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Li M, Wang Y, Lin X, Yang H, Zhang X, Bai Y, Li X, Zhang L, Cheng F, Cao C, Zhou Q. Evaluation of antitumor potential of an anti-glypican-1 monoclonal antibody in preclinical lung cancer models reveals a distinct mechanism of action. EXPLORATION OF TARGETED ANTI-TUMOR THERAPY 2024; 5:600-626. [PMID: 38966167 PMCID: PMC11220310 DOI: 10.37349/etat.2024.00238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/26/2024] [Indexed: 07/06/2024] Open
Abstract
Aim The main objective of this study was to investigate the antitumor effect of a mouse anti-human glypican-1 (GPC1) monoclonal antibody (mAb) on non-small cell lung carcinoma (NSCLC) and associated molecular mechanisms. Methods The anti-proliferative and anti-migratory activities of anti-GPC1 mAb were examined in A549 and H460 NSCLC cells and LL97A lung fibroblasts. The inhibitory effect of anti-GPC1 mAb on tumor growth was evaluated in an orthotopic lung tumor model. Results The in vitro study showed that anti-GPC1 mAb profoundly inhibited the anchorage-independent growth of A549 and H460 NSCLC cells and exhibited relatively high cytotoxic activities towards LL97A lung fibroblasts, A549/LL97A and H460/LL97A coculture spheroids. Moreover, anti-GPC1 mAb significantly decreased the expression of phospho-Src (p-Src; Tyr416), p-Akt (Ser473) and β-catenin in the co-cultured LL97A lung fibroblasts, and the expression of phospho-mitogen-activated protein kinase kinase (p-MEK; Ser217/221) and phospho-90 kDa ribosomal s6 kinase (p-p90RSK; Ser380) in co-cultured A549 cells. When anti-GPC1 mAb was administered to tumor-bearing mice, the inhibitory effect of anti-GPC1 mAb on the orthotopic lung tumor growth was not statistically significant. Nonetheless, results of Western blot analysis showed significant decrease in the phosphorylation of fibroblast growth factor receptor 1 (FGFR1) at Tyr766, Src at Tyr416, extracellular signal-regulated kinase (ERK) at Thr202/Tyr204, 90 kDa ribosomal S6 kinase (RSK) at Ser380, glycogen synthase kinases 3α (GSK3α) at Ser21 and GSK3β at Ser9 in tumor tissues. These data implicate that anti-GPC1 mAb treatment impairs the interaction between tumor cells and tumor associated fibroblasts by attenuating the paracrine FGFR signal transduction. Conclusions The relatively potent cytotoxicity of anti-GPC1 mAb in lung fibroblasts and its potential inhibitory effect on the paracrine FGFR signal transduction warrant further studies on the combined use of this mAb with targeted therapeutics to improve therapeutic outcomes in lung cancer.
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Affiliation(s)
- Minghua Li
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Yanhong Wang
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Xiaoyang Lin
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Haiqiang Yang
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Xiaolin Zhang
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Yun Bai
- MegaNano Biotech Inc., Tampa, FL 33612, USA
| | - Xiankun Li
- Zhengzhou Molecular Diagnosis Engineering Technology Research Center, Zhengzhou 450001, Henan Province, China
| | - Lulu Zhang
- Zhengzhou Molecular Diagnosis Engineering Technology Research Center, Zhengzhou 450001, Henan Province, China
| | - Feng Cheng
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Chuanhai Cao
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
| | - Qingyu Zhou
- Department of Pharmaceutical Sciences, Taneja College of Pharmacy, University of South Florida, Tampa, FL 33612, USA
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Jun BG, Lee WC, Jang JY, Jeong SW, Chang Y, Lee SH, Kim YD, Kim SG, Cheon GJ, Kim YS, Kim HS, Jin SY. Relation of fibroblast growth factor receptor 2 expression to hepatocellular carcinoma recurrence after liver resection. PLoS One 2020; 15:e0227440. [PMID: 31940413 PMCID: PMC6961981 DOI: 10.1371/journal.pone.0227440] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/18/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) recurrence after liver resection depends upon the stage and histological grade of the tumor and the expression of certain biomarkers. However, it remains unclear which of these factors has the highest predictive value regarding HCC recurrence after surgical resection. METHODS This study investigated the associations among clinicopathological characteristics, expression of biomarkers, and HCC recurrence after liver resection. Fifty-four patients having undergone liver resection for HCC were enrolled prospectively, and their data were analyzed retrospectively. Evaluated variables were clinical data, laboratory findings, modified Union for International Cancer Control (UICC) stage, vascular invasion, histological differentiation, and immunohistochemical staining for fibroblast growth factor receptor 2 (FGFR2), vascular endothelial growth factor, and tumor-necrosis-factor-related apoptosis-inducing ligand receptors 1 and 2. RESULTS Mean patient age was 58.6 years (range, 30-71), and the mean and SD for follow-up duration were 51.2 ± 34.8 months. Cumulative 1-, 3-, and 5-year recurrence rates were 32.9%, 53.6%, and 68.1%, respectively. In univariate analysis, FGFR2 (p = 0.026) and Edmonson-Steiner grade (E-S grade) (p = 0.030) were associated with recurrence after resection in HCC patients. In multivariate analyses, increased FGFR2 expression (p = 0.017) was the only significant predictor of HCC recurrence. CONCLUSIONS High FGFR2 expression had marginal association with poor E-S grade (p = 0.056). More intensive surveillance of HCC recurrence is warranted in HCC patients with increased FGFR2 expression.
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Affiliation(s)
- Baek Gyu Jun
- Department of Internal Medicine, University of Ulsan College of Medicine, Gangneung Asan Hospital, Gangneung, South Korea
| | - Woong Cheul Lee
- Institute for Digestive Research, Digestive Disease Center, Department of Internal Medicine, College of Medicine, Soonchunhyang University, Seoul, Korea
| | - Jae Young Jang
- Institute for Digestive Research, Digestive Disease Center, Department of Internal Medicine, College of Medicine, Soonchunhyang University, Seoul, Korea
| | - Soung Won Jeong
- Institute for Digestive Research, Digestive Disease Center, Department of Internal Medicine, College of Medicine, Soonchunhyang University, Seoul, Korea
| | - Young Chang
- Institute for Digestive Research, Digestive Disease Center, Department of Internal Medicine, College of Medicine, Soonchunhyang University, Seoul, Korea
| | - Sae Hwan Lee
- Department of Internal Medicine, College of Medicine, Soonchunhyang University, Cheonan, Korea
| | - Young don Kim
- Department of Internal Medicine, University of Ulsan College of Medicine, Gangneung Asan Hospital, Gangneung, South Korea
| | - Sang Gyune Kim
- Department of Internal Medicine, College of Medicine, Soonchunhyang University, Bucheon, Korea
| | - Gab Jin Cheon
- Department of Internal Medicine, University of Ulsan College of Medicine, Gangneung Asan Hospital, Gangneung, South Korea
| | - Young Seok Kim
- Department of Internal Medicine, College of Medicine, Soonchunhyang University, Bucheon, Korea
| | - Hong Soo Kim
- Department of Internal Medicine, College of Medicine, Soonchunhyang University, Cheonan, Korea
| | - So Young Jin
- Department of Pathology, College of Medicine, Soonchunhyang University, Seoul, Korea
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Barylko B, Chen YJ, Hennen J, Angert I, Chen Y, Mueller JD, Sun HQ, Taylor CA, Liou J, Yin H, Albanesi JP. Myristoylation-Dependent Palmitoylation of the Receptor Tyrosine Kinase Adaptor FRS2α. Biochemistry 2019; 58:2809-2813. [PMID: 31184863 DOI: 10.1021/acs.biochem.9b00299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
An early step in signaling from activated receptor tyrosine kinases (RTKs) is the recruitment of cytosolic adaptor proteins to autophosphorylated tyrosines in the receptor cytoplasmic domains. Fibroblast growth factor receptor substrate 2α (FRS2α) associates via its phosphotyrosine-binding domain (PTB) to FGF receptors (FGFRs). Upon FGFR activation, FRS2α undergoes phosphorylation on multiple tyrosines, triggering recruitment of the adaptor Grb2 and the tyrosine phosphatase Shp2, resulting in stimulation of PI3K/AKT and MAPK signaling pathways. FRS2α also undergoes N-myristoylation, which was shown to be important for its localization to membranes and its ability to stimulate downstream signaling events (Kouhara et al., 1997). Here we show that FRS2α is also palmitoylated in cells and that cysteines 4 and 5 account for the entire modification. We further show that mutation of those two cysteines interferes with FRS2α localization to the plasma membrane (PM), and we quantify this observation using fluorescence fluctuation spectroscopy approaches. Importantly, prevention of myristoylation by introduction of a G2A mutation also abrogates palmitoylation, raising the possibility that signaling defects previously ascribed to the G2A mutant may actually be due to a failure of that mutant to undergo palmitoylation. Our results demonstrate that FRS2α undergoes coupled myristoylation and palmitoylation. Unlike stable cotranslational modifications, such as myristoylation and prenylation, palmitoylation is reversible due to the relative lability of the thioester linkage. Therefore, palmitoylation may provide a mechanism, in addition to phosphorylation, for dynamic regulation of FRS2 and its downstream signaling pathways.
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Affiliation(s)
| | | | - Jared Hennen
- School of Physics and Astronomy , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Isaac Angert
- School of Physics and Astronomy , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Yan Chen
- School of Physics and Astronomy , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Joachim D Mueller
- School of Physics and Astronomy , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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Zamai M, Trullo A, Giordano M, Corti V, Arza Cuesta E, Francavilla C, Cavallaro U, Caiolfa VR. Number and brightness analysis reveals that NCAM and FGF2 elicit different assembly and dynamics of FGFR1 in live cells. J Cell Sci 2019; 132:jcs.220624. [PMID: 30478195 DOI: 10.1242/jcs.220624] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 11/15/2018] [Indexed: 12/31/2022] Open
Abstract
Both fibroblast growth factor-2 (FGF2) and neural cell adhesion molecule (NCAM) trigger FGF receptor 1 (FGFR1) signaling; however, they induce remarkably distinct receptor trafficking and cellular responses. The molecular basis of such a dichotomy and the role of distinct types of ligand-receptor interaction remain elusive. Number of molecules and brightness (N&B) analysis revealed that FGF2 and NCAM promote different FGFR1 assembly and dynamics at the plasma membrane. NCAM stimulation elicits long-lasting cycles of short-lived FGFR1 monomers and multimers, a behavior that might reflect a rapid FGFR1 internalization and recycling. FGF2, instead, induces stable dimerization at the dose that stimulates cell proliferation. Reducing the occupancy of FGFR1 in response to low FGF2 doses causes a switch towards cyclically exposed and unstable receptor dimers, consistently with previously reported biphasic response to FGF2 and with the divergent signaling elicited by different ligand concentrations. Similar instability was observed upon altering the endocytic pathway. Thus, FGF2 and NCAM induce differential FGFR1 clustering at the cell surface, which might account for the distinct intracellular fate of the receptor and, hence, for the different signaling cascades and cellular responses.
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Affiliation(s)
- Moreno Zamai
- Centro di Imaging Sperimentale (CIS), Ospedale San Raffaele, IRCCS, Milan 20132, Italy.,Microscopy and Dynamic Imaging Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid 28029, Spain
| | - Antonio Trullo
- Centro di Imaging Sperimentale (CIS), Ospedale San Raffaele, IRCCS, Milan 20132, Italy
| | - Marco Giordano
- Unit of Gynecological Oncology Research, European Institute of Oncology IRCCS, Milan 20141, Italy
| | - Valeria Corti
- Centro di Imaging Sperimentale (CIS), Ospedale San Raffaele, IRCCS, Milan 20132, Italy
| | - Elvira Arza Cuesta
- Microscopy and Dynamic Imaging Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid 28029, Spain
| | - Chiara Francavilla
- Division of Molecular and Cellular Functions, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Ugo Cavallaro
- Unit of Gynecological Oncology Research, European Institute of Oncology IRCCS, Milan 20141, Italy
| | - Valeria R Caiolfa
- Centro di Imaging Sperimentale (CIS), Ospedale San Raffaele, IRCCS, Milan 20132, Italy .,Microscopy and Dynamic Imaging Unit, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid 28029, Spain
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5
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Li Q, Ingram L, Kim S, Beharry Z, Cooper JA, Cai H. Paracrine Fibroblast Growth Factor Initiates Oncogenic Synergy with Epithelial FGFR/Src Transformation in Prostate Tumor Progression. Neoplasia 2018; 20:233-243. [PMID: 29444487 PMCID: PMC5814375 DOI: 10.1016/j.neo.2018.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/07/2018] [Accepted: 01/11/2018] [Indexed: 12/15/2022] Open
Abstract
Cross talk of stromal-epithelial cells plays an essential role in both normal development and tumor initiation and progression. Fibroblast growth factor (FGF)-FGF receptor (FGFR)-Src kinase axis is one of the major signal transduction pathways to mediate this cross talk. Numerous genomic studies have demonstrated that expression levels of FGFR/Src are deregulated in a variety of cancers including prostate cancer; however, the role that paracrine FGF (from stromal cells) plays in dysregulated expression of epithelial FGFRs/Src and tumor progression in vivo is not well evaluated. In this study, we demonstrate that ectopic expression of wild-type FGFR1/2 or Src kinase in epithelial cells was not sufficient to initiate prostate tumorigenesis under a normal stromal microenvironment in vivo. However, paracrine FGF10 synergized with ectopic expression of epithelial FGFR1 or FGFR2 to induce epithelial-mesenchymal transition. Additionally, paracrine FGF10 sensitized FGFR2-transformed epithelial cells to initiate prostate tumorigenesis. Next, paracrine FGF10 also synergized with overexpression of epithelial Src kinase to high-grade tumors. But loss of the myristoylation site in Src kinase inhibited paracrine FGF10-induced prostate tumorigenesis. Loss of myristoylation alters Src levels in the cell membrane and inhibited FGF-mediated signaling including inhibition of the phosphotyrosine pattern and FAK phosphorylation. Our study demonstrates the potential tumor progression by simultaneous deregulation of proteins in the FGF/FGFRs/Src signal axis and provides a therapeutic strategy of targeting myristoylation of Src kinase to interfere with the tumorigenic process.
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Affiliation(s)
- Qianjin Li
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602
| | - Lishann Ingram
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602
| | - Sungjin Kim
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602
| | - Zanna Beharry
- Department of Chemistry and Physics, Florida Gulf Coast University, Fort Myers, Florida 33965
| | | | - Houjian Cai
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602.
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6
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Lee M, Shi X, Barron AE, McGeer E, McGeer PL. Human antimicrobial peptide LL-37 induces glial-mediated neuroinflammation. Biochem Pharmacol 2015; 94:130-41. [PMID: 25686659 DOI: 10.1016/j.bcp.2015.02.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 01/30/2015] [Accepted: 02/06/2015] [Indexed: 12/29/2022]
Abstract
LL-37 is the sole cathelicidin-derived antimicrobial peptide found in humans. It becomes active upon C-terminal cleavage of its inactive precursor hCAP18. In addition to antimicrobial action, it also functions as an innate immune system stimulant in many tissues of the body. Here we report that hCAP18 and LL-37 are expressed in all organs of the human body that were studied with the highest basic levels being expressed in the GI tract and the brain. Its expression and functional role in the central nerve system (CNS) has not previously been reported. We found increased expression of LL-37 in IFNγ-stimulated human astrocytes and their surrogate U373 cells, as well as in LPS/IFNγ-stimulated human microglia and their surrogate monocyte-derived THP-1 cells. We found that treatment of microglia, astrocytes, THP-1 cells and U373 cells with LL-37 induced secretion of the inflammatory cytokines IL-1β and IL-6; the chemokines IL-8 and CCL-2, and other materials toxic to human neuroblastoma SH-SY5Y cells. The mechanism of LL-37 stimulation involves activation of intracellular proinflammatory pathways involving phospho-P38 MAP kinase and phospho-NFκB proteins. We blocked the inflammatory stimulant action of LL-37 by removing it with an anti-LL-37 antibody. The inflammatory effect was also prevented by treatment with inhibitors of PKC, PI3K and MEK-1/2 as well as with the intracellular Ca(2+)-chelator, BAPTA-AM. This indicates involvement of these intracellular pathways. Our data suggest that LL-37, in addition to its established roles, may play a role in the chronic neuroinflammation which is observed in neurodegenerative diseases such as Alzheimer's and Parkinson's disease.
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Affiliation(s)
- Moonhee Lee
- Kinsmen Laboratory of Neurological Research, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3
| | - Xiaolei Shi
- Kinsmen Laboratory of Neurological Research, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3
| | - Annelise E Barron
- Department of Bioengineering, Stanford University, Stanford, CA 94305, United States
| | - Edith McGeer
- Kinsmen Laboratory of Neurological Research, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3
| | - Patrick L McGeer
- Kinsmen Laboratory of Neurological Research, University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3.
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Chen PY, Qin L, Tellides G, Simons M. Fibroblast growth factor receptor 1 is a key inhibitor of TGFβ signaling in the endothelium. Sci Signal 2014; 7:ra90. [PMID: 25249657 DOI: 10.1126/scisignal.2005504] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abnormal vascular homeostasis can lead to increased proliferation of smooth muscle cells and deposition of extracellular matrix, resulting in neointima formation, which contributes to vascular lumen narrowing, a pathology that underlies diseases including transplant vasculopathy, the recurrence of stenosis, and atherosclerosis. Growth of neointima is in part due to endothelial-to-mesenchymal transition (EndMT), a transforming growth factor-β (TGFβ)-driven process, which leads to increased numbers of smooth muscle cells and fibroblasts and deposition of extracellular matrix. We reported that endothelial cell-specific knockout of fibroblast growth factor receptor 1 (FGFR1) led to activation of TGFβ signaling and development of EndMT in vitro and in vivo. Furthermore, EndMT in human diseased vasculature correlated with decreased abundance of FGFR1. These findings identify FGFR1 as the key regulator of TGFβ signaling and EndMT development.
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Affiliation(s)
- Pei-Yu Chen
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Lingfeng Qin
- Department of Surgery, Yale University School of Medicine, New Haven, CT 06520, USA
| | - George Tellides
- Department of Surgery, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Michael Simons
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA. Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA.
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8
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Zhou L, Talebian A, Meakin SO. The signaling adapter, FRS2, facilitates neuronal branching in primary cortical neurons via both Grb2- and Shp2-dependent mechanisms. J Mol Neurosci 2014; 55:663-77. [PMID: 25159185 DOI: 10.1007/s12031-014-0406-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 08/15/2014] [Indexed: 12/15/2022]
Abstract
The neurotrophins are a family of closely related growth factors that regulate proliferation and differentiation in the developing and mature nervous systems. Neurotrophins stimulate a family of receptor tyrosine kinases (Trk receptors) and utilize an intracellular docking protein termed fibroblast growth factor (FGF) receptor substrate 2 (FRS2) as a major downstream adapter to activate Ras, phosphatidylinositide 3-kinase (PI3K), and mitogen-activated protein kinase (MAPK) signaling cascades. The goals of this study were twofold: first, to investigate the complexity of neurotrophin-induced FRS2 interactions in primary cortical neurons and to determine which pathway(s) are important in regulating neuronal growth and, second, to determine whether the related signaling adapter, FRS3, stimulates neuron growth comparable to FRS2. We find that neurotrophin treatment of primary cortical neurons stimulates the tyrosine phosphorylation of FRS2 and the subsequent recruitment of Shp2, Grb2, and Gab2. With FRS2 mutants deficient in Grb2 or Shp2 binding, we demonstrate that FRS2 binds Gab1 and Gab2 through Grb2, providing an alternative route to activate PI3 kinase and Shp2. Using recombinant adenoviruses expressing FRS2, we demonstrate that FRS2 overexpression promotes neurite outgrowth and branching in cortical neurons relative to controls. In contrast, overexpression of FRS3 does not stimulate neuronal growth. Moreover, we find that while loss of Shp2, but not Grb2, reduces brain-derived neurotrophic factor (BDNF)-induced MAPK activation, the loss of either pathway impairs neuronal growth. Collectively, these experiments demonstrate that FRS2 functions as an adapter of a multiprotein complex that is activated by the Trk receptors and that the activation of both Grb2- and Shp2-dependent pathways facilitates cortical neuronal growth.
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Affiliation(s)
- Li Zhou
- Laboratory of Neural Signaling, Molecular Medicine Research Group, The Robarts Research Institute, 1151 Richmond St. N, London, Ontario, N6A 5B7, Canada
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9
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Yaqoob U, Jagavelu K, Shergill U, de Assuncao T, Cao S, Shah VH. FGF21 promotes endothelial cell angiogenesis through a dynamin-2 and Rab5 dependent pathway. PLoS One 2014; 9:e98130. [PMID: 24848261 PMCID: PMC4029959 DOI: 10.1371/journal.pone.0098130] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 04/28/2014] [Indexed: 12/26/2022] Open
Abstract
Binding of angiogenic molecules with cognate receptor tyrosine kinases (RTK) is required for angiogenesis however the precise link between RTK binding, endocytosis, and signaling requires further investigation. Here, we use FGFR1 as a model to test the effects of the large GTPase and endocytosis regulatory molecule dynamin-2 on angiogenic signaling in context of distinct FGF ligands. In vitro, overexpression of dominant negative dynamin-2 (DynK44A) attenuates FGFR1 activation of Erk and tubulogenesis by FGF2. Furthermore, we identify FGF21, a non-classical, FGF ligand implicated in diverse human pathologies as an angiogenic molecule acting through FGFR1 and β-Klotho coreceptor. Disruption of FGFR1 activation of ERK by FGF21 is achieved by perturbation of the function of both dynamin-2 and Rab5 GTPase. In vivo, mice harboring endothelial selective overexpression of DynK44A, show impaired angiogenesis in response to FGF21. In conclusion, dynamin dependent endocytosis of FGFR1 is required for in vitro and in vivo angiogenesis in response to FGF2 and the non-classical FGF ligand, FGF21. These studies extend our understanding of the relationships between RTK binding, internalization, endosomal targeting, and angiogenic signaling.
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Affiliation(s)
- Usman Yaqoob
- Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Kumaravelu Jagavelu
- Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Uday Shergill
- Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Thiago de Assuncao
- Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Sheng Cao
- Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail: (SC); (VHS)
| | - Vijay H. Shah
- Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail: (SC); (VHS)
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10
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Abstract
Age-related macular degeneration (AMD) is associated with a low level of macular carotenoids in the eye retina. Only two carotenoids, namely lutein and zeaxanthin are selectively accumulated in the human eye retina from blood plasma where more than twenty other carotenoids are available. The third carotenoid which is found in the human retina, meso-zeaxanthin is formed directly in the retina from lutein. All these carotenoids, named also macular xanthophylls, play key roles in eye health and retinal disease. Macular xanthophylls are thought to combat light-induced damage mediated by reactive oxygen species by absorbing the most damaging incoming wavelength of light prior to the formation of reactive oxygen species (a function expected of carotenoids in nerve fibers) and by chemically and physically quenching reactive oxygen species once they are formed (a function expected of carotenoids in photoreceptor outer segments). There are two major hypotheses about the precise location of macular xanthophylls in the nerve fiber layer of photoreceptor axons and in photoreceptor outer segments. According to the first, macular xanthophylls transversely incorporate in the lipid-bilayer portion of membranes of the human retina. According to the second, macular xanthophylls are protein-bound by membrane-associated, xanthophyll-binding proteins. In this review we indicate specific properties of macular xanthophylls that could help explain their selective accumulation in the primate retina with special attention paid to xanthophyll-membrane interactions.
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Affiliation(s)
- Justyna Widomska
- Department of Biophysics, Medical University of Lublin, Lublin, Poland
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Cota CD, Segade F, Davidson B. Heart genetics in a small package, exploiting the condensed genome of Ciona intestinalis. Brief Funct Genomics 2013; 13:3-14. [PMID: 24005910 DOI: 10.1093/bfgp/elt034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Defects in the initial establishment of cardiogenic cell fate are likely to contribute to pervasive human congenital cardiac abnormalities. However, the molecular underpinnings of nascent cardiac fate induction have proven difficult to decipher. In this review we explore the participation of extracellular, cellular and nuclear factors in comprehensive specification networks. At each level, we elaborate on insights gained through the study of cardiogenesis in the invertebrate chordate Ciona intestinalis and propose productive lines of future research. In-depth discussion of pre-cardiac induction is intended to serve as a paradigm, illustrating the potential use of Ciona to elucidate comprehensive networks underlying additional aspects of chordate cardiogenesis, including directed migration and subspecification of cardiac and pharyngeal lineages.
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12
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Feng L, Zhang HH, Wang W, Zheng J, Chen DB. Compartmentalizing proximal FGFR1 signaling in ovine placental artery endothelial cell caveolae. Biol Reprod 2012; 87:40. [PMID: 22674390 DOI: 10.1095/biolreprod.112.100750] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Caveolae orchestrate the dominant placental angiogenic growth factor fibroblast growth factor 2 (FGF2) signaling primarily via FGF receptor 1 (FGFR1) in placental artery endothelial cells; however, how the proximal FGF2/FGFR1 signaling is organized in the caveolae is obscure. We have shown in the present study that the FGFR substrate 2alpha (FRS2alpha) is physically associated with FGFR1, and both are targeted to the caveolae via interaction with caveolin-1 in ovine fetoplacental artery endothelial cells. Treatment with FGF2 rapidly stimulated time- and concentration-dependent FRS2alpha tyrosine phosphorylation and recruited the cytosolic growth factor receptor-bound protein 2 (GRB2)-GRB2-associated binding protein 1 (GAB1) complex to the caveolae, where they formed a ternary complex with FRS2alpha. Disruption of caveolae by cholesterol depletion with methyl-beta-cyclodextrin inhibited FGF2-induced FRS2alpha tyrosine phosphorylation, and it blocked the FGF2-induced recruitment of GRB2 and GAB1 to the caveolae and formation of the FRS2alpha-GRB2-GAB1 complex in the caveolae, as well as activation of the PI3K/AKT1 and MAPK1/2 pathways. Thus, these findings have demonstrated that the proximal fibroblast growth factor (FGF2/FGFR1) signaling is compartmentalized in the placental endothelial caveolae via the FGFR substrate 2α that mediates formation of a FRS2α-GRB2-GAB1 complex.
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Affiliation(s)
- Lin Feng
- Department of Obstetrics & Gynecology, University of California, Irvine, California 92697, USA
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13
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Elfenbein A, Lanahan A, Zhou TX, Yamasaki A, Tkachenko E, Matsuda M, Simons M. Syndecan 4 regulates FGFR1 signaling in endothelial cells by directing macropinocytosis. Sci Signal 2012; 5:ra36. [PMID: 22569333 DOI: 10.1126/scisignal.2002495] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fibroblast growth factor 2 (FGF2) induces endothelial cell migration and angiogenesis through two classes of receptors: receptor tyrosine kinases, such as FGF receptor 1 (FGFR1), and heparan sulfate proteoglycans, such as syndecan 4 (S4). We examined the distinct contributions of FGFR1 and S4 in shaping the endothelial response to FGF2. S4 determined the kinetics and magnitude of FGF2-induced mitogen-activated protein kinase (MAPK) signaling by promoting the macropinocytosis of the FGFR1-S4-FGF2 signaling complex. Internalization of the S4 receptor complex was independent of clathrin and dynamin, proceeded from lipid raft-enriched membranes, and required activation of the guanosine triphosphatases RhoG and Rab5. Genetic knockout of S4, disruption of S4 function, or inhibition of Rab5 led to increased endocytosis and MAPK signaling. These data define the mechanism by which FGFR1 and S4 coordinate downstream signaling upon FGF2 stimulation: FGFR1 initiates MAPK signaling, whereas S4-dependent FGFR1 macropinocytosis modulates the kinetics of MAPK activation. Our studies identify S4 as a regulator of MAPK signaling and address the question of how distinct classes of FGFRs individually contribute to signal transduction in endothelial cells.
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Affiliation(s)
- Arye Elfenbein
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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14
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Tomasovic A, Traub S, Tikkanen R. Molecular networks in FGF signaling: flotillin-1 and cbl-associated protein compete for the binding to fibroblast growth factor receptor substrate 2. PLoS One 2012; 7:e29739. [PMID: 22235335 PMCID: PMC3250484 DOI: 10.1371/journal.pone.0029739] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 12/04/2011] [Indexed: 11/18/2022] Open
Abstract
Fibroblast growth factor receptor substrate 2 (FRS2α) is a signaling adaptor protein that regulates downstream signaling of many receptor tyrosine kinases. During signal transduction, FRS2 can be both tyrosine and threonine phosphorylated and forms signaling complexes with other adaptor proteins and tyrosine phosphatases. We have here identified flotillin-1 and the cbl-associated protein/ponsin (CAP) as novel interaction partners of FRS2. Flotillin-1 binds to the phosphotyrosine binding domain (PTB) of FRS2 and competes for the binding with the fibroblast growth factor receptor. Flotillin-1 knockdown results in increased Tyr phosphorylation of FRS2, in line with the inhibition of ERK activity in the absence of flotillin-1. CAP directly interacts with FRS2 by means of its sorbin homology (SoHo) domain, which has previously been shown to interact with flotillin-1. In addition, the third SH3 domain in CAP binds to FRS2. Due to the overlapping binding domains, CAP and flotillin-1 appear to compete for the binding to FRS2. Thus, our results reveal a novel signaling network containing FRS2, CAP and flotillin-1, whose successive interactions are most likely required to regulate receptor tyrosine kinase signaling, especially the mitogen activated protein kinase pathway.
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Affiliation(s)
- Ana Tomasovic
- Institute of Biochemistry, University of Giessen, Giessen, Germany
- Institute of Biochemistry II, University Clinic of Frankfurt, Frankfurt am Main, Germany
| | - Stephanie Traub
- Institute of Biochemistry II, University Clinic of Frankfurt, Frankfurt am Main, Germany
| | - Ritva Tikkanen
- Institute of Biochemistry, University of Giessen, Giessen, Germany
- Institute of Biochemistry II, University Clinic of Frankfurt, Frankfurt am Main, Germany
- * E-mail:
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15
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Lee M, Kang Y, Suk K, Schwab C, Yu S, McGeer PL. Acidic fibroblast growth factor (FGF) potentiates glial-mediated neurotoxicity by activating FGFR2 IIIb protein. J Biol Chem 2011; 286:41230-41245. [PMID: 21990352 DOI: 10.1074/jbc.m111.270470] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous studies indicate that astrocytes are the brain cells that express acidic fibroblast growth factor (aFGF) and that the expression is increased upon activation. However, there has been no study investigating the significance of this phenomenon. Here we report that aFGF treatment of IFNγ-stimulated human astrocytes, and LPS/IFNγ-stimulated human microglia, enhances their secretion of inflammatory cytokines and other materials toxic to human neuroblastoma SH-SY5Y cells. The mechanism of aFGF enhancement involves stimulation of the receptor FGFR2 IIIb. We show by RT-PCR that this receptor, but not other FGF receptors, is robustly expressed by astrocytes and microglia. We establish by Western blotting, and immunohistochemistry on postmortem human brain tissue that the FGFR2 IIIb protein is expressed by both of these glial cell types. We blocked the inflammatory stimulant action of aFGF by transfecting microglia and astrocytes with a small inhibitory RNA (siRNA) to FGFR2 IIIb as well as by removal of aFGF using an anti-aFGF antibody. Treatment with bFGF in combination with the stimulants was without effect, but together with aFGF, it partially counteracted the action of aFGF, indicating that it may be a weak antagonist of FGFR2 IIIb. The inflammatory effect was also attenuated by treatment with inhibitors of protein kinase C, Src tyrosine kinase, and MEK-1/2 indicating the involvement of these intracellular pathways. Our data suggest that inhibition of expression or release of aFGF could have therapeutic potential by inhibiting inflammation in neurodegenerative diseases such as Alzheimer disease where many neuroinflammatory molecules are prominently expressed.
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Affiliation(s)
- Moonhee Lee
- Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Yunhee Kang
- Brain Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Kyoungho Suk
- Department of Pharmacology, Kyungpook National University School of Medicine, Brain Science and Engineering Institute, Daegu 700422, Korea
| | - Claudia Schwab
- Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Sheng Yu
- Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Patrick L McGeer
- Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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16
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Gibson NJ. Cell adhesion molecules in context: CAM function depends on the neighborhood. Cell Adh Migr 2011; 5:48-51. [PMID: 20948304 PMCID: PMC3038097 DOI: 10.4161/cam.5.1.13639] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 09/16/2010] [Indexed: 01/03/2023] Open
Abstract
Cell adhesion molecules (CAMs) are now known to mediate much more than adhesion between cells and between cells and the extracellular matrix. Work by many researchers has illuminated their roles in modulating activation of molecules such as receptor tyrosine kinases, with subsequent effects on cell survival, migration, and process extension. CAMs also are known to serve as substrates for proteases which can create diffusible fragments capable of signaling independently from the CAM. The diversity of interactions is further modulated by membrane rafts, which can co-localize or separate potential signaling partners to affect the likelihood of a given signaling pathway being activated. Given the ever-growing number of known CAMs and the fact that their heterophilic binding in cis or in trans can affect their interactions with other molecules, including membrane-bound receptors, one would predict a wide range of effects attributable to a particular CAM in a particular cell at a particular stage of development. The function(s) of a given CAM must therefore be considered in the context of the history of the cell expressing it and the repertoire of molecules expressed both by that cell and its neighbors.
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Affiliation(s)
- Nicholas J Gibson
- Department of Neuroscience, University of Arizona, Tucson, Arizona, USA.
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17
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Li Y, Liu J, Hudson M, Kim S, Hatch NE. FGF2 promotes Msx2 stimulated PC-1 expression via Frs2/MAPK signaling. J Cell Biochem 2010; 111:1346-58. [DOI: 10.1002/jcb.22861] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Abstract
Docking proteins comprise a distinct category of intracellular, noncatalytic signalling protein, that function downstream of a variety of receptor and receptor-associated tyrosine kinases and regulate diverse physiological and pathological processes. The growth factor receptor bound 2-associated binder/Daughter of Sevenless, insulin receptor substrate, fibroblast growth factor receptor substrate 2 and downstream of tyrosine kinases protein families fall into this category. This minireview focuses on the structure, function and regulation of these proteins.
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Affiliation(s)
- Tilman Brummer
- Centre for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
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19
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Subczynski WK, Wisniewska A, Widomska J. Location of macular xanthophylls in the most vulnerable regions of photoreceptor outer-segment membranes. Arch Biochem Biophys 2010; 504:61-6. [PMID: 20494651 DOI: 10.1016/j.abb.2010.05.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 05/14/2010] [Accepted: 05/18/2010] [Indexed: 11/16/2022]
Abstract
Lutein and zeaxanthin are two dietary carotenoids that compose the macular pigment of the primate retina. Another carotenoid, meso-zeaxanthin, is formed from lutein in the retina. A membrane location is one possible site where these dipolar, terminally dihydroxylated carotenoids, named macular xanthophylls, are accumulated in the nerve fibers and photoreceptor outer segments. Macular xanthophylls are oriented perpendicular to the membrane surface, which ensures their high solubility, stability, and significant effects on membrane properties. It was recently shown that they are selectively accumulated in membrane domains that contain unsaturated phospholipids, and thus are located in the most vulnerable regions of the membrane. This location is ideal if they are to act as lipid antioxidants, which is the most accepted mechanism through which lutein and zeaxanthin protect the retina from age-related macular degeneration. In this mini-review, we examine published data on carotenoid-membrane interactions and present our hypothesis that the specific orientation and location of macular xanthophylls maximize their protective action in membranes of the eye retina.
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Affiliation(s)
- Witold K Subczynski
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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20
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Hryciw T, MacDonald JIS, Phillips R, Seah C, Pasternak S, Meakin SO. The fibroblast growth factor receptor substrate 3 adapter is a developmentally regulated microtubule-associated protein expressed in migrating and differentiated neurons. J Neurochem 2009; 112:924-39. [PMID: 19943849 DOI: 10.1111/j.1471-4159.2009.06503.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fibroblast growth factor (FGF) mediated signaling is essential to many aspects of neural development. Activated FGF receptors signal primarily through the FGF receptor substrate (Frs) adapters, which include Frs2/Frs2alpha and Frs3/Frs2beta. While some studies suggest that Frs3 can compensate for the loss of Frs2 in transfected cells, the lack of an effective Frs3 specific antibody has prevented efforts to determine the role(s) of the endogenous protein. To this end, we have generated a Frs3 specific antibody and have characterized the pattern of Frs3 expression in the developing nervous system, its subcellular localization as well as its biochemical properties. We demonstrate that Frs3 is expressed at low levels in the ventricular zone of developing cortex, between E12 and E15, and it co-localizes with nestin and acetylated alpha-tubulin in radial processes in the ventricular/subventricular zones as well as with betaIII tubulin in differentiated cortical neurons. Subcellular fractionation studies demonstrate that endogenous Frs3 is both soluble and plasma membrane associated while Frs3 expressed in 293T cells associates exclusively with lipid rafts. Lastly, we demonstrate that neuronal Frs3 binds microtubules comparable to the microtubule-associated protein, MAP2, while Frs2 does not. Collectively, these data suggest that neuronal Frs3 functions as a novel microtubule binding protein and they provide the first biochemical evidence that neuronal Frs3 is functionally distinct from Frs2/Frs2alpha.
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Affiliation(s)
- Todd Hryciw
- Molecular Brain Research Group, Robarts Research Institute, London, Ontario, Canada
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21
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Gibson NJ, Tolbert LP, Oland LA. Roles of specific membrane lipid domains in EGF receptor activation and cell adhesion molecule stabilization in a developing olfactory system. PLoS One 2009; 4:e7222. [PMID: 19787046 PMCID: PMC2746287 DOI: 10.1371/journal.pone.0007222] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 09/06/2009] [Indexed: 11/18/2022] Open
Abstract
Background Reciprocal interactions between glial cells and olfactory receptor neurons (ORNs) cause ORN axons entering the brain to sort, to fasciculate into bundles destined for specific glomeruli, and to form stable protoglomeruli in the developing olfactory system of an experimentally advantageous animal species, the moth Manduca sexta. Epidermal growth factor receptors (EGFRs) and the cell adhesion molecules (IgCAMs) neuroglian and fasciclin II are known to be important players in these processes. Methodology/Principal Findings We report in situ and cell-culture studies that suggest a role for glycosphingolipid-rich membrane subdomains in neuron-glia interactions. Disruption of these subdomains by the use of methyl-β-cyclodextrin results in loss of EGFR activation, depletion of fasciclin II in ORN axons, and loss of neuroglian stabilization in the membrane. At the cellular level, disruption leads to aberrant ORN axon trajectories, small antennal lobes, abnormal arrays of olfactory glomerul, and loss of normal glial cell migration. Conclusions/Significance We propose that glycosphingolipid-rich membrane subdomains (possible membrane rafts or platforms) are essential for IgCAM-mediated EGFR activation and for anchoring of neuroglian to the cytoskeleton, both required for normal extension and sorting of ORN axons.
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Affiliation(s)
- Nicholas J Gibson
- Arizona Research Laboratories Division of Neurobiology, University of Arizona, Tucson, Arizona, United States of America.
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22
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Bryant MR, Marta CB, Kim FS, Bansal R. Phosphorylation and lipid raft association of fibroblast growth factor receptor-2 in oligodendrocytes. Glia 2009; 57:935-46. [PMID: 19053057 DOI: 10.1002/glia.20818] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fibroblast growth factors (FGFs) and their receptors (FGFRs) initiate diverse cellular responses that contribute to the regulation of oligodendrocyte (OL) function. To understand the mechanisms by which FGFRs elicit these cellular responses, we investigated the phosphorylation of signal transduction proteins and the role of cholesterol-glycosphingolipid-enriched "lipid raft" microdomains in differentiated OLs. Surprisingly, we found that the most abundant tyrosine-phosphorylated protein in OLs was the 120-kd isoform of FGFR2 and that it was phosphorylated even in the absence of FGF2, suggesting a potential ligand-independent function for this receptor. Furthermore, FGFR2, but not FGFR1, was associated with lipid raft microdomains in OLs and myelin (but not in astrocytes). This provides the first evidence for the association of FGFR with TX-100-insoluble lipid raft fractions. FGFR2 phosphorylated the key downstream target, FRS2 in OLs. Raft disruption resulted in loss of phosphorylated FRS2 from lipid rafts, coupled with the loss of Akt but not of Mek or Erk phosphorylation. This suggests that FGFR2-FRS2 signaling in lipid rafts operates via the PI3-Kinase/Akt pathway rather than the Ras/Mek/Erk pathway, emphasizing the importance of microenvironments within the cell membrane. Also present in lipid rafts in OLs and myelin, but not in astrocytes, was a novel 52-kd isoform of FGFR2 that lacked the extracellular ligand-binding region. These results demonstrate that FGFR2 in OLs and myelin possess unique characteristics that are specific both to receptor type and to OLs and provide a novel mechanism to elicit distinct cellular responses that mediate both FGF-dependent and -independent functions.
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Affiliation(s)
- M R Bryant
- Department of Neuroscience, University of Connecticut Medical School, Farmington, Connecticut 06030-3401, USA
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23
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Saulle E, Riccioni R, Coppola S, Parolini I, Diverio D, Riti V, Mariani G, Laufer S, Sargiacomo M, Testa U. Colocalization of the VEGF-R2 and the common IL-3/GM-CSF receptor beta chain to lipid rafts leads to enhanced p38 activation. Br J Haematol 2009; 145:399-411. [DOI: 10.1111/j.1365-2141.2009.07627.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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24
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Lipid rafts enriched in phosphatidylglucoside direct astroglial differentiation by regulating tyrosine kinase activity of epidermal growth factor receptors. Biochem J 2009; 419:565-75. [DOI: 10.1042/bj20081896] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Membrane lipid rafts provide a specialized microenvironment enriched with sphingolipids and phospholipids containing saturated fatty acids and serve as a platform for various intracellular signalling pathways. PtdGlc (phosphatidylglucoside) is a type of glycophospholipid localized in the outer leaflet of the plasma membrane. Owing to PtdGlc's unique fatty acid composition, exclusively composed of C18:0 at sn-1 and C20:0 at sn-2 of the glycerol backbone, it tends to form PGLRs (PtdGlc-enriched lipid rafts). Previously, we demonstrated that PGLRs reside on the cell surface of astroglial cells from fetal rat brain [Nagatsuka, Horibata, Yamazaki, Kinoshita, Shinoda, Hashikawa, Koshino, Nakamura and Hirabayashi (2006) Biochemistry 45, 8742–8750]. In the present study, we observed PGLRs in astroglial lineage cells at mid-embryonic to early-postnatal stages of developing mouse cortex. This suggests that PGLRs are developmentally correlated with astroglial differentiation during fetal cortical development. Our cell culture studies with multipotent neural progenitor cells prepared from fetal mouse telencephalon demonstrated that treatment with EGF (epidermal growth factor) or anti-PtdGlc antibody caused recruitment of EGFRs (EGF receptors) into lipid raft compartments, leading to activation of EGFRs. Moreover, the activation of EGFRs by antibody triggered downstream tyrosine kinase signalling and induced marked GFAP (glial fibrillary acidic protein) expression via the JAK (Janus kinase)/STAT (signal transducer and activator of transcription) signalling pathway. These findings strongly suggest that PGLRs are physiologically coupled to activated EGFRs on neural progenitor cells during fetal cortical development, and thereby play a distinct role in mediating astrogliogenesis.
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25
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Resistance of Human Erythrocyte Membranes to Triton X-100 and C12E8. J Membr Biol 2008; 227:39-48. [DOI: 10.1007/s00232-008-9142-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Accepted: 11/11/2008] [Indexed: 11/24/2022]
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26
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Lundgren TK, Stenqvist A, Scott RP, Pawson T, Ernfors P. Cell migration by a FRS2-adaptor dependent membrane relocation of ret receptors. J Cell Biochem 2008; 104:879-94. [PMID: 18189271 DOI: 10.1002/jcb.21671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
During development neural progenitor cells migrate with extraordinary precision to inhabit tissues and organs far from their initial position. Little is known about the cellular basis for directional guidance by tyrosine kinase receptors (RTKs). RET is a RTK with important functions in guiding the migration of neuronal cells, and RET dysregulation leads to clinical disease such as agangliosis of the colon. We show here that RET migration in neuroepitheliomal and non-neuronal cells is elicited by the activation of specific signaling pathways initiated by the competitive recruitment of the FRS2 adaptor molecule to tyrosine 1062 (Y1062) in RET. FRS2 selectively recruited RET to focal complexes and led to activation of SRC family kinases and focal adhesion kinase (FAK). Activation of SRC depended on its direct interaction with RET at a different intracellular tyrosine (Y981) and activation of molecular signaling from these two separate sites in concert regulated migration. Our data suggest that an important function for FRS2 is to concentrate RET in membrane foci, leading to an engagement of specific signaling complexes localized in these membrane domains.
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Affiliation(s)
- T Kalle Lundgren
- Unit of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden
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27
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Lundgren TK, Luebke M, Stenqvist A, Ernfors P. Differential membrane compartmentalization of Ret by PTB-adaptor engagement. FEBS J 2008; 275:2055-66. [DOI: 10.1111/j.1742-4658.2008.06360.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Elasticity, strength, and water permeability of bilayers that contain raft microdomain-forming lipids. Biophys J 2008; 94:4725-36. [PMID: 18339739 DOI: 10.1529/biophysj.107.121731] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Bilayers composed of phosphatidylcholine (PC), sphingomyelin (SM), and cholesterol (CHOL) are commonly used as systems to model the raft-lipid domain structure believed to compartmentalize particular cell membrane proteins. In this work, micropipette aspiration of giant unilamellar vesicles was used to test the elasticities, water permeabilities, and rupture tensions of single-component PC, binary 1:1 PC/CHOL, and 1:1 SM/CHOL, and ternary 1:1:1 PC/SM/CHOL bilayers, one set of measurements with dioleoyl PC (DOPC; C18:1/C18:1 PC) and the other with stearoyloleoyl PC (SOPC; C18:0/C18:1 PC). Defining the elastic moduli (K(A)), the initial slopes of the increase in tension (sigma) versus stretch in lipid surface area (alpha(e)) were determined for all systems at low (15 degrees C) and high (32-33 degrees C) temperatures. The moduli for the single-component PC and binary phospholipid/CHOL bilayers followed a descending hierarchy of stretch resistance with SM/CHOL > SOPC/CHOL > DOPC/CHOL > PC. Although much more resistant to stretch than the single-component PC bilayers, the elastic response of vesicle bilayers made from the ternary phospholipid/CHOL mixtures showed an abrupt softening (discontinuity in slope), when immediately subjected to a steady ramp of tension at the low temperature (15 degrees C). However, the discontinuities in elastic stretch resistance at low temperature vanished when the bilayers were held at approximately 1 mN/m prestress for long times before a tension ramp and when tested at the higher temperature 32-33 degrees C. The elastic moduli of single-component PC and DOPC/CHOL bilayers changed very little with temperature, whereas the moduli of the binary SOPC/CHOL and SM/CHOL bilayers diminished markedly with increase in temperature, as did the ternary SOPC/SM/CHOL system. For all systems, increasing temperature increased the water permeability but decreased rupture tension. Concomitantly, the measurements of permeability exhibited a prominent correlation with the rupture tension across all the systems. Together, these micromechanical tests of binary and ternary phospholipid/CHOL bilayers demonstrate that PC hydrocarbon chain unsaturation and temperature are major determinants of the mechanical and permeation properties of membranes composed of raft microdomain-forming lipids.
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Abstract
Transient lateral microdomains (rafts) in cell membranes have been postulated to perform a number of important functions in normal cells, and are also thought to be critically involved in several pathological conditions. However, there are still a number of fundamental unanswered questions concerning the composition, size, dynamics, and stability of membrane rafts. These questions are currently being addressed by a number of sophisticated biophysical, biochemical, and computational methodologies.
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de Laurentiis A, Donovan L, Arcaro A. Lipid rafts and caveolae in signaling by growth factor receptors. Open Biochem J 2007; 1:12-32. [PMID: 18949068 PMCID: PMC2570545 DOI: 10.2174/1874091x00701010012] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 08/15/2007] [Accepted: 08/16/2007] [Indexed: 12/29/2022] Open
Abstract
Lipid rafts and caveolae are microdomains of the plasma membrane enriched in sphingolipids and cholesterol, and hence are less fluid than the remainder of the membrane. Caveolae have an invaginated structure, while lipid rafts are flat regions of the membrane. The two types of microdomains have different protein compositions (growth factor receptors and their downstream molecules) suggesting that lipid rafts and caveolae have a role in the regulation of signaling by these receptors. The purpose of this review is to discuss this model, and the implications that it might have regarding a potential role for lipid rafts and caveolae in human cancer. Particular attention will be paid to the epidermal growth factor receptor, for which the largest amount of information is available. It has been proposed that caveolins act as tumor suppressors. The role of lipid rafts is less clear, but they seem to be capable of acting as 'signaling platforms', in which signal initiation and propagation can occur efficiently.
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Affiliation(s)
- Angela de Laurentiis
- Division of Clinical Chemistry and Biochemistry, University Children’s Hospital Zurich, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland
| | - Lorna Donovan
- Division of Medicine, Imperial College Faculty of Medicine, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK
| | - Alexandre Arcaro
- Division of Clinical Chemistry and Biochemistry, University Children’s Hospital Zurich, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland
- Division of Medicine, Imperial College Faculty of Medicine, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK
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31
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Limpert AS, Karlo JC, Landreth GE. Nerve growth factor stimulates the concentration of TrkA within lipid rafts and extracellular signal-regulated kinase activation through c-Cbl-associated protein. Mol Cell Biol 2007; 27:5686-98. [PMID: 17548467 PMCID: PMC1952120 DOI: 10.1128/mcb.01109-06] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Nerve growth factor (NGF) acts through its receptor, TrkA, to elicit the neuronal differentiation of PC12 cells through the action of extracellular signal-regulated kinase 1 (ERK1) and ERK2. Upon NGF binding, TrkA translocates and concentrates in cholesterol-rich membrane microdomains or lipid rafts, facilitating formation of receptor-associated signaling complexes, activation of downstream signaling pathways, and internalization into endosomes. We have investigated the mechanisms responsible for the localization of TrkA within lipid rafts and its ability to activate ERK1 and ERK2. We report that NGF treatment results in the translocation of activated forms of TrkA to lipid rafts, and this localization is important for efficient activation of the ERKs. TrkA is recruited and retained within lipid rafts through its association with flotillin, an intrinsic constituent of these membrane microdomains, via the adapter protein, c-Cbl associated protein (CAP). Mutant forms of CAP that lack protein interaction domains block TrkA localization to lipid rafts and attenuate ERK activation. Importantly, suppression of endogenous CAP expression inhibited NGF-stimulated neurite outgrowth from primary dorsal root ganglion neurons. These data provide a mechanism for the lipid raft localization of TrkA and establish the importance of the CAP adaptor protein for NGF activation of the ERKs and neuronal differentiation.
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Affiliation(s)
- Allison S Limpert
- Department of Neurosciences, Alzheimer Research Laboratory, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4928, USA
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ZHOU YONGXING, FLINT NICOLEC, MURTIE JOSHUAC, LE TUANQ, ARMSTRONG REGINAC. Retroviral lineage analysis of fibroblast growth factor receptor signaling in FGF2 inhibition of oligodendrocyte progenitor differentiation. Glia 2006; 54:578-90. [PMID: 16921523 PMCID: PMC1876694 DOI: 10.1002/glia.20410] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Fibroblast growth factor 2 (FGF2) inhibits oligodendrocyte progenitor cell (OPC) differentiation during development and limits remyelination following chronic demyelination. The current study examines the mechanism underlying this effect of FGF2 expression on OPC differentiation. Retroviral lineage tracing demonstrates a direct in vivo effect of FGF receptor (FGFR) signaling on OPC differentiation. Retrovirus expressing a dominant negative FGFR construct (FGFRdn) and green fluorescent protein (GFP) was injected into the dorsal columns of postnatal day 7 (P7) mice followed by perfusion at P28. Among the GFP-labeled cells, FGFRdn retrovirus generated a higher proportion of oligodendrocytes than did control infections. This result from FGFRdn expression in OPCs was similar to the result obtained in our previous study using control retrovirus in FGF2 null mice. Further, in vitro retroviral siRNA expression distinguishes the function of specific FGFR isoforms in OPC responses to FGF2. FGF2 inhibition of OPC differentiation was effectively blocked by siRNA targeted to FGFR1, but not FGFR2 or FGFR3. We propose a model of direct FGF2 activation of FGFR1 leading to inhibition of OPC differentiation. This signaling pathway may be an important regulator of oligodendrocyte generation during myelination in development and may perturb OPC generation of remyelinating oligodendrocytes in demyelinating disease.
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MESH Headings
- Animals
- Animals, Newborn
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cell Lineage/drug effects
- Cell Lineage/physiology
- Cells, Cultured
- Fibroblast Growth Factor 2/metabolism
- Fibroblast Growth Factor 2/pharmacology
- Genetic Vectors/genetics
- Green Fluorescent Proteins
- Growth Inhibitors/metabolism
- Growth Inhibitors/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Nerve Fibers, Myelinated/drug effects
- Nerve Fibers, Myelinated/metabolism
- Nerve Regeneration/physiology
- Oligodendroglia/drug effects
- Oligodendroglia/metabolism
- RNA, Small Interfering/genetics
- Rats
- Receptor, Fibroblast Growth Factor, Type 1/drug effects
- Receptor, Fibroblast Growth Factor, Type 1/metabolism
- Recombinant Fusion Proteins/genetics
- Retroviridae/genetics
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Stem Cells/drug effects
- Stem Cells/metabolism
- Transfection/methods
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Affiliation(s)
- YONG-XING ZHOU
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - NICOLE C. FLINT
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - JOSHUA C. MURTIE
- Program in Molecular and Cell Biology and Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - TUAN Q. LE
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - REGINA C. ARMSTRONG
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
- Program in Molecular and Cell Biology and Uniformed Services University of the Health Sciences, Bethesda, Maryland
- Neuroscience Program; Uniformed Services University of the Health Sciences, Bethesda, Maryland
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Sobke ACS, Selimovic D, Orlova V, Hassan M, Chavakis T, Athanasopoulos AN, Schubert U, Hussain M, Thiel G, Preissner KT, Herrmann M. The extracellular adherence protein fromStaphylococcus aureusabrogates angiogenic responses of endothelial cells by blocking Ras activation. FASEB J 2006; 20:2621-3. [PMID: 17077291 DOI: 10.1096/fj.06-5764fje] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The extracellular adherence protein (Eap), a broad-spectrum adhesin secreted by Staphylococcus aureus, was previously shown to curb acute inflammatory responses, presumably through its binding to endothelial cell (EC) ICAM-1. Examining the effect of Eap on endothelial function in more detail, we here show that, in addition, Eap functions as a potent angiostatic agent. Concomitant treatment of EC with purified Eap resulted in the complete blockage of the mitogenic and sprouting responses elicited by vascular endothelial growth factor (VEGF)165 or basic fibroblast growth factor (bFGF). Moreover, the induction of tissue factor and decay-accelerating factor were repressed by Eap, as determined by qRT-polymerase chain reaction (qRT-PCR), with a corresponding reduction in Egr-1 protein up-regulation seen. This angiostatic activity was accompanied by a corresponding inhibition in ERK1/2 phosphorylation, while activation of p38 was not affected. Inhibition occurred downstream of tyrosine kinase receptor activation, as comparable effects were seen on TPA-induced ERK1/2 phosphorylation. Similar to previously described angiostatic agents like angiopoietin-1 or the 16-kDa prolactin fragment, Eap blockage of the Ras/Raf/MEK/ERK cascade was localized by pull-down assay at the level of Ras activation. Eap's combined anti-inflammatory and antiangiogenic properties render this bacterial protein not only an important virulence factor during S. aureus infection but open new perspectives for therapeutic applications in pathological neovascularization.
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Affiliation(s)
- Astrid C S Sobke
- Institute of Medical Microbiology and Hygiene, University of Saarland Hospital, D-66421 Homburg/Saar, Germany.
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The Fibroblast Growth Factor (FGF) – FGF Receptor Complex: Progress Towards the Physiological State. Top Curr Chem (Cham) 2006. [DOI: 10.1007/128_068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Hatch NE, Hudson M, Seto ML, Cunningham ML, Bothwell M. Intracellular retention, degradation, and signaling of glycosylation-deficient FGFR2 and craniosynostosis syndrome-associated FGFR2C278F. J Biol Chem 2006; 281:27292-305. [PMID: 16844695 DOI: 10.1074/jbc.m600448200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fibroblast growth factors (FGFs) and their receptors (FGFRs) are known to play a critical role in a variety of fundamental processes, including wound healing, angiogenesis, and development of multiple organ systems. Mutations in the FGFR gene family have been linked to a series of syndromes (the craniosynostosis syndromes) whose primary phenotype involves aberrant development of the craniofacial skeleton. Craniosynostosis syndrome-linked FGFR mutations have been shown to be gain of function in terms of receptor activation and have been presumed to result in increased levels of FGF/FGFR signaling. Unfortunately, studies attempting to link expression of mutant FGFRs with changes in cellular phenotype have yielded conflicting results. In an effort to better understand the biochemical consequences of these mutations on receptor function, here we have investigated the effect of the FGFR2C278F mutation of Crouzon craniosynostosis syndrome on receptor trafficking, ubiquitination, degradation, and signaling. We find that FGFR2C278F exhibits diminished glycosylation, increased degradation, and limited cellular sublocalization in the osteoblastic cell line, MC3T3E1(C4). Additionally, we show that trafficking and autoactivation of wild type FGFR2 is glycosylation-dependent. Both FGFR2C278F and unglycosylated wild type FGFR2 signal through phospholipase Cgamma in a ligand-independent manner as well as exhibit dramatically increased binding to the adaptor protein, Frs2. These findings suggest that autoactive FGFR2 can signal from intracellular compartments. Based upon our results, we propose that the functional signaling of craniosynostosis mutant, autoactive receptors is limited in some cell types by protective cellular responses, such as increased trafficking to lysosomes and proteasomes for degradation.
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Affiliation(s)
- Nan E Hatch
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA.
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36
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Heo K, Jariwala U, Woo J, Zhan Y, Burke KA, Zhu L, Anderson WF, Zhao Y. Involvement of Niemann-Pick type C2 protein in hematopoiesis regulation. Stem Cells 2006; 24:1549-55. [PMID: 16484344 DOI: 10.1634/stemcells.2005-0458] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Niemann-Pick type C2 (NPC2) protein has been characterized as a cholesterol-binding protein. Its loss leads to NPC2 disease, an inherited neurodegenerative disorder. When analyzing gene expression profile, we noticed high expression of both NPC2 and its receptor, mannose 6-phosphate receptor (MPR), in murine hematopoietic stem cells. NPC2 protein, in the presence of thrombopoietin (TPO), causes an increase in CFU-GEMM (colony-forming unit-granulocyte-erythroid-macrophage-megakaryocyte) and a decrease in CFU-GM (colony-forming unit-granulocyte-macrophage) colony number in colony-forming cell (CFC) assays. This effect is independent of cholesterol binding but does require the presence of MPR. With M07e cells, a TPO-dependent hematopoietic leukemia cell line, NPC2 can inhibit TPO-induced differentiation and enhance TPO-mediated anti-apoptosis effects. Strikingly, these results are not observed under the standard 20% O(2) level of the standard incubator, but rather at 7% O(2), the physiological oxygen level of bone marrow. Furthermore, NPC2 protein upregulates hypoxia inducible factor 1-alpha protein level at 7% O(2), but not at 20% O(2). Our results demonstrate that NPC2 protein plays a role in hematopoiesis at the physiologic bone marrow level of O(2).
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Affiliation(s)
- Kyu Heo
- Department of Biochemistry and Molecular Biology, University of Southern California, Keck School of Medicine, Los Angeles, 90033, USA
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Gouzi JY, Moog-Lutz C, Vigny M, Brunet-de Carvalho N. Role of the subcellular localization of ALK tyrosine kinase domain in neuronal differentiation of PC12 cells. J Cell Sci 2005; 118:5811-23. [PMID: 16317043 DOI: 10.1242/jcs.02695] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase essentially and transiently expressed in specific areas of the developing central and peripheral nervous systems. We previously demonstrated that a membrane-bound and constitutively active form of the ALK protein tyrosine kinase (PTK) domain induced the neuron-like differentiation of PC12 cells through specific activation of the mitogen-activated protein kinase (MAP kinase) pathway. Its PTK domain had been originally identified in a nucleo-cytosolic and constitutively active transforming protein, NPM-ALK. Downstream targets involved in oncogenic proliferation and survival processes have been proposed to include phospholipase Cgamma (PLCgamma), phosphoinositide 3-kinase (PI 3-kinase)/AKT, STAT 3/5 and Src. We therefore postulated that activation of specific signaling pathways leading to differentiation or proliferation can be differently controlled depending on the subcellular localization of ALK PTK domain. To increase knowledge of its physiological role in the nervous system, we focused in the present study on the influence of its subcellular localization on neuronal differentiation. To achieve this goal, we characterized biological responses and transduction pathways in PC12 cells elicited by various constructs encoding membrane-bound (through transmembrane or myristyl sequences) or cytosolic ALK-derived proteins. In order to control the activation of their PTK domain, we used an inducible dimerization system. Here, we demonstrate that membrane attachment of the ALK PTK domain, in PC12 cells, is crucial for initiation of neurite outgrowth and proliferation arrest through a decrease of DNA synthesis. Furthermore, we show that this differentiation process relies on specific and sustained activation of ERK 1/2 proteins. By contrast, activation of the cytosolic form of this domain fails to induce MAP kinase activation and cell differentiation but promotes a PI 3-kinase/AKT-dependent PC12 cell proliferation. These data indicate that subcellular localization of the ALK PTK domain was a determinant for the control and specificity of downstream transduction cascades and was crucial for deciding the fate to which the neuronal cell will be committed.
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Affiliation(s)
- Jean Y Gouzi
- INSERM, U706, Institut du Fer à Moulin, 17 rue du Fer à Moulin, Paris, F-75005, France
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Gopalakrishnan M, Forsten-Williams K, Nugent MA, Täuber UC. Effects of receptor clustering on ligand dissociation kinetics: theory and simulations. Biophys J 2005; 89:3686-700. [PMID: 16150967 PMCID: PMC1366939 DOI: 10.1529/biophysj.105.065300] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Receptor-ligand binding is a critical first step in signal transduction and the duration of the interaction can impact signal generation. In mammalian cells, clustering of receptors may be facilitated by heterogeneous zones of lipids, known as lipid rafts. In vitro experiments show that disruption of rafts significantly alters the dissociation of fibroblast growth factor-2 (FGF-2) from heparan sulfate proteoglycans (HSPGs), co-receptors for FGF-2. In this article, we develop a continuum stochastic formalism to address how receptor clustering might influence ligand rebinding. We find that clusters reduce the effective dissociation rate dramatically when the clusters are dense and the overall surface density of receptors is low. The effect is much less pronounced in the case of high receptor density and shows nonmonotonic behavior with time. These predictions are verified via lattice Monte Carlo simulations. Comparison with FGF-2-HSPG experimental results is made and suggests that the theory could be used to analyze similar biological systems. We further present an analysis of an additional cooperative internal-diffusion model that might be used by other systems to increase ligand retention when simple rebinding is insufficient.
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Affiliation(s)
- Manoj Gopalakrishnan
- Department of Biological Physics, Max-Planck-Institut für Physik Komplexer Systeme, Dresden, Germany
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39
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Pike LJ. Growth factor receptors, lipid rafts and caveolae: an evolving story. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1746:260-73. [PMID: 15951036 DOI: 10.1016/j.bbamcr.2005.05.005] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 04/25/2005] [Accepted: 05/13/2005] [Indexed: 11/16/2022]
Abstract
Growth factor receptors have been shown to be localized to lipid rafts and caveolae. Consistent with a role for these cholesterol-enriched membrane domains in growth factor receptor function, the binding and kinase activities of growth factor receptors are susceptible to regulation by changes in cholesterol content. Furthermore, knockouts of caveolin-1, the structural protein of caveolae, have confirmed that this protein, and by implication caveolae, modulate the ability of growth factor receptors to signal. This article reviews the findings pertinent to the relationship between growth factor receptors, lipid rafts and caveolae and presents a model for understanding the disparate observations regarding the role of membrane microdomains in the regulation of growth factor receptor function.
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Affiliation(s)
- Linda J Pike
- Washington University School of Medicine, Department of Biochemistry and Molecular Biophysics, 660 So. Euclid, Box 8231, St. Louis, MO 63110, USA.
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40
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Puri C, Tosoni D, Comai R, Rabellino A, Segat D, Caneva F, Luzzi P, Di Fiore PP, Tacchetti C. Relationships between EGFR signaling-competent and endocytosis-competent membrane microdomains. Mol Biol Cell 2005; 16:2704-18. [PMID: 15772153 PMCID: PMC1142418 DOI: 10.1091/mbc.e04-07-0596] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Membrane microdomains, the so-called lipid rafts, function as platforms to concentrate receptors and assemble the signal transduction machinery. Internalization, in most cases, is carried out by different specialized structures, the clathrin-coated pits. Here, we show that several endocytic proteins are efficiently recruited to morphologically identified plasma membrane lipid rafts, upon activation of the epidermal growth factor (EGF) receptor (EGFR), a receptor tyrosine kinase. Analysis of detergent-resistant membrane fractions revealed that the EGF-dependent association of endocytic proteins with rafts is as efficient as that of signaling effector molecules, such as Grb2 or Shc. Finally, the EGFR, but not the nonsignaling transferrin receptor, could be localized in nascent coated pits that almost invariably contained raft membranes. Thus, specialized membrane microdomains have the ability to assemble both the molecular machineries necessary for intracellular propagation of EGFR effector signals and for receptor internalization.
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Affiliation(s)
- Claudia Puri
- MicroScoBio Research Center, Department of Experimental Medicine, University of Genoa, 16132 Genoa, Italy
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Huang L, Gotoh N, Zhang S, Shibuya M, Yamamoto T, Tsuchida N. SNT-2 interacts with ERK2 and negatively regulates ERK2 signaling in response to EGF stimulation. Biochem Biophys Res Commun 2004; 324:1011-7. [PMID: 15485655 DOI: 10.1016/j.bbrc.2004.09.152] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Indexed: 11/17/2022]
Abstract
The control of cellular responses with fibroblast growth factors and neurotrophins is mediated through membrane-linked docking proteins, SNT (suc1-binding neurotrophic target)-1/FRS2alpha and SNT-2/FRS2beta. ERK1/2 are members of the mitogen-activated protein kinase family that regulate diverse cellular activities in response to various stimuli. Here, we demonstrate that SNT-2 does not become tyrosine phosphorylated significantly in response to EGF but forms a complex with ERK2 via the region of 186-252 amino acid residues, and the complex formation is enhanced upon EGF stimulation. SNT-2 downregulates ERK2 phosphorylation, suppresses and delays ERK2 nuclear accumulation which occurs following EGF stimulation. In contrast, the mutant SNT-2 which carries deletion of 186-252 amino acids and lacks ERK2 binding does not have these effects. These observations suggest that SNT-2 negatively regulates ERK2 signaling activated via EGF stimulation through direct binding to ERK2.
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Affiliation(s)
- Lin Huang
- Department of Molecular Cellular Oncology and Microbiology, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yujima, Bunkyo-ku, Tokyo 113-8510, Japan
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Soriano JV, Liu N, Gao Y, Yao ZJ, Ishibashi T, Underhill C, Burke TR, Bottaro DP. Inhibition of angiogenesis by growth factor receptor bound protein 2-Src homology 2 domain bound antagonists. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.1289.3.10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Abstract
Growth factor receptor bound protein 2 (Grb2) is an intracellular adaptor protein that participates in the signal transduction cascades of several angiogenic factors, including hepatocyte growth factor, basic fibroblast growth factor, and vascular endothelial growth factor. We described previously the potent blockade of hepatocyte growth factor–stimulated cell motility, matrix invasion, and epithelial tubulogenesis by synthetic Grb2-Src homology 2 (SH2) domain binding antagonists. Here, we show that these binding antagonists block basic morphogenetic events required for angiogenesis, including hepatocyte growth factor–, vascular endothelial growth factor–, and basic fibroblast growth factor–stimulated endothelial cell proliferation and migration, as well as phorbol 12-myristate 13-acetate–stimulated endothelial cell migration and matrix invasion. The Grb2-SH2 domain binding antagonists also impair angiogenesis in vitro, as shown by the inhibition of cord formation by macrovascular endothelial cells on Matrigel. We further show that a representative compound inhibits angiogenesis in vivo as measured using a chick chorioallantoic membrane assay. These results suggest that Grb2 is an important mediator of key proangiogenic events, with potential application to pathologic conditions where neovascularization contributes to disease progression. In particular, the well-characterized role of Grb2 in signaling cell cycle progression together with our present findings suggests that Grb2-SH2 domain binding antagonists have the potential to act as anticancer drugs that target both tumor and vascular cell compartments.
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Affiliation(s)
| | - Ningfei Liu
- 4Department of Cell Biology, Georgetown University, Washington, District of Columbia
| | - Yang Gao
- 2Medicinal Chemistry, National Cancer Institute, NIH, Bethesda, Maryland
| | - Zhu-Jun Yao
- 2Medicinal Chemistry, National Cancer Institute, NIH, Bethesda, Maryland
| | - Toshio Ishibashi
- 3Department of Otolaryngology, Social Insurance Central General Hospital, Tokyo, Japan; and
| | - Charles Underhill
- 4Department of Cell Biology, Georgetown University, Washington, District of Columbia
| | - Terrence R. Burke
- 2Medicinal Chemistry, National Cancer Institute, NIH, Bethesda, Maryland
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Abstract
Newly formed oligodendrocytes in the CNS derive survival cues from their target axons. These cues are provided in part by laminins expressed on the axon, which are recognized by alpha6beta1 integrin on the oligdendrocyte and amplify platelet-derived growth factor (PDGF) signaling through the phosphatidylinositol 3'-kinase (PI3K) pathway. The alpha6beta1 integrin is localized in oligodendrocyte lipid rafts. We show here using the sphingolipid synthesis inhibitor fumonisin-B1 to deplete rafts that this localization is important for normal survival signaling, because depletion increases oligodendrocyte apoptosis and inhibits PI3K signaling. We have shown previously that PDGF-mediated integrin activation is an important component of oligodendrocyte proliferation signaling, and here we present evidence that a similar mechanism operates in survival signaling. Integrin activation using manganese increases raft localization and rescues the effects of both raft depletion and PDGF removal on survival and PI3K signaling. Together, these results point to an essential role for rafts in oligodendrocyte survival signaling on the basis of the provision of a favorable environment for growth factor-mediated integrin activation.
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Affiliation(s)
- Laurence Decker
- Department of Pathology, and Cambridge Centre for Brain Repair, University of Cambridge, Cambridge, CB2 1QP, United Kingdom
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Alsina B, Giraldez F, Varela-Nieto I. Growth Factors and Early Development of Otic Neurons: Interactions between Intrinsic and Extrinsic Signals. Curr Top Dev Biol 2003; 57:177-206. [PMID: 14674481 DOI: 10.1016/s0070-2153(03)57006-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Berta Alsina
- DCEXS-Universitat Pomepu Fabra, Dr Aiguader 80, 08003 Barcelona, Spain
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