1
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Joshi O, Skóra T, Yarema A, Rabbitt RD, Bidone TC. Contributions of the individual domains of α IIbβ 3 integrin to its extension: Insights from multiscale modeling. Cytoskeleton (Hoboken) 2024; 81:393-408. [PMID: 38682753 PMCID: PMC11333186 DOI: 10.1002/cm.21865] [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: 11/14/2023] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 05/01/2024]
Abstract
The platelet integrin αIIbβ3 undergoes long-range conformational transitions between bent and extended conformations to regulate platelet aggregation during hemostasis and thrombosis. However, how exactly αIIbβ3 transitions between conformations remains largely elusive. Here, we studied how transitions across bent and extended-closed conformations of αIIbβ3 integrin are regulated by effective interactions between its functional domains. We first carried out μs-long equilibrium molecular dynamics (MD) simulations of full-length αIIbβ3 integrins in bent and intermediate conformations, the latter characterized by an extended headpiece and closed legs. Then, we built heterogeneous elastic network models, perturbed inter-domain interactions, and evaluated their relative contributions to the energy barriers between conformations. Results showed that integrin extension emerges from: (i) changes in interfaces between functional domains; (ii) allosteric coupling of the head and upper leg domains with flexible lower leg domains. Collectively, these results provide new insights into integrin conformational activation based on short- and long-range interactions between its functional domains and highlight the importance of the lower legs in the regulation of integrin allostery.
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Affiliation(s)
- Onkar Joshi
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah, USA
| | - Tomasz Skóra
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah, USA
| | - Anna Yarema
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Richard D Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Tamara C Bidone
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah, USA
- Department of Molecular Pharmaceutics, University of Utah, Salt Lake City, Utah, USA
- Department of Biochemistry, University of Utah, Salt Lake City, Utah, USA
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2
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Gaikwad HK, Jaswandkar SV, Katti KS, Haage A, Katti DR. Molecular basis of conformational changes and mechanics of integrins. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220243. [PMID: 37211038 DOI: 10.1098/rsta.2022.0243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 01/13/2023] [Indexed: 05/23/2023]
Abstract
Integrin, as a mechanotransducer, establishes the mechanical reciprocity between the extracellular matrix (ECM) and cells at integrin-mediated adhesion sites. This study used steered molecular dynamics (SMD) simulations to investigate the mechanical responses of integrin αvβ3 with and without 10th type III fibronectin (FnIII10) binding for tensile, bending and torsional loading conditions. The ligand-binding integrin confirmed the integrin activation during equilibration and altered the integrin dynamics by changing the interface interaction between β-tail, hybrid and epidermal growth factor domains during initial tensile loading. The tensile deformation in integrin molecules indicated that fibronectin ligand binding modulates its mechanical responses in the folded and unfolded conformation states. The bending deformation responses of extended integrin models reveal the change in behaviour of integrin molecules in the presence of Mn2+ ion and ligand based on the application of force in the folding and unfolding directions of integrin. Furthermore, these SMD simulation results were used to predict the mechanical properties of integrin underlying the mechanism of integrin-based adhesion. The evaluation of integrin mechanics provides new insights into understanding the mechanotransmission (force transmission) between cells and ECM and contributes to developing an accurate model for integrin-mediated adhesion. This article is part of a discussion meeting issue 'Supercomputing simulations of advanced materials'.
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Affiliation(s)
- Hanmant K Gaikwad
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND 58105, USA
| | - Sharad V Jaswandkar
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND 58105, USA
| | - Kalpana S Katti
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND 58105, USA
| | - Amanda Haage
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND 58202, USA
| | - Dinesh R Katti
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND 58105, USA
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3
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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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4
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Sun H, Lagarrigue F, Ginsberg MH. The Connection Between Rap1 and Talin1 in the Activation of Integrins in Blood Cells. Front Cell Dev Biol 2022; 10:908622. [PMID: 35721481 PMCID: PMC9198492 DOI: 10.3389/fcell.2022.908622] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/25/2022] [Indexed: 01/13/2023] Open
Abstract
Integrins regulate the adhesion and migration of blood cells to ensure the proper positioning of these cells in the environment. Integrins detect physical and chemical stimuli in the extracellular matrix and regulate signaling pathways in blood cells that mediate their functions. Integrins are usually in a resting state in blood cells until agonist stimulation results in a high-affinity conformation ("integrin activation"), which is central to integrins' contribution to blood cells' trafficking and functions. In this review, we summarize the mechanisms of integrin activation in blood cells with a focus on recent advances understanding of mechanisms whereby Rap1 regulates talin1-integrin interaction to trigger integrin activation in lymphocytes, platelets, and neutrophils.
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Affiliation(s)
- Hao Sun
- Department of Medicine, University of California San Diego, San Diego, CA, United States
| | - Frederic Lagarrigue
- Institut de Pharmacologie et Biologie Structurale, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Mark H. Ginsberg
- Department of Medicine, University of California San Diego, San Diego, CA, United States
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5
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Anderson JM, Li J, Springer TA. Regulation by metal ions and the ADMIDAS of integrin α5β1 conformational states and intrinsic affinities. Mol Biol Cell 2022; 33:ar56. [PMID: 35108026 PMCID: PMC9265148 DOI: 10.1091/mbc.e21-11-0536] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Activation of integrins by Mn2+ is a benchmark in the integrin field, but how Mn2+ works and whether it reproduces physiological activation is unknown. We show that Mn2+ and high Mg2+ concentrations compete with Ca2+ at the ADMIDAS and shift the conformational equilibrium toward the open state, but the shift is far from complete. Additionally, replacement of Mg2+ by Mn2+ at the MIDAS increases the intrinsic affinities of both the high-affinity open and low-affinity closed states of integrins, in agreement with stronger binding of Mn2+ than Mg2+ to oxygen atoms. Mutation of the ADMIDAS increases the affinity of closed states and decreases the affinity of the open state and thus reduces the difference in affinity between the open and closed states. An important biological function of the ADMIDAS may be to stabilize integrins in highly discrete states, so that when integrins support cell adhesion and migration, their high and low affinity correspond to discrete on and off states, respectively.
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Affiliation(s)
- Jordan M Anderson
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston MA 02115.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston MA 02115
| | - Jing Li
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston MA 02115.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston MA 02115
| | - Timothy A Springer
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston MA 02115.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston MA 02115
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6
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Luo W, Lin Z, Chen J, Chen G, Zhang S, Liu M, Li H, He D, Liang S, Luo Q, Zhang D, Nie Q, Zhang X. TMEM182 interacts with integrin beta 1 and regulates myoblast differentiation and muscle regeneration. J Cachexia Sarcopenia Muscle 2021; 12:1704-1723. [PMID: 34427057 PMCID: PMC8718073 DOI: 10.1002/jcsm.12767] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/28/2021] [Accepted: 07/10/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Transmembrane proteins are vital for intercellular signalling and play important roles in the control of cell fate. However, their physiological functions and mechanisms of action in myogenesis and muscle disorders remain largely unexplored. It has been found that transmembrane protein 182 (TMEM182) is dramatically up-regulated during myogenesis, but its detailed functions remain unclear. This study aimed to analyse the function of TMEM182 during myogenesis and muscle regeneration. METHODS RNA sequencing, quantitative real-time polymerase chain reaction, and immunofluorescence approaches were used to analyse TMEM182 expression during myoblast differentiation. A dual-luciferase reporter assay was used to identify the promoter region of the TMEM182 gene, and a chromatin immunoprecipitation assay was used to investigate the regulation TMEM182 transcription by MyoD. We used chickens and TMEM182-knockout mice as in vivo models to examine the function of TMEM182 in muscle growth and muscle regeneration. Chickens and mouse primary myoblasts were used to extend the findings to in vitro effects on myoblast differentiation and fusion. Co-immunoprecipitation and mass spectrometry were used to identify the interaction between TMEM182 and integrin beta 1 (ITGB1). The molecular mechanism by which TMEM182 regulates myogenesis and muscle regeneration was examined by Transwell migration, cell wound healing, adhesion, glutathione-S-transferse pull down, protein purification, and RNA immunoprecipitation assays. RESULTS TMEM182 was specifically expressed in skeletal muscle and adipose tissue and was regulated at the transcriptional level by the myogenic regulatory factor MyoD1. Functionally, TMEM182 inhibited myoblast differentiation and fusion. The in vivo studies indicated that TMEM182 induced muscle fibre atrophy and delayed muscle regeneration. TMEM182 knockout in mice led to significant increases in body weight, muscle mass, muscle fibre number, and muscle fibre diameter. Skeletal muscle regeneration was accelerated in TMEM182-knockout mice. Furthermore, we revealed that the inhibitory roles of TMEM182 in skeletal muscle depend on ITGB1, an essential membrane receptor involved in cell adhesion and muscle formation. TMEM182 directly interacted with ITGB1, and this interaction required an extracellular hybrid domain of ITGB1 (aa 387-470) and a conserved region (aa 52-62) within the large extracellular loop of TMEM182. Mechanistically, TMEM182 modulated ITGB1 activation by coordinating the association between ITGB1 and laminin and regulating the intracellular signalling of ITGB1. Myogenic deletion of TMEM182 increased the binding activity of ITGB1 to laminin and induced the activation of the FAK-ERK and FAK-Akt signalling axes during myogenesis. CONCLUSIONS Our data reveal that TMEM182 is a novel negative regulator of myogenic differentiation and muscle regeneration.
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Affiliation(s)
- Wen Luo
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China.,Department of Orthaepedics and Traumatology, The Chinese University of Hong Kong, Hongkong
| | - Zetong Lin
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Jiahui Chen
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Genghua Chen
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Siyu Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Manqing Liu
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Hongmei Li
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Danlin He
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Shaodong Liang
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Qingbin Luo
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Dexiang Zhang
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China
| | - Qinghua Nie
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, China
| | - Xiquan Zhang
- Lingnan Guangdong Laboratory of Agriculture, South China Agricultural University, Guangzhou, China.,Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affair, South China Agricultural University, Guangzhou, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, China
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7
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Arimori T, Miyazaki N, Mihara E, Takizawa M, Taniguchi Y, Cabañas C, Sekiguchi K, Takagi J. Structural mechanism of laminin recognition by integrin. Nat Commun 2021; 12:4012. [PMID: 34188035 PMCID: PMC8241838 DOI: 10.1038/s41467-021-24184-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 06/04/2021] [Indexed: 02/06/2023] Open
Abstract
Recognition of laminin by integrin receptors is central to the epithelial cell adhesion to basement membrane, but the structural background of this molecular interaction remained elusive. Here, we report the structures of the prototypic laminin receptor α6β1 integrin alone and in complex with three-chain laminin-511 fragment determined via crystallography and cryo-electron microscopy, respectively. The laminin-integrin interface is made up of several binding sites located on all five subunits, with the laminin γ1 chain C-terminal portion providing focal interaction using two carboxylate anchor points to bridge metal-ion dependent adhesion site of integrin β1 subunit and Asn189 of integrin α6 subunit. Laminin α5 chain also contributes to the affinity and specificity by making electrostatic interactions with large surface on the β-propeller domain of α6, part of which comprises an alternatively spliced X1 region. The propeller sheet corresponding to this region shows unusually high mobility, suggesting its unique role in ligand capture.
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Affiliation(s)
- Takao Arimori
- grid.136593.b0000 0004 0373 3971Laboratory for Protein Synthesis and Expression, Institute for Protein Research, Osaka University, Suita, Osaka Japan
| | - Naoyuki Miyazaki
- grid.136593.b0000 0004 0373 3971Laboratory for Protein Synthesis and Expression, Institute for Protein Research, Osaka University, Suita, Osaka Japan ,grid.20515.330000 0001 2369 4728Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Ibaraki, Japan
| | - Emiko Mihara
- grid.136593.b0000 0004 0373 3971Laboratory for Protein Synthesis and Expression, Institute for Protein Research, Osaka University, Suita, Osaka Japan
| | - Mamoru Takizawa
- grid.136593.b0000 0004 0373 3971Division of Matrixome Research and Application, Institute for Protein Research, Osaka University, Suita, Osaka Japan
| | - Yukimasa Taniguchi
- grid.136593.b0000 0004 0373 3971Division of Matrixome Research and Application, Institute for Protein Research, Osaka University, Suita, Osaka Japan
| | - Carlos Cabañas
- grid.465524.4Cell-cell Communication & Inflammation Unit, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain ,grid.4795.f0000 0001 2157 7667Department of Immunology, Ophthalmology and Otorhinolaryngology (IOO), Faculty of Medicine, Universidad Complutense de Madrid, Madrid, Spain ,grid.144756.50000 0001 1945 5329Instituto de Investigación Sanitaria Hospital 12 Octubre (i+12), Madrid, Spain
| | - Kiyotoshi Sekiguchi
- grid.136593.b0000 0004 0373 3971Division of Matrixome Research and Application, Institute for Protein Research, Osaka University, Suita, Osaka Japan
| | - Junichi Takagi
- grid.136593.b0000 0004 0373 3971Laboratory for Protein Synthesis and Expression, Institute for Protein Research, Osaka University, Suita, Osaka Japan
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8
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Wu Y, Huang Y, Zhang W, Gunst SJ. The proprotein convertase furin inhibits IL-13-induced inflammation in airway smooth muscle by regulating integrin-associated signaling complexes. Am J Physiol Lung Cell Mol Physiol 2021; 321:L102-L115. [PMID: 34009050 DOI: 10.1152/ajplung.00618.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Furin is a proprotein convertase that regulates the activation and the inactivation of multiple proteins including matrix metalloproteinases, integrins, and cytokines. It is a serine endoprotease that localizes to the plasma membrane and can be secreted into the extracellular space. The role of furin in regulating inflammation in isolated canine airway smooth muscle tissues was investigated. The treatment of airway tissues with recombinant furin (rFurin) inhibited the activation of Akt and eotaxin secretion induced by IL-13, and it prevented the IL-13-induced suppression of smooth muscle myosin heavy chain expression. rFurin promoted a differentiated phenotype by activating β1-integrin proteins and stimulating the activation of the adhesome proteins vinculin and paxillin by talin. Activated paxillin induced the binding of Akt to β-parvin IPP [integrin-linked kinase (ILK), PINCH, parvin] complexes, which inhibits Akt activation. Treatment of tissues with a furin inhibitor or the depletion of endogenous furin using shRNA resulted in Akt activation and inflammatory responses similar to those induced by IL-13. Furin inactivation or IL-13 caused talin cleavage and integrin inactivation, resulting in the inactivation of vinculin and paxillin. Paxillin inactivation resulted in the coupling of Akt to α-parvin IPP complexes, which catalyze Akt activation and an inflammatory response. The results demonstrate that furin inhibits inflammation in airway smooth muscle induced by IL-13 and that the anti-inflammatory effects of furin are mediated by activating integrin proteins and integrin-associated signaling complexes that regulate Akt-mediated pathways to the nucleus. Furin may have therapeutic potential for the treatment of inflammatory conditions of the lungs and airways.
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Affiliation(s)
- Yidi Wu
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Youliang Huang
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Wenwu Zhang
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Susan J Gunst
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana
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9
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Cai C, Sun H, Hu L, Fan Z. Visualization of integrin molecules by fluorescence imaging and techniques. ACTA ACUST UNITED AC 2021; 45:229-257. [PMID: 34219865 PMCID: PMC8249084 DOI: 10.32604/biocell.2021.014338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Integrin molecules are transmembrane αβ heterodimers involved in cell adhesion, trafficking, and signaling. Upon activation, integrins undergo dynamic conformational changes that regulate their affinity to ligands. The physiological functions and activation mechanisms of integrins have been heavily discussed in previous studies and reviews, but the fluorescence imaging techniques -which are powerful tools for biological studies- have not. Here we review the fluorescence labeling methods, imaging techniques, as well as Förster resonance energy transfer assays used to study integrin expression, localization, activation, and functions.
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Affiliation(s)
- Chen Cai
- Department of Immunology, School of Medicine, UConn Health, Farmington, 06030, USA
| | - Hao Sun
- Department of Medicine, University of California, San Diego, La Jolla, 92093, USA
| | - Liang Hu
- Cardiovascular Institute of Zhengzhou University, Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450051, China
| | - Zhichao Fan
- Department of Immunology, School of Medicine, UConn Health, Farmington, 06030, USA
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10
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Shen C, Liu M, Tian H, Li J, Xu R, Mwangi J, Lu Q, Hao X, Lai R. Conformation-Specific Blockade of αIIbβ3 by a Non-RGD Peptide to Inhibit Platelet Activation without Causing Significant Bleeding and Thrombocytopenia. Thromb Haemost 2020; 120:1432-1441. [PMID: 32717755 DOI: 10.1055/s-0040-1714215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Bleeding and thrombocytopenia to readministration are the most serious side effects of clinical integrin αIIbβ3 antagonists such as RGD-containing peptides. Here we show that a non-RGD peptide ZDPI, identified from skin secretions of Amolops loloensis, inhibited platelet aggregation induced by agonists, such as adenosine diphosphate, collagen, arachidonic acid, PAR1AP, and integrin αIIbβ3 allosteric activator, and reduces soluble fibrinogen binding to activated platelets without perturbing adhesion numbers on immobilized fibrinogen. Further study showed that ZDPI preferred to bind to the active conformation of integrin αIIbβ3, and thus inhibited c-Src-mediated integrin signaling transduction. In contrast to currently used clinical blockers of integrin αIIbβ3, which are all conformation-unspecific blockers, ZDPI conformation specifically binds to activated integrin αIIbβ3, subsequently suppressing platelet spreading. In vivo study revealed that ZDPI inhibited carotid arterial thrombosis with limited bleeding and thrombocytopenia. A non-RGD peptide which targets the active conformation of integrin αIIbβ3, such as ZDPI, might be an excellent candidate or template to develop antithrombotics without significant bleeding and thrombocytopenia side effects.
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Affiliation(s)
- Chuanbin Shen
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan, China.,KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Ming Liu
- Department of Molecular and Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Huiwen Tian
- Department of Zoology, Life Sciences College of Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Jiameng Li
- Department of Zoology, Life Sciences College of Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Runjia Xu
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan, China.,KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - James Mwangi
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan, China.,KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Qiumin Lu
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan, China.,KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Xue Hao
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan, China.,KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Ren Lai
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, Yunnan, China.,KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Department of Zoology, Life Sciences College of Nanjing Agricultural University, Nanjing, Jiangsu, China.,Sino-African Joint Research Center, CAS, Kunming Institute of Zoology, Kunming, Yunnan, China
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11
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Lv Z, Qiu L, Wang W, Liu Z, Liu Q, Wang L, Song L. The Members of the Highly Diverse Crassostrea gigas Integrin Family Cooperate for the Generation of Various Immune Responses. Front Immunol 2020; 11:1420. [PMID: 32793197 PMCID: PMC7390872 DOI: 10.3389/fimmu.2020.01420] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 06/02/2020] [Indexed: 12/25/2022] Open
Abstract
Studies on invertebrate immune receptors can provide insights into characteristics specific to innate immune system. Here, eight α and three β integrins are identified from an invertebrate, the Pacific oyster Crassostrea gigas, and their possible immune functions are studied. Oyster α/β integrins exhibit a higher degree of sequence and structural variability than the members from Homo sapiens and Drosophila melanogaster. The analysis reveals that oyster RGD- and laminin-binding receptor homologs are present in the phylogenetic tree of α integrins, but the other six oyster α integrins mainly form a species-specific branch; meanwhile, oyster β integrins are clustered with insect β integrins but distinct from a member from the mollusk Biomphalaria glabrata. Although phylogenetically lacking the important α integrin branches of LDV-binding, PS3-type, and αI-containing integrins, oyster integrins can bind to most ECM ligands, including RGDCP, LDVCP, GFOGERCP, and laminin protein in a distinct binding pattern. Besides, oyster integrins are distributed in different hemocyte subpopulations, while only specific integrins are selectively involved in hemocyte phagocytosis, migration, and encapsulation, and some of them participate in more than one immune response in a sophisticated pattern. Especially, oyster β integrins are arranged in the core to mediate complex immune responses, unlike the counterparts in humans that mainly depend on αI-containing integrins to incite immune reactions. This study represents the first comprehensive attempt to reveal the structural and evolutionary features of the integrin family and their involvement in cellular immune responses in the non-model invertebrate C. gigas and sheds light on the characteristics specific to the innate immune system in the integrin family.
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Affiliation(s)
- Zhao Lv
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Limei Qiu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Weilin Wang
- Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China.,Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Zhaoqun Liu
- Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China.,Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Qing Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Lingling Wang
- Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China.,Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
| | - Linsheng Song
- Laboratory of Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China.,Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, China
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12
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Ca 2+-based allosteric switches and shape shifting in RGLG1 VWA domain. Comput Struct Biotechnol J 2020; 18:821-833. [PMID: 32308929 PMCID: PMC7155146 DOI: 10.1016/j.csbj.2020.03.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/12/2022] Open
Abstract
RGLG1 is an E3 ubiquitin ligase in Arabidopsis thaliana that participates in ABA signaling and regulates apical dominance. Here, we present crystal structures of RGLG1 VWA domain, revealing two novel calcium ions binding sites (NCBS1 and NCBS2). Furthermore, the structures with guided mutagenesis in NCBS1 prove that Ca2+ ions play important roles in controlling conformational change of VWA, which is stabilized in open state with Ca2+ bound and converted to closed state after Ca2+ removal. This allosteric regulation mechanism is distinct from the ever reported one involving the C-terminal helix in integrin α and β I domains. The mutation of a key residue in NCBS2 do not abolish its Ca2+-binding potential, with no conformational change. MD simulations reveals that open state of RGLG1 VWA has higher ligand affinity than its closed state, consisting with integrin. Structural comparison of ion-free-MIDAS with Mg2+-MIDAS reveals that Mg2+ binding to MIDAS does not induce conformational change. With acquisition of first structure of plant VWA domain in both open state and closed state, we carefully analyze the conformational change and propose a totally new paradigm for its transition of open-closed states, which will be of great value for guiding future researches on VWA proteins and their important biological significance.
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13
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Sasada M, Iyoda T, Asayama T, Suenaga Y, Sakai S, Kase N, Kodama H, Yokoi S, Isohama Y, Fukai F. Inactivation of beta1 integrin induces proteasomal degradation of Myc oncoproteins. Oncotarget 2019; 10:4960-4972. [PMID: 31452837 PMCID: PMC6697639 DOI: 10.18632/oncotarget.27131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 07/15/2019] [Indexed: 11/25/2022] Open
Abstract
The MYC family oncogenes (MYC, MYCN, and MYCL) contribute to the genesis of many human cancers. Among them, amplification of the MYCN gene and over-expression of N-Myc protein are the most reliable risk factors in neuroblastoma patients. On the other hand, we previously found that a peptide derived from fibronectin, termed FNIII14, is capable of inducing functional inactivation in β1-integrins. Here, we demonstrate that inactivation of β1-integrin by FNIII14 induced proteasomal degradation in N-Myc of neuroblastoma cells with MYCN amplification. This N-Myc degradation by FNIII14 reduced the malignant properties, including the anchorage-independent proliferation and invasive migration, of neuroblastoma cells. An in vivo experiment using a mouse xenograft model showed that the administration of FNIII14 can inhibit tumor growth, and concomitantly a remarkable decrease in N-Myc levels in tumor tissues. Of note, the activation of proteasomal degradation based on β1-integrin inactivation is applicable to another Myc family oncoprotein, c-myc, which also reverses cancer-associated properties in pancreatic cancer cells. Collectively, β1-integrin inactivation could be a new chemotherapeutic strategy for cancers with highly expressed Myc. FNIII14, which is a unique pharmacological agent able to induce β1-integrin inactivation, may be a promising drug targeting Myc oncoproteins for cancer chemotherapy.
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Affiliation(s)
- Manabu Sasada
- Department of Molecular Pathophysiology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan.,Translational Research Center, Research Institute of Science and Technology, Tokyo University of Science, Chiba, Japan.,Laboratory of Applied Pharmacology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan.,Cancer Genome Center, Chiba Cancer Center Research Institute, Chiba City, Chiba, Japan
| | - Takuya Iyoda
- Department of Molecular Pathophysiology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan.,Department of Pharmacy, Faculty of Pharmaceutical Sciences, Sanyo-Onoda City University, Sanyo-Onoda City, Yamaguchi, Japan
| | - Tatsufumi Asayama
- Department of Molecular Pathophysiology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
| | - Yusuke Suenaga
- Cancer Genome Center, Chiba Cancer Center Research Institute, Chiba City, Chiba, Japan
| | - Shunsuke Sakai
- Department of Molecular Pathophysiology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
| | - Naoya Kase
- Department of Molecular Pathophysiology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
| | - Hiroaki Kodama
- Faculty of Science and Engineering, Saga University, Saga, Japan
| | - Sana Yokoi
- Cancer Genome Center, Chiba Cancer Center Research Institute, Chiba City, Chiba, Japan
| | - Yoichiro Isohama
- Translational Research Center, Research Institute of Science and Technology, Tokyo University of Science, Chiba, Japan.,Laboratory of Applied Pharmacology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
| | - Fumio Fukai
- Department of Molecular Pathophysiology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan.,Translational Research Center, Research Institute of Science and Technology, Tokyo University of Science, Chiba, Japan
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14
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Bidone TC, Polley A, Jin J, Driscoll T, Iwamoto DV, Calderwood DA, Schwartz MA, Voth GA. Coarse-Grained Simulation of Full-Length Integrin Activation. Biophys J 2019; 116:1000-1010. [PMID: 30851876 DOI: 10.1016/j.bpj.2019.02.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/25/2018] [Accepted: 02/13/2019] [Indexed: 01/01/2023] Open
Abstract
Integrin conformational dynamics are critical to their receptor and signaling functions in many cellular processes, including spreading, adhesion, and migration. However, assessing integrin conformations is both experimentally and computationally challenging because of limitations in resolution and dynamic sampling. Thus, structural changes that underlie transitions between conformations are largely unknown. Here, focusing on integrin αvβ3, we developed a modified form of the coarse-grained heterogeneous elastic network model (hENM), which allows sampling conformations at the onset of activation by formally separating local fluctuations from global motions. Both local fluctuations and global motions are extracted from all-atom molecular dynamics simulations of the full-length αvβ3 bent integrin conformer, but whereas the former are incorporated in the hENM as effective harmonic interactions between groups of residues, the latter emerge by systematically identifying and treating weak interactions between long-distance domains with flexible and anharmonic connections. The new hENM model allows integrins and single-point mutant integrins to explore various conformational states, including the initiation of separation between α- and β-subunit cytoplasmic regions, headpiece extension, and legs opening.
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Affiliation(s)
- Tamara C Bidone
- Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois
| | - Anirban Polley
- Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois
| | - Jaehyeok Jin
- Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois
| | - Tristan Driscoll
- Yale Cardiovascular Research Center and Department of Internal Medicine (Section of Cardiovascular Medicine), Yale School of Medicine, New Haven, Connecticut
| | | | - David A Calderwood
- Department of Pharmacology, New Haven, Connecticut; Department of Cell Biology, Yale University, New Haven, Connecticut
| | - Martin A Schwartz
- Departments of Cell Biology and Biomedical Engineering, Yale University, New Haven, Connecticut; Yale Cardiovascular Research Center and Department of Internal Medicine (Section of Cardiovascular Medicine), Yale School of Medicine, New Haven, Connecticut
| | - Gregory A Voth
- Department of Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois.
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15
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Klann JE, Kim SH, Remedios KA, He Z, Metz PJ, Lopez J, Tysl T, Olvera JG, Ablack JN, Cantor JM, Boland BS, Yeo G, Zheng Y, Lu LF, Bui JD, Ginsberg MH, Petrich BG, Chang JT. Integrin Activation Controls Regulatory T Cell-Mediated Peripheral Tolerance. THE JOURNAL OF IMMUNOLOGY 2018; 200:4012-4023. [PMID: 29703862 DOI: 10.4049/jimmunol.1800112] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 04/09/2018] [Indexed: 12/22/2022]
Abstract
Maintenance of the regulatory T (Treg) cell pool is essential for peripheral tolerance and prevention of autoimmunity. Integrins, heterodimeric transmembrane proteins consisting of α and β subunits that mediate cell-to-cell and cell-to-extracellular matrix interactions, play an important role in facilitating Treg cell contact-mediated suppression. In this article, we show that integrin activation plays an essential, previously unappreciated role in maintaining murine Treg cell function. Treg cell-specific loss of talin, a β integrin-binding protein, or expression of talin(L325R), a mutant that selectively abrogates integrin activation, resulted in lethal systemic autoimmunity. This dysfunction could be attributed, in part, to a global dysregulation of the Treg cell transcriptome. Activation of integrin α4β1 led to increased suppressive capacity of the Treg cell pool, suggesting that modulating integrin activation on Treg cells may be a useful therapeutic strategy for autoimmune and inflammatory disorders. Taken together, these results reveal a critical role for integrin-mediated signals in controlling peripheral tolerance by virtue of maintaining Treg cell function.
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Affiliation(s)
- Jane E Klann
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Stephanie H Kim
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Kelly A Remedios
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Zhaoren He
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Patrick J Metz
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Justine Lopez
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Tiffani Tysl
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Jocelyn G Olvera
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Jailal N Ablack
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Joseph M Cantor
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Brigid S Boland
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Gene Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093.,Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Ye Zheng
- Nomis Foundation Laboratories for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, CA 92037
| | - Li-Fan Lu
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
| | - Jack D Bui
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093; and
| | - Mark H Ginsberg
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Brian G Petrich
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322
| | - John T Chang
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093;
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16
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Fu S, Xu X, Ma Y, Zhang S, Zhang S. RGD peptide-based non-viral gene delivery vectors targeting integrin α vβ 3 for cancer therapy. J Drug Target 2018; 27:1-11. [PMID: 29564914 DOI: 10.1080/1061186x.2018.1455841] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Integrin αvβ3 is restrictedly expressed on angiogenic blood vessels and tumour cells. It plays a key role in angiogenesis for tumour growth and metastasis. RGD peptide can specifically recognise the integrin αvβ3, which serves as targeted molecular for anti-angiogenesis strategies. Therefore, the targeted delivery of therapeutics by RGD peptide-based non-viral vectors to tumour vasculature and tumour cells is recognised as a promising approach for treating cancer. In this review, we illustrate the interaction between RGD peptide and integrin αvβ3 from different perspectives. Meanwhile, four types of RGD peptide-based non-viral gene delivery vectors for cancer therapy, including RGD-based cationic polymers, lipids, peptides and hybrid systems, are summarised. The aim is to particularly highlight the enhanced therapeutic effects and specific targeting ability exhibited by these vectors for cancer gene therapy both in vitro and in vivo.
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Affiliation(s)
- Shuang Fu
- a State Key Laboratory of Fine Chemicals , Dalian University of Technology , Dalian , China.,b Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education , Dalian Minzu University , Dalian , China
| | - Xiaodong Xu
- b Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education , Dalian Minzu University , Dalian , China
| | - Yu Ma
- b Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education , Dalian Minzu University , Dalian , China
| | - Shubiao Zhang
- b Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education , Dalian Minzu University , Dalian , China
| | - Shufen Zhang
- a State Key Laboratory of Fine Chemicals , Dalian University of Technology , Dalian , China
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17
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High Affinity vs. Native Fibronectin in the Modulation of αvβ3 Integrin Conformational Dynamics: Insights from Computational Analyses and Implications for Molecular Design. PLoS Comput Biol 2017; 13:e1005334. [PMID: 28114375 PMCID: PMC5293283 DOI: 10.1371/journal.pcbi.1005334] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 02/06/2017] [Accepted: 12/23/2016] [Indexed: 11/19/2022] Open
Abstract
Understanding how binding events modulate functional motions of multidomain proteins is a major issue in chemical biology. We address several aspects of this problem by analyzing the differential dynamics of αvβ3 integrin bound to wild type (wtFN10, agonist) or high affinity (hFN10, antagonist) mutants of fibronectin. We compare the dynamics of complexes from large-scale domain motions to inter-residue coordinated fluctuations to characterize the distinctive traits of conformational evolution and shed light on the determinants of differential αvβ3 activation induced by different FN sequences. We propose an allosteric model for ligand-based integrin modulation: the conserved integrin binding pocket anchors the ligand, while different residues on the two FN10's act as the drivers that reorganize relevant interaction networks, guiding the shift towards inactive (hFN10-bound) or active states (wtFN10-bound). We discuss the implications of results for the design of integrin inhibitors.
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18
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Abstract
Mechanical force regulates a broad range of molecular interactions in biology. Three types of counterintuitive mechanical regulation of receptor–ligand dissociation have been described. Catch bonds are strengthened by constant forces, as opposed to slip bonds that are weakened by constant forces. The phenomenon that bonds become stronger with prior application of cyclic forces is termed cyclic mechanical reinforcement (CMR). Slip and catch bonds have respectively been explained by two-state models. However, they assume fast equilibration between internal states and hence are inadequate for CMR. Here we propose a three-state model for CMR where both loading and unloading regulate the transition of bonds among the short-lived, intermediate, and long-lived state. Cyclic forces favor bonds in the long-lived state, hence greatly prolonging their lifetimes. The three-state model explains the force history effect and agrees with the experimental CMR effect of integrin α5β1–fibronectin interaction. This model helps decipher the distinctive ways by which molecular bonds are mechanically strengthened: catch bonds by constant forces and CMR by cyclic forces. The different types of mechanical regulation may enable the cell to fine tune its mechanotransduction via membrane receptors.
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19
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Mould AP, Askari JA, Byron A, Takada Y, Jowitt TA, Humphries MJ. Ligand-induced Epitope Masking: DISSOCIATION OF INTEGRIN α5β1-FIBRONECTIN COMPLEXES ONLY BY MONOCLONAL ANTIBODIES WITH AN ALLOSTERIC MODE OF ACTION. J Biol Chem 2016; 291:20993-21007. [PMID: 27484800 PMCID: PMC5076510 DOI: 10.1074/jbc.m116.736942] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/29/2016] [Indexed: 11/06/2022] Open
Abstract
We previously demonstrated that Arg-Gly-Asp (RGD)-containing ligand-mimetic inhibitors of integrins are unable to dissociate pre-formed integrin-fibronectin complexes (IFCs). These observations suggested that amino acid residues involved in integrin-fibronectin binding become obscured in the ligand-occupied state. Because the epitopes of some function-blocking anti-integrin monoclonal antibodies (mAbs) lie near the ligand-binding pocket, it follows that the epitopes of these mAbs may become shielded in the ligand-occupied state. Here, we tested whether function-blocking mAbs directed against α5β1 can interact with the integrin after it forms a complex with an RGD-containing fragment of fibronectin. We showed that the anti-α5 subunit mAbs JBS5, SNAKA52, 16, and P1D6 failed to disrupt IFCs and hence appeared unable to bind to the ligand-occupied state. In contrast, the allosteric anti-β1 subunit mAbs 13, 4B4, and AIIB2 could dissociate IFCs and therefore were able to interact with the ligand-bound state. However, another class of function-blocking anti-β1 mAbs, exemplified by Lia1/2, could not disrupt IFCs. This second class of mAbs was also distinguished from 13, 4B4, and AIIB2 by their ability to induce homotypic cell aggregation. Although the epitope of Lia1/2 was closely overlapping with those of 13, 4B4, and AIIB2, it appeared to lie closer to the ligand-binding pocket. A new model of the α5β1-fibronectin complex supports our hypothesis that the epitopes of mAbs that fail to bind to the ligand-occupied state lie within, or very close to, the integrin-fibronectin interface. Importantly, our findings imply that the efficacy of some therapeutic anti-integrin mAbs could be limited by epitope masking.
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Affiliation(s)
- A Paul Mould
- From the Biomolecular Analysis Core Facility and
| | - Janet A Askari
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Adam Byron
- the Edinburgh Cancer Research UK Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XR, Scotland, United Kingdom, and
| | - Yoshikazu Takada
- the Department of Vascular Biology, VB-1, The Scripps Research Institute, La Jolla, California 92037
| | | | - Martin J Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom,
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20
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Abstract
Whether β1 integrin ectodomains visit conformational states similarly to β2 and β3 integrins has not been characterized. Furthermore, despite a wealth of activating and inhibitory antibodies to β1 integrins, the conformational states that these antibodies stabilize, and the relation of these conformations to function, remain incompletely characterized. Using negative-stain electron microscopy, we show that the integrin α5β1 ectodomain adopts extended-closed and extended-open conformations as well as a bent conformation. Antibodies SNAKA51, 8E3, N29, and 9EG7 bind to different domains in the α5 or β1 legs, activate, and stabilize extended ectodomain conformations. Antibodies 12G10 and HUTS-4 bind to the β1 βI domain and hybrid domains, respectively, activate, and stabilize the open headpiece conformation. Antibody TS2/16 binds a similar epitope as 12G10, activates, and appears to stabilize an open βI domain conformation without requiring extension or hybrid domain swing-out. mAb13 and SG/19 bind to the βI domain and βI-hybrid domain interface, respectively, inhibit, and stabilize the closed conformation of the headpiece. The effects of the antibodies on cell adhesion to fibronectin substrates suggest that the extended-open conformation of α5β1 is adhesive and that the extended-closed and bent-closed conformations are nonadhesive. The functional effects and binding sites of antibodies and fibronectin were consistent with their ability in binding to α5β1 on cell surfaces to cross-enhance or inhibit one another by competitive or noncompetitive (allosteric) mechanisms.
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21
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Rational design of a protein that binds integrin αvβ3 outside the ligand binding site. Nat Commun 2016; 7:11675. [PMID: 27241473 PMCID: PMC4895024 DOI: 10.1038/ncomms11675] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 04/19/2016] [Indexed: 12/28/2022] Open
Abstract
Integrin αvβ3 expression is altered in various diseases and has been proposed as a drug target. Here we use a rational design approach to develop a therapeutic protein, which we call ProAgio, that binds to integrin αvβ3 outside the classical ligand-binding site. We show ProAgio induces apoptosis of integrin αvβ3-expressing cells by recruiting and activating caspase 8 to the cytoplasmic domain of integrin αvβ3. ProAgio also has anti-angiogenic activity and strongly inhibits growth of tumour xenografts, but does not affect the established vasculature. Toxicity analyses demonstrate that ProAgio is not toxic to mice. Our study reports a new integrin-targeting agent with a unique mechanism of action, and provides a template for the development of integrin-targeting therapeutics. Integrins are transmembrane proteins that have important roles in cell adhesion and signalling. Here the authors design a therapeutic protein that binds integrin αvβ3, has anti-angiogenic activity, and reduces tumour growth in xenograft models, while being seemingly well tolerated.
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22
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Navarro AP, Collins MA, Folker ES. The nucleus is a conserved mechanosensation and mechanoresponse organelle. Cytoskeleton (Hoboken) 2016; 73:59-67. [PMID: 26849407 DOI: 10.1002/cm.21277] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 01/22/2016] [Accepted: 01/22/2016] [Indexed: 11/05/2022]
Abstract
Cells in vivo exist in a dynamic environment where they experience variable mechanical influences. The precise mechanical environment influences cell-cell interactions, cell-extracellular matrix interactions, and in-turn, cell morphology and cell function. Therefore, the ability of each cell to constantly and rapidly alter their behavior in response to variations in their mechanical environment is essential for cell viability, development, and function. Mechanotransduction, the process by which mechanical force is translated into a biochemical signal to activate downstream cellular responses, is thus crucial to cell function during development and homeostasis. Although much research has focused on how protein complexes at the cell cortex respond to mechanical stress to initiate mechanotransduction, the nucleus has emerged as crucial to the ability of the cell to perceive and respond to changes in its mechanical environment. This additional method for mechanosensing allows for direct transmission of force through the cytoskeleton to the nucleus, which can increase the speed at which a cell changes its transcriptional profile. This review discusses recent work demonstrating the importance of the nucleus in mediating the cellular response to internal and external force, establishing the nucleus as an important mechanosensing organelle.
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Affiliation(s)
- Alexandra P Navarro
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02142
| | - Mary Ann Collins
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, 02467
| | - Eric S Folker
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, 02467
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Fujii Y, Matsunaga Y, Arimori T, Kitago Y, Ogasawara S, Kaneko MK, Kato Y, Takagi J. Tailored placement of a turn-forming PA tag into the structured domain of a protein to probe its conformational state. J Cell Sci 2016; 129:1512-22. [DOI: 10.1242/jcs.176685] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 02/10/2016] [Indexed: 11/20/2022] Open
Abstract
Placement of a tag sequence is usually limited to either terminal of the target protein, reducing the potential of epitope tags for various labeling applications. The PA tag is a dodecapeptide (GVAMPGAEDDVV) that is recognized by a high-affinity antibody NZ-1. We determined the crystal structure of the PA tag/NZ-1 complex and found that NZ-1 recognized a central segment of the PA tag peptide in a tight β-turn configuration, suggesting its compatibility with the insertion into a loop. This possibility was tested and confirmed using multiple integrin subunits and semaphorin. More specifically, the PA tag can be inserted at multiple locations within the αIIb subunit of the fibrinogen receptor αIIbβ3 integrin without affecting the structural and functional integrity, while maintaining its high affinity toward NZ-1. The large choice of the sites for "epitope grafting" enabled the placement of the PA tag at a location whose accessibility is modulated during the biological action of the receptor. Thus, we succeeded in converting a general anti-tag antibody into a special reporter/activator anti-β1 integrin antibody that can be classified as a ligand-induced binding site antibody.
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Affiliation(s)
- Yuki Fujii
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
- Department of Regional Innovation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Yukiko Matsunaga
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takao Arimori
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yu Kitago
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Satoshi Ogasawara
- Department of Regional Innovation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Mika K. Kaneko
- Department of Regional Innovation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Yukinari Kato
- Department of Regional Innovation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Junichi Takagi
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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24
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Takada Y, Fujita M. Secreted Phospholipase A2 Type IIA (sPLA2-IIA) Activates Integrins in an Allosteric Manner. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 925:103-115. [PMID: 27864802 DOI: 10.1007/5584_2016_95] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Secreted phospholipase A2 type IIA (sPLA2-IIA) is a well-established pro-inflammatory protein and has been a major target for drug discovery. However, the mechanism of its signaling action has not been fully understood. We previously found that sPLA2-IIA binds to integrins αvβ3 and α4β1 in human and that this interaction plays a role in sPLA2-IIA's signaling action. Our recent studies found that sPLA2-IIA activates integrins in an allosteric manner through direct binding to a newly identified binding site of integrins (site 2), which is distinct from the classical RGD-binding site (site 1). The sPLA2-IIA-induced integrin activation may be related to the signaling action of sPLA2-IIA. Since sPLA2-IIA is present in normal human tears in addition to rheumatoid synovial fluid at high concentrations the sPLA2-IIA-mediated integrin activation on leukocytes may be involved in immune responses in normal and pathological conditions.
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Affiliation(s)
- Yoshikazu Takada
- Department of Dermatology, Biochemistry and Molecular Medicine, UC Davis School of Medicine, Research III Suite 3300, 4645 Second Avenue, Sacramento, CA, 95817, USA. .,The PhD Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, 250 Wu-Hsing Street, Taipei, 11031, Taiwan, Republic of China.
| | - Masaaki Fujita
- Department of Clinical Immunology and Rheumatology, The Tazuke-Kofukai Medical Research Institute, Kitano Hospital, 2-4-20 Ohgimachi, Kita-ku, Osaka, 530-8480, Japan
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25
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A fibronectin mimetic motif improves integrin mediated cell biding to recombinant spider silk matrices. Biomaterials 2015; 74:256-66. [PMID: 26461118 DOI: 10.1016/j.biomaterials.2015.10.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/08/2023]
Abstract
The cell binding motif RGD is the most widely used peptide to improve cell binding properties of various biomaterials, including recombinant spider silk. In this paper we use genetic engineering to further enhance the cell supportive capacity of spider silk by presenting the RGD motif as a turn loop, similar to the one found in fibronectin (FN), but in the silk stabilized by cysteines, and therefore denoted FNCC. Human primary cells cultured on FNCC-silk showed increased attachment, spreading, stress fiber formation and focal adhesions, not only compared to RGD-silk, but also to silk fused with linear controls of the RGD containing motif from fibronectin. Cell binding to FNCC-silk was shown to involve the α5β1 integrin, and to support proliferation and migration of keratinocytes. The FNCC-silk protein allowed efficient assembly, and could even be transformed into free standing films, on which keratinocytes could readily form a monolayer culture. The results hold promise for future applications within tissue engineering.
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26
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Disruption of integrin-fibronectin complexes by allosteric but not ligand-mimetic inhibitors. Biochem J 2015; 464:301-13. [PMID: 25333419 DOI: 10.1042/bj20141047] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Failure of Arg-Gly-Asp (RGD)-based inhibitors to reverse integrin-ligand binding has been reported, but the prevalence of this phenomenon among integrin heterodimers is currently unknown. In the present study we have investigated the interaction of four different RGD-binding integrins (α5β1, αVβ1, αVβ3 and αVβ6) with fibronectin (FN) using surface plasmon resonance. The ability of inhibitors to reverse ligand binding was assessed by their capacity to increase the dissociation rate of pre-formed integrin-FN complexes. For all four receptors we showed that RGD-based inhibitors (such as cilengitide) were completely unable to increase the dissociation rate. Formation of the non-reversible state occurred very rapidly and did not rely on the time-dependent formation of a high-affinity state of the integrin, or the integrin leg regions. In contrast with RGD-based inhibitors, Ca2+ (but not Mg2+) was able to greatly increase the dissociation rate of integrin-FN complexes, with a half-maximal response at ~0.4 mM Ca2+ for αVβ3-FN. The effect of Ca2+ was overcome by co-addition of Mn2+, but not Mg2+. A stimulatory anti-β1 monoclonal antibody (mAb) abrogated the effect of Ca2+ on α5β1-FN complexes; conversely, a function-blocking mAb mimicked the effect of Ca2+. These results imply that Ca2+ acts allosterically, probably through binding to the adjacent metal-ion-dependent adhesion site (ADMIDAS), and that the α1 helix in the β subunit I domain is the key element affected by allosteric modulators. The data suggest an explanation for the limited clinical efficacy of RGD-based integrin antagonists, and we propose that allosteric antagonists could prove to be of greater therapeutic benefit.
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27
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Fujita M, Zhu K, Fujita CK, Zhao M, Lam KS, Kurth MJ, Takada YK, Takada Y. Proinflammatory secreted phospholipase A2 type IIA (sPLA-IIA) induces integrin activation through direct binding to a newly identified binding site (site 2) in integrins αvβ3, α4β1, and α5β1. J Biol Chem 2015; 290:259-71. [PMID: 25398877 PMCID: PMC4281730 DOI: 10.1074/jbc.m114.579946] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 11/12/2014] [Indexed: 11/06/2022] Open
Abstract
Integrins are activated by signaling from inside the cell (inside-out signaling) through global conformational changes of integrins. We recently discovered that fractalkine activates integrins in the absence of CX3CR1 through the direct binding of fractalkine to a ligand-binding site in the integrin headpiece (site 2) that is distinct from the classical RGD-binding site (site 1). We propose that fractalkine binding to the newly identified site 2 induces activation of site 1 though conformational changes (in an allosteric mechanism). We reasoned that site 2-mediated activation of integrins is not limited to fractalkine. Human secreted phospholipase A2 type IIA (sPLA2-IIA), a proinflammatory protein, binds to integrins αvβ3 and α4β1 (site 1), and this interaction initiates a signaling pathway that leads to cell proliferation and inflammation. Human sPLA2-IIA does not bind to M-type receptor very well. Here we describe that sPLA2-IIA directly activated purified soluble integrin αvβ3 and transmembrane αvβ3 on the cell surface. This activation did not require catalytic activity or M-type receptor. Docking simulation predicted that sPLA2-IIA binds to site 2 in the closed-headpiece of αvβ3. A peptide from site 2 of integrin β1 specifically bound to sPLA2-IIA and suppressed sPLA2-IIA-induced integrin activation. This suggests that sPLA2-IIA activates αvβ3 through binding to site 2. sPLA2-IIA also activated integrins α4β1 and α5β1 in a site 2-mediated manner. We recently identified small compounds that bind to sPLA2-IIA and suppress integrin-sPLA2-IIA interaction (e.g. compound 21 (Cmpd21)). Cmpd21 effectively suppressed sPLA2-IIA-induced integrin activation. These results define a novel mechanism of proinflammatory action of sPLA2-IIA through integrin activation.
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Affiliation(s)
- Masaaki Fujita
- From the Departments of Dermatology and Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, California 95817, Department of Clinical Immunology and Rheumatology, The Tazuke-Kofukai Medical Research Institute, Kitano Hospital, Osaka 530-8480, Japan
| | - Kan Zhu
- From the Departments of Dermatology and
| | - Chitose K Fujita
- Department of Clinical Immunology and Rheumatology, The Tazuke-Kofukai Medical Research Institute, Kitano Hospital, Osaka 530-8480, Japan
| | - Min Zhao
- From the Departments of Dermatology and
| | - Kit S Lam
- Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, California 95817
| | - Mark J Kurth
- Department of Chemistry, UC Davis, Davis, California 95616, and
| | - Yoko K Takada
- From the Departments of Dermatology and Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, California 95817
| | - Yoshikazu Takada
- From the Departments of Dermatology and Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, California 95817,
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28
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Yu YP, Wang Q, Liu YC, Xie Y. Molecular basis for the targeted binding of RGD-containing peptide to integrin αVβ3. Biomaterials 2013; 35:1667-75. [PMID: 24268666 DOI: 10.1016/j.biomaterials.2013.10.072] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 10/27/2013] [Indexed: 12/11/2022]
Abstract
Integrin αVβ3-targeting peptides with an exposed arginine-glycine-aspartate (RGD) sequence play a crucial role in targeted anticancer drug delivery. The effects of RGD-containing peptide structure and quantity on mechanism of targeted binding of RGD-containing peptide to integrin αVβ3 were studied intensively at the molecular level via molecular dynamic simulations. Targeted recognization was mainly driven by the electrostatic interactions between the residues in RGD and the metal ions in integrin αVβ3, and cyclic arginine-glycine-aspartate-phenylalanine-valine (RGDFV) peptide appeared to be a better vector than the linear RGD-containing peptides. In addition, the optimal molar concentration ratio of RGD peptides to integrin αVβ3 appeared to be 2:1. These results will help improve the current understanding on the mechanism of interactions between RGD and integrin αVβ3, and promote the application prospects of RGD-based vectors in tumor imaging, diagnosis, and cancer therapy.
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Affiliation(s)
- Yu-Ping Yu
- Soft Matter Research Center, Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China
| | - Qi Wang
- Soft Matter Research Center, Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China
| | - Ying-Chun Liu
- Soft Matter Research Center, Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
| | - Ying Xie
- Department of Pharmaceutics, Peking University, Beijing 100191, PR China.
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29
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Abstract
Crystals soaked with RGD peptides reveal six intermediate conformational states between the closed and higher affinity, fully open state of the integrin αIIbβ3 headpiece. Carefully soaking crystals with Arg-Gly-Asp (RGD) peptides, we captured eight distinct RGD-bound conformations of the αIIbβ3 integrin headpiece. Starting from the closed βI domain conformation, we saw six intermediate βI conformations and finally the fully open βI with the hybrid domain swung out in the crystal lattice. The β1-α1 backbone that hydrogen bonds to the Asp side chain of RGD was the first element to move followed by adjacent to metal ion-dependent adhesion site Ca2+, α1 helix, α1’ helix, β6-α7 loop, α7 helix, and hybrid domain. We define in atomic detail how conformational change was transmitted over long distances in integrins, 40 Å from the ligand binding site to the opposite end of the βI domain and 80 Å to the far end of the hybrid domain. During these movements, RGD slid in its binding groove toward αIIb, and its Arg side chain became ordered. RGD concentration requirements in soaking suggested a >200-fold higher affinity after opening. The thermodynamic cycle shows how higher affinity pays the energetic cost of opening.
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Affiliation(s)
- Jieqing Zhu
- Department of Biological Chemistry and Molecular Pharmacology, Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
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30
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Kong F, Li Z, Parks WM, Dumbauld DW, García AJ, Mould AP, Humphries MJ, Zhu C. Cyclic mechanical reinforcement of integrin-ligand interactions. Mol Cell 2013; 49:1060-8. [PMID: 23416109 PMCID: PMC3615084 DOI: 10.1016/j.molcel.2013.01.015] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 11/12/2012] [Accepted: 01/11/2013] [Indexed: 12/11/2022]
Abstract
Cells regulate adhesion in response to internally generated and externally applied forces. Integrins connect the extracellular matrix to the cytoskeleton and provide cells with mechanical anchorages and signaling platforms. Here we show that cyclic forces applied to a fibronectin-integrin α5β1 bond switch the bond from a short-lived state with 1 s lifetime to a long-lived state with 100 s lifetime. We term this phenomenon "cyclic mechanical reinforcement," as the bond strength remembers the history of force application and accumulates over repeated cycles, but does not require force to be sustained. Cyclic mechanical reinforcement strengthens the fibronectin-integrin α5β1 bond through the RGD binding site of the ligand with the synergy binding site greatly facilitating the process. A flexible integrin hybrid domain is also important for cyclic mechanical reinforcement. Our results reveal a mechanical regulation of receptor-ligand interactions and identify a molecular mechanism for cell adhesion strengthening by cyclic forces.
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Affiliation(s)
- Fang Kong
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Zhenhai Li
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - William M. Parks
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - David W. Dumbauld
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Andrés J. García
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - A. Paul Mould
- Welcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, England, UK
| | - Martin J. Humphries
- Welcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, England, UK
| | - Cheng Zhu
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
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31
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Gohlke H, Schmitz B, Sommerfeld A, Reinehr R, Häussinger D. α5 β1-integrins are sensors for tauroursodeoxycholic acid in hepatocytes. Hepatology 2013; 57:1117-29. [PMID: 22865233 DOI: 10.1002/hep.25992] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 07/21/2012] [Indexed: 01/02/2023]
Abstract
UNLABELLED Ursodeoxycholic acid, which in vivo is converted to its taurine conjugate tauroursodeoxycholic acid (TUDC), is a mainstay for the treatment of cholestatic liver disease. Earlier work showed that TUDC exerts its choleretic properties in the perfused rat liver in an α5 β1 integrin-mediated way. However, the molecular basis of TUDC-sensing in the liver is unknown. We herein show that TUDC (20 μmol/L) induces in perfused rat liver and human HepG2 cells the rapid appearance of the active conformation of the β1 subunit of α5 β1 integrins, followed by an activating phosphorylation of extracellular signal-regulated kinases. TUDC-induced kinase activation was no longer observed after β1 integrin knockdown in isolated rat hepatocytes or in the presence of an integrin-antagonistic hexapeptide in perfused rat liver. TUDC-induced β1 integrin activation occurred predominantly inside the hepatocyte and required TUDC uptake by way of the Na(+) /taurocholate cotransporting peptide. Molecular dynamics simulations of a 3D model of α5 β1 integrin with TUDC bound revealed significant conformational changes within the head region that have been linked to integrin activation before. CONCLUSIONS TUDC can directly activate intrahepatocytic β1 integrins, which trigger signal transduction pathways toward choleresis. (HEPATOLOGY 2013).
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Affiliation(s)
- Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Department of Mathematics and Natural Sciences, Heinrich-Heine-University Düsseldorf, Germany
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32
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33
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Dong X, Mi LZ, Zhu J, Wang W, Hu P, Luo BH, Springer TA. α(V)β(3) integrin crystal structures and their functional implications. Biochemistry 2012; 51:8814-28. [PMID: 23106217 PMCID: PMC3495331 DOI: 10.1021/bi300734n] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many questions about the significance of structural features of integrin α(V)β(3) with respect to its mechanism of activation remain. We have determined and re-refined crystal structures of the α(V)β(3) ectodomain linked to C-terminal coiled coils (α(V)β(3)-AB) and four transmembrane (TM) residues in each subunit (α(V)β(3)-1TM), respectively. The α(V) and β(3) subunits with four and eight extracellular domains, respectively, are bent at knees between the integrin headpiece and lower legs, and the headpiece has the closed, low-affinity conformation. The structures differ in the occupancy of three metal-binding sites in the βI domain. Occupancy appears to be related to the pH of crystallization, rather than to the physiologic regulation of ligand binding at the central, metal ion-dependent adhesion site. No electron density was observed for TM residues and much of the α(V) linker. α(V)β(3)-AB and α(V)β(3)-1TM demonstrate flexibility in the linker between their extracellular and TM domains, rather than the previously proposed rigid linkage. A previously postulated interface between the α(V) and β(3) subunits at their knees was also not supported, because it lacks high-quality density, required rebuilding in α(V)β(3)-1TM, and differed markedly between α(V)β(3)-1TM and α(V)β(3)-AB. Together with the variation in domain-domain orientation within their bent ectodomains between α(V)β(3)-AB and α(V)β(3)-1TM, these findings are compatible with the requirement for large structural changes, such as extension at the knees and headpiece opening, in conveying activation signals between the extracellular ligand-binding site and the cytoplasm.
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Affiliation(s)
- Xianchi Dong
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
| | - Li-Zhi Mi
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
| | - Jianghai Zhu
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
| | - Wei Wang
- Department of Biological Sciences, 202 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803
| | - Ping Hu
- Department of Biological Sciences, 202 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803
| | - Bing-Hao Luo
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
- Department of Biological Sciences, 202 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803
| | - Timothy A. Springer
- Immune Disease Institute, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
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34
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The primacy of β1 integrin activation in the metastatic cascade. PLoS One 2012; 7:e46576. [PMID: 23056350 PMCID: PMC3463578 DOI: 10.1371/journal.pone.0046576] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 08/31/2012] [Indexed: 11/19/2022] Open
Abstract
After neoplastic cells leave the primary tumor and circulate, they may extravasate from the vasculature and colonize tissues to form metastases. β1 integrins play diverse roles in tumorigenesis and tumor progression, including extravasation. In blood cells, activation of β1 integrins can be regulated by “inside-out” signals leading to extravasation from the circulation into tissues. However, a role for inside-out β1 activation in tumor cell metastasis is uncertain. Here we show that β1 integrin activation promotes tumor metastasis and that activated β1 integrin may serve as a biomarker of metastatic human melanoma. To determine whether β1 integrin activation can influence tumor cell metastasis, the β1 integrin subunit in melanoma and breast cancer cell lines was stably knocked down with shRNA and replaced with wild-type or constitutively-active β1. When tumor cells expressing constitutively-active β1 integrins were injected intravenously into chick embryos or mice, they demonstrated increased colonization of the liver when compared to cells expressing wild-type β1 integrins. Rescue expression with mutant β1 integrins revealed that tumor cell extravasation and hepatic colonization required extracellular ligand binding to β1 as well as β1 interaction with talin, an intracellular mediator of integrin activation by the Rap1 GTPase. Furthermore, shRNA-mediated knock down of talin reduced hepatic colonization by tumor cells expressing wild-type β1, but not constitutively-active β1. Overexpression in tumor cells of the tumor suppressor, Rap1GAP, inhibited Rap1 and β1 integrin activation as well as hepatic colonization. Using an antibody that detects activated β1 integrin, we found higher levels of activated β1 integrins in human metastatic melanomas compared to primary melanomas, suggesting that activated β1 integrin may serve as a biomarker of invasive tumor cells. Altogether, these studies establish that inside-out activation of β1 integrins promotes tumor cell extravasation and colonization, suggesting diagnostic and therapeutic approaches for targeting of β1 integrin signaling in neoplasia.
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35
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Chigaev A, Sklar LA. Aspects of VLA-4 and LFA-1 regulation that may contribute to rolling and firm adhesion. Front Immunol 2012; 3:242. [PMID: 22876249 PMCID: PMC3410440 DOI: 10.3389/fimmu.2012.00242] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 07/18/2012] [Indexed: 01/21/2023] Open
Abstract
Very Late Antigen-4 (CD49d/CD29, alpha4 beta1) and Lymphocyte Function-associated Antigen-1 (CD11a/CD18, alphaL beta2) integrins are representatives of a large family of adhesion receptors widely expressed on immune cells. They participate in cell recruitment to sites of inflammation, as well as multiple immune cell interactions. A unique feature of integrins is that integrin-dependent cell adhesion can be rapidly and reversibly modulated in response to cell signaling, because of a series of conformational changes within the molecule, which include changes in the affinity of the ligand binding pocket, molecular extension (unbending) and others. Here, we provide a concise comparative analysis of the conformational regulation of the two integrins with specific attention to the physiological differences between these molecules. We focus on recent data obtained using a novel technology, based on small fluorescent ligand-mimicking probes for the detection of integrin conformation in real-time on live cells at natural receptor abundance.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque NM, USA
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36
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The leucocyte β2 (CD18) integrins: the structure, functional regulation and signalling properties. Biosci Rep 2012; 32:241-69. [PMID: 22458844 DOI: 10.1042/bsr20110101] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Leucocytes are highly motile cells. Their ability to migrate into tissues and organs is dependent on cell adhesion molecules. The integrins are a family of heterodimeric transmembrane cell adhesion molecules that are also signalling receptors. They are involved in many biological processes, including the development of metazoans, immunity, haemostasis, wound healing and cell survival, proliferation and differentiation. The leucocyte-restricted β2 integrins comprise four members, namely αLβ2, αMβ2, αXβ2 and αDβ2, which are required for a functional immune system. In this paper, the structure, functional regulation and signalling properties of these integrins are reviewed.
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37
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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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Wang W, Jiang Y, Wang C, Luo BH. Effects of the Association between the α-Subunit Thigh and the β-Subunit EGF2 Domains on Integrin Activation and Signaling. Biochemistry 2011; 50:9264-72. [DOI: 10.1021/bi200744g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Wei Wang
- Department of Biological Sciences,
202 Life Sciences
Building, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Yan Jiang
- Department of Biological Sciences,
202 Life Sciences
Building, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Chen Wang
- Department of Biological Sciences,
202 Life Sciences
Building, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Bing-Hao Luo
- Department of Biological Sciences,
202 Life Sciences
Building, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
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39
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Abstract
Integrins are large, membrane-spanning, heterodimeric proteins that are essential for a metazoan existence. All members of the integrin family adopt a shape that resembles a large "head" on two "legs," with the head containing the sites for ligand binding and subunit association. Most of the receptor dimer is extracellular, but both subunits traverse the plasma membrane and terminate in short cytoplasmic domains. These domains initiate the assembly of large signaling complexes and thereby bridge the extracellular matrix to the intracellular cytoskeleton. To allow cells to sample and respond to a dynamic pericellular environment, integrins have evolved a highly responsive receptor activation mechanism that is regulated primarily by changes in tertiary and quaternary structure. This review summarizes recent progress in the structural and molecular functional studies of this important class of adhesion receptor.
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Affiliation(s)
- Iain D Campbell
- Department of Biochemistry, University of Oxford, United Kingdom.
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40
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Chigaev A, Wu Y, Williams DB, Smagley Y, Sklar LA. Discovery of very late antigen-4 (VLA-4, alpha4beta1 integrin) allosteric antagonists. J Biol Chem 2011; 286:5455-63. [PMID: 21131351 PMCID: PMC3037658 DOI: 10.1074/jbc.m110.162636] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 11/19/2010] [Indexed: 11/06/2022] Open
Abstract
Integrins are cell adhesion receptors that mediate cell-to-cell, or cell-to-extracellular matrix adhesion. They represent an attractive target for treatment of multiple diseases. Two classes of small molecule integrin inhibitors have been developed. Competitive antagonists bind directly to the integrin ligand binding pocket and thus disrupt the ligand-receptor interaction. Allosteric antagonists have been developed primarily for α(L)β(2)- integrin (LFA-1, lymphocyte function-associated antigen-1). Here we present the results of screening the Prestwick Chemical Library using a recently developed assay for the detection of α(4)β(1)-integrin allosteric antagonists. Secondary assays confirmed that the compounds identified: 1) do not behave like competitive (direct) antagonists; 2) decrease ligand binding affinity for VLA-4 ∼2 orders of magnitude; 3) exhibit antagonistic properties at low temperature. In a cell based adhesion assay in vitro, the compounds rapidly disrupted cellular aggregates. In accord with reports that VLA-4 antagonists in vivo induce mobilization of hematopoietic progenitors into the peripheral blood, we found that administration of one of the compounds significantly increased the number of colony-forming units in mice. This effect was comparable to AMD3100, a well known progenitor mobilizing agent. Because all the identified compounds are structurally related, previously used, or currently marketed drugs, this result opens a range of therapeutic possibilities for VLA-4-related pathologies.
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Affiliation(s)
- Alexandre Chigaev
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Yang Wu
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - D. Bart Williams
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Yelena Smagley
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Larry A. Sklar
- From the Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
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41
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Abstract
Integrins are cell adhesion molecules that play important roles in many biological processes including hemostasis, immune responses, development, and cancer. Their adhesiveness is dynamically regulated through a process termed inside-out signaling. In addition, ligand binding transduces outside-in signals from the extracellular domain to the cytoplasm. Advances in the past several years have shed light on structural basis for integrin regulation and signaling, especially how the large-scale reorientations of the ectodomain are related to the inter-domain and intra-domain shape shifting that changes ligand-binding affinity. Experiments have also shown how the conformational changes of the ectodomain are linked to changes in the α- and β-subunit transmembrane and cytoplasmic domains.
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Affiliation(s)
- Guanyuan Fu
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
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42
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Abstract
Interaction of the integrin receptors with ligands determines the molecular basis of integrin-dependent cell adhesion. Integrin ligands are typically large proteins with relatively low binding affinities. This makes direct ligand-binding kinetic measurements somewhat difficult. Here we examine several real-time methods, aimed to overcome these experimental limitations and to distinguish the regulation of integrin conformation and affinity. This chapter includes: the use of a small ligand-mimetic probe for studies of inside-out regulation of integrin affinity and unbending, real-time cell aggregation and disaggregation kinetics to probe integrin conformational states and the number of integrin-ligand bonds, as well as the real-time monitoring of ligand-induced epitopes under signaling through G-protein-coupled receptors, and others. Experimental data obtained using these novel methods are summarized in terms of the current model of integrin activation.
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Affiliation(s)
- Alexandre Chigaev
- Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
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Pan Y, Zhang K, Qi J, Yue J, Springer TA, Chen J. Cation-pi interaction regulates ligand-binding affinity and signaling of integrin alpha4beta7. Proc Natl Acad Sci U S A 2010; 107:21388-93. [PMID: 21098296 PMCID: PMC3003088 DOI: 10.1073/pnas.1015487107] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Integrin α(4)β(7) mediates rolling and firm adhesion of leucocytes, two of the critical steps in leukocyte migration and tissue specific homing. Affinity of α(4)β(7) for ligand is dynamically regulated by three interlinked metal ion-binding sites in β(7)-subunit I domain. In this study, we found that Phe185 (F185), a highly conserved aromatic residue in β(7)-subunit, links the specificity-determining loop and the synergistic metal ion-binding site (SyMBS) through cation-π interaction. Mutations of F185 that disrupted the SyMBS cation-F185 interaction led to deficient firm cell adhesion mediated by high affinity α(4)β(7), and only slightly affected rolling adhesion mediated by low affinity α(4)β(7). Disruption of SyMBS cation-F185 interaction induced partial extension of integrin ectodomain and separation of cytoplasmic tails, and impaired α(4)β(7)-mediated bidirectional signaling. In addition, loss of SyMBS cation-F185 interaction increased paxillin expression and promoted paxillin-integrin binding, leading to deficient cell spreading. Furthermore, integrin α(4)β(7)-mediated cell migration was decreased by the abolishment of SyMBS cation-F185 interaction. Thus, these findings reveal a cation-π interaction playing vital roles in the regulation of integrin affinity, signaling, and biological functions.
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Affiliation(s)
- YouDong Pan
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Kun Zhang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - JunPeng Qi
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Jiao Yue
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
| | - Timothy A. Springer
- The Immune Disease Institute, Children’s Hospital Boston, and Department of Pathology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115
| | - JianFeng Chen
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; and
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44
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Abstract
An allosteric model is used to describe changes in lifetimes of biological receptor-ligand bonds subjected to an external force. Force-induced transitions between the two states of the allosteric site lead to changes in the receptor conformation. The ligand bound to the receptor fluctuates between two different potentials formed by the two receptor conformations. The effect of the force on the receptor-ligand interaction potential is described by the Bell mechanism. The probability of detecting the ligand in the bound state is found to depend on the relaxation times of both ligand and allosteric sites. An analytic expression for the bond lifetime is derived as a function of force. The formal theoretical results are used to explain the anomalous force and time dependences of the integrin-fibronectin bond lifetimes measured by atomic force microscopy (Kong, F.; et al J. Cell Biol. 2009, 185, 1275-1284). The analytic expression and model parameters describe very well all anomalous dependences identified in the experiments.
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Affiliation(s)
| | - Oleg V. Prezhdo
- Department of Chemistry, University of Washington, Seattle, WA 98195
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45
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Pillitteri D, Pilgrimm AK, Kirchmaier CM. Novel Mutations in the GPIIb and GPIIIa Genes in Glanzmann Thrombasthenia. Transfus Med Hemother 2010; 37:268-277. [PMID: 21113249 PMCID: PMC2980511 DOI: 10.1159/000320258] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 08/17/2010] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND: Glanzmann thrombasthenia (GT) is an inherited autosomal recessive platelet disorder characterized by a complete or partial lack, or mutation, of the GPIIb/IIIa complex (integrin α(IIb)β(3)) on the thrombocytes' surface, leading to a severe bleeding syndrome. MATERIAL AND METHODS: Molecular genetic analysis was performed in patients with suspected GT. The aim of the present study was the identification of new natural variants, their impact on platelet function, and their relation to the risk of bleeding. RESULTS: Expression of the platelet integrin α(IIb)β(3) was determined by flow cytometry. Mutations were identified through sequencing of cDNA and genomic DNA. In addition, platelet function studies (PAC-binding, aggregations) were implemented. The study included 25 patients revealing 13 mutations (GPIIb: n = 9; GPIIIa: n = 4). Two of the 13 mutations were previously described (T207I; L214P). The remaining mutations have not been published yet, whereas 1 mutation in 2 unrelated families was identical (3062 T→C). CONCLUSION: All patients with less than 25% of present α(IIb)β(3) have a medical history of bleeding.
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Affiliation(s)
- Daniele Pillitteri
- Deutsche Klinik für Diagnostik, Sektion Innere Medizin I, Arbeitsgruppe: «Thrombose, Hämostase und vaskuläre Medizin», Wiesbaden, Germany
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46
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Freeman SA, McLeod SJ, Dukowski J, Austin P, Lee CCY, Millen-Martin B, Kubes P, McCafferty DM, Gold MR, Roskelley CD. Preventing the activation or cycling of the Rap1 GTPase alters adhesion and cytoskeletal dynamics and blocks metastatic melanoma cell extravasation into the lungs. Cancer Res 2010; 70:4590-601. [PMID: 20484042 DOI: 10.1158/0008-5472.can-09-3414] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Rap1 GTPase is a master regulator of cell adhesion, polarity, and migration. We show that both blocking Rap1 activation and expressing a constitutively active form of Rap1 reduced the ability of B16F1 melanoma cells to extravasate from the microvasculature and form metastatic lesions in the lungs. This correlated with a decreased ability of the tumor cells to undergo transendothelial migration (TEM) in vitro and form dynamic, F-actin-rich pseudopodia that penetrate capillary endothelial walls in vivo. Using multiple tumor cell lines, we show that the inability to form these membrane protrusions, which likely promote TEM and extravasation, can be explained by altered adhesion dynamics and impaired cell polarization that result when Rap1 activation or cycling is perturbed. Thus, targeting Rap1 could be a useful approach for reducing the metastatic dissemination of tumor cells that undergo active TEM.
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Affiliation(s)
- Spencer A Freeman
- Departments of Cellular and Physiological Sciences and Microbiology and Immunology and I3 and CELL Research Groups, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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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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48
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Provasi D, Murcia M, Coller BS, Filizola M. Targeted molecular dynamics reveals overall common conformational changes upon hybrid domain swing-out in beta3 integrins. Proteins 2009; 77:477-89. [PMID: 19455709 DOI: 10.1002/prot.22463] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The beta3 integrin family members alphaIIbeta3 and alphaVbeta3 signal bidirectionally through long-range allosteric changes, including a transition from a bent unliganded-closed low-affinity state to an extended liganded-open high-affinity state. To obtain an atomic-level description of this transition in an explicit solvent, we carried out targeted molecular dynamics simulations of the headpieces of alphaIIbeta3 and alphaVbeta3 integrins. Although minor differences were observed between these receptors, our results suggest a common transition pathway in which the hybrid domain swing-out is accompanied by conformational changes within the beta3 betaA (I-like) domain that propagate through the alpha7 helix C-terminus, and are followed by the alpha7 helix downward motion and the opening of the beta6-alpha7 loop. Breaking of contact interactions between the beta6-alpha7 loop and the alpha1 helix N-terminus results in helix straightening, internal rearrangements of the specificity determining loop (SDL), movement of the beta1-alpha1 loop toward the metal ion dependent adhesion site (MIDAS), and final changes at the interfaces between the beta3 betaA (I-like) domain and either the hybrid or the alpha beta-propeller domains. Taken together, our results suggest novel testable hypotheses of intradomain and interdomain interactions responsible for beta3 integrin activation.
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Affiliation(s)
- Davide Provasi
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, NY 10029-6574, USA
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49
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Gaillard T, Dejaegere A, Stote RH. Dynamics of beta3 integrin I-like and hybrid domains: insight from simulations on the mechanism of transition between open and closed forms. Proteins 2009; 76:977-94. [PMID: 19350618 DOI: 10.1002/prot.22404] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The conformational dynamics of the I-like and Hybrid domains from the beta3 integrin headpiece were studied by molecular dynamics simulation and normal mode analysis. Crystallographic structures of integrins show that the integrin headpiece can exist in largely different conformations manifested by a significant difference in the angle between the I-like and Hybrid domains. The relative orientation of these two domains is believed to be a crucial element of integrin function, as it may relate local structural modifications induced by ligand binding into large-scale conformational changes. To investigate the detailed mechanisms responsible for this coupling, we carried out molecular dynamics simulations of the I-like/Hybrid system and employed quasi-harmonic and normal mode analyses to characterize the large-scale motions. Our results show that the conformational transition of I-like and Hybrid domains inferred from crystallographic data is contained in the low-frequency dynamics of the system. Using targeted molecular dynamics simulations, we investigated the roles played by two structural elements of the I-like domain, the alpha7 and alpha1 helices, in the interdomain transition. From our results, we propose that these two helices function in tandem to initiate large-scale, interdomain conformational transition apparent in integrin activation and signaling.
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Affiliation(s)
- Thomas Gaillard
- Laboratoire de Biophysicochimie Moléculaire, Institut de Chimie de Strasbourg, Université de Strasbourg, Strasbourg, France
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50
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Mould AP, Koper E, Byron A, Zahn G, Humphries MJ. Mapping the ligand-binding pocket of integrin alpha5beta1 using a gain-of-function approach. Biochem J 2009; 424:179-89. [PMID: 19747169 PMCID: PMC3329623 DOI: 10.1042/bj20090992] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Integrin alpha5beta1 is a key receptor for the extracellular matrix protein fibronectin. Antagonists of human integrin alpha5beta1 have therapeutic potential as anti-angiogenic agents in cancer and diseases of the eye. However, the structure of the integrin is unsolved and the atomic basis of fibronectin and antagonist binding by integrin alpha5beta1 is poorly understood. In the present study, we demonstrate that zebrafish alpha5beta1 integrins do not interact with human fibronectin or the human alpha5beta1 antagonists JSM6427 and cyclic peptide CRRETAWAC. Zebrafish alpha5beta1 integrins do bind zebrafish fibronectin-1, and mutagenesis of residues on the upper surface and side of the zebrafish alpha5 subunit beta-propeller domain shows that these residues are important for the recognition of the Arg-Gly-Asp (RGD) motif and the synergy sequence [Pro-His-Ser-Arg-Asn (PHSRN)] in fibronectin. Using a gain-of-function analysis involving swapping regions of the zebrafish integrin alpha5 subunit with the corresponding regions of human alpha5 we show that blades 1-4 of the beta-propeller are required for human fibronectin recognition, suggesting that fibronectin binding involves a broad interface on the side and upper face of the beta-propeller domain. We find that the loop connecting blades 2 and 3 of the beta-propeller, the D3-A3 loop, contains residues critical for antagonist recognition, with a minor role played by residues in neighbouring loops. A new homology model of human integrin alpha5beta1 supports an important function for D3-A3 loop residues Trp157 and Ala158 in the binding of antagonists. These results will aid the development of reagents that block integrin alpha5beta1 functions in vivo.
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Affiliation(s)
- A. Paul Mould
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Ewa Koper
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Adam Byron
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | | | - Martin J. Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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