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Goonoo N. Vascularization and angiogenesis in electrospun tissue engineered constructs: towards the creation of long-term functional networks. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aaab03] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Di Q, Cheng Z, Kim W, Liu Z, Song H, Li X, Nan Y, Wang C, Cheng X. Impaired cross-activation of β3 integrin and VEGFR-2 on endothelial progenitor cells with aging decreases angiogenesis in response to hypoxia. Int J Cardiol 2013; 168:2167-76. [DOI: 10.1016/j.ijcard.2013.01.240] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 12/15/2012] [Accepted: 01/18/2013] [Indexed: 11/26/2022]
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3
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Wang L, Pedroja BS, Meyers EE, Garcia AL, Twining SS, Bernstein AM. Degradation of internalized αvβ5 integrin is controlled by uPAR bound uPA: effect on β1 integrin activity and α-SMA stress fiber assembly. PLoS One 2012; 7:e33915. [PMID: 22470492 PMCID: PMC3309951 DOI: 10.1371/journal.pone.0033915] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 02/19/2012] [Indexed: 02/06/2023] Open
Abstract
Myofibroblasts (Mfs) that persist in a healing wound promote extracellular matrix (ECM) accumulation and excessive tissue contraction. Increased levels of integrin αvβ5 promote the Mf phenotype and other fibrotic markers. Previously we reported that maintaining uPA (urokinase plasminogen activator) bound to its cell-surface receptor, uPAR prevented TGFβ-induced Mf differentiation. We now demonstrate that uPA/uPAR controls integrin β5 protein levels and in turn, the Mf phenotype. When cell-surface uPA was increased, integrin β5 levels were reduced (61%). In contrast, when uPA/uPAR was silenced, integrin β5 total and cell-surface levels were increased (2–4 fold). Integrin β5 accumulation resulted from a significant decrease in β5 ubiquitination leading to a decrease in the degradation rate of internalized β5. uPA-silencing also induced α-SMA stress fiber organization in cells that were seeded on collagen, increased cell area (1.7 fold), and increased integrin β1 binding to the collagen matrix, with reduced activation of β1. Elevated cell-surface integrin β5 was necessary for these changes after uPA-silencing since blocking αvβ5 function reversed these effects. Our data support a novel mechanism by which downregulation of uPA/uPAR results in increased integrin αvβ5 cell-surface protein levels that regulate the activity of β1 integrins, promoting characteristics of the persistent Mf.
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Affiliation(s)
- Lingyan Wang
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Benjamin S. Pedroja
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Erin E. Meyers
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Angelo L. Garcia
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Sally S. Twining
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Audrey M. Bernstein
- Department of Ophthalmology, Mount Sinai School of Medicine, New York, New York, United States of America
- * E-mail:
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West XZ, Meller N, Malinin NL, Deshmukh L, Meller J, Mahabeleshwar GH, Weber ME, Kerr BA, Vinogradova O, Byzova TV. Integrin β3 crosstalk with VEGFR accommodating tyrosine phosphorylation as a regulatory switch. PLoS One 2012; 7:e31071. [PMID: 22363548 PMCID: PMC3281915 DOI: 10.1371/journal.pone.0031071] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 01/01/2012] [Indexed: 02/05/2023] Open
Abstract
Integrins mediate cell adhesion, migration, and survival by connecting intracellular machinery with the surrounding extracellular matrix. Previous studies demonstrated the importance of the interaction between β3 integrin and VEGF type 2 receptor (VEGFR2) in VEGF-induced angiogenesis. Here we present in vitro evidence of the direct association between the cytoplasmic tails (CTs) of β3 and VEGFR2. Specifically, the membrane-proximal motif around 801YLSI in VEGFR2 mediates its binding to non-phosphorylated β3CT, accommodating an α-helical turn in integrin bound conformation. We also show that Y747 phosphorylation of β3 enhances the above interaction. To demonstrate the importance of β3 phosphorylation in endothelial cell functions, we synthesized β3CT-mimicking Y747 phosphorylated and unphosphorylated membrane permeable peptides. We show that a peptide containing phospho-Y747 but not F747 significantly inhibits VEGF-induced signaling and angiogenesis. Moreover, phospho-Y747 peptide exhibits inhibitory effect only in WT but not in β3 integrin knock-out or β3 integrin knock-in cells expressing β3 with two tyrosines substituted for phenylalanines, demonstrating its specificity. Importantly, these peptides have no effect on fibroblast growth factor receptor signaling. Collectively these data provide novel mechanistic insights into phosphorylation dependent cross-talk between integrin and VEGFR2.
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Affiliation(s)
- Xiaoxia Z. West
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Nahum Meller
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Nikolay L. Malinin
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Lalit Deshmukh
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut, United States of America
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Julia Meller
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Ganapati H. Mahabeleshwar
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- University Hospitals Harrington-McLaughlin Heart & Vascular Institute and Case Cardiovascular Research Institute, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Malory E. Weber
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Bethany A. Kerr
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Olga Vinogradova
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut, United States of America
- * E-mail: (OV); (TVB)
| | - Tatiana V. Byzova
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- * E-mail: (OV); (TVB)
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5
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Cho H, Balaji S, Sheikh AQ, Hurley JR, Tian YF, Collier JH, Crombleholme TM, Narmoneva DA. Regulation of endothelial cell activation and angiogenesis by injectable peptide nanofibers. Acta Biomater 2012; 8:154-64. [PMID: 21925628 DOI: 10.1016/j.actbio.2011.08.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 08/12/2011] [Accepted: 08/31/2011] [Indexed: 11/17/2022]
Abstract
RAD16-II peptide nanofibers are promising for vascular tissue engineering and were shown to enhance angiogenesis in vitro and in vivo, although the mechanism remains unknown. We hypothesized that the pro-angiogenic effect of RAD16-II results from low-affinity integrin-dependent interactions of microvascular endothelial cells (MVECs) with RAD motifs. Mouse MVECs were cultured on RAD16-II with or without integrin and MAPK/ERK pathway inhibitors, and angiogenic responses were quantified. The results were validated in vivo using a mouse diabetic wound healing model with impaired neovascularization. RAD16-II stimulated spontaneous capillary morphogenesis, and increased β(3) integrin phosphorylation and VEGF expression in MVECs. These responses were abrogated in the presence of β(3) and MAPK/ERK pathway inhibitors or on the control peptide without RAD motifs. Wide-spectrum integrin inhibitor echistatin completely abolished RAD16-II-mediated capillary morphogenesis in vitro and neovascularization and VEGF expression in the wound in vivo. The addition of the RGD motif to RAD16-II did not change nanofiber architecture or mechanical properties, but resulted in significant decrease in capillary morphogenesis. Overall, these results suggest that low-affinity non-specific interactions between cells and RAD motifs can trigger angiogenic responses via phosphorylation of β(3) integrin and MAPK/ERK pathway, indicating that low-affinity sequences can be used to functionalize biocompatible materials for the regulation of cell migration and angiogenesis, thus expanding the current pool of available motifs that can be used for such functionalization. Incorporation of RAD or similar motifs into protein engineered or hybrid peptide scaffolds may represent a novel strategy for vascular tissue engineering and will further enhance design opportunities for new scaffold materials.
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Affiliation(s)
- Hongkwan Cho
- School of Energy, Environmental, Biological, and Medical Engineering, University of Cincinnati, Cincinnati, OH 45221, USA
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6
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Mersich AT, Miller MR, Chkourko H, Blystone SD. The formin FRL1 (FMNL1) is an essential component of macrophage podosomes. Cytoskeleton (Hoboken) 2010; 67:573-85. [PMID: 20617518 DOI: 10.1002/cm.20468] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Podosomes are highly dynamic actin-rich adhesion structures in cells of myeloid lineage and some transformed cells. Unlike transformed mesenchymal cell types, podosomes are the sole adhesion structure in macrophage and thus mediate all contact with adhesion substrate, including movement through complex tissues for immune surveillance. The existence of podosomes in inflammatory macrophages and transformed cell types suggest an important role in tissue invasion. The proteome, assembly, and maintenance of podosomes are emerging, but remain incompletely defined. Previously, we reported a formin homology sequence and actin assembly activity in association with macrophage beta-3 integrin. In this study we demonstrate by quantitative reverse transcriptase polymerase chain reaction and Western blotting that the formin FRL1 is specifically upregulated during monocyte differentiation to macrophages. We show that the formin FRL1 localizes to the actin-rich cores of primary macrophage podosomes. FRL1 co-precipitates with beta-3 integrin and both fixed and live cell fluorescence microscopy show that endogenous and overexpressed FRL1 selectively localize to macrophage podosomes. Targeted disruption of FRL1 by siRNA results in reduced cell adhesion and disruption of podosome dynamics. Our data suggest that FRL1 is responsible for modifying actin at the macrophage podosome and may be involved in actin cytoskeleton dynamics during adhesion and migration within tissues.
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Affiliation(s)
- Akos T Mersich
- Department of Cell and Development Biology, SUNY Upstate Medical University, Syracuse, New York 13210, USA
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7
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Bledzka K, Bialkowska K, Nie H, Qin J, Byzova T, Wu C, Plow EF, Ma YQ. Tyrosine phosphorylation of integrin beta3 regulates kindlin-2 binding and integrin activation. J Biol Chem 2010; 285:30370-4. [PMID: 20702409 DOI: 10.1074/jbc.c110.134247] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Kindlins are essential for integrin activation in cell systems and do so by working in a cooperative fashion with talin via their direct interaction with integrin β cytoplasmic tails (CTs). Kindlins interact with the membrane-distal NxxY motif, which is distinct from the talin-binding site within the membrane-proximal NxxY motif. The Tyr residues in both motifs can be phosphorylated, and it has been suggested that this modification of the membrane-proximal NxxY motif negatively regulates interaction with the talin head domain. However, the influence of Tyr phosphorylation of the membrane-distal NxxY motif on kindlin binding is unknown. Using mutational analyses and phosphorylated peptides, we show that phosphorylation of the membrane-distal NITY(759) motif in the β(3) CT disrupts kindlin-2 recognition. Phosphorylation of this membrane-distal Tyr also disables the ability of kindlin-2 to coactivate the integrin. In direct binding studies, peptides corresponding to the non-phosphorylated β(3) CT interacted well with kindlin-2, whereas the Tyr(759)-phosphorylated peptide failed to bind kindlin-2 with measurable affinity. These observations indicate that transitions between the phosphorylated and non-phosphorylated states of the integrin β(3) CT determine reactivity with kindlin-2 and govern the role of kindlin-2 in regulating integrin activation.
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Affiliation(s)
- Kamila Bledzka
- Department of Molecular Cardiology, Joseph J Jacobs Center for Thrombosis and Vascular Biology, Cleveland Clinic, Cleveland, Ohio 44195, USA
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8
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Anthis NJ, Haling JR, Oxley CL, Memo M, Wegener KL, Lim CJ, Ginsberg MH, Campbell ID. Beta integrin tyrosine phosphorylation is a conserved mechanism for regulating talin-induced integrin activation. J Biol Chem 2009; 284:36700-36710. [PMID: 19843520 PMCID: PMC2794784 DOI: 10.1074/jbc.m109.061275] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Revised: 10/09/2009] [Indexed: 01/04/2023] Open
Abstract
Integrins are large membrane-spanning receptors fundamental to cell adhesion and migration. Integrin adhesiveness for the extracellular matrix is activated by the cytoskeletal protein talin via direct binding of its phosphotyrosine-binding-like F3 domain to the cytoplasmic tail of the beta integrin subunit. The phosphotyrosine-binding domain of the signaling protein Dok1, on the other hand, has an inactivating effect on integrins, a phenomenon that is modulated by integrin tyrosine phosphorylation. Using full-length tyrosine-phosphorylated (15)N-labeled beta3, beta1A, and beta7 integrin tails and an NMR-based protein-protein interaction assay, we show that talin1 binds to the NPXY motif and the membrane-proximal portion of beta3, beta1A, and beta7 tails, and that the affinity of this interaction is decreased by integrin tyrosine phosphorylation. Dok1 only interacts weakly with unphosphorylated tails, but its affinity is greatly increased by integrin tyrosine phosphorylation. The Dok1 interaction remains restricted to the integrin NPXY region, thus phosphorylation inhibits integrin activation by increasing the affinity of beta integrin tails for a talin competitor that does not form activating membrane-proximal interactions with the integrin. Key residues governing these specificities were identified by detailed structural analysis, and talin1 was engineered to bind preferentially to phosphorylated integrins by introducing the mutation D372R. As predicted, this mutation affects talin1 localization in live cells in an integrin phosphorylation-specific manner. Together, these results indicate that tyrosine phosphorylation is a common mechanism for regulating integrin activation, despite subtle differences in how these integrins interact with their binding proteins.
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Affiliation(s)
- Nicholas J Anthis
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3DR, United Kingdom, California 92093.
| | - Jacob R Haling
- Department of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Camilla L Oxley
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3DR, United Kingdom, California 92093
| | - Massimiliano Memo
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3DR, United Kingdom, California 92093
| | - Kate L Wegener
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3DR, United Kingdom, California 92093
| | - Chinten J Lim
- Department of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Mark H Ginsberg
- Department of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Iain D Campbell
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3DR, United Kingdom, California 92093.
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Aziz MM, Ishihara S, Mishima Y, Oshima N, Moriyama I, Yuki T, Kadowaki Y, Rumi MAK, Amano Y, Kinoshita Y. MFG-E8 Attenuates Intestinal Inflammation in Murine Experimental Colitis by Modulating Osteopontin-Dependent αvβ3 Integrin Signaling. THE JOURNAL OF IMMUNOLOGY 2009; 182:7222-32. [DOI: 10.4049/jimmunol.0803711] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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10
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Somanath PR, Malinin NL, Byzova TV. Cooperation between integrin alphavbeta3 and VEGFR2 in angiogenesis. Angiogenesis 2009; 12:177-85. [PMID: 19267251 DOI: 10.1007/s10456-009-9141-9] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 02/16/2009] [Indexed: 11/30/2022]
Abstract
The cross-talk between receptor tyrosine kinases and integrin receptors are known to be crucial for a number of cellular functions. On endothelial cells, an interaction between integrin alphavbeta3 and VEGFR2 seems to be particularly important process during vascularization. Importantly, the functional association between VEGFR2 and integrin alphavbeta3 is of reciprocal nature since each receptor is able to promote activation of its counterpart. This mutually beneficial relationship regulates a number of cellular activities involved in angiogenesis, including endothelial cell migration, survival and tube formation, and hematopoietic cell functions within vasculature. This article discusses several possible mechanisms reported by different labs which mediate formation of the complex between VEGFR-2 and alphavbeta3 on endothelial cells. The pathological consequences and regulatory events involved in this receptor cross-talk are also presented.
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Affiliation(s)
- Payaningal R Somanath
- Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Department of Molecular Cardiology, NB50, Lerner Research Institute, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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11
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Feng W, McCabe NP, Mahabeleshwar GH, Somanath PR, Phillips DR, Byzova TV. The angiogenic response is dictated by beta3 integrin on bone marrow-derived cells. ACTA ACUST UNITED AC 2009; 183:1145-57. [PMID: 19075116 PMCID: PMC2600740 DOI: 10.1083/jcb.200802179] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Angiogenesis is dependent on the coordinated action of numerous cell types. A key adhesion molecule expressed by these cells is the αvβ3 integrin. Here, we show that although this receptor is present on most vascular and blood cells, the key regulatory function in tumor and wound angiogenesis is performed by β3 integrin on bone marrow–derived cells (BMDCs) recruited to sites of neovascularization. Using knockin mice expressing functionally stunted β3 integrin, we show that bone marrow transplantation rescues impaired angiogenesis in these mice by normalizing BMDC recruitment. We demonstrate that αvβ3 integrin enhances BMDC recruitment and retention at angiogenic sites by mediating cellular adhesion and transmigration of BMDCs through the endothelial monolayer but not their release from the bone niche. Thus, β3 integrin has the potential to control processes such as tumor growth and wound healing by regulating BMDC recruitment to sites undergoing pathological and adaptive angiogenesis.
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Affiliation(s)
- Weiyi Feng
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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12
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Oxley CL, Anthis NJ, Lowe ED, Vakonakis I, Campbell ID, Wegener KL. An integrin phosphorylation switch: the effect of beta3 integrin tail phosphorylation on Dok1 and talin binding. J Biol Chem 2007; 283:5420-6. [PMID: 18156175 DOI: 10.1074/jbc.m709435200] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Integrins play a fundamental role in cell migration and adhesion; knowledge of how they are regulated and controlled is vital for understanding these processes. Recent work showed that Dok1 negatively regulates integrin activation, presumably by competition with talin. To understand how this occurs, we used NMR spectroscopy and x-ray crystallography to investigate the molecular details of interactions with integrins. The binding affinities of beta3 integrin tails for the Dok1 and talin phosphotyrosine binding domains were quantified using 15N-1H hetero-nuclear single quantum correlation titrations, revealing that the unphosphorylated integrin tail binds more strongly to talin than Dok1. Chemical shift mapping showed that unlike talin, Dok1 exclusively interacts with the canonical NPXY motif of the beta3 integrin tail. Upon phosphorylation of Tyr 747 in the beta3 integrin tail, however, Dok1 then binds much more strongly than talin. Thus, we show that phosphorylation of Tyr 747 provides a switch for integrin ligand binding. This switch may represent an in vivo mechanism for control of integrin receptor activation. These results have implications for the control of integrin signaling by proteins containing phosphotyrosine binding domains.
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Affiliation(s)
- Camilla L Oxley
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
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Mahabeleshwar GH, Feng W, Reddy K, Plow EF, Byzova TV. Mechanisms of integrin-vascular endothelial growth factor receptor cross-activation in angiogenesis. Circ Res 2007; 101:570-80. [PMID: 17641225 PMCID: PMC2723825 DOI: 10.1161/circresaha.107.155655] [Citation(s) in RCA: 233] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The functional responses of endothelial cells are dependent on signaling from peptide growth factors and the cellular adhesion receptors, integrins. These include cell adhesion, migration, and proliferation, which, in turn, are essential for more complex processes such as formation of the endothelial tube network during angiogenesis. This study identifies the molecular requirements for the cross-activation between beta3 integrin and tyrosine kinase receptor 2 for vascular endothelial growth factor (VEGF) receptor (VEGFR-2) on endothelium. The relationship between VEGFR-2 and beta3 integrin appears to be synergistic, because VEGFR-2 activation induces beta3 integrin tyrosine phosphorylation, which, in turn, is crucial for VEGF-induced tyrosine phosphorylation of VEGFR-2. We demonstrate here that adhesion- and growth factor-induced beta3 integrin tyrosine phosphorylation are directly mediated by c-Src. VEGF-stimulated recruitment and activation of c-Src and subsequent beta3 integrin tyrosine phosphorylation are critical for interaction between VEGFR-2 and beta3 integrin. Moreover, c-Src mediates growth factor-induced beta3 integrin activation, ligand binding, beta3 integrin-dependent cell adhesion, directional migration of endothelial cells, and initiation of angiogenic programming in endothelial cells. Thus, the present study determines the molecular mechanisms and consequences of the synergism between 2 cell surface receptor systems, growth factor receptor and integrins, and opens new avenues for the development of pro- and antiangiogenic strategies.
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Affiliation(s)
- Ganapati H Mahabeleshwar
- Department of Molecular Cardiology, The Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
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Patsenker E, Popov Y, Wiesner M, Goodman SL, Schuppan D. Pharmacological inhibition of the vitronectin receptor abrogates PDGF-BB-induced hepatic stellate cell migration and activation in vitro. J Hepatol 2007; 46:878-87. [PMID: 17258347 DOI: 10.1016/j.jhep.2006.11.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 11/07/2006] [Accepted: 11/13/2006] [Indexed: 01/18/2023]
Abstract
BACKGROUND/AIMS Activated hepatic stellate cells (HSC) play a central role in the development of liver fibrosis. Platelet-derived growth factor (PDGF)-BB and the integrin alphavbeta3 mediate mesenchymal cell migration and proliferation. However, their contribution and interaction during fibrogenic activation of HSC remains unclear. To this aim we investigated if PDFGF-BB and alphavbeta3 interact, and how far small molecular inhibitors of alphavbeta3 modulate PDGF-BB and serum-induced migration, proliferation and fibrogenic activation of HSC. METHODS Rat and human HSC were subjected to migration and proliferation assays in the presence or absence of a peptide or a nonpeptide alphavbeta3 inhibitor. Activation of mitogen-activated protein kinases (ERK1/2, p38), Akt, focal adhesion kinase (FAK), paxillin and beta3 integrin was evaluated by phospho-specific Western blotting. Fibrosis related transcripts were determined by quantitative real-time PCR. RESULTS PDGF-BB-stimulated HSC migration which was blocked dose-dependently by the alphavbeta3 antagonists, with complete inhibition at 10(-6)M. alphavbeta3 blockage did not affect cell viability or proliferation, while it decreased phosphorylation of FAK, paxillin, beta3 integrin and p38, but not of ERK1/2 or Akt. alphavbeta3 inhibition led to downregulation of certain profibrogenic transcripts, while it upregulated fibrolytic MMP-13 mRNA. CONCLUSIONS Inhibition of integrin alphavbeta3 leads to abrogation of migration of HSC stimulated with PDGF-BB and to an antifibrogenic gene expression pattern.
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Affiliation(s)
- Eleonora Patsenker
- Institute of Clinical Pharmacology, University of Bern, Bern, Switzerland
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15
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Sun YX, Fang M, Wang J, Cooper CR, Pienta KJ, Taichman RS. Expression and activation of alpha v beta 3 integrins by SDF-1/CXC12 increases the aggressiveness of prostate cancer cells. Prostate 2007; 67:61-73. [PMID: 17034033 DOI: 10.1002/pros.20500] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Stromal cell-derived factor-1 (SDF-1 or CXCL12) and CXCR4 are key elements in the metastasis of prostate cancer cells to bone--but the mechanisms as to how it localizes to the marrow remains unclear. METHODS Prostate cancer cell lines were stimulated with SDF-1 and evaluated for alterations in the expression of adhesion molecules using microarrays, FACs, and Western blotting to identify alpha(v)beta(3) receptors. Cell-cell adhesion and invasion assays were used to verify that activation of the receptor is responsive to SDF-1. RESULTS We demonstrate that SDF-1 transiently regulates the number and affinity of alpha(v)beta(3) receptors by prostate cancer cells to enhance their metastatic behavior by increasing adhesiveness and invasiveness. SDF-1 transiently increased the expression of beta(3) receptor subunit and increased its phosphorylation in metastatic but not nonmetastatic cells. CONCLUSIONS The transition from a locally invasive phenotype to a metastatic phenotype may be primed by the elevated expression of alpha(v)beta(3) receptors. Activation and increased expression of alpha(v)beta(3) within SDF-1-rich organs may participate in metastatic localization.
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Affiliation(s)
- Yan-Xi Sun
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI 48109-1078, USA
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16
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Wang HQ, Bai L, Shen BR, Yan ZQ, Jiang ZL. Coculture with endothelial cells enhances vascular smooth muscle cell adhesion and spreading via activation of β1-integrin and phosphatidylinositol 3-kinase/Akt. Eur J Cell Biol 2007; 86:51-62. [PMID: 17141917 DOI: 10.1016/j.ejcb.2006.09.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 09/25/2006] [Accepted: 09/28/2006] [Indexed: 10/23/2022] Open
Abstract
The interactions between endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) play significant roles in the homeostasis of the blood vessel during vascular remodeling. Cell adhesion and spreading are an essential process for VSMC migration, survival and proliferation in the events of vascular physiology and pathophysiology. However, effects of ECs on adhesion and spreading of VSMCs have not been characterized yet. Here, the interaction of ECs and VSMCs on adhesion and spreading of VSMCs were investigated by using a coculture system. The results showed that VSMCs cocultured with ECs exhibited a significant increase in the number of adherent and spreading cells, and much more mRNA (twofold, P<0.01) and protein (threefold, P<0.05) expression of beta(1)-integrin comparing to the control, i.e., VSMCs cultured alone. Furthermore, the enhanced functional activity of beta(1)-integrin expression was confirmed by FACS. A beta(1)-integrin blocking antibody (P5D2) could inhibit the EC-induced VSMC adhesion and spreading. It was demonstrated that in correspondence with enhanced cell adhesion, ECs also prompted focal adhesion complex assembly and stress fiber formation of VSMCs. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway was more pronouncedly activated in response to VSMC attachment. Our results for the first time show that coculture with ECs enhances VSMC adhesion and spreading by up-regulating beta(1)-integrin expression and activating the PI3K/Akt pathway, suggesting that the interaction between ECs and VSMCs serves an important role in vascular homeostasis and remodeling.
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Affiliation(s)
- Han-Qin Wang
- Institute of Mechanobiology and Medical Engineering, Shanghai Jiao Tong University, Mailbox 888, 800 Dongchuan Road, Minhang, Shanghai 200240, China
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Mahabeleshwar GH, Feng W, Phillips DR, Byzova TV. Integrin signaling is critical for pathological angiogenesis. ACTA ACUST UNITED AC 2006; 203:2495-507. [PMID: 17030947 PMCID: PMC2118124 DOI: 10.1084/jem.20060807] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The process of postnatal angiogenesis plays a crucial role in pathogenesis of numerous diseases, including but not limited to tumor growth/metastasis, diabetic retinopathy, and in tissue remodeling upon injury. However, the molecular events underlying this complex process are not well understood and numerous issues remain controversial, including the regulatory function of integrin receptors. To analyze the role of integrin phosphorylation and signaling in angiogenesis, we generated knock-in mice that express a mutant beta3 integrin unable to undergo tyrosine phosphorylation. Two distinct models of pathological angiogenesis revealed that neovascularization is impaired in mutant beta3 knock-in mice. In an ex vivo angiogenesis assay, mutant beta3 knock-in endothelial cells did not form complete capillaries in response to vascular endothelial growth factor (VEGF) stimulation. At the cellular level, defective tyrosine phosphorylation in mutant beta3 knock-in cells resulted in impaired adhesion, spreading, and migration of endothelial cells. At the molecular level, VEGF stimulated complex formation between VEGF receptor-2 and beta3 integrin in wild-type but not in mutant beta3 knock-in endothelial cells. Moreover, phosphorylation of VEGF receptor-2 was significantly reduced in cells expressing mutant beta3 compared to wild type, leading to impaired integrin activation in these cells. These findings provide novel mechanistic insights into the role of integrin-VEGF axis in pathological angiogenesis.
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Affiliation(s)
- Ganapati H Mahabeleshwar
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, NB50, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Wiesner S, Lange A, Fässler R. Local call: from integrins to actin assembly. Trends Cell Biol 2006; 16:327-9. [PMID: 16769214 DOI: 10.1016/j.tcb.2006.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Revised: 04/10/2006] [Accepted: 05/15/2006] [Indexed: 11/25/2022]
Abstract
Integrins link the extracellular matrix to the actin cytoskeleton by triggering the assembly of different types of adhesion complex. One of their major components is filamentous actin (F-actin), and they are important signaling hubs for actin cytoskeleton reorganization in response to chemical and mechanical signals. In an exciting publication, Butler et al. have demonstrated for the first time that purified adhesion complexes possess the entire machinery necessary to actively assemble F-actin as a function of integrin activity and clustering.
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Affiliation(s)
- Sebastian Wiesner
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
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Butler B, Gao C, Mersich AT, Blystone SD. Purified Integrin Adhesion Complexes Exhibit Actin-Polymerization Activity. Curr Biol 2006; 16:242-51. [PMID: 16461277 DOI: 10.1016/j.cub.2005.12.033] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 12/14/2005] [Accepted: 12/15/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND Cell adhesion and motility are accomplished through a functional linkage of the extracellular matrix with the actin cytoskeleton via adhesion complexes composed of integrin receptors and associated proteins. To determine whether this linkage is attained actively or passively, we isolated integrin complexes from nonadherent hematopoietic cells and determined their influence on the polymerization of actin. RESULTS We observed that alpha(V)beta3 complexes are capable of dramatically accelerating the rate of actin assembly, resulting in actin fibers tethered at their growing ends by clustered integrins. The ability to enhance actin polymerization was dependent upon Arg-Gly-Asp-ligand-induced beta3 tyrosine phosphorylation, agonist-induced cellular activation, sequestration of Diaphanous formins, and clustering of the receptor. CONCLUSIONS These results suggest that adhesion complexes actively promote actin assembly from their cytosolic face in order to establish a mechanical linkage with the extracellular matrix.
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Affiliation(s)
- Boyd Butler
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 East Adams St, Syracuse, New York 13210, USA
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Yamodo IH, Blystone SD. Integrin alphaIIb-subunit cytoplasmic domain mutations demonstrate a requirement for tyrosine phosphorylation of beta3-subunits in actin cytoskeletal organization. ACTA ACUST UNITED AC 2005; 11:121-35. [PMID: 16194880 DOI: 10.1080/15419060500212508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Using truncated or mutated alphaIIb integrin cytoplasmic domains fused to the alphaV extracellular domain and expressed with the beta3 integrin subunit, we demonstrate that the double mutation of proline residues 998 and 999 to alanine (PP998/999AA), previously shown to disturb the C-terminal conformation of the alphaIIb integrin cytoplasmic domain, prevents tyrosine phosphorylation of beta3 integrin induced by Arg-Gly-Asp peptide ligation. This mutation also inhibits integrin mediated actin assembly and cell adhesion to vitronectin. In contrast, progressive truncation of the alphaIIb-subunit cytoplasmic domain did not reproduce these effects. Interestingly, the PP998/999AA mutations of alphaIIb did not affect beta3 tyrosine phosphorylation, cell adhesion, or actin polymerization induced by manganese. Exogenous addition of manganese was sufficient to rescue beta3 phosphorylation, cell adhesion, and actin assembly in cells expressing the PP998/999AA mutation when presented with a vitronectin substrate. Further, induction of the high affinity conformation of this mutant beta3 integrin by incubation with either Arg-Gly-Asp peptide or exogenous manganese was equivalent. These results suggest that the extracellular structure of beta3 integrins in the high affinity conformation is not directly related to the structure of the cytoplasmic face of the integrin. Moreover, the requirement for beta3 phosphorylation is demonstrated without mutation of the beta3 subunit. In support of our previous hypothesis of a role for beta3 phosphorylation in adhesion, these studies demonstrate a strong correlation between beta3 tyrosine phosphorylation and assembly of a cytoskeleton competent to support firm cell adhesion.
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Affiliation(s)
- Innocent H Yamodo
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York 13210, USA
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Gao C, Schaefer E, Lakkis M, Blystone SD. β3 Tyrosine Phosphorylation and αvβ3-mediated Adhesion Are Required for Vav1 Association and Rho Activation in Leukocytes. J Biol Chem 2005; 280:15422-9. [PMID: 15699036 DOI: 10.1074/jbc.m414457200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Integrin alpha(v)beta(3)-mediated adhesion of hematopoietic cells to vitronectin results in activation of the Rho GTPases. Mutation of beta(3) tyrosine residue 747, previously shown to disrupt cell adhesion, results in sustained activation of Cdc42 and diminished Rac and Rho activity. We investigated the role of the hematopoietically restricted guanine nucleotide exchange factor Vav1 in alpha(v)beta(3)-mediated adhesion. We find that Vav1, a guanine nucleotide exchange factor for Rac and Rho, associates with alpha(v)beta(3) upon cell adhesion to vitronectin and that this association requires beta(3) tyrosine phosphorylation. Expression of exogenous Vav1 demonstrates that Y160F, but not wild type or the Vav1Y174F mutant, inhibits Rac and Rho activation during alpha(v)beta(3)-mediated cell adhesion to vitronectin. Cells expressing Vav1Y160F exhibit a sustained Cdc42 activation similar to nonphosphorylatable beta(3) mutants. In addition, cytoskeletal reorganization and cell adhesion are severely suppressed in Vav1Y160F-transfected cells, and Vav1Y160F fails to associate with beta(3) integrins. Furthermore, Vav1 itself is selectively phosphorylated upon tyrosine 160 after alpha(v)beta(3)-mediated adhesion, and the association between Vav1 and beta(3) occurs in specific response to adhesion to substrate. These studies describe a phosphorylation-dependent association between beta(3) integrin and Vav1 which is essential for cell progression to a Rho-dominant phenotype during cell adhesion.
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Affiliation(s)
- Chunlei Gao
- Department of Cell and Development Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, USA
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Butler B, Blystone SD. Tyrosine phosphorylation of beta3 integrin provides a binding site for Pyk2. J Biol Chem 2005; 280:14556-62. [PMID: 15695828 DOI: 10.1074/jbc.m411765200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Integrins expressed on leukocytes possess the ability to maintain themselves in a non-adhesive state, thus preventing unwarranted adhesion and uncontrolled inflammation. Leukocyte adhesion is regulated through the modulation of integrin receptors such as alpha(V)beta(3). Firm adhesion to the extracellular matrix and directed cellular motility requires the reorganization of the actin cytoskeleton. The ability of beta(3) to recruit signaling and scaffolding molecules to propagate alpha(V)beta(3) -mediated signals is regulated in part by the phosphorylation of the beta(3) cytoplasmic tail. The identities of integrin-associated signaling molecules within alpha(V)beta(3) podosomes and in particular the proximal binding partners of the beta(3) cytoplasmic tail are not completely known. Here we show that alpha(V)beta(3) ligation induces Pyk2-Tyr-402 phosphorylation and its association with the beta(3) cytoplasmic tail in a beta(3)-Tyr-747 phosphorylation-dependent manner. Pyk2 binding to the beta(3) cytoplasmic tail is direct and dependent upon Pyk2-Tyr-402 and beta(3) -Tyr-747 phosphorylations. These data identify Pyk2 as a phosphorylated beta(3) binding partner, providing a potential structural and signaling platform to achieve alpha(V)beta(3) -mediated remodeling of the actin cytoskeleton.
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Affiliation(s)
- Boyd Butler
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York 13210, USA
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Blystone SD. Integrating an integrin: a direct route to actin. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1692:47-54. [PMID: 15246678 DOI: 10.1016/j.bbamcr.2004.04.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Accepted: 04/08/2004] [Indexed: 01/13/2023]
Abstract
Integrins were so named for their ability to link the extracellular and intracellular skeletons. Now almost 20 years into integrin research, numerous questions remain as to how this interaction is accomplished and how it is modified to achieve a desired phenotype. As the cell adhesion and actin assembly fields are merging in combined approaches, novel actin assembly mechanisms are being uncovered. Some of the earliest identified cytoplasmic linker molecules, believed to mediate integrin-actin binding, are once again the subject of scrutiny as potential dynamic mediators of cell anchorage. It seems plausible that each unique cellular morphology occurs as the result of activation of distinct actin assembly systems that are either stabilized by unique bundling and linker proteins or modified for progression to a new phenotype. While this research initiative is likely to continue rapidly in a forward fashion, it remains to be clarified how integrins assemble the most stable and basic cytoskeletal phenotype, the adherent cell with prominent stress fibers. Recent investigations point towards a shift in the current model of anchoring at the cell periphery by providing both mechanisms and evidence for de novo actin assembly orchestrated by the adhesion site. Lacking a complete pathway from integrin ligation to an integrated extracellular-intracellular skeleton in any single system, this review proposes a simple model of integrin-mediated stress fiber integration by drawing from work in multiple systems.
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Affiliation(s)
- Scott D Blystone
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
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