1
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Dasetty S, Bidone TC, Ferguson AL. Data-driven prediction of α IIbβ 3 integrin activation paths using manifold learning and deep generative modeling. Biophys J 2024; 123:2716-2729. [PMID: 38098231 PMCID: PMC11393677 DOI: 10.1016/j.bpj.2023.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 01/06/2024] Open
Abstract
The integrin heterodimer is a transmembrane protein critical for driving cellular process and is a therapeutic target in the treatment of multiple diseases linked to its malfunction. Activation of integrin involves conformational transitions between bent and extended states. Some of the conformations that are intermediate between bent and extended states of the heterodimer have been experimentally characterized, but the full activation pathways remain unresolved both experimentally due to their transient nature and computationally due to the challenges in simulating rare barrier crossing events in these large molecular systems. An understanding of the activation pathways can provide new fundamental understanding of the biophysical processes associated with the dynamic interconversions between bent and extended states and can unveil new putative therapeutic targets. In this work, we apply nonlinear manifold learning to coarse-grained molecular dynamics simulations of bent, extended, and two intermediate states of αIIbβ3 integrin to learn a low-dimensional embedding of the configurational phase space. We then train deep generative models to learn an inverse mapping between the low-dimensional embedding and high-dimensional molecular space and use these models to interpolate the molecular configurations constituting the activation pathways between the experimentally characterized states. This work furnishes plausible predictions of integrin activation pathways and reports a generic and transferable multiscale technique to predict transition pathways for biomolecular systems.
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Affiliation(s)
- Siva Dasetty
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois
| | - Tamara C Bidone
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah
| | - Andrew L Ferguson
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois.
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2
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Artemenko EO, Obydennyi SI, Troyanova KS, Novichkova GA, Nechipurenko DY, Panteleev MA. Adhesive properties of plasma-circulating and platelet-derived microvesicles from healthy individuals. Thromb Res 2024; 233:119-126. [PMID: 38039724 DOI: 10.1016/j.thromres.2023.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/31/2023] [Accepted: 11/15/2023] [Indexed: 12/03/2023]
Abstract
BACKGROUND Microvesicles (MVs) produced by platelets upon activation possess high procoagulant activity and represent a possible thrombotic risk marker. However, direct experimental evaluation of the adhesive properties of MVs and their potential role in thrombus growth is lacking. OBJECTIVES We investigated integrin αIIbβ3 status and adhesive properties of plasma-circulating and platelet-derived MVs from healthy individuals. METHODS MVs were isolated from whole blood or produced from activated platelets. Flow cytometry was used for quantification of fluorescently labeled PAC-1 and fibrinogen binding to MVs. Confocal microscopy was used for evaluation of MVs adhesion to fibrinogen and for estimation of their involvement in whole blood thrombus formation in a parallel-plate flow chambers under arterial shear conditions. RESULTS AND CONCLUSIONS Neither circulating plasma MVs, nor platelet-activation-produced MVs bound PAC-1. However, both types of MVs specifically and weakly bound fibrinogen (about 400 molecules of bound fibrinogen per MV versus >100,000 per non-procoagulant activated platelet). Still, the MVs did not adhere stably to the immobilized fibrinogen. Both types of MVs were weakly incorporated into a thrombus and did not affect thrombus formation: average thrombus height in the recalcified whole blood in the presence of platelet-activation-produced MVs was 4.19 ± 1.38 μm versus 4.87 ± 1.72 μm (n = 6, p > 0.05) in the control experiments. This suggests that MVs present in plasma of healthy individuals are not likely to be directly involved in thrombus formation under arterial flow conditions.
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Affiliation(s)
- E O Artemenko
- Centre for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia; National Scientific and Practical Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia.
| | - S I Obydennyi
- Centre for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia; National Scientific and Practical Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - K S Troyanova
- Centre for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia; Faculty of Physics, Moscow State University, Moscow, Russia
| | - G A Novichkova
- National Scientific and Practical Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - D Y Nechipurenko
- Centre for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia; National Scientific and Practical Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia; Faculty of Physics, Moscow State University, Moscow, Russia
| | - M A Panteleev
- Centre for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia; National Scientific and Practical Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia; Faculty of Physics, Moscow State University, Moscow, Russia
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3
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Takada Y, Fujita M, Takada YK. Virtual Screening of Protein Data Bank via Docking Simulation Identified the Role of Integrins in Growth Factor Signaling, the Allosteric Activation of Integrins, and P-Selectin as a New Integrin Ligand. Cells 2023; 12:2265. [PMID: 37759488 PMCID: PMC10527219 DOI: 10.3390/cells12182265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/02/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Integrins were originally identified as receptors for extracellular matrix (ECM) and cell-surface molecules (e.g., VCAM-1 and ICAM-1). Later, we discovered that many soluble growth factors/cytokines bind to integrins and play a critical role in growth factor/cytokine signaling (growth factor-integrin crosstalk). We performed a virtual screening of protein data bank (PDB) using docking simulations with the integrin headpiece as a target. We showed that several growth factors (e.g., FGF1 and IGF1) induce a integrin-growth factor-cognate receptor ternary complex on the surface. Growth factor/cytokine mutants defective in integrin binding were defective in signaling functions and act as antagonists of growth factor signaling. Unexpectedly, several growth factor/cytokines activated integrins by binding to the allosteric site (site 2) in the integrin headpiece, which is distinct from the classical ligand (RGD)-binding site (site 1). Since 25-hydroxycholesterol, a major inflammatory mediator, binds to site 2, activates integrins, and induces inflammatory signaling (e.g., IL-6 and TNFα secretion), it has been proposed that site 2 is involved in inflammatory signaling. We showed that several inflammatory factors (CX3CL1, CXCL12, CCL5, sPLA2-IIA, and P-selectin) bind to site 2 and activate integrins. We propose that site 2 is involved in the pro-inflammatory action of these proteins and a potential therapeutic target. It has been well-established that platelet integrin αIIbβ3 is activated by signals from the inside of platelets induced by platelet agonists (inside-out signaling). In addition to the canonical inside-out signaling, we showed that αIIbβ3 can be allosterically activated by inflammatory cytokines/chemokines that are stored in platelet granules (e.g., CCL5, CXCL12) in the absence of inside-out signaling (e.g., soluble integrins in cell-free conditions). Thus, the allosteric activation may be involved in αIIbβ3 activation, platelet aggregation, and thrombosis. Inhibitory chemokine PF4 (CXCL4) binds to site 2 but did not activate integrins, Unexpectedly, we found that PF4/anti-PF4 complex was able to activate integrins, indicating that the anti-PF4 antibody changed the phenotype of PF4 from inhibitory to inflammatory. Since autoantibodies to PF4 are detected in vaccine-induced thrombocytopenic thrombosis (VIPP) and autoimmune diseases (e.g., SLE, and rheumatoid arthritis), we propose that this phenomenon is related to the pathogenesis of these diseases. P-selectin is known to bind exclusively to glycans (e.g., sLex) and involved in cell-cell interaction by binding to PSGL-1 (CD62P glycoprotein ligand-1). Unexpectedly, through docking simulation, we discovered that the P-selectin C-type lectin domain functions as an integrin ligand. It is interesting that no one has studied whether P-selectin binds to integrins in the last few decades. The integrin-binding site and glycan-binding site were close but distinct. Also, P-selectin lectin domain bound to site 2 and allosterically activated integrins.
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Affiliation(s)
- Yoshikazu Takada
- Department of Dermatology, UC Davis School of Medicine, Sacramento, CA 95817, USA; (M.F.); (Y.K.T.)
- Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, CA 95817, USA
| | - Masaaki Fujita
- Department of Dermatology, UC Davis School of Medicine, Sacramento, CA 95817, USA; (M.F.); (Y.K.T.)
| | - Yoko K. Takada
- Department of Dermatology, UC Davis School of Medicine, Sacramento, CA 95817, USA; (M.F.); (Y.K.T.)
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4
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Takada YK, Shimoda M, Takada Y. CD40L Activates Platelet Integrin αIIbβ3 by Binding to the Allosteric Site (Site 2) in a KGD-Independent Manner and HIGM1 Mutations Are Clustered in the Integrin-Binding Sites of CD40L. Cells 2023; 12:1977. [PMID: 37566056 PMCID: PMC10416995 DOI: 10.3390/cells12151977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/20/2023] [Accepted: 07/25/2023] [Indexed: 08/12/2023] Open
Abstract
CD40L is expressed in activated T cells, and it plays a major role in immune response and is a major therapeutic target for inflammation. High IgM syndrome type 1 (HIGM1) is a congenital functional defect in CD40L/CD40 signaling due to defective CD40L. CD40L is also stored in platelet granules and transported to the surface upon platelet activation. Platelet integrin αIIbβ3 is known to bind to fibrinogen and activation of αIIbβ3 is a key event that triggers platelet aggregation. Also, the KGD motif is critical for αIIbβ3 binding and the interaction stabilizes thrombus. Previous studies showed that CD40L binds to and activates integrins αvβ3 and α5β1 and that HIGM1 mutations are clustered in the integrin-binding sites. However, the specifics of CD40L binding to αIIbβ3 were unclear. Here, we show that CD40L binds to αIIbβ3 in a KGD-independent manner using CD40L that lacks the KGD motif. Two HIGM1 mutants, S128E/E129G and L155P, reduced the binding of CD40L to the classical ligand-binding site (site 1) of αIIbβ3, indicating that αIIbβ3 binds to the outer surface of CD40L trimer. Also, CD40L bound to the allosteric site (site 2) of αIIbβ3 and allosterically activated αIIbβ3 without inside-out signaling. Two HIMG1 mutants, K143T and G144E, on the surface of trimeric CD40L suppressed CD40L-induced αIIbβ3 activation. These findings suggest that CD40L binds to αIIbβ3 in a manner different from that of αvβ3 and α5β1 and induces αIIbβ3 activation. HIGM1 mutations are clustered in αIIbβ3 binding sites in CD40L and are predicted to suppress thrombus formation and immune responses through αIIbβ3.
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Affiliation(s)
- Yoko K. Takada
- Department of Dermatology, School of Medicine, UC Davis, Sacramento, CA 95817, USA (M.S.)
| | - Michiko Shimoda
- Department of Dermatology, School of Medicine, UC Davis, Sacramento, CA 95817, USA (M.S.)
| | - Yoshikazu Takada
- Department of Dermatology, School of Medicine, UC Davis, Sacramento, CA 95817, USA (M.S.)
- Department of Biochemistry and Molecular Medicine, School of Medicine, UC Davis, Sacramento, CA 95817, USA
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5
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Tong D, Soley N, Kolasangiani R, Schwartz MA, Bidone TC. Integrin α IIbβ 3 intermediates: From molecular dynamics to adhesion assembly. Biophys J 2023; 122:533-543. [PMID: 36566352 PMCID: PMC9941721 DOI: 10.1016/j.bpj.2022.12.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/14/2022] [Accepted: 12/21/2022] [Indexed: 12/25/2022] Open
Abstract
The platelet integrin αIIbβ3 undergoes long-range conformational transitions associated with its functional conversion from inactive (low-affinity) to active (high-affinity) during hemostasis. Although new conformations that are intermediate between the well-characterized bent and extended states have been identified, their molecular dynamic properties and functions in the assembly of adhesions remain largely unexplored. In this study, we evaluated the properties of intermediate conformations of integrin αIIbβ3 and characterized their effects on the assembly of adhesions by combining all-atom simulations, principal component analysis, and mesoscale modeling. Our results show that in the low-affinity, bent conformation, the integrin ectodomain tends to pivot around the legs; in intermediate conformations, the headpiece becomes partially extended, away from the lower legs. In the fully open, active state, αIIbβ3 is flexible, and the motions between headpiece and lower legs are accompanied by fluctuations of the transmembrane helices. At the mesoscale, bent integrins form only unstable adhesions, but intermediate or open conformations stabilize the adhesions. These studies reveal a mechanism by which small variations in ligand binding affinity and enhancement of the ligand-bound lifetime in the presence of actin retrograde flow stabilize αIIbβ3 integrin adhesions.
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Affiliation(s)
- Dudu Tong
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah
| | - Nidhi Soley
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah
| | - Reza Kolasangiani
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah
| | - Martin A Schwartz
- Yale Cardiovascular Research Center, Department of Internal Medicine (Cardiology), Yale University, New Haven, Connecticut; Department of Cell Biology, Yale University, New Haven, Connecticut; Department of Biomedical Engineering, School of Engineering and Applied Science, Yale University, New Haven, Connecticut
| | - Tamara C Bidone
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah; Department of Biochemistry, University of Utah, Salt Lake City, Utah; Department of Molecular Pharmaceutics, University of Utah, Salt Lake City, Utah.
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6
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Takada YK, Fujita M, Takada Y. Pro-Inflammatory Chemokines CCL5, CXCL12, and CX3CL1 Bind to and Activate Platelet Integrin αIIbβ3 in an Allosteric Manner. Cells 2022; 11:cells11193059. [PMID: 36231020 PMCID: PMC9563052 DOI: 10.3390/cells11193059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 09/23/2022] [Accepted: 09/24/2022] [Indexed: 11/16/2022] Open
Abstract
Activation of platelet integrin αIIbβ3, a key event for hemostasis and thrombus formation, is known to be mediated exclusively by inside-out signaling. We showed that inflammatory chemokines CX3CL1 and CXCL12 in previous studies, and CCL5 in this study, bound to the allosteric binding site (site 2) of vascular integrin αvβ3, in addition to the classical ligand binding site (site 1), and allosterically activated integrins independent of inside-out signaling. Since αIIbβ3 is exposed to inflammatory chemokines at increased concentrations during inflammation (e.g., cytokine/chemokine storm) and platelet activation, we hypothesized that these chemokines bind to and activate αIIbβ3 in an allosteric activation mechanism. We found that these chemokines bound to αIIbβ3. Notably, they activated soluble αIIbβ3 in 1 mM Ca2+ by binding to site 2. They activated cell-surface αIIbβ3 on CHO cells, which lack machinery for inside-out signaling or chemokine receptors, quickly (<1 min) and at low concentrations (1–10 ng/mL) compared to activation of soluble αIIbβ3, probably because chemokines bind to cell surface proteoglycans. Furthermore, activation of αIIbβ3 by the chemokines was several times more potent than 1 mM Mn2+. We propose that CCL5 and CXCL12 (stored in platelet granules) may allosterically activate αIIbβ3 upon platelet activation and trigger platelet aggregation. Transmembrane CX3CL1 on activated endothelial cells may mediate platelet–endothelial interaction by binding to and activating αIIbβ3. Additionally, these chemokines in circulation over-produced during inflammation may trigger αIIbβ3 activation, which is a possible missing link between inflammation and thrombosis.
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Affiliation(s)
- Yoko K. Takada
- Department of Dermatology, School of Medicine, University of California–Davis, 4645 Second Ave., Research III Suite 3300, Sacramento, CA 95817, USA
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA
| | - Masaaki Fujita
- Department of Dermatology, School of Medicine, University of California–Davis, 4645 Second Ave., Research III Suite 3300, Sacramento, CA 95817, USA
| | - Yoshikazu Takada
- Department of Dermatology, School of Medicine, University of California–Davis, 4645 Second Ave., Research III Suite 3300, Sacramento, CA 95817, USA
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Sacramento, CA 95817, USA
- Correspondence:
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7
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Benk LT, Benk AS, Lira RB, Cavalcanti-Adam EA, Dimova R, Lipowsky R, Geiger B, Spatz JP. Integrin α
IIb
β
3
Activation and Clustering in Minimal Synthetic Cells. ADVANCED NANOBIOMED RESEARCH 2022. [DOI: 10.1002/anbr.202100094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Lucia T. Benk
- Department of Cellular Biophysics Max Planck Institute for Medical Research Jahnstr. 29 69120 Heidelberg Germany
| | - Amelie S. Benk
- Department of Cellular Biophysics Max Planck Institute for Medical Research Jahnstr. 29 69120 Heidelberg Germany
| | - Rafael B. Lira
- Theory & Bio-Systems Max Planck Institute of Colloids and Interfaces 14424 Potsdam Germany
- Faculty of Science and Engineering Molecular Biophysics Zernike Institute for Advanced Materials 9747 AG Groningen The Netherlands
| | - Elisabetta Ada Cavalcanti-Adam
- Department of Cellular Biophysics Max Planck Institute for Medical Research Jahnstr. 29 69120 Heidelberg Germany
- Max Planck School Matter to Life Jahnstr. 29 69120 Heidelberg Germany
| | - Rumiana Dimova
- Theory & Bio-Systems Max Planck Institute of Colloids and Interfaces 14424 Potsdam Germany
| | - Reinhard Lipowsky
- Theory & Bio-Systems Max Planck Institute of Colloids and Interfaces 14424 Potsdam Germany
- Max Planck School Matter to Life Jahnstr. 29 69120 Heidelberg Germany
| | - Benjamin Geiger
- Department of Molecular Cell Biology Weizmann Institute of Science Rehovot 76100 Israel
| | - Joachim P. Spatz
- Department of Cellular Biophysics Max Planck Institute for Medical Research Jahnstr. 29 69120 Heidelberg Germany
- Max Planck School Matter to Life Jahnstr. 29 69120 Heidelberg Germany
- Institute for Molecular Systems Engineering (IMSE) Heidelberg University 69120 Heidelberg Germany
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8
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Soluble CD40L activates soluble and cell-surface integrin αvβ3, α5β1, and α4β1 by binding to the allosteric ligand-binding site (site 2). J Biol Chem 2021; 296:100399. [PMID: 33571526 PMCID: PMC7960543 DOI: 10.1016/j.jbc.2021.100399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/27/2021] [Accepted: 02/04/2021] [Indexed: 11/20/2022] Open
Abstract
CD40L is a member of the TNF superfamily that participates in immune cell activation. It binds to and signals through several integrins, including αvβ3 and α5β1, which bind to the trimeric interface of CD40L. We previously showed that several integrin ligands can bind to the allosteric site (site 2), which is distinct from the classical ligand-binding site (site 1), raising the question of if CD40L activates integrins. In our explorations of this question, we determined that integrin α4β1, which is prevalently expressed on the same CD4+ T cells as CD40L, is another receptor for CD40L. Soluble (s)CD40L activated soluble integrins αvβ3, α5β1, and α4β1 in cell-free conditions, indicating that this activation does not require inside-out signaling. Moreover, sCD40L activated cell-surface integrins in CHO cells that do not express CD40. To learn more about the mechanism of binding, we determined that sCD40L bound to a cyclic peptide from site 2. Docking simulations predicted that the residues of CD40L that bind to site 2 are located outside of the CD40L trimer interface, at a site where four HIGM1 (hyper-IgM syndrome type 1) mutations are clustered. We tested the effect of these mutations, finding that the K143T and G144E mutants were the most defective in integrin activation, providing support that this region interacts with site 2. We propose that allosteric integrin activation by CD40L also plays a role in CD40L signaling, and defective site 2 binding may be related to the impaired CD40L signaling functions of these HIGM1 mutants.
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9
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Grimm TM, Dierdorf NI, Betz K, Paone C, Hauck CR. PPM1F controls integrin activity via a conserved phospho-switch. J Cell Biol 2020; 219:211512. [PMID: 33119040 PMCID: PMC7604772 DOI: 10.1083/jcb.202001057] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 07/20/2020] [Accepted: 09/11/2020] [Indexed: 01/04/2023] Open
Abstract
Control of integrin activity is vital during development and tissue homeostasis, while derailment of integrin function contributes to pathophysiological processes. Phosphorylation of a conserved threonine motif (T788/T789) in the integrin β cytoplasmic domain increases integrin activity. Here, we report that T788/T789 functions as a phospho-switch, which determines the association with either talin and kindlin-2, the major integrin activators, or filaminA, an integrin activity suppressor. A genetic screen identifies the phosphatase PPM1F as the critical enzyme, which selectively and directly dephosphorylates the T788/T789 motif. PPM1F-deficient cell lines show constitutive integrin phosphorylation, exaggerated talin binding, increased integrin activity, and enhanced cell adhesion. These gain-of-function phenotypes are reverted by reexpression of active PPM1F, but not a phosphatase-dead mutant. Disruption of the ppm1f gene in mice results in early embryonic death at day E10.5. Together, PPM1F controls the T788/T789 phospho-switch in the integrin β1 cytoplasmic tail and constitutes a novel target to modulate integrin activity.
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Affiliation(s)
- Tanja M. Grimm
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany,Konstanz Research School Chemical Biology, Universität Konstanz, Konstanz, Germany
| | - Nina I. Dierdorf
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany,Konstanz Research School Chemical Biology, Universität Konstanz, Konstanz, Germany
| | - Karin Betz
- Konstanz Research School Chemical Biology, Universität Konstanz, Konstanz, Germany,Lehrstuhl Zelluläre Chemie, Fachbereich Chemie, Universität Konstanz, Konstanz, Germany
| | - Christoph Paone
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany,Konstanz Research School Chemical Biology, Universität Konstanz, Konstanz, Germany
| | - Christof R. Hauck
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany,Konstanz Research School Chemical Biology, Universität Konstanz, Konstanz, Germany,Correspondence to Christof R. Hauck:
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10
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Kukkurainen S, Azizi L, Zhang P, Jacquier MC, Baikoghli M, von Essen M, Tuukkanen A, Laitaoja M, Liu X, Rahikainen R, Orłowski A, Jänis J, Määttä JAE, Varjosalo M, Vattulainen I, Róg T, Svergun D, Cheng RH, Wu J, Hytönen VP, Wehrle-Haller B. The F1 loop of the talin head domain acts as a gatekeeper in integrin activation and clustering. J Cell Sci 2020; 133:jcs239202. [PMID: 33046605 PMCID: PMC10679385 DOI: 10.1242/jcs.239202] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 07/31/2020] [Indexed: 12/15/2022] Open
Abstract
Integrin activation and clustering by talin are early steps of cell adhesion. Membrane-bound talin head domain and kindlin bind to the β integrin cytoplasmic tail, cooperating to activate the heterodimeric integrin, and the talin head domain induces integrin clustering in the presence of Mn2+ Here we show that kindlin-1 can replace Mn2+ to mediate β3 integrin clustering induced by the talin head, but not that induced by the F2-F3 fragment of talin. Integrin clustering mediated by kindlin-1 and the talin head was lost upon deletion of the flexible loop within the talin head F1 subdomain. Further mutagenesis identified hydrophobic and acidic motifs in the F1 loop responsible for β3 integrin clustering. Modeling, computational and cysteine crosslinking studies showed direct and catalytic interactions of the acidic F1 loop motif with the juxtamembrane domains of α- and β3-integrins, in order to activate the β3 integrin heterodimer, further detailing the mechanism by which the talin-kindlin complex activates and clusters integrins. Moreover, the F1 loop interaction with the β3 integrin tail required the newly identified compact FERM fold of the talin head, which positions the F1 loop next to the inner membrane clasp of the talin-bound integrin heterodimer.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sampo Kukkurainen
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, FI-33520 Tampere, Finland
- Fimlab Laboratories, Biokatu 4, FI-33520 Tampere, Finland
| | - Latifeh Azizi
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, FI-33520 Tampere, Finland
- Fimlab Laboratories, Biokatu 4, FI-33520 Tampere, Finland
| | - Pingfeng Zhang
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Marie-Claude Jacquier
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
| | - Mo Baikoghli
- Department of Molecular and Cellular Biology, University of California, 1 Shields Ave, Davis, CA 95616, USA
| | - Magdaléna von Essen
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, FI-33520 Tampere, Finland
- Fimlab Laboratories, Biokatu 4, FI-33520 Tampere, Finland
| | - Anne Tuukkanen
- EMBL Hamburg c/o DESY, European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
- European Bioinformatics Institute (EMBL-EBI), European Molecular Biology Laboratory, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
| | - Mikko Laitaoja
- Department of Chemistry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Xiaonan Liu
- Proteomics Unit, Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
| | - Rolle Rahikainen
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, FI-33520 Tampere, Finland
- Fimlab Laboratories, Biokatu 4, FI-33520 Tampere, Finland
| | - Adam Orłowski
- Proteomics Unit, Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
| | - Janne Jänis
- Department of Chemistry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Juha A E Määttä
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, FI-33520 Tampere, Finland
- Fimlab Laboratories, Biokatu 4, FI-33520 Tampere, Finland
| | - Markku Varjosalo
- Proteomics Unit, Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland
| | - Ilpo Vattulainen
- Computational Physics Laboratory, Tampere University, FI-33520 Tampere, Finland
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Computational Physics Laboratory, Tampere University, FI-33520 Tampere, Finland
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Dmitri Svergun
- EMBL Hamburg c/o DESY, European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
| | - R Holland Cheng
- Department of Molecular and Cellular Biology, University of California, 1 Shields Ave, Davis, CA 95616, USA
| | - Jinhua Wu
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Vesa P Hytönen
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, FI-33520 Tampere, Finland
- Fimlab Laboratories, Biokatu 4, FI-33520 Tampere, Finland
| | - Bernhard Wehrle-Haller
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
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11
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Aulakh GK. Lack of CD34 produces defects in platelets, microparticles, and lung inflammation. Cell Tissue Res 2020; 382:405-419. [PMID: 32700121 DOI: 10.1007/s00441-020-03243-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 06/15/2020] [Indexed: 01/08/2023]
Abstract
Lung innate immune activation results in acute lung inflammation, which is characterized by alveolar barrier disruption and accumulation of cellular lung aggregates comprising neutrophils, platelets, mononuclear cells, and microparticles. CD34 is a sialomucin, with pan-selectin affinity and recently shown to protect the endothelial barrier in a bleomycin-induced lung injury model. However, there is very little information about the fundamental role of CD34 in regulation of the lung innate immune response. We hypothesized that CD34 regulates leukocyte recruitment by promoting optimal platelet activation (aggregation and spread) during bacterial lipopolysaccharide (LPS)-induced acute lung injury. Therefore, we utilized CD34 knock-out (KO) and wild-type (WT) mice to analyze and compare the morphology and expression of leukocyte subsets from the pulmonary and systemic compartments. We utilized the chemotactic N-formylated tri-peptide, fMLP, to understand platelet aggregation in vitro, and the fundamental immune stimulant, LPS, to induce lung injury and understand platelet activation ex vivo. Our data reveal that under steady-state conditions, KO mice possess large aggregates of integrin β3 (CD61)-positive microparticles in peripheral blood. Moreover, the KO mice recruit a large number of neutrophils to lungs, which are not cleared even at 36-h post-LPS exposure. The KO mice display an increased platelet CD61 expression, which aggregates, but does not spread normally in response to in vitro fMLP treatment. The KO platelets display similar deficits in their spreading ability even after ex vivo LPS exposure. Thus, our data demonstrate that CD34 modulates platelet biology, microparticle aggregation, and neutrophil recruitment during murine lung inflammation.
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Affiliation(s)
- Gurpreet Kaur Aulakh
- Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
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Abstract
Integrins are heterodimeric cell surface receptors ensuring the mechanical connection between cells and the extracellular matrix. In addition to the anchorage of cells to the extracellular matrix, these receptors have critical functions in intracellular signaling, but are also taking center stage in many physiological and pathological conditions. In this review, we provide some historical, structural, and physiological notes so that the diverse functions of these receptors can be appreciated and put into the context of the emerging field of mechanobiology. We propose that the exciting journey of the exploration of these receptors will continue for at least another new generation of researchers.
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Affiliation(s)
- Michael Bachmann
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire , Geneva , Switzerland ; and Faculty of Medicine and Health Technology, Tampere University, and Fimlab Laboratories , Tampere , Finland
| | - Sampo Kukkurainen
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire , Geneva , Switzerland ; and Faculty of Medicine and Health Technology, Tampere University, and Fimlab Laboratories , Tampere , Finland
| | - Vesa P Hytönen
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire , Geneva , Switzerland ; and Faculty of Medicine and Health Technology, Tampere University, and Fimlab Laboratories , Tampere , Finland
| | - Bernhard Wehrle-Haller
- Department of Cell Physiology and Metabolism, University of Geneva, Centre Médical Universitaire , Geneva , Switzerland ; and Faculty of Medicine and Health Technology, Tampere University, and Fimlab Laboratories , Tampere , Finland
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13
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Multiscale model of integrin adhesion assembly. PLoS Comput Biol 2019; 15:e1007077. [PMID: 31163027 PMCID: PMC6568411 DOI: 10.1371/journal.pcbi.1007077] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/14/2019] [Accepted: 05/08/2019] [Indexed: 01/09/2023] Open
Abstract
The ability of adherent cells to form adhesions is critical to numerous phases of their physiology. The assembly of adhesions is mediated by several types of integrins. These integrins differ in physical properties, including rate of diffusion on the plasma membrane, rapidity of changing conformation from bent to extended, affinity for extracellular matrix ligands, and lifetimes of their ligand-bound states. However, the way in which nanoscale physical properties of integrins ensure proper adhesion assembly remains elusive. We observe experimentally that both β-1 and β-3 integrins localize in nascent adhesions at the cell leading edge. In order to understand how different nanoscale parameters of β-1 and β-3 integrins mediate proper adhesion assembly, we therefore develop a coarse-grained computational model. Results from the model demonstrate that morphology and distribution of nascent adhesions depend on ligand binding affinity and strength of pairwise interactions. Organization of nascent adhesions depends on the relative amounts of integrins with different bond kinetics. Moreover, the model shows that the architecture of an actin filament network does not perturb the total amount of integrin clustering and ligand binding; however, only bundled actin architectures favor adhesion stability and ultimately maturation. Together, our results support the view that cells can finely tune the expression of different integrin types to determine both structural and dynamic properties of adhesions.
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14
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Kaneva VN, Martyanov AA, Morozova DS, Panteleev MA, Sveshnikova AN. Platelet Integrin αIIbβ3: Mechanisms of Activation and Clustering; Involvement into the Formation of the Thrombus Heterogeneous Structure. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2019. [DOI: 10.1134/s1990747819010033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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15
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16
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Zhou F, Chen Y, Felner E, Zhu C, Lu H. Microfluidic auto-alignment of protein patterns for dissecting multi-receptor crosstalk in platelets. LAB ON A CHIP 2018; 18:2966-2974. [PMID: 30167612 PMCID: PMC6165598 DOI: 10.1039/c8lc00464a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Cell adhesion plays a critical role in many cellular functions, such as the hemostatic/thrombotic process, inflammatory reactions, and adaptive immune response. Many cell adhesion processes involve crosstalk between multiple ligand-receptor systems through intracellular signaling. To elucidate such crosstalk requires analysis of the synergistic or antagonistic effects of binding and signalling of multi-receptor species. Current techniques for these analyses, e.g., atomic force microscopy (AFM) and biomembrane force probe (BFP) assays, are either labor-intensive, low-throughput, or limited in the types of ligands they can interrogate. Circumventing these limitations requires a technique for manipulating ligand interactions with and measuring the functional response of a population of cells. In this work, we have developed a microfluidic platform for studying the binding and signaling of multi-receptor species by separating their actions in space and time. The platform directs cells through a single channel and uses sequentially presented ligands for pre-processing and stimulating cells, followed by reporting of cell activation states and functional consequences. Our method precisely patterns multiple proteins in different spatial regions without gaps. We demonstrate the utility of our method by using this platform to analyze the crosstalk between platelet receptors, glycoprotein Ib and IIb-IIIa, in the context of platelet adhesion and signaling under flow. We show the clinical utility of this platform by applying it to analyze whole blood samples and to assess differences in the activation of platelets between healthy and diabetic patients.
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Affiliation(s)
- F. Zhou
- Woodruff School of Mechanical Engineering. Georgia Institute of Technology, 801 Ferst Drive NW, Atlanta, Georgia 30332, USA
| | - Y. Chen
- Woodruff School of Mechanical Engineering. Georgia Institute of Technology, 801 Ferst Drive NW, Atlanta, Georgia 30332, USA
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology
| | - E.I. Felner
- Division of Endocrinology & Diabetes Department of Pediatrics, Emory University, 1648 Pierce Dr NE, Atlanta, GA 30307
| | - C. Zhu
- Woodruff School of Mechanical Engineering. Georgia Institute of Technology, 801 Ferst Drive NW, Atlanta, Georgia 30332, USA
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology
- Coulter Department of Biomedical Engineering. Georgia Institute of Technology, 313 Ferst Drive NW, Atlanta, Georgia 30332, USA
| | - H. Lu
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332, USA. E-mail: ; Fax: +1 404 894 4200; Tel: +1 404 804 8473
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Hanein D, Volkmann N. Conformational Equilibrium of Human Platelet Integrin Investigated by Three-Dimensional Electron Cryo-Microscopy. Subcell Biochem 2018; 87:353-363. [PMID: 29464566 DOI: 10.1007/978-981-10-7757-9_12] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Integrins are bidirectional transmembrane receptors that play central roles in hemostasis and arterial thrombosis. They have been subject to structural studies for many years, in particular using X-ray crystallography, nuclear magnetic resonance spectroscopy, and two-dimensional negative stain electron microscopy. Despite considerable progress, a full consensus on the molecular mechanism of integrin activation is still lacking. Three-dimensional reconstructions of full-length human platelet integrin αIIbβ3 in lipid-bilayer nanodiscs obtained by electron cryo-microscopy and single-particle reconstruction have shed new light on the activation process. These studies show that integrin αIIbβ3 exists in a continuous conformational equilibrium ranging from a compact nodular conformation similar to that obtained in crystal structures to a fully extended state with the leg domains separated. This equilibrium is shifted towards the extended conformation when extracellular ligands, cytosolic activators and lipid-bilayer nanodiscs are added. Addition of cytosolic activators and extracellular ligands in the absense of nanodiscs produces significantly less dramatic shifts, emphasizing the importance of the membrane bilayer in the activation process.
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Affiliation(s)
- Dorit Hanein
- Bioinformatics and Structural Biology Program, Sanford-Burnham-Prebys Medical Discovery Institute, San Diego, CA, USA
| | - Niels Volkmann
- Bioinformatics and Structural Biology Program, Sanford-Burnham-Prebys Medical Discovery Institute, San Diego, CA, USA.
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18
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Poulter NS, Pollitt AY, Owen DM, Gardiner EE, Andrews RK, Shimizu H, Ishikawa D, Bihan D, Farndale RW, Moroi M, Watson SP, Jung SM. Clustering of glycoprotein VI (GPVI) dimers upon adhesion to collagen as a mechanism to regulate GPVI signaling in platelets. J Thromb Haemost 2017; 15:549-564. [PMID: 28058806 PMCID: PMC5347898 DOI: 10.1111/jth.13613] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Indexed: 01/01/2023]
Abstract
Essentials Dimeric high-affinity collagen receptor glycoprotein VI (GPVI) is present on resting platelets. Spatio-temporal organization of platelet GPVI-dimers was evaluated using advanced microscopy. Upon platelet adhesion to collagenous substrates, GPVI-dimers coalesce to form clusters. Clustering of GPVI-dimers may increase avidity and facilitate platelet activation SUMMARY: Background Platelet glycoprotein VI (GPVI) binding to subendothelial collagen exposed upon blood vessel injury initiates thrombus formation. Dimeric GPVI has high affinity for collagen, and occurs constitutively on resting platelets. Objective To identify higher-order oligomerization (clustering) of pre-existing GPVI dimers upon interaction with collagen as a mechanism to initiate GPVI-mediated signaling. Methods GPVI was located by use of fluorophore-conjugated GPVI dimer-specific Fab (antigen-binding fragment). The tested substrates include Horm collagen I fibers, soluble collagen III, GPVI-specific collagen peptides, and fibrinogen. GPVI dimer clusters on the platelet surface interacting with these substrates were visualized with complementary imaging techniques: total internal reflection fluorescence microscopy to monitor real-time interactions, and direct stochastic optical reconstruction microscopy (dSTORM), providing relative quantification of GPVI cluster size and density. Confocal microscopy was used to locate GPVI dimer clusters, glycoprotein Ib, integrin α2 β1 , and phosphotyrosine. Results Upon platelet adhesion to all collagenous substrates, GPVI dimers coalesced to form clusters; notably clusters formed along the fibers of Horm collagen. dSTORM revealed that GPVI density within clusters depended on the substrate, collagen III being the most effective. Clusters on fibrinogen-adhered platelets were much smaller and more numerous; whether these are pre-existing oligomers of GPVI dimers or fibrinogen-induced is not clear. Some GPVI dimer clusters colocalized with areas of phosphotyrosine, indicative of signaling activity. Integrin α2 β1 was localized to collagen fibers close to GPVI dimer clusters. GPVI clustering depends on a dynamic actin cytoskeleton. Conclusions Platelet adhesion to collagen induces GPVI dimer clustering. GPVI clustering increases both avidity for collagen and the proximity of GPVI-associated signaling molecules, which may be crucial for the initiation and persistence of signaling.
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Affiliation(s)
- N. S. Poulter
- Institute of Cardiovascular SciencesCollege of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
- Centre for Membrane Proteins and Receptors (COMPARE)College of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
| | - A. Y. Pollitt
- Institute of Cardiovascular SciencesCollege of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
- Present address: Institute for Cardiovascular and Metabolic ResearchSchool of Biological SciencesUniversity of ReadingReadingRG6 6ASUK
| | - D. M. Owen
- Department of Physics and Randall Division of Cell and Molecular BiophysicsKing's College LondonLondonUK
| | - E. E. Gardiner
- Department of Cancer Biology and TherapeuticsJohn Curtin School of Medical ResearchAustralian National UniversityCanberraACTAustralia
| | - R. K. Andrews
- Australian Centre for Blood DiseasesMonash UniversityMelbourneVictoriaAustralia
| | - H. Shimizu
- Research DepartmentChemo‐Sero‐Therapeutic Research InstituteKaketsukenKumamotoJapan
| | - D. Ishikawa
- Research DepartmentChemo‐Sero‐Therapeutic Research InstituteKaketsukenKumamotoJapan
| | - D. Bihan
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - R. W. Farndale
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - M. Moroi
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - S. P. Watson
- Institute of Cardiovascular SciencesCollege of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
- Centre for Membrane Proteins and Receptors (COMPARE)College of Medical and Dental SciencesUniversity of BirminghamBirminghamUK
| | - S. M. Jung
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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19
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Rognoni E, Ruppert R, Fässler R. The kindlin family: functions, signaling properties and implications for human disease. J Cell Sci 2016; 129:17-27. [PMID: 26729028 DOI: 10.1242/jcs.161190] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The kindlin (or fermitin) family of proteins comprises three members (kindlin-1,-2 and -3) of evolutionarily conserved focal adhesion (FA) proteins, whose best-known task is to increase integrin affinity for a ligand (also referred as integrin activation) through binding of β-integrin tails. The consequence of kindlin-mediated integrin activation and integrin-ligand binding is cell adhesion, spreading and migration, assembly of the extracellular matrix (ECM), cell survival, proliferation and differentiation. Another hallmark of kindlins is their involvement in disease. Mutations in the KINDLIN-1 (also known as FERMT1) gene cause Kindler syndrome (KS)--in which mainly skin and intestine are affected, whereas mutations in the KINDLIN-3 (also known as FERMT3) gene cause leukocyte adhesion deficiency type III (LAD III), which is characterized by impaired extravasation of blood effector cells and severe, spontaneous bleedings. Also, aberrant expression of kindlins in various forms of cancer and in tissue fibrosis has been reported. Although the malfunctioning of integrins represent a major cause leading to kindlin-associated diseases, increasing evidence also point to integrin-independent functions of kindlins that play an important role in the pathogenesis of certain disease aspects. Furthermore, isoform-specific kindlin functions have been discovered, explaining, for example, why loss of kindlins differentially affects tissue stem cell homeostasis or tumor development. This Commentary focuses on new and isoform-specific kindlin functions in different tissues and discusses their potential role in disease development and progression.
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Affiliation(s)
- Emanuel Rognoni
- Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Raphael Ruppert
- Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Reinhard Fässler
- Max Planck Institute of Biochemistry, Martinsried 82152, Germany
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20
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Li Z, Lee H, Zhu C. Molecular mechanisms of mechanotransduction in integrin-mediated cell-matrix adhesion. Exp Cell Res 2016; 349:85-94. [PMID: 27720950 DOI: 10.1016/j.yexcr.2016.10.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/30/2016] [Accepted: 10/03/2016] [Indexed: 01/09/2023]
Abstract
Cell-matrix adhesion complexes are multi-protein structures linking the extracellular matrix (ECM) to the cytoskeleton. They are essential to both cell motility and function by bidirectionally sensing and transmitting mechanical and biochemical stimulations. Several types of cell-matrix adhesions have been identified and they share many key molecular components, such as integrins and actin-integrin linkers. Mechanochemical coupling between ECM molecules and the actin cytoskeleton has been observed from the single cell to the single molecule level and from immune cells to neuronal cells. However, the mechanisms underlying force regulation of integrin-mediated mechanotransduction still need to be elucidated. In this review article, we focus on integrin-mediated adhesions and discuss force regulation of cell-matrix adhesions and key adaptor molecules, three different force-dependent behaviors, and molecular mechanisms for mechanochemical coupling in force regulation.
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Affiliation(s)
- Zhenhai Li
- Molecular Modeling and Simulation Group, National Institutes for Quantum and Radiological Science and Technology, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan
| | - Hyunjung Lee
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Cheng Zhu
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; George W Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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21
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Liu J, Quan J, Feng J, Zhang Q, Xu Y, Liu J, Huang W, Liu J, Tian L. High glucose regulates LN expression in human liver sinusoidal endothelial cells through ROS/integrin αvβ3 pathway. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 42:231-236. [PMID: 26896612 DOI: 10.1016/j.etap.2016.01.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 01/24/2016] [Accepted: 01/25/2016] [Indexed: 06/05/2023]
Abstract
Diabetes mellitus can cause a wide variety of vascular complications and is one of the major risk factors for Non Alcoholic Fatty Liver Disease (NAFLD). The present study was designed investigate the expression of laminin (LN) in human liver sinusoidal endothelial cells (HLSECs) induced by high glucose and the role of reactive oxygen species (ROS) and integrin αvβ3 in the regulation of LN expression. HLSECs were cultured and treated with media containing 25 mM glucose in the presence or absence of N-acetylcysteine (NAC) or clone LM609. The level of intracellular ROS of HLSECs was measured with 2',7' dichloro-fluorescein diacetate (DCFH-DA) probe. Expression of integrin αvβ3 was measured using RT-PCR and Western blot. Expression of LN was testified by immunofluorescence assay. Compared with that in control group, ROS level and the expression of integrin αvβ3 and LN increased in high glucose group. Compared with that in high glucose group, antioxidant NAC inhibited the expression of integrin αvβ3, NAC and the anti-body for blocking integrin αvβ3 (clone LM609) down-regulated the expression of LN. However, the above parameters did not differ between control and mannitol groups. High glucose up-regulates expression of LN in HLSECs through ROS/integrin αvβ3 pathway.
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Affiliation(s)
- Jing Liu
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China
| | - Jinxing Quan
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China
| | - Jing Feng
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China
| | - Qi Zhang
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China
| | - Yanjia Xu
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China
| | - Jia Liu
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China
| | - Wenhui Huang
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China
| | - Juxiang Liu
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China
| | - Limin Tian
- Department of Endocrinology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, China.
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22
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IPP Complex Reinforces Adhesion by Relaying Tension-Dependent Signals to Inhibit Integrin Turnover. Cell Rep 2016; 14:2668-82. [DOI: 10.1016/j.celrep.2016.02.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 01/05/2016] [Accepted: 02/08/2016] [Indexed: 12/19/2022] Open
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23
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Minagawa S, Lou J, Seed RI, Cormier A, Wu S, Cheng Y, Murray L, Tsui P, Connor J, Herbst R, Govaerts C, Barker T, Cambier S, Yanagisawa H, Goodsell A, Hashimoto M, Brand OJ, Cheng R, Ma R, McKnelly KJ, Wen W, Hill A, Jablons D, Wolters P, Kitamura H, Araya J, Barczak AJ, Erle DJ, Reichardt LF, Marks JD, Baron JL, Nishimura SL. Selective targeting of TGF-β activation to treat fibroinflammatory airway disease. Sci Transl Med 2015; 6:241ra79. [PMID: 24944194 DOI: 10.1126/scitranslmed.3008074] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Airway remodeling, caused by inflammation and fibrosis, is a major component of chronic obstructive pulmonary disease (COPD) and currently has no effective treatment. Transforming growth factor-β (TGF-β) has been widely implicated in the pathogenesis of airway remodeling in COPD. TGF-β is expressed in a latent form that requires activation. The integrin αvβ8 (encoded by the itgb8 gene) is a receptor for latent TGF-β and is essential for its activation. Expression of integrin αvβ8 is increased in airway fibroblasts in COPD and thus is an attractive therapeutic target for the treatment of airway remodeling in COPD. We demonstrate that an engineered optimized antibody to human αvβ8 (B5) inhibited TGF-β activation in transgenic mice expressing only human and not mouse ITGB8. The B5 engineered antibody blocked fibroinflammatory responses induced by tobacco smoke, cytokines, and allergens by inhibiting TGF-β activation. To clarify the mechanism of action of B5, we used hydrodynamic, mutational, and electron microscopic methods to demonstrate that αvβ8 predominantly adopts a constitutively active, extended-closed headpiece conformation. Epitope mapping and functional characterization of B5 revealed an allosteric mechanism of action due to locking-in of a low-affinity αvβ8 conformation. Collectively, these data demonstrate a new model for integrin function and present a strategy to selectively target the TGF-β pathway to treat fibroinflammatory airway diseases.
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Affiliation(s)
- Shunsuke Minagawa
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Jianlong Lou
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Robert I Seed
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Anthony Cormier
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Shenping Wu
- The Keck Advanced Microscopy Laboratory, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Yifan Cheng
- The Keck Advanced Microscopy Laboratory, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Lynne Murray
- Department of Respiratory, Inflammation and Autoimmunity, MedImmune, Gaithersburg, MD 20878, USA. Department of Respiratory, Inflammation and Autoimmunity, MedImmune, Cambridge CB21 6GH, UK
| | - Ping Tsui
- Department of Respiratory, Inflammation and Autoimmunity, MedImmune, Gaithersburg, MD 20878, USA
| | - Jane Connor
- Department of Respiratory, Inflammation and Autoimmunity, MedImmune, Gaithersburg, MD 20878, USA
| | - Ronald Herbst
- Department of Respiratory, Inflammation and Autoimmunity, MedImmune, Gaithersburg, MD 20878, USA
| | - Cedric Govaerts
- Department of Respiratory, Inflammation and Autoimmunity, MedImmune, Cambridge CB21 6GH, UK
| | - Tyren Barker
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Stephanie Cambier
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Haruhiko Yanagisawa
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Amanda Goodsell
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Mitsuo Hashimoto
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Oliver J Brand
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Ran Cheng
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Royce Ma
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Kate J McKnelly
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Weihua Wen
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Arthur Hill
- Department of Surgery, University of California, San Francisco, San Francisco, CA 94110, USA
| | - David Jablons
- Department of Surgery, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Paul Wolters
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Hideya Kitamura
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Jun Araya
- Department of Pulmonary Medicine, Jikei University, Tokyo 105 8461, Japan
| | - Andrea J Barczak
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - David J Erle
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Louis F Reichardt
- Genetics, Development, and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94110, USA
| | - James D Marks
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Jody L Baron
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94110, USA
| | - Stephen L Nishimura
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94110, USA.
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24
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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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25
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Li X, Liu Y, Haas TA. Peptides derived from central turn motifs within integrin αIIb and αV cytoplasmic tails inhibit integrin activation. Peptides 2014; 62:38-48. [PMID: 25290158 DOI: 10.1016/j.peptides.2014.07.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/07/2014] [Accepted: 07/07/2014] [Indexed: 11/16/2022]
Abstract
We previously found that peptides derived from the full length of integrin αIIb and αV cytoplasmic tails inhibited their parent integrin activation, respectively. Here we showed that the cell-permeable peptides corresponding to the conserved central turn motif within αIIb and αV cytoplasmic tails, myr-KRNRPPLEED (αIIb peptide) and myr-KRVRPPQEEQ (αV peptide), similarly inhibited both αIIb and αV integrin activation. Pre-treatment with αIIb or αV peptides inhibited Mn(2+)-activated αIIbβ3 binding to soluble fibrinogen as well as the binding of αIIbβ3-expressing Chinese Hamster Ovary cells to immobilized fibrinogen. Our turn peptides also inhibited adhesion of two breast cancer cell lines (MDA-MB-435 and MCF7) to αV ligand vitronectin. These results suggest that αIIb and αV peptides share a same mechanism in regulating integrin function. Using αIIb peptide as a model, we found that replacement of RPP with AAA significantly attenuated the inhibitory activity of αIIb peptide. Furthermore, we found that αIIb peptide specifically bound to β-tubulin in cells. Our work suggests that the central motif of α tails is an anchoring point for cytoskeletons during integrin activation and integrin-mediated cell adhesion, and its function depends on the turn structure at RPP. However, post-treatment of peptides derived from the full-length tail or from the turn motif did not reverse αIIb and αV integrin activation.
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Affiliation(s)
- Xinlei Li
- Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Yongqing Liu
- Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5
| | - Thomas A Haas
- Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E5.
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Ellis SJ, Lostchuck E, Goult BT, Bouaouina M, Fairchild MJ, López-Ceballos P, Calderwood DA, Tanentzapf G. The talin head domain reinforces integrin-mediated adhesion by promoting adhesion complex stability and clustering. PLoS Genet 2014; 10:e1004756. [PMID: 25393120 PMCID: PMC4230843 DOI: 10.1371/journal.pgen.1004756] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 09/15/2014] [Indexed: 11/18/2022] Open
Abstract
Talin serves an essential function during integrin-mediated adhesion in linking integrins to actin via the intracellular adhesion complex. In addition, the N-terminal head domain of talin regulates the affinity of integrins for their ECM-ligands, a process known as inside-out activation. We previously showed that in Drosophila, mutating the integrin binding site in the talin head domain resulted in weakened adhesion to the ECM. Intriguingly, subsequent studies showed that canonical inside-out activation of integrin might not take place in flies. Consistent with this, a mutation in talin that specifically blocks its ability to activate mammalian integrins does not significantly impinge on talin function during fly development. Here, we describe results suggesting that the talin head domain reinforces and stabilizes the integrin adhesion complex by promoting integrin clustering distinct from its ability to support inside-out activation. Specifically, we show that an allele of talin containing a mutation that disrupts intramolecular interactions within the talin head attenuates the assembly and reinforcement of the integrin adhesion complex. Importantly, we provide evidence that this mutation blocks integrin clustering in vivo. We propose that the talin head domain is essential for regulating integrin avidity in Drosophila and that this is crucial for integrin-mediated adhesion during animal development. Cells are the building blocks of our bodies. How do cells rearrange to form three-dimensional body plans and maintain specific tissue structures? Specialized adhesion molecules on the cell surface mediate attachment between cells and their surrounding environment to hold tissues together. Our work uses the developing fruit fly embryo to demonstrate how such connections are regulated during tissue growth. Since the genes and molecules involved in this process are highly similar between flies and humans, we can also apply our findings to our understanding of how human tissues form and are maintained. We observe that, in late developing muscles, clusters of cell adhesion molecules concentrate together to create stronger attachments between muscle cells and tendon cells. This strengthening mechanism allows the fruit fly to accommodate increasing amounts of force imposed by larger, more active muscles. We identify specific genetic mutations that disrupt these strengthening mechanisms and lead to severe developmental defects during fly development. Our results illustrate how subtle fine-tuning of the connections between cells and their surrounding environment is important to form and maintain normal tissue structure across the animal kingdom.
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Affiliation(s)
- Stephanie J. Ellis
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Emily Lostchuck
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Benjamin T. Goult
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
| | - Mohamed Bouaouina
- Department of Pharmacology, Yale University, New Haven, Connecticut, United States of America
- Carnegie Mellon University Qatar, Education City, Doha, Qatar
| | - Michael J. Fairchild
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - Pablo López-Ceballos
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
| | - David A. Calderwood
- Department of Pharmacology, Yale University, New Haven, Connecticut, United States of America
| | - Guy Tanentzapf
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada
- * E-mail:
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Bachir AI, Zareno J, Moissoglu K, Plow EF, Gratton E, Horwitz AR. Integrin-associated complexes form hierarchically with variable stoichiometry in nascent adhesions. Curr Biol 2014; 24:1845-53. [PMID: 25088556 DOI: 10.1016/j.cub.2014.07.011] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/03/2014] [Accepted: 07/04/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND A complex network of putative molecular interactions underlies the architecture and function of cell-matrix adhesions. Most of these interactions are implicated from coimmunoprecipitation studies using expressed components, but few have been demonstrated or characterized functionally in living cells. RESULTS We introduce fluorescence fluctuation methods to determine, at high spatial and temporal resolution, "when" and "where" molecular complexes form and their stoichiometry in nascent adhesions (NAs). We focus on integrin-associated molecules implicated in integrin activation and in the integrin-actin linkage in NAs and show that these molecules form integrin-containing complexes hierarchically within the adhesion itself. Integrin and kindlin reside in a molecular complex as soon as adhesions are visible; talin, although also present early, associates with the integrin-kindlin complex only after NAs have formed and in response to myosin II activity. Furthermore, talin and vinculin association precedes the formation of the integrin-talin complex. Finally, α-actinin enters NAs periodically and in clusters that transiently associate with integrins. The absolute number and stoichiometry of these molecules varies among the molecules studied and changes as adhesions mature. CONCLUSIONS These observations suggest a working model for NA assembly whereby transient α-actinin-integrin complexes help nucleate NAs within the lamellipodium. Subsequently, integrin complexes containing kindlin, but not talin, emerge. Once NAs have formed, myosin II activity promotes talin association with the integrin-kindlin complex in a stoichiometry consistent with each talin molecule linking two integrin-kindlin complexes.
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Affiliation(s)
- Alexia I Bachir
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA.
| | - Jessica Zareno
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Konstadinos Moissoglu
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Edward F Plow
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Enrico Gratton
- Laboratory of Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA
| | - Alan R Horwitz
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
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28
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Mierke CT. The fundamental role of mechanical properties in the progression of cancer disease and inflammation. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:076602. [PMID: 25006689 DOI: 10.1088/0034-4885/77/7/076602] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The role of mechanical properties in cancer disease and inflammation is still underinvestigated and even ignored in many oncological and immunological reviews. In particular, eight classical hallmarks of cancer have been proposed, but they still ignore the mechanics behind the processes that facilitate cancer progression. To define the malignant transformation of neoplasms and finally reveal the functional pathway that enables cancer cells to promote cancer progression, these classical hallmarks of cancer require the inclusion of specific mechanical properties of cancer cells and their microenvironment such as the extracellular matrix as well as embedded cells such as fibroblasts, macrophages or endothelial cells. Thus, this review will present current cancer research from a biophysical point of view and will therefore focus on novel physical aspects and biophysical methods to investigate the aggressiveness of cancer cells and the process of inflammation. As cancer or immune cells are embedded in a certain microenvironment such as the extracellular matrix, the mechanical properties of this microenvironment cannot be neglected, and alterations of the microenvironment may have an impact on the mechanical properties of the cancer or immune cells. Here, it is highlighted how biophysical approaches, both experimental and theoretical, have an impact on the classical hallmarks of cancer and inflammation. It is even pointed out how these biophysical approaches contribute to the understanding of the regulation of cancer disease and inflammatory responses after tissue injury through physical microenvironmental property sensing mechanisms. The recognized physical signals are transduced into biochemical signaling events that guide cellular responses, such as malignant tumor progression, after the transition of cancer cells from an epithelial to a mesenchymal phenotype or an inflammatory response due to tissue injury. Moreover, cell adaptation to mechanical alterations, in particular the understanding of mechano-coupling and mechano-regulating functions in cell invasion, appears as an important step in cancer progression and inflammatory response to injuries. This may lead to novel insights into cancer disease and inflammatory diseases and will overcome classical views on cancer and inflammation. In addition, this review will discuss how the physics of cancer and inflammation can help to reveal whether cancer cells will invade connective tissue and metastasize or how leukocytes extravasate and migrate through the tissue. In this review, the physical concepts of cancer progression, including the tissue basement membrane a cancer cell is crossing, its invasion and transendothelial migration as well as the basic physical concepts of inflammatory processes and the cellular responses to the mechanical stress of the microenvironment such as external forces and matrix stiffness, are presented and discussed. In conclusion, this review will finally show how physical measurements can improve classical approaches that investigate cancer and inflammatory diseases, and how these physical insights can be integrated into classical tumor biological approaches.
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Affiliation(s)
- Claudia Tanja Mierke
- Faculty of Physics and Earth Science, Institute of Experimental Physics I, Biological Physics Division, University of Leipzig, Linnéstr. 5, 04103 Leipzig, Germany
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29
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Pinon P, Pärssinen J, Vazquez P, Bachmann M, Rahikainen R, Jacquier MC, Azizi L, Määttä JA, Bastmeyer M, Hytönen VP, Wehrle-Haller B. Talin-bound NPLY motif recruits integrin-signaling adapters to regulate cell spreading and mechanosensing. ACTA ACUST UNITED AC 2014; 205:265-81. [PMID: 24778313 PMCID: PMC4003243 DOI: 10.1083/jcb.201308136] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
β3 integrin residue Y747 is required for cell spreading and paxillin adapter recruitment to substrate-bound integrins in response to substrate stiffness. Integrin-dependent cell adhesion and spreading are critical for morphogenesis, tissue regeneration, and immune defense but also tumor growth. However, the mechanisms that induce integrin-mediated cell spreading and provide mechanosensing on different extracellular matrix conditions are not fully understood. By expressing β3-GFP-integrins with enhanced talin-binding affinity, we experimentally uncoupled integrin activation, clustering, and substrate binding from its function in cell spreading. Mutational analysis revealed Tyr747, located in the first cytoplasmic NPLY747 motif, to induce spreading and paxillin adapter recruitment to substrate- and talin-bound integrins. In addition, integrin-mediated spreading, but not focal adhesion localization, was affected by mutating adjacent sequence motifs known to be involved in kindlin binding. On soft, spreading-repellent fibronectin substrates, high-affinity talin-binding integrins formed adhesions, but normal spreading was only possible with integrins competent to recruit the signaling adapter protein paxillin. This proposes that integrin-dependent cell–matrix adhesion and cell spreading are independently controlled, offering new therapeutic strategies to modify cell behavior in normal and pathological conditions.
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Affiliation(s)
- Perrine Pinon
- Department of Cell Physiology and Metabolism, University Medical Center, University of Geneva, 1211 Geneva, Switzerland
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30
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Anderson LR, Owens TW, Naylor MJ. Structural and mechanical functions of integrins. Biophys Rev 2014; 6:203-213. [PMID: 28510180 PMCID: PMC5418412 DOI: 10.1007/s12551-013-0124-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/28/2013] [Indexed: 01/09/2023] Open
Abstract
Integrins are ubiquitously expressed cell surface receptors that play a critical role in regulating the interaction between a cell and its microenvironment to control cell fate. These molecules are regulated either via their expression on the cell surface or through a unique bidirectional signalling mechanism. However, integrins are just the tip of the adhesome iceberg, initiating the assembly of a large range of adaptor and signalling proteins that mediate the structural and signalling functions of integrin. In this review, we summarise the structure of integrins and mechanisms by which integrin activation is controlled. The different adhesion structures formed by integrins are discussed, as well as the mechanical and structural roles integrins play during cell migration. As the function of integrin signalling can be quite varied based on cell type and context, an in depth understanding of these processes will aid our understanding of aberrant adhesion and migration, which is often associated with human pathologies such as cancer.
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Affiliation(s)
- Luke R Anderson
- Discipline of Physiology & Bosch Institute, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Thomas W Owens
- Discipline of Physiology & Bosch Institute, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Matthew J Naylor
- Discipline of Physiology & Bosch Institute, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia.
- The University of Sydney, Room E212, Anderson Stuart Building (F13), Sydney, NSW, 2006, Australia.
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31
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Terada C, Mori J, Okazaki H, Satake M, Tadokoro K. Effects of riboflavin and ultraviolet light treatment on platelet thrombus formation on collagen via integrin αIIbβ3 activation. Transfusion 2014; 54:1808-16. [DOI: 10.1111/trf.12566] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 11/29/2013] [Accepted: 12/02/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Chikahiro Terada
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
| | - Junpei Mori
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
| | - Hitoshi Okazaki
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
| | - Masahiro Satake
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
| | - Kenji Tadokoro
- Department of Research and Development; Central Blood Institute; Japanese Red Cross Society; Tokyo Japan
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32
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Hytönen VP, Wehrle-Haller B. Protein conformation as a regulator of cell–matrix adhesion. Phys Chem Chem Phys 2014; 16:6342-57. [DOI: 10.1039/c3cp54884h] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conformational changes within proteins play key roles in the regulation of cell–matrix adhesion. We discuss the mechanisms involved in conformational regulation, including mechanical signals, posttranslational modifications and intrinsically disordered proteins.
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Affiliation(s)
- Vesa P. Hytönen
- University of Tampere
- Institute of Biomedical Technology and BioMediTech
- 33520 Tampere, Finland
- Fimlab Laboratories
- 33014 Tampere, Finland
| | - Bernhard Wehrle-Haller
- University of Geneva
- Department of Cell Physiology and Metabolism
- Centre Médical Universitaire
- 1211 Geneva 4, Switzerland
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33
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Wehrle-Haller B, Bastmeyer M. Intracellular signaling and perception of neuronal scaffold through integrins and their adapter proteins. PROGRESS IN BRAIN RESEARCH 2014; 214:443-60. [DOI: 10.1016/b978-0-444-63486-3.00018-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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34
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Ye F, Petrich BG, Anekal P, Lefort CT, Kasirer-Friede A, Shattil SJ, Ruppert R, Moser M, Fässler R, Ginsberg MH. The mechanism of kindlin-mediated activation of integrin αIIbβ3. Curr Biol 2013; 23:2288-2295. [PMID: 24210614 DOI: 10.1016/j.cub.2013.09.050] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/30/2013] [Accepted: 09/24/2013] [Indexed: 01/11/2023]
Abstract
Increased ligand binding to cellular integrins ("activation") plays important roles in processes such as development, cell migration, extracellular matrix assembly, tumor metastasis, hemostasis, and thrombosis. Integrin activation encompasses both increased integrin monomer affinity and increased receptor clustering and depends on integrin-talin interactions. Loss of kindlins results in reduced activation of integrins. Kindlins might promote talin binding to integrins through a cooperative mechanism; however, kindlins do not increase talin association with integrins. Here, we report that, unlike talin head domain (THD), kindlin-3 has little effect on the affinity of purified monomeric αIIbβ3, and it does not enhance activation by THD. Furthermore, studies with ligands of varying valency show that kindlins primarily increase cellular αIIbβ3 avidity rather than monomer affinity. In platelets or nucleated cells, loss of kindlins markedly reduces αIIbβ3 binding to multivalent but not monovalent ligands. Finally, silencing of kindlins reduces the clustering of ligand-occupied αIIbβ3 as revealed by total internal reflection fluorescence and electron microscopy. Thus, in contrast to talins, kindlins have little primary effect on integrin αIIbβ3 affinity for monovalent ligands and increase multivalent ligand binding by promoting the clustering of talin-activated integrins.
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Affiliation(s)
- Feng Ye
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Brian G Petrich
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Praju Anekal
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Craig T Lefort
- La Jolla Institute for Allergy & Immunology, La Jolla, CA 92093, USA
| | - Ana Kasirer-Friede
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sanford J Shattil
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Raphael Ruppert
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Markus Moser
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mark H Ginsberg
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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35
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Calderwood DA, Campbell ID, Critchley DR. Talins and kindlins: partners in integrin-mediated adhesion. Nat Rev Mol Cell Biol 2013; 14:503-17. [PMID: 23860236 PMCID: PMC4116690 DOI: 10.1038/nrm3624] [Citation(s) in RCA: 420] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Integrin receptors provide a dynamic, tightly-regulated link between the extracellular matrix (or cellular counter-receptors) and intracellular cytoskeletal and signalling networks, enabling cells to sense and respond to their chemical and physical environment. Talins and kindlins, two families of FERM-domain proteins, bind the cytoplasmic tail of integrins, recruit cytoskeletal and signalling proteins involved in mechanotransduction and synergize to activate integrin binding to extracellular ligands. New data reveal the domain structure of full-length talin, provide insights into talin-mediated integrin activation and show that RIAM recruits talin to the plasma membrane, whereas vinculin stabilizes talin in cell-matrix junctions. How kindlins act is less well-defined, but disease-causing mutations show that kindlins are also essential for integrin activation, adhesion, cell spreading and signalling.
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Affiliation(s)
- David A Calderwood
- Departments of Pharmacology and of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Iain D Campbell
- Department of Biochemistry, University of Oxford, S. Parks Rd., Oxford, OX1 3QU, UK
| | - David R Critchley
- Department of Biochemistry, University of Leicester, Leicester LE1 7RH
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36
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Das M, Ithychanda S, Qin J, Plow EF. Mechanisms of talin-dependent integrin signaling and crosstalk. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:579-88. [PMID: 23891718 DOI: 10.1016/j.bbamem.2013.07.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 07/03/2013] [Accepted: 07/15/2013] [Indexed: 01/01/2023]
Abstract
Cells undergo dynamic remodeling of the cytoskeleton during adhesion and migration on various extracellular matrix (ECM) substrates in response to physiological and pathological cues. The major mediators of such cellular responses are the heterodimeric adhesion receptors, the integrins. Extracellular or intracellular signals emanating from different signaling cascades cause inside-out signaling of integrins via talin, a cystokeletal protein that links integrins to the actin cytoskeleton. Various integrin subfamilies communicate with each other and growth factor receptors under diverse cellular contexts to facilitate or inhibit various integrin-mediated functions. Since talin is an essential mediator of integrin activation, much of the integrin crosstalk would therefore be influenced by talin. However, despite the existence of an extensive body of knowledge on the role of talin in integrin activation and as a stabilizer of ECM-actin linkage, information on its role in regulating inter-integrin communication is limited. This review will focus on the structure of talin, its regulation of integrin activation and discuss its potential role in integrin crosstalk. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Mitali Das
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Lerner Research Institute, Cleveland Clinic
| | - Sujay Ithychanda
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Lerner Research Institute, Cleveland Clinic
| | - Jun Qin
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Lerner Research Institute, Cleveland Clinic
| | - Edward F Plow
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Lerner Research Institute, Cleveland Clinic
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37
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Assembly and disassembly of cell matrix adhesions. Curr Opin Cell Biol 2012; 24:569-81. [DOI: 10.1016/j.ceb.2012.06.010] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 06/12/2012] [Accepted: 06/28/2012] [Indexed: 11/22/2022]
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38
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Arora N, Mainali D, Smith EA. Unraveling the role of membrane proteins Notch, Pvr, and EGFR in altering integrin diffusion and clustering. Anal Bioanal Chem 2012; 404:2339-48. [DOI: 10.1007/s00216-012-6362-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 08/07/2012] [Accepted: 08/14/2012] [Indexed: 02/07/2023]
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39
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Coyer SR, Singh A, Dumbauld DW, Calderwood DA, Craig SW, Delamarche E, García AJ. Nanopatterning reveals an ECM area threshold for focal adhesion assembly and force transmission that is regulated by integrin activation and cytoskeleton tension. J Cell Sci 2012; 125:5110-23. [PMID: 22899715 DOI: 10.1242/jcs.108035] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Integrin-based focal adhesions (FA) transmit anchorage and traction forces between the cell and the extracellular matrix (ECM). To gain further insight into the physical parameters of the ECM that control FA assembly and force transduction in non-migrating cells, we used fibronectin (FN) nanopatterning within a cell adhesion-resistant background to establish the threshold area of ECM ligand required for stable FA assembly and force transduction. Integrin-FN clustering and adhesive force were strongly modulated by the geometry of the nanoscale adhesive area. Individual nanoisland area, not the number of nanoislands or total adhesive area, controlled integrin-FN clustering and adhesion strength. Importantly, below an area threshold (0.11 µm(2)), very few integrin-FN clusters and negligible adhesive forces were generated. We then asked whether this adhesive area threshold could be modulated by intracellular pathways known to influence either adhesive force, cytoskeletal tension, or the structural link between the two. Expression of talin- or vinculin-head domains that increase integrin activation or clustering overcame this nanolimit for stable integrin-FN clustering and increased adhesive force. Inhibition of myosin contractility in cells expressing a vinculin mutant that enhances cytoskeleton-integrin coupling also restored integrin-FN clustering below the nanolimit. We conclude that the minimum area of integrin-FN clusters required for stable assembly of nanoscale FA and adhesive force transduction is not a constant; rather it has a dynamic threshold that results from an equilibrium between pathways controlling adhesive force, cytoskeletal tension, and the structural linkage that transmits these forces, allowing the balance to be tipped by factors that regulate these mechanical parameters.
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Affiliation(s)
- Sean R Coyer
- Woodruff School of Mechanical Engineering and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30330, USA
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40
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Boettiger D. Mechanical control of integrin-mediated adhesion and signaling. Curr Opin Cell Biol 2012; 24:592-9. [PMID: 22857903 DOI: 10.1016/j.ceb.2012.07.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 06/14/2012] [Accepted: 07/11/2012] [Indexed: 01/13/2023]
Abstract
Integrin-mediated adhesion is controlled by the number of bonds between cell surface integrins and substrate-bound ligands. Integrin-ligand affinity is modulated by chemical allostery, mechanical allostery and integrin clustering. This review analyzes how each of these factors changes through the phases of cell attachment, adhesion strengthening, and clustering. The analysis predicts a dominant role of mechanical factors in both adhesive regulation and integrin signaling for adherent cells. New approaches and experimental analyses will be required to substantiate this hypothesis.
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Affiliation(s)
- David Boettiger
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Integrin inside-out signaling and the immunological synapse. Curr Opin Cell Biol 2011; 24:107-15. [PMID: 22129583 DOI: 10.1016/j.ceb.2011.10.004] [Citation(s) in RCA: 291] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 10/19/2011] [Indexed: 11/22/2022]
Abstract
Integrins dynamically equilibrate between three conformational states on cell surfaces. A bent conformation has a closed headpiece. Two extended conformations contain either a closed or an open headpiece. Headpiece opening involves hybrid domain swing-out and a 70 Å separation at the integrin knees, which is conveyed by allostery from the hybrid-proximal end of the βI domain to a 3 Å rearrangement of the ligand-binding site at the opposite end of the βI domain. Both bent-closed and extended-closed integrins have low affinity, whereas extended-open integrin affinity is 10(3) to 10(4) higher. Integrin-mediated adhesion requires the extended-open conformation, which in physiological contexts is stabilized by post-ligand binding events. Integrins thus discriminate between substrate-bound and soluble ligands. Analysis of LFA-1-ICAM-1 interactions in the immunological synapse suggests that bond lifetimes are on the order of seconds, which is consistent with high affinity interactions subjected to cytoskeletal forces that increase the dissociation rate. LFA-1 βI domain antagonists abrogate function in the immunological synapse, further supporting a critical role for high affinity LFA-1.
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Das M, Ithychanda SS, Qin J, Plow EF. Migfilin and filamin as regulators of integrin activation in endothelial cells and neutrophils. PLoS One 2011; 6:e26355. [PMID: 22043318 PMCID: PMC3197140 DOI: 10.1371/journal.pone.0026355] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 09/25/2011] [Indexed: 12/18/2022] Open
Abstract
Cell adhesion and migration depend on engagement of extracellular matrix ligands by integrins. Integrin activation is dynamically regulated by interactions of various cytoplasmic proteins, such as filamin and integrin activators, talin and kindlin, with the cytoplasmic tail of the integrin β subunit. Although filamin has been suggested to be an inhibitor of integrin activation, direct functional evidence for the inhibitory role of filamin is limited. Migfilin, a filamin-binding protein enriched at cell-cell and cell-extracellular matrix contact sites, can displace filamin from β1 and β3 integrins and promote integrin activation. However, its role in activation and functions of different β integrins in human vascular cells is unknown. In this study, using flow cytometry, we demonstrate that filamin inhibits β1 and αIIbβ3 integrin activation, and migfilin can overcome its inhibitory effect. Migfilin protein is widely expressed in different adherent and circulating blood cells and can regulate integrin activation in naturally-occurring vascular cells, endothelial cells and neutrophils. Migfilin can activate β1, β2 and β3 integrins and promote integrin mediated responses while migfilin depletion impairs the spreading and migration of endothelial cells. Thus, filamin can act broadly as an inhibitor and migfilin is a promoter of integrin activation.
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Affiliation(s)
- Mitali Das
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Sujay Subbayya Ithychanda
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Jun Qin
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Edward F. Plow
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- * E-mail:
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Hyduk SJ, Rullo J, Cano AP, Xiao H, Chen M, Moser M, Cybulsky MI. Talin-1 and kindlin-3 regulate alpha4beta1 integrin-mediated adhesion stabilization, but not G protein-coupled receptor-induced affinity upregulation. THE JOURNAL OF IMMUNOLOGY 2011; 187:4360-8. [PMID: 21911599 DOI: 10.4049/jimmunol.1003725] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chemokine/chemoattractant G protein-coupled receptors trigger an inside-out signaling network that rapidly activates integrins, a key step in inflammatory leukocyte recruitment. Integrins mediate leukocyte arrest and adhesion to endothelium through multivalent binding, and they transmit outside-in signals to stabilize adhesion and coordinate cell spreading and migration. In the present study, we used RNA interference in the U937 monocytic cell line to investigate the role of talin-1, kindlin-3, and α-actinin-1 in the fMLF- and SDF-1α-induced upregulation of α(4)β(1) integrin affinity and consequent adhesive events. Affinity upregulation of α(4)β(1) integrin was not impaired by small interfering RNA knockdown of talin-1, kindlin-3, or α-actinin-1. Only kindlin-3 knockdown increased flow-induced detachment from VCAM-1-coated surfaces in response to fluid flow, whereas knockdown of either talin-1 or kindlin-3 increased detachment from ICAM-1-coated surfaces. Biochemical analyses revealed that α(4)β(1) expression was highly enriched in U937 cell microridges and murine lymphocyte microvilli. Kindlin-3 was present throughout the cell, whereas talin-1 was largely excluded from microridges/microvilli. The subcellular colocalization of α(4)β(1) and kindlin-3 in microridges may explain why kindlin-3 rapidly associates with α(4)β(1) after G protein-coupled receptor signaling and contributes to adhesion strengthening. Talin-1 contributed to α(4)β(1)-dependent chemotaxis, suggesting that it participates in a later stage of the leukocyte adhesion cascade when the leukocyte cytoskeleton undergoes dramatic rearrangement.
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Affiliation(s)
- Sharon J Hyduk
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5G 1L7, Canada.
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Kendall T, Mukai L, Jannuzi AL, Bunch TA. Identification of integrin beta subunit mutations that alter affinity for extracellular matrix ligand. J Biol Chem 2011; 286:30981-30993. [PMID: 21757698 DOI: 10.1074/jbc.m111.254797] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We examined over 50 mutations in the Drosophila βPS integrin subunit that alter integrin function in situ for their ability to bind a soluble monovalent ligand, TWOW-1. Surprisingly, very few of the mutations, which were selected for conditional lethality in the fly, reduce the ligand binding ability of the integrin. The most prevalent class of mutations activates the integrin heterodimer. These findings emphasize the importance of integrin affinity regulation and point out how molecular interactions throughout the integrin molecule are important in keeping the integrin in a low affinity state. Mutations strongly support the controversial deadbolt hypothesis, where the CD loop in the β tail domain acts to restrain the I domain in the inactive, bent conformation. Site-directed mutations in the cytoplasmic domains of βPS and αPS2C reveal different effects on ligand binding from those observed for αIIbβ3 integrins and identify for the first time a cytoplasmic cysteine residue, conserved in three human integrins, as being important in affinity regulation. In the fly, we find that genetic interactions of the βPS mutations with reduction in talin function are consistent with the integrin affinity differences measured in cells. Additionally, these genetic interactions report on increased and decreased integrin functions that do not result in affinity changes in the PS2C integrin measured in cultured cells.
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Affiliation(s)
- Timmy Kendall
- Department of Molecular and Cellular Biology, Arizona Cancer Center, Tucson, Arizona 85724
| | - Leona Mukai
- Department of Molecular and Cellular Biology, Arizona Cancer Center, Tucson, Arizona 85724
| | - Alison L Jannuzi
- Department of Molecular and Cellular Biology, Arizona Cancer Center, Tucson, Arizona 85724
| | - Thomas A Bunch
- Department of Molecular and Cellular Biology, Arizona Cancer Center, Tucson, Arizona 85724.
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Pinon P, Wehrle-Haller B. Integrins: versatile receptors controlling melanocyte adhesion, migration and proliferation. Pigment Cell Melanoma Res 2010; 24:282-94. [PMID: 21087420 DOI: 10.1111/j.1755-148x.2010.00806.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
From the onset of melanocyte specification from the neural crest, throughout their migration during embryogenesis and until they reside in their niche in the basal keratinocyte layer, melanocytes interact in dynamic ways with the extracellular environment of the growing embryo. To recognize and to adhere to their environment, melanocytes depend on heterodimeric cell surface receptors of the family of integrins. In addition to the control of adhesive interactions between melanocytes and the extracellular matrix scaffold secreted by fibroblasts and keratinocytes, the integrin receptors allow cells also to sense the mechanical condition of the extracellular environment, responding by intracellular signaling, triggering cell survival, proliferation or migration events. In this review, we summarize the recently emerged concepts that explain integrin-dependent adhesion and how this adhesion system interfaces with integrin-dependent signaling events. The gained information will help to understand melanocyte behavior in pathological situations such as melanoma growth and metastasis formation.
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Affiliation(s)
- Perrine Pinon
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, Medical School, Geneva, Switzerland
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46
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Recent advances in the understanding of the molecular mechanisms regulating platelet integrin αIIbβ3 activation. Protein Cell 2010; 1:627-37. [PMID: 21203935 DOI: 10.1007/s13238-010-0089-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2010] [Accepted: 06/24/2010] [Indexed: 12/26/2022] Open
Abstract
Integrins are allosteric cell adhesion receptors that cycle from a low to a high affinity ligand binding state, a complex process of receptor activation that is of particular importance in blood cells such as platelets or leukocytes. Here we highlight recent progress in the understanding of the molecular pathways that regulate integrin activation in platelets and leukocytes, with a special focus on the structural changes in platelet integrin αIIbβ3 brought about by key intracellular proteins, namely talin and kindlins, that are of crucial importance in the regulation of integrin function. Evidence that the small GTPase Rap1 and its guanine exchange factor CalDAG-GEF1, together with RIAM, a Rap1GTP adaptor protein, promote the interaction of talin with the integrin β subunit, has greatly contributed to fill the gap in our understanding of the signaling pathway from G-coupled agonist receptors and their phospholipase C-dependant second messengers, to integrin activation. Studies of patients with the rare blood cell disorder LAD-III have contributed to the identification of kindlins as new co-regulators of the talin-dependent integrin activation process in platelets and leukocytes, underlining the relevance for the in-depth investigation of patients with rare genetic blood cell disorders.
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Askari JA, Tynan CJ, Webb SED, Martin-Fernandez ML, Ballestrem C, Humphries MJ. Focal adhesions are sites of integrin extension. ACTA ACUST UNITED AC 2010; 188:891-903. [PMID: 20231384 PMCID: PMC2845069 DOI: 10.1083/jcb.200907174] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
FRET experiments model integrin conformation changes in adherent cells. Integrins undergo global conformational changes that specify their activation state. Current models portray the inactive receptor in a bent conformation that upon activation converts to a fully extended form in which the integrin subunit leg regions are separated to enable ligand binding and subsequent signaling. To test the applicability of this model in adherent cells, we used a fluorescent resonance energy transfer (FRET)–based approach, in combination with engineered integrin mutants and monoclonal antibody reporters, to image integrin α5β1 conformation. We find that restricting leg separation causes the integrin to adopt a bent conformation that is unable to respond to agonists and mediate cell spreading. By measuring FRET between labeled α5β1 and the cell membrane, we find extended receptors are enriched in focal adhesions compared with adjacent regions of the plasma membrane. These results demonstrate definitely that major quaternary rearrangements of β1-integrin subunits occur in adherent cells and that conversion from a bent to extended form takes place at focal adhesions.
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Affiliation(s)
- Janet A Askari
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, England, UK
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