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Sendo S, Kiosses WB, Yang S, Wu DJ, Lee DWK, Liu L, Aschner Y, Vela AJ, Downey GP, Santelli E, Bottini N. Clustering of phosphatase RPTPα promotes Src signaling and the arthritogenic action of synovial fibroblasts. Sci Signal 2023; 16:eabn8668. [PMID: 37402225 PMCID: PMC10544828 DOI: 10.1126/scisignal.abn8668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/15/2023] [Indexed: 07/06/2023]
Abstract
Receptor-type protein phosphatase α (RPTPα) promotes fibroblast-dependent arthritis and fibrosis, in part, by enhancing the activation of the kinase SRC. Synovial fibroblasts lining joint tissue mediate inflammation and tissue damage, and their infiltration into adjacent tissues promotes disease progression. RPTPα includes an ectodomain and two intracellular catalytic domains (D1 and D2) and, in cancer cells, undergoes inhibitory homodimerization, which is dependent on a D1 wedge motif. Through single-molecule localization and labeled molecule interaction microscopy of migrating synovial fibroblasts, we investigated the role of RPTPα dimerization in the activation of SRC, the migration of synovial fibroblasts, and joint damage in a mouse model of arthritis. RPTPα clustered with other RPTPα and with SRC molecules in the context of actin-rich structures. A known dimerization-impairing mutation in the wedge motif (P210L/P211L) and the deletion of the D2 domain reduced RPTPα-RPTPα clustering; however, it also unexpectedly reduced RPTPα-SRC association. The same mutations also reduced recruitment of RPTPα to actin-rich structures and inhibited SRC activation and cellular migration. An antibody against the RPTPα ectodomain that prevented the clustering of RPTPα also inhibited RPTPα-SRC association and SRC activation and attenuated fibroblast migration and joint damage in arthritic mice. A catalytically inactivating RPTPα-C469S mutation protected mice from arthritis and reduced SRC activation in synovial fibroblasts. We conclude that RPTPα clustering retains it to actin-rich structures to promote SRC-mediated fibroblast migration and can be modulated through the extracellular domain.
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Affiliation(s)
- Sho Sendo
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - William B. Kiosses
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
- La Jolla Institute for Immunology, La Jolla, CA 92037
| | - Shen Yang
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Dennis J. Wu
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Daniel W. K. Lee
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Lin Liu
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Yael Aschner
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Allison J. Vela
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Gregory P. Downey
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado, Aurora, Colorado
- Department of Pediatrics, National Jewish Health, Denver, Colorado
| | - Eugenio Santelli
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Nunzio Bottini
- Dept. of Medicine, University of California San Diego, La Jolla, CA 92093
- Department of Medicine, Kao Autoimmunity Institute, Cedars Sinai Medical Center, Los Angeles, CA, USA
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2
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Aschner Y, Correll KA, Beke K, Foster DG, Roybal HM, Nelson MR, Meador CL, Strand M, Anderson KC, Moore CM, Reynolds PR, Kopf KW, Burnham EL, Downey GP. PTPα Promotes Fibroproliferative Responses After Acute Lung Injury. Am J Physiol Lung Cell Mol Physiol 2022; 323:L69-L83. [PMID: 35670474 DOI: 10.1152/ajplung.00436.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Acute Respiratory Distress Syndrome (ARDS) is a major healthcare problem, accounting for significant mortality and long-term disability. Approximately 25% of patients with ARDS will develop an over-exuberant fibrotic response, termed fibroproliferative ARDS (FP-ARDS) that portends a poor prognosis and increased mortality. The cellular pathologic processes that drive FP-ARDS remain incompletely understood. We have previously shown that the transmembrane receptor-type tyrosine phosphatase Protein Tyrosine Phosphatase-a (PTPa) promotes pulmonary fibrosis in preclinical murine models through regulation of TGF-b signaling. In this study, we examine the role of PTPa in the pathogenesis of FP-ARDS in a preclinical murine model of acid (HCl)-induced acute lung injury. We demonstrate that while mice genetically deficient in PTPa (Ptpra-/-) are susceptible to early HCl-induced lung injury, they exhibit markedly attenuated fibroproliferative responses. Additionally, early pro-fibrotic gene expression is reduced in lung tissue after acute lung injury in Ptpra-/- mice, and stimulation of naïve lung fibroblasts with the BAL fluid from these mice results in attenuated fibrotic outcomes compared to wild type littermate controls. Transcriptomic analyses demonstrates reduced Extracellular Matrix (ECM) deposition and remodeling in mice genetically deficient in PTPa. Importantly, human lung fibroblasts modified with a CRISPR-targeted deletion of PTPRA exhibit reduced expression of profibrotic genes in response to TGF-β stimulation, demonstrating the importance of PTPa in human lung fibroblasts. Together, these findings demonstrate that PTPa is a key regulator of fibroproliferative processes following acute lung injury and could serve as a therapeutic target for patients at risk for poor long-term outcomes in ARDS.
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Affiliation(s)
- Yael Aschner
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, CO, United States.,Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Kelly A Correll
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Keriann Beke
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Daniel G Foster
- Department of Medicine, National Jewish Health, Denver, CO, United States.,Department of Pediatrics, National Jewish Health, Denver, CO, United States
| | - Helen M Roybal
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Meghan R Nelson
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Carly L Meador
- Department of Medicine, National Jewish Health, Denver, CO, United States
| | - Matthew Strand
- Division of Biostatistics, National Jewish Health, Denver, CO, United States
| | - Kelsey C Anderson
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, United States
| | - Camille M Moore
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, United States.,Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO, United States
| | - Paul R Reynolds
- Department of Medicine, National Jewish Health, Denver, CO, United States.,Department of Pediatrics, National Jewish Health, Denver, CO, United States
| | - Katrina W Kopf
- Office of Academic Affairs, National Jewish Health, Denver, CO, United States
| | - Ellen L Burnham
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, CO, United States
| | - Gregory P Downey
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, CO, United States.,Department of Medicine, National Jewish Health, Denver, CO, United States.,Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO, United States.,Department of Pediatrics, National Jewish Health, Denver, CO, United States.,Office of Academic Affairs, National Jewish Health, Denver, CO, United States.,Department of Immunology and Microbiology, University of Colorado, Aurora, CO, United States
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3
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Lin C, Xin S, Huang X, Zhang F. PTPRA facilitates cancer growth and migration via the TNF-α-mediated PTPRA-NF-κB pathway in MCF-7 breast cancer cells. Oncol Lett 2020; 20:131. [PMID: 32934700 PMCID: PMC7471670 DOI: 10.3892/ol.2020.11992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 04/20/2020] [Indexed: 02/05/2023] Open
Abstract
Protein tyrosine phosphatase receptor type A (PTPRA), one of the classic protein tyrosine phosphatases, is crucial for modulating tumorigenesis and metastasis in breast cancer; however, its functional mechanism has not fully elucidated. The present study assessed PTPRA expression and estimated its clinical impact on survival using the Gene Expression Profiling Interactive Analysis database (GEPIA). Growth curves, colony formations and Transwell assays were utilized to examine cell proliferation and migration. Additionally, luciferase reporter assays were used to examine the potential tumor signaling pathways targeted by PTPRA in HEK293T cells. Furthermore, quantitative PCR (qPCR) was utilized to confirm the transcriptional regulation of PTPRA expression. Bioinformatic analyses of data from GEPIA identified PTPRA overexpression in patients with breast cancer. The growth curve, colony formation and transwell experiments demonstrated that PTPRA upregulation significantly promoted the cell proliferation and migration of MCF-7 breast cancer cells. In contrast, PTPRA knockdown significantly attenuated cell proliferation and migration. Mechanistic experiments revealed that the transcriptional activity of NF-κB was higher compared with other classic tumor pathways when they were activated by PTPRA in HEK293T cells. Furthermore, the transcriptional activity of NF-κB was altered in a PTPRA-dose-dependent manner. Additionally, following exposure to TNF-α, PTPRA-deficient MCF-7 cells exhibited lower NF-κB transcriptional activity compared with normal control cells. The results of the present study demonstrate that PTPRA overexpression accelerates inflammatory tumor phenotypes in breast cancer and that the TNF-α-mediated PTPRA-NF-κB pathway may offer novel insight into early diagnosis and optimum treatment for breast cancer.
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Affiliation(s)
- Canfeng Lin
- Department of Oncology, Shantou Central Hospital, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - Shubo Xin
- Department of Pharmacy, Shantou Central Hospital, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - Xiaoguang Huang
- Department of Oncology, Shantou Central Hospital, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
| | - Feiran Zhang
- Department of General Surgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
- Correspondence to: Dr Feiran Zhang, Department of General Surgery, The First Affiliated Hospital of Shantou University Medical College, 57 Changping Road, Shantou, Guangdong 515041, P.R. China, E-mail:
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4
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Aschner Y, Nelson M, Brenner M, Roybal H, Beke K, Meador C, Foster D, Correll KA, Reynolds PR, Anderson K, Redente EF, Matsuda J, Riches DWH, Groshong SD, Pozzi A, Sap J, Wang Q, Rajshankar D, McCulloch CAG, Zemans RL, Downey GP. Protein tyrosine phosphatase-α amplifies transforming growth factor-β-dependent profibrotic signaling in lung fibroblasts. Am J Physiol Lung Cell Mol Physiol 2020; 319:L294-L311. [PMID: 32491951 PMCID: PMC7473933 DOI: 10.1152/ajplung.00235.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 04/06/2020] [Accepted: 04/25/2020] [Indexed: 01/06/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive, often fatal, fibrosing lung disease for which treatment remains suboptimal. Fibrogenic cytokines, including transforming growth factor-β (TGF-β), are central to its pathogenesis. Protein tyrosine phosphatase-α (PTPα) has emerged as a key regulator of fibrogenic signaling in fibroblasts. We have reported that mice globally deficient in PTPα (Ptpra-/-) were protected from experimental pulmonary fibrosis, in part via alterations in TGF-β signaling. The goal of this study was to determine the lung cell types and mechanisms by which PTPα controls fibrogenic pathways and whether these pathways are relevant to human disease. Immunohistochemical analysis of lungs from patients with IPF revealed that PTPα was highly expressed by mesenchymal cells in fibroblastic foci and by airway and alveolar epithelial cells. To determine whether PTPα promotes profibrotic signaling pathways in lung fibroblasts and/or epithelial cells, we generated mice with conditional (floxed) Ptpra alleles (Ptpraf/f). These mice were crossed with Dermo1-Cre or with Sftpc-CreERT2 mice to delete Ptpra in mesenchymal cells and alveolar type II cells, respectively. Dermo1-Cre/Ptpraf/f mice were protected from bleomycin-induced pulmonary fibrosis, whereas Sftpc-CreERT2/Ptpraf/f mice developed pulmonary fibrosis equivalent to controls. Both canonical and noncanonical TGF-β signaling and downstream TGF-β-induced fibrogenic responses were attenuated in isolated Ptpra-/- compared with wild-type fibroblasts. Furthermore, TGF-β-induced tyrosine phosphorylation of TGF-β type II receptor and of PTPα were attenuated in Ptpra-/- compared with wild-type fibroblasts. The phenotype of cells genetically deficient in PTPα was recapitulated with the use of a Src inhibitor. These findings suggest that PTPα amplifies profibrotic TGF-β-dependent pathway signaling in lung fibroblasts.
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Affiliation(s)
- Yael Aschner
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Meghan Nelson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Matthew Brenner
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Helen Roybal
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Keriann Beke
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Carly Meador
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Daniel Foster
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Kelly A Correll
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Paul R Reynolds
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Kelsey Anderson
- Center for Genes, Environment, and Health, National Jewish Health, Denver, Colorado
| | - Elizabeth F Redente
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
- Division of Cell Biology, Department of Pediatrics, National Jewish Health, Denver, Colorado
- Veterans Affairs Eastern Colorado Heath Care System, Denver, Colorado
| | - Jennifer Matsuda
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
| | - David W H Riches
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
- Division of Cell Biology, Department of Pediatrics, National Jewish Health, Denver, Colorado
- Veterans Affairs Eastern Colorado Heath Care System, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado, Aurora, Colorado
| | - Steve D Groshong
- Division of Pathology, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Ambra Pozzi
- Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee
- Veterans Affairs Medical Center, Nashville, Tennessee
| | - Jan Sap
- Epigenetics and Cell Fate, Université Paris, Paris, France
| | - Qin Wang
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Dhaarmini Rajshankar
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | | | - Rachel L Zemans
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Gregory P Downey
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Department of Pediatrics, National Jewish Health, Denver, Colorado
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado, Aurora, Colorado
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5
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A ternary complex comprising FAK, PTPα and IP3 receptor 1 functionally engages focal adhesions and the endoplasmic reticulum to mediate IL-1-induced Ca2+ signalling in fibroblasts. Biochem J 2015; 473:397-410. [PMID: 26611753 DOI: 10.1042/bj20150907] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/26/2015] [Indexed: 11/17/2022]
Abstract
Ca(2+) release is tightly sequestered in eukaryotic cells to enable fine spatio-temporal control of signalling but how Ca(2+) release from the endoplasmic reticulum (ER) is linked to cell adhesions is not defined. We examined the spatial restriction of Ca(2+) release through the inositol 1,4,5-triphosphate receptor 1 (IP3R1) in response to interleukin-1 (IL-1) and the functions of the adhesion-associated proteins, focal adhesion kinase (FAK) and protein tyrosine phosphatase-α (PTPα). In cultured fibroblasts IL-1 treatment promoted co-localization of PTPα and FAK with the ER and increased association of IP3R1 with PTPα and FAK at focal adhesions (FAs). GST pull-down assays of purified proteins demonstrated that PTPα and FAK directly interacted with IP3R1. These interactions depended on the focal adhesion-targeting (FAT) and band4.1-ezrin-radixin-moesin (FERM) domains of FAK. PTPα was required for the association of IP3R1 with Src, which mediated IP3R1 phosphorylation and consequently ER Ca(2+) release. Collectively, these data indicate that PTPα and FAK, which are enriched in FAs, interact with IP3R1 at adjacent ER sites to spatially sequester IL-1-induced Ca(2+) signalling.
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6
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Wang Y, Wang Q, Arora PD, Rajshankar D, McCulloch CA. Cell adhesion proteins: roles in periodontal physiology and discovery by proteomics. Periodontol 2000 2015; 63:48-58. [PMID: 23931053 DOI: 10.1111/prd.12026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2012] [Indexed: 12/29/2022]
Abstract
Adhesion molecules expressed by periodontal connective tissue cells are involved in cell migration, matrix remodeling and inflammatory responses to infection. Currently, the processes by which the biologic activity of these molecules are appropriately regulated in time and space to preserve tissue homeostasis, and to control inflammatory responses and tissue regeneration, are not defined. As cell adhesions are heterogeneous, dynamic, contain a complex group of interacting molecules and are strongly influenced by the type of substrate to which they adhere, we focus on how cell adhesions in periodontal connective tissues contribute to information generation and processing that regulate periodontal structure and function. We also consider how proteomic methods can be applied to discover novel cell-adhesion proteins that could potentially contribute to the form and function of periodontal tissues.
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7
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Wang Q, Wang Y, Fritz D, Rajshankar D, Downey GP, McCulloch CA. Interactions of the protein-tyrosine phosphatase-α with the focal adhesion targeting domain of focal adhesion kinase are involved in interleukin-1 signaling in fibroblasts. J Biol Chem 2014; 289:18427-41. [PMID: 24821720 DOI: 10.1074/jbc.m113.540294] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interleukin-1 (IL-1) signaling in fibroblasts is mediated through focal adhesions, organelles that are enriched with adaptor and cytoskeletal proteins that regulate signal transduction. We examined interactions of the focal adhesion kinase (FAK) with protein-tyrosine phosphatase-α (PTP-α) in IL-1 signaling. In wild type and FAK knock-out mouse embryonic fibroblasts, we found by immunoblotting, immunoprecipitation, immunostaining, and gene silencing that FAK is required for IL-1-mediated sequestration of PTPα to focal adhesions. Immunoprecipitation and pulldown assays of purified proteins demonstrated a direct interaction between FAK and PTPα, which was dependent on the FAT domain of FAK and by an intact membrane-proximal phosphatase domain of PTPα. Recruitment of PTPα to focal adhesions, IL-1-induced Ca(2+) release from the endoplasmic reticulum, ERK activation, and IL-6, MMP-3, and MMP-9 expression were all blocked in FAK knock-out fibroblasts. These processes were restored in FAK knock-out cells transfected with wild type FAK, FAT domain, and FRNK. Our data indicate that IL-1-induced signaling through focal adhesions involves interactions between the FAT domain of FAK and PTPα.
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Affiliation(s)
- Qin Wang
- From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada
| | - Yongqiang Wang
- From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada
| | - Dominik Fritz
- From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada
| | - Dhaarmini Rajshankar
- From the Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada
| | - Gregory P Downey
- the Division of Pulmonary, Sleep, and Critical Care Medicine, Department of Medicine, National Jewish Health, Denver, Colorado 80206, and the Division of Pulmonary Sciences and Critical Care Medicine, Departments of Medicine and Integrated Department of Immunology, University of Colorado, Aurora, Colorado 80045
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8
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Aschner Y, Khalifah AP, Briones N, Yamashita C, Dolgonos L, Young SK, Campbell MN, Riches DWH, Redente EF, Janssen WJ, Henson PM, Sap J, Vacaresse N, Kapus A, McCulloch CAG, Zemans RL, Downey GP. Protein tyrosine phosphatase α mediates profibrotic signaling in lung fibroblasts through TGF-β responsiveness. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1489-502. [PMID: 24650563 DOI: 10.1016/j.ajpath.2014.01.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 12/23/2013] [Accepted: 01/14/2014] [Indexed: 02/07/2023]
Abstract
Fibrotic lung diseases represent a diverse group of progressive and often fatal disorders with limited treatment options. Although the pathogenesis of these conditions remains incompletely understood, receptor type protein tyrosine phosphatase α (PTP-α encoded by PTPRA) has emerged as a key regulator of fibroblast signaling. We previously reported that PTP-α regulates cellular responses to cytokines and growth factors through integrin-mediated signaling and that PTP-α promotes fibroblast expression of matrix metalloproteinase 3, a matrix-degrading proteinase linked to pulmonary fibrosis. Here, we sought to determine more directly the role of PTP-α in pulmonary fibrosis. Mice genetically deficient in PTP-α (Ptpra(-/-)) were protected from pulmonary fibrosis induced by intratracheal bleomycin, with minimal alterations in the early inflammatory response or production of TGF-β. Ptpra(-/-) mice were also protected from pulmonary fibrosis induced by adenoviral-mediated expression of active TGF-β1. In reciprocal bone marrow chimera experiments, the protective phenotype tracked with lung parenchymal cells but not bone marrow-derived cells. Because fibroblasts are key contributors to tissue fibrosis, we compared profibrotic responses in wild-type and Ptpra(-/-) mouse embryonic and lung fibroblasts. Ptpra(-/-) fibroblasts exhibited hyporesponsiveness to TGF-β, manifested by diminished expression of αSMA, EDA-fibronectin, collagen 1A, and CTGF. Ptpra(-/-) fibroblasts exhibited markedly attenuated TGF-β-induced Smad2/3 transcriptional activity. We conclude that PTP-α promotes profibrotic signaling pathways in fibroblasts through control of cellular responsiveness to TGF-β.
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Affiliation(s)
- Yael Aschner
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado; Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Anthony P Khalifah
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado; Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Natalie Briones
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Cory Yamashita
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado; Division of Respirology, Department of Medicine, University of Western Ontario, London, Ontario, Canada
| | - Lior Dolgonos
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado; Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Scott K Young
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Megan N Campbell
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - David W H Riches
- Department of Pediatrics, National Jewish Health, Denver, Colorado
| | | | - William J Janssen
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado; Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Peter M Henson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado; Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado; Department of Pediatrics, National Jewish Health, Denver, Colorado; Department of Immunology, University of Colorado, Aurora, Colorado
| | - Jan Sap
- Unit of Epigenetics and Cell Fate, UMR7216, University of Paris-Diderot, Paris, France
| | - Nathalie Vacaresse
- Sunnybrook Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Andras Kapus
- Keenan Research Center, Li Ka Shing Knowledge Institute-St. Michael's Hospital, University of Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Ontario, Canada
| | | | - Rachel L Zemans
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado; Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Gregory P Downey
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado; Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado; Department of Pediatrics, National Jewish Health, Denver, Colorado; Department of Immunology, University of Colorado, Aurora, Colorado.
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9
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Molecular Mechanisms Underlying the Force-Dependent Regulation of Actin-to-ECM Linkage at the Focal Adhesions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:135-54. [DOI: 10.1016/b978-0-12-394624-9.00006-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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10
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Rajshankar D, Sima C, Wang Q, Goldberg SR, Kazembe M, Wang Y, Glogauer M, Downey GP, McCulloch CA. Role of PTPα in the destruction of periodontal connective tissues. PLoS One 2013; 8:e70659. [PMID: 23940616 PMCID: PMC3734242 DOI: 10.1371/journal.pone.0070659] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 06/20/2013] [Indexed: 01/24/2023] Open
Abstract
IL-1β contributes to connective tissue destruction in part by up-regulating stromelysin-1 (MMP-3), which in fibroblasts is a focal adhesion-dependent process. Protein tyrosine phosphatase-α (PTPα) is enriched in and regulates the formation of focal adhesions, but the role of PTPα in connective tissue destruction is not defined. We first examined destruction of periodontal connective tissues in adult PTPα+/+ and PTPα−/− mice subjected to ligature-induced periodontitis, which increases the levels of multiple cytokines, including IL-1β. Three weeks after ligation, maxillae were processed for morphometry, micro-computed tomography and histomorphometry. Compared with unligated controls, there was ∼1.5–3 times greater bone loss as well as 3-fold reduction of the thickness of the gingival lamina propria and 20-fold reduction of the amount of collagen fibers in WT than PTPα−/− mice. Immunohistochemical staining of periodontal tissue showed elevated expression of MMP-3 at ligated sites. Second, to examine mechanisms by which PTPα may regulate matrix degradation, human MMP arrays were used to screen conditioned media from human gingival fibroblasts treated with vehicle, IL-1β or TNFα. Although MMP-3 was upregulated by both cytokines, only IL-1β stimulated ERK activation in human gingival fibroblasts plated on fibronectin. TIRF microscopy and immunoblotting analyses of cells depleted of PTPα activity with the use of various mutated constructs or with siRNA or PTPαKO and matched wild type fibroblasts were plated on fibronectin to enable focal adhesion formation and stimulated with IL-1β. These data showed that the catalytic and adaptor functions of PTPα were required for IL-1β-induced focal adhesion formation, ERK activation and MMP-3 release. We conclude that inflammation-induced connective tissue degradation involving fibroblasts requires functionally active PTPα and in part is mediated by IL-1β signaling through focal adhesions.
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Affiliation(s)
- Dhaarmini Rajshankar
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada.
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11
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Huang YS, Cheng CY, Chueh SH, Hueng DY, Huang YF, Chu CM, Wu ST, Tai MC, Liang CM, Liao MH, Chen CC, Shen LH, Ma KH. Involvement of SHP2 in focal adhesion, migration and differentiation of neural stem cells. Brain Dev 2012; 34:674-84. [PMID: 22118986 DOI: 10.1016/j.braindev.2011.10.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 10/10/2011] [Accepted: 10/26/2011] [Indexed: 11/25/2022]
Abstract
OBJECTIVES SHP2 (Src-homology-2 domain-containing protein tyrosine phosphatase) plays an important role in cell adhesion, migration and cell signaling. However, its role in focal adhesion, differentiation and migration of neural stem cells is still unclear. METHODS In this study, rat neurospheres were cultured in suspension and differentiated neural stem cells were cultured on collagen-coated surfaces. RESULTS The results showed that p-SHP2 co-localized with focal adhesion kinase (FAK) and paxillin in neurospheres and in differentiated neural precursor cells, astrocytes, neurons, and oligodendrocytes. Suppression of SHP2 activity by PTP4 or siRNA-mediated SHP2 silencing caused reduction in the cell migration and neurite outgrowth, and thinning of glial cell processes. Differentiation-induced activation of FAK, Src, paxillin, ERK1/2, and RhoA was decreased by SHP2 inactivation. CONCLUSIONS These results indicate that SHP2 is recruited in focal adhesions of neural stem cells and regulates focal adhesion formation. SHP2-mediated regulation of neural differentiation and migration may be related to formation of focal adhesions and RhoA and ERK1/2 activation.
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Affiliation(s)
- Yuahn-Sieh Huang
- Department of Anatomy, Faculty of Medicine, Chung Shan Medical University, Taichung, Taiwan, ROC
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12
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Protein tyrosine phosphatase α phosphotyrosyl-789 binds BCAR3 to position Cas for activation at integrin-mediated focal adhesions. Mol Cell Biol 2012; 32:3776-89. [PMID: 22801373 DOI: 10.1128/mcb.00214-12] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Integrin-mediated focal adhesions connect the extracellular matrix and cytoskeleton to regulate cell responses, such as migration. Protein tyrosine phosphatase α (PTPα) regulates integrin signaling, focal adhesion formation, and migration, but its roles in these events are incompletely understood. The integrin-proximal action of PTPα activates Src family kinases, and subsequent phosphorylation of PTPα at Tyr789 acts in an unknown manner to promote migration. PTPα-null cells were used in reconstitution assays to distinguish PTPα-Tyr789-dependent signaling events. This showed that PTPα-Tyr789 regulates the localization of PTPα and the scaffolding protein Cas to adhesion sites where Cas interacts with and is phosphorylated by Src to initiate Cas signaling. Linking these events, we identify BCAR3 as a molecular connector of PTPα and Cas, with phospho-Tyr789 PTPα serving as the first defined cellular ligand for the BCAR3 SH2 domain that recruits BCAR3-Cas to adhesions. Our findings reveal a novel role of PTPα in integrin-induced adhesion assembly that enables Src-mediated activation of the pivotal function of Cas in migration.
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13
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Roca-Cusachs P, Iskratsch T, Sheetz MP. Finding the weakest link: exploring integrin-mediated mechanical molecular pathways. J Cell Sci 2012; 125:3025-38. [PMID: 22797926 DOI: 10.1242/jcs.095794] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
From the extracellular matrix to the cytoskeleton, a network of molecular links connects cells to their environment. Molecules in this network transmit and detect mechanical forces, which subsequently determine cell behavior and fate. Here, we reconstruct the mechanical pathway followed by these forces. From matrix proteins to actin through integrins and adaptor proteins, we review how forces affect the lifetime of bonds and stretch or alter the conformation of proteins, and how these mechanical changes are converted into biochemical signals in mechanotransduction events. We evaluate which of the proteins in the network can participate in mechanotransduction and which are simply responsible for transmitting forces in a dynamic network. Besides their individual properties, we also analyze how the mechanical responses of a protein are determined by their serial connections from the matrix to actin, their parallel connections in integrin clusters and by the rate at which force is applied to them. All these define mechanical molecular pathways in cells, which are emerging as key regulators of cell function alongside better studied biochemical pathways.
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Affiliation(s)
- Pere Roca-Cusachs
- University of Barcelona and Institute for Bioengineering of Catalonia, Barcelona, Spain.
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14
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Mohammad I, Arora PD, Naghibzadeh Y, Wang Y, Li J, Mascarenhas W, Janmey PA, Dawson JF, McCulloch CA. Flightless I is a focal adhesion-associated actin-capping protein that regulates cell migration. FASEB J 2012; 26:3260-72. [PMID: 22581781 DOI: 10.1096/fj.11-202051] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The role of adhesion-associated actin-binding proteins in cell migration is not well defined. In mouse fibroblasts we screened for focal adhesion-associated proteins that were isolated with collagen-coated beads and detected by tandem mass spectrometry. We identified flightless I (FliI) as an actin-binding protein in focal adhesion fractions, which was verified by immunoblotting. By confocal microscopy most FliI was distributed throughout the cytosol and in focal adhesions. By sedimentation assays and in vitro binding assays, we found that FliI associates with actin filaments and actin monomers. Assays using purified proteins showed that FliI inhibits actin polymerization and caps but does not sever actin filaments. Cells with FliI knockdown or cells overexpressing FliI migrated more or less rapidly, respectively, than wild-type controls. Compared with controls, cells with FliI knockdown were less adherent than wild-type cells, exhibited reduced numbers of focal adhesions containing activated β1 integrins and vinculin, and exhibited increased incorporation of actin monomers into nascent filaments at focal adhesions. These data indicate that FliI regulates cell migration through its localization to focal adhesions and its ability to cap actin filaments, which collectively affect focal adhesion maturation.
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Affiliation(s)
- Ibrahim Mohammad
- Matrix Dynamics Group, University of Toronto, Toronto, Ontario, Canada
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15
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Tremper-Wells B, Resnick RJ, Zheng X, Holsinger LJ, Shalloway D. Extracellular domain dependence of PTPalpha transforming activity. Genes Cells 2010; 15:711-724. [PMID: 20545765 DOI: 10.1111/j.1365-2443.2010.01410.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Two isoforms of the transmembrane protein tyrosine phosphatase PTPalpha, which differ by nine amino acids in their extracellular regions, are expressed in a tissue-specific manner. Over-expression of the shorter isoform transforms rodent cells, and it has previously been reasonable to assume that this was a direct consequence of its dephosphorylation and activation of Src. Transformation by the longer wild-type isoform has not previously been studied. We tested the activities of both isoforms in NIH3T3 cells and found that, while both dephosphorylated and activated Src similarly, only the shorter isoform induced focus formation or anchorage-independent growth. Differences in phosphorylation of PTPalpha at its known regulatory sites, Grb2 binding to PTPalpha, phosphorylation level of focal adhesion kinase by PTPalpha, or overall localization were excluded as possible explanations for the differences in transforming activities. The results suggest that transformation by PTPalpha involves at least one function other than, or in addition to, its activation of Src and that this depends on PTPalpha's extracellular domain. Previous studies have suggested that PTPalpha might be a useful target in breast and colon cancer therapy, and the results presented here suggest that it may be advantageous to develop isoform-specific therapeutic reagents.
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Affiliation(s)
- Barbara Tremper-Wells
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Ross J Resnick
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Xinmin Zheng
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | | | - David Shalloway
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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16
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Wang Q, Rajshankar D, Laschinger C, Talior-Volodarsky I, Wang Y, Downey GP, McCulloch CA. Importance of protein-tyrosine phosphatase-alpha catalytic domains for interactions with SHP-2 and interleukin-1-induced matrix metalloproteinase-3 expression. J Biol Chem 2010; 285:22308-17. [PMID: 20472558 DOI: 10.1074/jbc.m110.102426] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Interleukin-1 (IL-1) induces extracellular matrix degradation as a result of increased expression of matrix metalloproteinases (MMPs). We examined adhesion-restricted signaling pathways that enable IL-1-induced MMP release in human gingival and murine fibroblasts. Of the seven MMPs and three tissue inhibitors of MMPs screened, IL-1 enhanced release only of MMP3 when cells formed focal adhesions. Inhibition of protein-tyrosine phosphatases (PTPs), which are enriched in focal adhesions, blocked IL-1-induced MMP3 release. Accordingly, in contrast to wild-type cells, fibroblasts null for PTPalpha did not exhibit IL-1-induced MMP3 release. IL-1 treatment enhanced the recruitment of SHP-2 and PTPalpha to focal adhesions and the association of PTPalpha with SHP-2. Pulldown assays confirmed a direct interaction between PTPalpha and SHP-2, which was dependent on the intact, membrane-proximal phosphatase domain of PTPalpha. Interactions between SHP-2 and PTPalpha, recruitment of SHP-2 to focal adhesions, IL-1-induced ERK activation, and MMP3 expression were all blocked by point mutations in the phosphatase domains of PTPalpha. These data indicate that IL-1-induced signaling through focal adhesions leading to MMP3 release and interactions between SHP-2 and PTPalpha are dependent on the integrity of the catalytic domains of PTPalpha.
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Affiliation(s)
- Qin Wang
- Matrix Dynamics Group, University of Toronto, Toronto, Ontario M5S 3E2, Canada
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17
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Serine dephosphorylation of receptor protein tyrosine phosphatase alpha in mitosis induces Src binding and activation. Mol Cell Biol 2010; 30:2850-61. [PMID: 20385765 DOI: 10.1128/mcb.01202-09] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Receptor protein tyrosine phosphatase alpha (RPTPalpha) is the mitotic activator of the protein tyrosine kinase Src. RPTPalpha serine hyperphosphorylation was proposed to mediate mitotic activation of Src. We raised phosphospecific antibodies to the two main serine phosphorylation sites, and we discovered that RPTPalpha Ser204 was almost completely dephosphorylated in mitotic NIH 3T3 and HeLa cells, whereas Ser180 and Tyr789 phosphorylation were only marginally reduced in mitosis. Concomitantly, Src pTyr527 and pTyr416 were dephosphorylated, resulting in 2.3-fold activation of Src in mitosis. Using inhibitors and knockdown experiments, we demonstrated that dephosphorylation of RPTPalpha pSer204 in mitosis was mediated by PP2A. Mutation of Ser204 to Ala did not activate RPTPalpha, and intrinsic catalytic activity of RPTPalpha was not affected in mitosis. Interestingly, binding of endogenous Src to RPTPalpha was induced in mitosis. GRB2 binding to RPTPalpha, which was proposed to compete with Src binding to RPTPalpha, was only modestly reduced in mitosis, which could not account for enhanced Src binding. Moreover, we demonstrate that Src bound to mutant RPTPalpha-Y789F, lacking the GRB2 binding site, and mutant Src with an impaired Src homology 2 (SH2) domain bound to RPTPalpha, illustrating that Src binding to RPTPalpha is not mediated by a pTyr-SH2 interaction. Mutation of RPTPalpha Ser204 to Asp, mimicking phosphorylation, reduced coimmunoprecipitation with Src, suggesting that phosphorylation of Ser204 prohibits binding to Src. Based on our results, we propose a new model for mitotic activation of Src in which PP2A-mediated dephosphorylation of RPTPalpha pSer204 facilitates Src binding, leading to RPTPalpha-mediated dephosphorylation of Src pTyr527 and pTyr416 and hence modest activation of Src.
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18
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van Eekelen M, Runtuwene V, Overvoorde J, den Hertog J. RPTPα and PTPε signaling via Fyn/Yes and RhoA is essential for zebrafish convergence and extension cell movements during gastrulation. Dev Biol 2010; 340:626-39. [DOI: 10.1016/j.ydbio.2010.02.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 02/15/2010] [Accepted: 02/16/2010] [Indexed: 10/19/2022]
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19
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Geny B, Grassart A, Manich M, Chicanne G, Payrastre B, Sauvonnet N, Popoff MR. Rac1 inactivation by lethal toxin from Clostridium sordellii modifies focal adhesions upstream of actin depolymerization. Cell Microbiol 2009; 12:217-32. [PMID: 19840028 DOI: 10.1111/j.1462-5822.2009.01392.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inactivation of different small GTPases upon their glucosylation by lethal toxin from Clostridium sordellii strain IP82 (LT-82) is already known to lead to cell rounding, adherens junction (AJ) disorganization and actin depolymerization. In the present work, we observed that LT-82 induces a rapid dephosphorylation of paxillin, a protein regulating focal adhesion (FA), independently of inactivation of paxillin kinases such as Src, Fak and Pyk2. Among the small GTPases inactivated by this toxin, including Rac, Ras, Rap and Ral, we identified Rac1, as responsible for paxillin dephosphorylation using cells overexpressing Rac1(V12). Rac1 inactivation by LT-82 modifies interactions between proteins from AJ and FA complexes as shown by pull-down assays. We showed that in Triton X-100-insoluble membrane proteins from these complexes, namely E-cadherin, beta-catenin, p120-catenin and talin, are decreased upon LT-82 intoxication, a treatment that also induces a rapid decrease in cell phosphoinositide content. Therefore, we proposed that Rac inactivation by LT-82 alters phosphoinositide metabolism leading to FA and AJ complex disorganization and actin depolymerization.
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Affiliation(s)
- Blandine Geny
- Unité des Bactéries Anaérobies et Toxines, Department of Microbiology, Institut Pasteur, 25 rue du Docteur Roux, Paris Cedex 15, France.
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20
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Granot-Attas S, Luxenburg C, Finkelshtein E, Elson A. Protein tyrosine phosphatase epsilon regulates integrin-mediated podosome stability in osteoclasts by activating Src. Mol Biol Cell 2009; 20:4324-34. [PMID: 19692574 DOI: 10.1091/mbc.e08-11-1158] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The nonreceptor isoform of tyrosine phosphatase epsilon (cyt-PTPe) supports osteoclast adhesion and activity in vivo, leading to increased bone mass in female mice lacking PTPe (EKO mice). The structure and organization of the podosomal adhesion structures of EKO osteoclasts are abnormal; the molecular mechanism behind this is unknown. We show here that EKO podosomes are disorganized, unusually stable, and reorganize poorly in response to physical contact. Phosphorylation and activities of Src, Pyk2, and Rac are decreased and Rho activity is increased in EKO osteoclasts, suggesting that integrin signaling is defective in these cells. Integrin activation regulates cyt-PTPe by inducing Src-dependent phosphorylation of cyt-PTPe at Y638. This phosphorylation event is crucial because wild-type-but not Y638F-cyt-PTPe binds and further activates Src and restores normal stability to podosomes in EKO osteoclasts. Increasing Src activity or inhibiting Rho or its downstream effector Rho kinase in EKO osteoclasts rescues their podosomal stability phenotype, indicating that cyt-PTPe affects podosome stability by functioning upstream of these molecules. We conclude that cyt-PTPe participates in a feedback loop that ensures proper Src activation downstream of integrins, thus linking integrin signaling with Src activation and accurate organization and stability of podosomes in osteoclasts.
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Affiliation(s)
- Shira Granot-Attas
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
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21
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Wang Q, Rajshankar D, Branch DR, Siminovitch KA, Herrera Abreu MT, Downey GP, McCulloch CA. Protein-tyrosine phosphatase-alpha and Src functionally link focal adhesions to the endoplasmic reticulum to mediate interleukin-1-induced Ca2+ signaling. J Biol Chem 2009; 284:20763-72. [PMID: 19497848 DOI: 10.1074/jbc.m808828200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Calcium (Ca2+) signaling by the pro-inflammatory cytokine interleukin-1 (IL-1) is dependent on focal adhesions, which contain diverse structural and signaling proteins including protein phosphatases. We examined here the role of protein-tyrosine phosphatase (PTP) alpha in regulating IL-1-induced Ca2+ signaling in fibroblasts. IL-1 promoted recruitment of PTPalpha to focal adhesions and endoplasmic reticulum (ER) fractions, as well as tyrosine phosphorylation of the ER Ca2+ release channel IP3R. In response to IL-1, catalytically active PTPalpha was required for Ca2+ release from the ER, Src-dependent phosphorylation of IP3R1 and accumulation of IP3R1 in focal adhesions. In pulldown assays and immunoprecipitations PTPalpha was required for the association of PTPalpha with IP3R1 and c-Src, and this association was increased by IL-1. Collectively, these data indicate that PTPalpha acts as an adaptor to mediate functional links between focal adhesions and the ER that enable IL-1-induced Ca2+ signaling.
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Affiliation(s)
- Qin Wang
- Canadian Institutes of Health Research Group in Matrix Dynamics, Faculty of Dentistry, University of Toronto, Toronto, Ontario M5S 3E2, Canada
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22
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Vacaresse N, Møller B, Danielsen EM, Okada M, Sap J. Activation of c-Src and Fyn kinases by protein-tyrosine phosphatase RPTPalpha is substrate-specific and compatible with lipid raft localization. J Biol Chem 2008; 283:35815-24. [PMID: 18948260 DOI: 10.1074/jbc.m807964200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Src family tyrosine kinases (SFKs) function in multiple signaling pathways, raising the question of how appropriate regulation and substrate choice are achieved. SFK activity is modulated by several protein-tyrosine phosphatases, among which RPTPalpha and SHP2 are the best established. We studied how RPTPalpha affects substrate specificity and regulation of c-Src and Fyn in response to epidermal growth factor and platelet-derived growth factor. We find that RPTPalpha, in a growth factor-specific manner, directs the specificity of these kinases toward a specific subset of SFK substrates, particularly the focal adhesion protein Paxillin and the lipid raft scaffolding protein Cbp/PAG. A significant fraction of RPTPalpha is present in lipid rafts, where its targets Fyn and Cbp/PAG reside, and growth factor-mediated SFK activation within this compartment is strictly dependent on RPTPalpha. Forced concentration of RPTPalpha into lipid rafts is compatible with activation of Fyn. Finally, RPTPalpha-induced phosphorylation of Paxillin and Cbp/PAG induces recruitment of the SFK inhibitory kinase Csk, indicative of negative feedback loops limiting SFK activation by RPTPalpha. Our findings indicate that individual SFK-controlling PTPs play important and specific roles in dictating SFK substrate specificity and regulatory mechanism.
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Affiliation(s)
- Nathalie Vacaresse
- Biotech Research and Innovation Center, Copenhagen Biocenter, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
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