell-cell adhesion at adherens junctions. A complex chain of cis- and trans- interactions between cadherin ectodomains establishes a cadherin adhesive cluster. A principal adhesive interaction in such clusters is an exchange of β strands between the first extracellular cadherin domains (EC1). The structure of cadherin adhesive clusters can be modified by other adherens junction proteins including additional transmembrane proteins, nectins and various intracellular proteins that directly or indirectly interact with the intracellular cadherin region. These interactions determine the dynamics and stability of cadherin adhesive structures.
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Affiliation(s)
- Sergey Troyanovsky
- Department of Dermatology, Feinberg School of Medicine, Northwestern University, 60611, Chicago, IL, USA,
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