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Nickoloff-Bybel EA, Festa L, Meucci O, Gaskill PJ. Co-receptor signaling in the pathogenesis of neuroHIV. Retrovirology 2021; 18:24. [PMID: 34429135 PMCID: PMC8385912 DOI: 10.1186/s12977-021-00569-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022] Open
Abstract
The HIV co-receptors, CCR5 and CXCR4, are necessary for HIV entry into target cells, interacting with the HIV envelope protein, gp120, to initiate several signaling cascades thought to be important to the entry process. Co-receptor signaling may also promote the development of neuroHIV by contributing to both persistent neuroinflammation and indirect neurotoxicity. But despite the critical importance of CXCR4 and CCR5 signaling to HIV pathogenesis, there is only one therapeutic (the CCR5 inhibitor Maraviroc) that targets these receptors. Moreover, our understanding of co-receptor signaling in the specific context of neuroHIV is relatively poor. Research into co-receptor signaling has largely stalled in the past decade, possibly owing to the complexity of the signaling cascades and functions mediated by these receptors. Examining the many signaling pathways triggered by co-receptor activation has been challenging due to the lack of specific molecular tools targeting many of the proteins involved in these pathways and the wide array of model systems used across these experiments. Studies examining the impact of co-receptor signaling on HIV neuropathogenesis often show activation of multiple overlapping pathways by similar stimuli, leading to contradictory data on the effects of co-receptor activation. To address this, we will broadly review HIV infection and neuropathogenesis, examine different co-receptor mediated signaling pathways and functions, then discuss the HIV mediated signaling and the differences between activation induced by HIV and cognate ligands. We will assess the specific effects of co-receptor activation on neuropathogenesis, focusing on neuroinflammation. We will also explore how the use of substances of abuse, which are highly prevalent in people living with HIV, can exacerbate the neuropathogenic effects of co-receptor signaling. Finally, we will discuss the current state of therapeutics targeting co-receptors, highlighting challenges the field has faced and areas in which research into co-receptor signaling would yield the most therapeutic benefit in the context of HIV infection. This discussion will provide a comprehensive overview of what is known and what remains to be explored in regard to co-receptor signaling and HIV infection, and will emphasize the potential value of HIV co-receptors as a target for future therapeutic development. ![]()
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Affiliation(s)
- E A Nickoloff-Bybel
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - L Festa
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, 240 S. 40th Street, Philadelphia, PA, 19104, USA
| | - O Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.,Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, 19102, USA
| | - P J Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.
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Ingles-Prieto A, Furthmann N, Crossman SH, Tichy AM, Hoyer N, Petersen M, Zheden V, Biebl J, Reichhart E, Gyoergy A, Siekhaus DE, Soba P, Winklhofer KF, Janovjak H. Optogenetic delivery of trophic signals in a genetic model of Parkinson's disease. PLoS Genet 2021; 17:e1009479. [PMID: 33857132 PMCID: PMC8049241 DOI: 10.1371/journal.pgen.1009479] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/10/2021] [Indexed: 12/19/2022] Open
Abstract
Optogenetics has been harnessed to shed new mechanistic light on current and future therapeutic strategies. This has been to date achieved by the regulation of ion flow and electrical signals in neuronal cells and neural circuits that are known to be affected by disease. In contrast, the optogenetic delivery of trophic biochemical signals, which support cell survival and are implicated in degenerative disorders, has never been demonstrated in an animal model of disease. Here, we reengineered the human and Drosophila melanogaster REarranged during Transfection (hRET and dRET) receptors to be activated by light, creating one-component optogenetic tools termed Opto-hRET and Opto-dRET. Upon blue light stimulation, these receptors robustly induced the MAPK/ERK proliferative signaling pathway in cultured cells. In PINK1B9 flies that exhibit loss of PTEN-induced putative kinase 1 (PINK1), a kinase associated with familial Parkinson's disease (PD), light activation of Opto-dRET suppressed mitochondrial defects, tissue degeneration and behavioral deficits. In human cells with PINK1 loss-of-function, mitochondrial fragmentation was rescued using Opto-dRET via the PI3K/NF-кB pathway. Our results demonstrate that a light-activated receptor can ameliorate disease hallmarks in a genetic model of PD. The optogenetic delivery of trophic signals is cell type-specific and reversible and thus has the potential to inspire novel strategies towards a spatio-temporal regulation of tissue repair.
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Affiliation(s)
- Alvaro Ingles-Prieto
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Nikolas Furthmann
- Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Samuel H. Crossman
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, Australia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, Australia
| | - Alexandra-Madelaine Tichy
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, Australia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, Australia
| | - Nina Hoyer
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Meike Petersen
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Vanessa Zheden
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Julia Biebl
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Eva Reichhart
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, Australia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, Australia
| | - Attila Gyoergy
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Daria E. Siekhaus
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Peter Soba
- Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Konstanze F. Winklhofer
- Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Harald Janovjak
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, Australia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, Australia
- * E-mail:
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Liu S, Chen L, Xu Y. Significance of PYK2 level as a prognosis predictor in patients with colon adenocarcinoma after surgical resection. Onco Targets Ther 2018; 11:7625-7634. [PMID: 30464511 PMCID: PMC6217216 DOI: 10.2147/ott.s169531] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background Proline-rich/Ca2+-activated tyrosine kinase 2 (PYK2) belongs to the non-receptor tyrosine kinase family, regulates downstream signaling via catalyzing protein phosphorylation. We aimed to investigate clinical significance and mechanisms of PYK2 in colon adenocarcinoma (CAC). Methods Real time quantitative PCR and immunohistochemistry staining was used to evaluate the expression of PYK2 in clinical CAC tissues. Its association with clinicopathologic characteristics was analyzed by Chi-square test. Kaplan-Meier univariate survival analysis and multivariate Cox regression analysis were used to identify clinical significance of PYK2 in the overall survival of CAC patients. Transfection of PYK2 were conducted to reveal the underlying mechanism in regulating CAC progression. Results We found that PYK2 was upregulated in CAC tissues compared with normal colon tissues on both RNA and protein levels. Higher tissue PYK2 expression level was closely associated with lymph node metastasis. Statistical analyses indicated PYK2 as an independent prognostic biomarker for CAC. Cellular studies demonstrated that PYK2 enhanced the capacities of tumor proliferation and invasion. Moreover, the phosphorylation level of AKT was positively correlated with PYK2 expression, subsequently modulate expression of c-Myc and Cyclin D1, suggesting that PYK2 may promote tumor progression through activating AKT signaling. Conclusion High PYK2 in CAC tissues indicate poor prognosis.
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Affiliation(s)
- Shufang Liu
- Department of Laboratory Medicine, Linyi Central Hospital, Linyi, Shandong 276400, China
| | - Lingling Chen
- Department of Laboratory Medicine, Linyi Central Hospital, Linyi, Shandong 276400, China
| | - Yunfei Xu
- Department of General Surgery, Qilu Hospital Affiliated to Shandong University, Jinan, Shandong 250012, China,
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Presence of Androgen Receptor Variant in Neuronal Lipid Rafts. eNeuro 2017; 4:eN-NWR-0109-17. [PMID: 28856243 PMCID: PMC5575139 DOI: 10.1523/eneuro.0109-17.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 08/03/2017] [Accepted: 08/14/2017] [Indexed: 11/21/2022] Open
Abstract
Fast, nongenomic androgen actions have been described in various cell types, including neurons. However, the receptor mediating this cell membrane–initiated rapid signaling remains unknown. This study found a putative androgen receptor splice variant in a dopaminergic N27 cell line and in several brain regions (substantia nigra pars compacta, entorhinal cortex, and hippocampus) from gonadally intact and gonadectomized (young and middle-aged) male rats. This putative splice variant protein has a molecular weight of 45 kDa and lacks an N-terminal domain, indicating it is homologous to the human AR45 splice variant. Interestingly, AR45 was highly expressed in all brain regions examined. In dopaminergic neurons, AR45 is localized to plasma membrane lipid rafts, a microdomain involved in cellular signaling. Further, AR45 protein interacts with membrane-associated G proteins Gαq and Gαo. Neither age nor hormone levels altered AR45 expression in dopaminergic neurons. These results provide the first evidence of AR45 protein expression in the brain, specifically plasma membrane lipid rafts. AR45 presence in lipid rafts indicates that it may function as a membrane androgen receptor to mediate fast, nongenomic androgen actions.
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Meng XQ, Dai YY, Jing LD, Bai J, Liu SZ, Zheng KG, Pan J. Subcellular localization of proline-rich tyrosine kinase 2 during oocyte fertilization and early-embryo development in mice. J Reprod Dev 2016; 62:351-8. [PMID: 27086609 PMCID: PMC5004790 DOI: 10.1262/jrd.2016-015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Proline-rich tyrosine kinase 2 (Pyk2), a non-receptor tyrosine kinase, is a member of
the focal adhesion kinase family and is highly expressed in oocytes. Using a combination
of confocal microscopy and RNAi, we localized and studied the function of both Pyk2 and
tyrosine-phosphorylated Pyk2 (p-Pyk2) during mouse oocyte fertilization and early embryo
development. At the onset of fertilization, Pyk2 and p-Pyk2 were detected predominantly in
sperm heads and the oocyte cytoplasm. Upon formation of male and female pronuclei, Pyk2
and its activated form leave the cytoplasm and accumulate in the two pronuclei. We
detected Pyk2 in blastomere nuclei and found both Pyk2 and p-Pyk2 in the pre-blastula
cytoplasm. Pyk2 and its activated form then disappeared from the blastula nuclei and
localized to the perinuclear regions, where blastula cells come into contact with each
other. Pyk2 knockdown via microinjection of siRNA into the zygote did not inhibit early
embryo development. Our results suggest that Pyk2 plays multiple functional roles in mouse
oocyte fertilization as well as throughout early embryo development.
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Affiliation(s)
- Xiao-Qian Meng
- Key Laboratory of Animal Resistance Research, College of Life Science, Shandong Normal University, Jinan 250014, China
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Conroy BD, Herek TA, Shew TD, Latner M, Larson JJ, Allen L, Davis PH, Helikar T, Cutucache CE. Design, Assessment, and in vivo Evaluation of a Computational Model Illustrating the Role of CAV1 in CD4(+) T-lymphocytes. Front Immunol 2014; 5:599. [PMID: 25538703 PMCID: PMC4257089 DOI: 10.3389/fimmu.2014.00599] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/07/2014] [Indexed: 01/08/2023] Open
Abstract
Caveolin-1 (CAV1) is a vital scaffold protein heterogeneously expressed in both healthy and malignant tissue. We focus on the role of CAV1 when overexpressed in T-cell leukemia. Previously, we have shown that CAV1 is involved in cell-to-cell communication, cellular proliferation, and immune synapse formation; however, the molecular mechanisms have not been elucidated. We hypothesize that the role of CAV1 in immune synapse formation contributes to immune regulation during leukemic progression, thereby warranting studies of the role of CAV1 in CD4+ T-cells in relation to antigen-presenting cells. To address this need, we developed a computational model of a CD4+ immune effector T-cell to mimic cellular dynamics and molecular signaling under healthy and immunocompromised conditions (i.e., leukemic conditions). Using the Cell Collective computational modeling software, the CD4+ T-cell model was constructed and simulated under CAV1+/+, CAV1+/−, and CAV1−/− conditions to produce a hypothetical immune response. This model allowed us to predict and examine the heterogeneous effects and mechanisms of CAV1 in silico. Experimental results indicate a signature of molecules involved in cellular proliferation, cell survival, and cytoskeletal rearrangement that were highly affected by CAV1 knock out. With this comprehensive model of a CD4+ T-cell, we then validated in vivo protein expression levels. Based on this study, we modeled a CD4+ T-cell, manipulated gene expression in immunocompromised versus competent settings, validated these manipulations in an in vivo murine model, and corroborated acute T-cell leukemia gene expression profiles in human beings. Moreover, we can model an immunocompetent versus an immunocompromised microenvironment to better understand how signaling is regulated in patients with leukemia.
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Affiliation(s)
- Brittany D Conroy
- Department of Biology, University of Nebraska at Omaha , Omaha, NE , USA
| | - Tyler A Herek
- Department of Biology, University of Nebraska at Omaha , Omaha, NE , USA
| | - Timothy D Shew
- Department of Biology, University of Nebraska at Omaha , Omaha, NE , USA
| | - Matthew Latner
- Department of Biology, University of Nebraska at Omaha , Omaha, NE , USA
| | - Joshua J Larson
- Department of Biology, University of Nebraska at Omaha , Omaha, NE , USA
| | - Laura Allen
- Department of Biology, University of Nebraska at Omaha , Omaha, NE , USA
| | - Paul H Davis
- Department of Biology, University of Nebraska at Omaha , Omaha, NE , USA
| | - Tomáš Helikar
- Department of Biochemistry, University of Nebraska at Lincoln , Lincoln, NE , USA
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Chapman NM, Yoder AN, Barbón KM, Bilal MY, Connolly SF, Houtman JCD. Proline-rich tyrosine kinase 2 controls PI3-kinase activation downstream of the T cell antigen receptor in human T cells. J Leukoc Biol 2014; 97:285-96. [PMID: 25387834 DOI: 10.1189/jlb.2a1013-568rrr] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
TCR-induced signaling controls T cell activation that drives adaptive immunity against infections, but it can also induce dysfunctional T cell responses that promote pathologic disease. The PI3K pathway regulates many downstream effector responses after TCR stimulation. However, the molecular mechanisms that induce PI3K function downstream of the TCR are not fully understood. We have previously shown that Pyk2 is activated downstream of the TCR in a PI3K-independent manner. Although Pyk2 controls adhesion, proliferation, and cytokine production in T cells, the mechanisms by which it controls these processes are not known. In this study, we generated Pyk2-deficient human T cells to elucidate further the role that this kinase plays in TCR-induced effector functions and signaling. We observed that Pyk2 localized with the p85 regulatory subunit of PI3K at the LAT complex and that PI3K-dependent signaling was impaired in Pyk2-deficient T cells. Likewise, functions downstream of PI3K, including IFN-γ production and proliferation, were also suppressed in human T cells deficient in Pyk2. Collectively, these data demonstrate that Pyk2 is a critical regulator of PI3K function downstream of the TCR.
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Affiliation(s)
- Nicole M Chapman
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Ashley N Yoder
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Kathryn M Barbón
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Mahmood Y Bilal
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Sean F Connolly
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Jon C D Houtman
- *Interdisciplinary Graduate Program in Immunology and Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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Revuelta-López E, Castellano J, Roura S, Gálvez-Montón C, Nasarre L, Benitez S, Bayes-Genis A, Badimon L, Llorente-Cortés V. Hypoxia Induces Metalloproteinase-9 Activation and Human Vascular Smooth Muscle Cell Migration Through Low-Density Lipoprotein Receptor–Related Protein 1–Mediated Pyk2 Phosphorylation. Arterioscler Thromb Vasc Biol 2013; 33:2877-87. [DOI: 10.1161/atvbaha.113.302323] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Elena Revuelta-López
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
| | - José Castellano
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
| | - Santiago Roura
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
| | - Carolina Gálvez-Montón
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
| | - Laura Nasarre
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
| | - Sonia Benitez
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
| | - Antoni Bayes-Genis
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
| | - Lina Badimon
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
| | - Vicenta Llorente-Cortés
- From the Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Barcelona, Spain (E.R.-L., J.C., L.N., L.B.); ICREC Research Program, Fundació Institut d´Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Badalona, Spain (S.R., C.G.-M., A.B.-G.); and Cardiovascular Biochemistry Group, Biomedical Research Institute Sant Pau, IIB-Sant Pau, Barcelona, Spain (S.B.)
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Bijli KM, Fazal F, Rahman A. Regulation of Rela/p65 and endothelial cell inflammation by proline-rich tyrosine kinase 2. Am J Respir Cell Mol Biol 2012; 47:660-8. [PMID: 22842493 PMCID: PMC3547104 DOI: 10.1165/rcmb.2012-0047oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Accepted: 07/16/2012] [Indexed: 01/01/2023] Open
Abstract
We investigated the role of proline-rich tyrosine kinase 2 (Pyk2) in the mechanism of NF-κB activation and endothelial cell (EC) inflammation induced by thrombin, a procoagulant serine protease released in high amounts during sepsis and other inflammatory conditions. Stimulation of ECs with thrombin resulted in a time-dependent activation of Pyk2. RNA interference knockdown of Pyk2 attenuated thrombin-induced activity of NF-κB and expression of its target genes, vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1. Pyk2 knockdown impaired thrombin-induced activation of IκB kinase (IKK) and phosphorylation (Ser32 and Ser36) of IkappaBα, but, surprisingly, failed to prevent IκBα degradation. However, depletion of IKKα or IKKβ was effective in inhibiting IκBα phosphorylation/degradation, as expected. Intriguingly, Pyk2 knockdown impaired nuclear translocation and DNA binding of RelA/p65, despite the inability to prevent IκBα degradation. In addition, Pyk2 knockdown was associated with inhibition of RelA/p65 phosphorylation at Ser536, which is important for transcriptional activity of RelA/p65. Depletion of IKKα or IKKβ each impaired RelA/p65 phosphorylation. Taken together, these data identify Pyk2 as a critical regulator of EC inflammation by virtue of engaging IKK to promote the release and the transcriptional capacity of RelA/p65, and, additionally, by its ability to facilitate the nuclear translocation of the released RelA/p65. Thus, specific targeting of Pyk2 may be an effective anti-inflammatory strategy in vascular diseases associated with EC inflammation and intravascular coagulation.
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Affiliation(s)
- Kaiser M Bijli
- Department of Pediatrics (Neonatology), Lung Biology and Disease Program, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Fabeha Fazal
- Department of Pediatrics (Neonatology), Lung Biology and Disease Program, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Arshad Rahman
- Department of Pediatrics (Neonatology), Lung Biology and Disease Program, University of Rochester School of Medicine and Dentistry, Rochester, New York
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Abstract
G protein-coupled receptors (GPCRs) play important roles in inflammation. Inflammatory cells such as polymorphonuclear leukocytes (PMN), monocytes and macrophages express a large number of GPCRs for classic chemoattractants and chemokines. These receptors are critical to the migration of phagocytes and their accumulation at sites of inflammation, where these cells can exacerbate inflammation but also contribute to its resolution. Besides chemoattractant GPCRs, protease activated receptors (PARs) such as PAR1 are involved in the regulation of vascular endothelial permeability. Prostaglandin receptors play different roles in inflammatory cell activation, and can mediate both proinflammatory and anti-inflammatory functions. Many GPCRs present in inflammatory cells also mediate transcription factor activation, resulting in the synthesis and secretion of inflammatory factors and, in some cases, molecules that suppress inflammation. An understanding of the signaling paradigms of GPCRs in inflammatory cells is likely to facilitate translational research and development of improved anti-inflammatory therapies.
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Vomaske J, Varnum S, Melnychuk R, Smith P, Pasa-Tolic L, Shutthanandan JI, Streblow DN. HCMV pUS28 initiates pro-migratory signaling via activation of Pyk2 kinase. HERPESVIRIDAE 2010; 1:2. [PMID: 21429240 PMCID: PMC3050435 DOI: 10.1186/2042-4280-1-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 12/07/2010] [Indexed: 12/20/2022]
Abstract
Background Human Cytomegalovirus (HCMV) has been implicated in the acceleration of vascular disease and chronic allograft rejection. Recently, the virus has been associated with glioblastoma and other tumors. We have previously shown that the HCMV-encoded chemokine receptor pUS28 mediates smooth muscle cell (SMC) and macrophage motility and this activity has been implicated in the acceleration of vascular disease. pUS28 induced SMC migration involves the activation of the protein tyrosine kinases (PTKs) Src and Focal adhesion kinase as well as the small GTPase RhoA. The PTK Pyk2 has been shown to play a role in cellular migration and formation of cancer, especially glioblastoma. The role of Pyk2 in pUS28 signaling and migration are unknown. Methods In the current study, we examined the involvement of the PTK Pyk2 in pUS28-induced cellular motility. We utilized in vitro migration of SMC to determine the requirements for Pyk2 in pUS28 pro-migratory signaling. We performed biochemical analysis of Pyk2 signaling in response to pUS28 activation to determine the mechanisms involved in pUS28 migration. We performed mass spectrometric analysis of Pyk2 complexes to identify novel Pyk2 binding partners. Results Expression of a mutant form of Pyk2 lacking the autophosphorylation site (Tyr-402) blocks pUS28-mediated SMC migration in response to CCL5, while the kinase-inactive Pyk2 mutant failed to elicit the same negative effect on migration. pUS28 stimulation with CCL5 results in ligand-dependent and calcium-dependent phosphorylation of Pyk2 Tyr-402 and induced the formation of an active Pyk2 kinase complex containing several novel Pyk2 binding proteins. Expression of the autophosphorylation null mutant Pyk2 F402Y did not abrogate the formation of an active Pyk2 kinase complex, but instead prevented pUS28-mediated activation of RhoA. Additionally, pUS28 activated RhoA via Pyk2 in the U373 glioblastoma cells. Interestingly, the Pyk2 kinase complex in U373 contained several proteins known to participate in glioma tumorigenesis. Conclusions These findings represent the first demonstration that pUS28 signals through Pyk2 and that this PTK participates in pUS28-mediated cellular motility via activation of RhoA. Furthermore, these results provide a potential mechanistic link between HCMV-pUS28 and glioblastoma cell activation.
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Affiliation(s)
- Jennifer Vomaske
- The Vaccine & Gene Therapy Institute, Oregon Health & Science University, Beaverton OR 97006 USA.
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12
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Cardioprotective signaling by endothelin. Trends Cardiovasc Med 2009; 18:233-9. [PMID: 19232951 DOI: 10.1016/j.tcm.2008.11.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 11/18/2008] [Accepted: 11/20/2008] [Indexed: 02/08/2023]
Abstract
The endothelin axis promotes vasoconstriction, suggesting that antagonists of endothelin signaling might be useful in treatment of heart failure. However, promising results from animal trials have not been recapitulated in heart failure patients. Here we review the role of major signaling pathways in the heart that are involved in cell survival initiated by ET-1. These pathways include mitogen-activated protein kinase, phosphatidyl inositol-1,4,5-triphosphate kinase (PI3K-AKT), nuclear factor-kappaB (NF-kappaB), and calcineurin signaling. A better understanding of endothelin-mediated signaling in cardiac cell survival may allow a reevaluation of endothelin receptor antagonists (ETRAs) in the treatment of heart failure.
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13
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Suzuki N, Hajicek N, Kozasa T. Regulation and physiological functions of G12/13-mediated signaling pathways. Neurosignals 2009; 17:55-70. [PMID: 19212140 DOI: 10.1159/000186690] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 10/10/2008] [Indexed: 12/12/2022] Open
Abstract
Accumulating data indicate that G12 subfamily (Galpha12/13)-mediated signaling pathways play pivotal roles in a variety of physiological processes, while aberrant regulation of this pathway has been identified in various human diseases. It has been demonstrated that Galpha12/13-mediated signals form networks with other signaling proteins at various levels, from cell surface receptors to transcription factors, to regulate cellular responses. Galpha12/13 have slow rates of nucleotide exchange and GTP hydrolysis, and specifically target RhoGEFs containing an amino-terminal RGS homology domain (RH-RhoGEFs), which uniquely function both as a GAP and an effector for Galpha12/13. In this review, we will focus on the mechanisms regulating the Galpha12/13 signaling system, particularly the Galpha12/13-RH-RhoGEF-Rho pathway, which can regulate a wide variety of cellular functions from migration to transformation.
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Affiliation(s)
- Nobuchika Suzuki
- Laboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.
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14
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beta-Arrestin1 interacts with the G-protein subunits beta1gamma2 and promotes beta1gamma2-dependent Akt signalling for NF-kappaB activation. Biochem J 2009; 417:287-96. [PMID: 18729826 DOI: 10.1042/bj20081561] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
beta-Arrestins are known to regulate G-protein signalling through interactions with their downstream effectors. In the present study, we report that beta-arrestin1 associates with the G-protein beta1gamma2 subunits in transfected cells, and purified beta-arrestin1 interacts with G(beta1gamma2) derived from in vitro translation. Deletion mutagenesis of beta-arrestin1 led to the identification of a region, comprising amino acids 181-280, as being responsible for its interaction with G(beta1gamma2). Overexpression of beta-arrestin1 facilitates G(beta1gamma2)-mediated Akt phosphorylation, and inhibition of endogenous beta-arrestin1 expression by siRNA (small interfering RNA) diminishes this effect. Through investigation of NF-kappaB (nuclear factor kappaB), a transcription factor regulated by Akt signalling, we have found that overexpression of beta-arrestin1 significantly enhances G(beta1gamma2)-mediated nuclear translocation of NF-kappaB proteins and expression of a NF-kappaB-directed luciferase reporter. Overexpression of beta-arrestin1 also promotes bradykinin-induced, G(betagamma)-mediated NF-kappaB luciferase-reporter expression, which is reverted by silencing the endogenous beta-arrestin1 with a specific siRNA. These results identify novel functions of beta-arrestin1 in binding to the beta1gamma2 subunits of heterotrimeric G-proteins and promoting G(betagamma)-mediated Akt signalling for NF-kappaB activation.
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15
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Cho H, Kehrl JH. Chapter 9 Regulation of Immune Function by G Protein‐Coupled Receptors, Trimeric G Proteins, and RGS Proteins. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 86:249-98. [DOI: 10.1016/s1877-1173(09)86009-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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G-protein-dependent and -independent pathways regulate proteinase-activated receptor-2 mediated p65 NFκB serine 536 phosphorylation in human keratinocytes. Cell Signal 2008; 20:1267-74. [DOI: 10.1016/j.cellsig.2008.02.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 02/22/2008] [Indexed: 01/15/2023]
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17
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Essential role for epidermal growth factor receptor in glutamate receptor signaling to NF-kappaB. Mol Cell Biol 2008; 28:5061-70. [PMID: 18541671 DOI: 10.1128/mcb.00578-08] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Glutamate is a critical neurotransmitter of the central nervous system (CNS) and also an important regulator of cell survival and proliferation. The binding of glutamate to metabotropic glutamate receptors induces signal transduction cascades that lead to gene-specific transcription. The transcription factor NF-kappaB, which regulates cell proliferation and survival, is activated by glutamate; however, the glutamate receptor-induced signaling pathways that lead to this activation are not clearly defined. Here we investigate the glutamate-induced activation of NF-kappaB in glial cells of the CNS, including primary astrocytes. We show that glutamate induces phosphorylation, nuclear accumulation, DNA binding, and transcriptional activation function of glial p65. The glutamate-induced activation of NF-kappaB requires calcium-dependent IkappaB kinase alpha (IKKalpha) and IKKbeta activation and induces p65-IkappaBalpha dissociation in the absence of IkappaBalpha phosphorylation or degradation. Moreover, glutamate-induced IKK preferentially targets the phosphorylation of p65 but not IkappaBalpha. Finally, we show that the ability of glutamate to activate NF-kappaB requires cross-coupled signaling with the epidermal growth factor receptor. Our results provide insight into a glutamate-induced regulatory pathway distinct from that described for cytokine-induced NF-kappaB activation and have important implications with regard to both normal glial cell physiology and pathogenesis.
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Schindler EM, Baumgartner M, Gribben EM, Li L, Efimova T. The role of proline-rich protein tyrosine kinase 2 in differentiation-dependent signaling in human epidermal keratinocytes. J Invest Dermatol 2007; 127:1094-106. [PMID: 17205062 DOI: 10.1038/sj.jid.5700662] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Non-receptor tyrosine kinase proline-rich protein tyrosine kinase 2 (Pyk2) functions as an integrator of multiple signaling pathways involved in the regulation of fundamental cellular processes. Pyk2 expression, regulation, and functions in skin have not been examined. Here we investigated the expression and subcellular localization of Pyk2 in human epidermis and in primary human keratinocytes, and studied the mechanisms of Pyk2 activation by differentiation-inducing stimuli, and the role of Pyk2 as a regulator of keratinocyte differentiation. We demonstrate that Pyk2 is abundantly expressed in skin keratinocytes. Notably, the endogenous Pyk2 protein is predominantly localized in keratinocyte nuclei throughout all layers of healthy human epidermis, and in cultured human keratinocytes. Pyk2 is activated by treatment with keratinocyte-differentiating agents, 12-O-tetradecanoylphorbol-13-acetate and calcium via a mechanism that requires intracellular calcium release and functional protein kinase C (PKC) and Src activities. Particularly, differentiation-promoting PKC delta and PKC eta elicit Pyk2 activation. Our data show that Pyk2 increases promoter activity and endogenous protein levels of involucrin, a marker of keratinocyte terminal differentiation. This regulation is associated with increased expression of Fra-1 and JunD, activator protein-1 transcription factors known to be required for involucrin expression. Altogether, these results provide insights into Pyk2 signaling in epidermis and reveal a novel role for Pyk2 in regulation of keratinocyte differentiation.
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Affiliation(s)
- Eva M Schindler
- Division of Dermatology, Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA
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19
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Strappazzon F, Torch S, Trioulier Y, Blot B, Sadoul R, Verna JM. Survival response-linked Pyk2 activation during potassium depletion-induced apoptosis of cerebellar granule neurons. Mol Cell Neurosci 2006; 34:355-65. [PMID: 17188509 DOI: 10.1016/j.mcn.2006.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 10/27/2006] [Accepted: 11/14/2006] [Indexed: 11/16/2022] Open
Abstract
Numerous extracellular stimuli trigger trans-autophosphorylation at Tyr402 of Pyk2, inducing its activation. Pyk2 is a key mediator of several signaling pathways and has been implicated in apoptosis induced by specific stress signals. We investigated whether Pyk2 participates in cerebellar granule neuron (CGN) apoptosis induced by the suppression of membrane depolarization. We demonstrate that shifting CGN cultures from 25 mM to 5 mM KCl-containing medium induces an early, transient 70% increase in phosphorylated Tyr402 and Tyr580 Pyk2 levels that is triggered by Ca(2+) released from intracellular stores and mediated by calmodulin (CaM). Overexpression of Pyk2 increases CGN survival after 24 h by 70% compared to the control, thus suggesting that Pyk2 is involved in an anti-apoptotic response to K+ lowering. Furthermore, we show that CGN grown in K25 medium exhibit detectable CaM-dependent Pyk2 activity. When silencing Pyk2 activity by expressing a dominant-negative form, only 40% of the transfected neurons were alive 24 h after transfection when compared to the control. Overall, the present findings demonstrate for the first time that Pyk2 is a critical mediator of CGN survival.
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Affiliation(s)
- Flavie Strappazzon
- Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire Neurodégénérescence et Plasticité, EMI108, France
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20
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Minuz P, Fumagalli L, Gaino S, Tommasoli R, Degan M, Cavallini C, Lecchi A, Cattaneo M, Lechi Santonastaso C, Berton G. Rapid stimulation of tyrosine phosphorylation signals downstream of G-protein-coupled receptors for thromboxane A2 in human platelets. Biochem J 2006; 400:127-34. [PMID: 16859489 PMCID: PMC1635449 DOI: 10.1042/bj20061015] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Signals ensuing from trimeric G-protein-coupled receptors synergize to induce platelet activation. At low doses, the thromboxane A2 analogue U46619 does not activate integrin alphaIIbbeta3 or trigger platelet aggregation, but it induces shape changes. In the present study, we addressed whether low doses of U46619 trigger tyrosine phosphorylation independently of integrin alphaIIbbeta3 activation and ADP secretion, and synergize with adrenaline (epinephrine) to induce aggregation in acetylsalicylic acid (aspirin)-treated platelets. Low doses of U46619 triggered tyrosine phosphorylation of different proteins, including FAK (focal adhesion kinase), Src and Syk, independently of signals ensuing from integrin alphaIIbbeta3 or ADP receptors engaged by secreted ADP. The G(12/13)-mediated Rho/Rho-kinase pathway was also increased by low doses of U46619; however, this pathway was not upstream of tyrosine phosphorylation, because this occurred in the presence of the Rho-kinase inhibitor Y-27632. Although low doses of U46619 or adrenaline alone were unable to trigger platelet aggregation and integrin alphaIIbbeta3 activation, the combination of the two stimuli effectively induced these responses. PP2, a tyrosine kinase inhibitor, and Y-27632 inhibited platelet activation induced by low doses of U46619 plus adrenaline and, when used in combination, totally suppressed this platelet response. In addition, the two inhibitors selectively blocked tyrosine kinases and the Rho/Rho-kinase pathway respectively. These findings suggest that both tyrosine phosphorylation and the Rho/Rho-kinase pathway are required to activate platelet aggregation via G(12/13) plus G(z) signalling.
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Affiliation(s)
- Pietro Minuz
- *Department of Biomedical and Surgical Sciences, University of Verona, Verona, Italy
| | - Laura Fumagalli
- †Department of Pathology, Section of General Pathology, University of Verona, Verona, Italy
| | - Stefania Gaino
- ‡Department of Morphological and Biomedical Sciences, University of Verona, Verona, Italy
| | - Rosa M. Tommasoli
- ‡Department of Morphological and Biomedical Sciences, University of Verona, Verona, Italy
| | - Maurizio Degan
- ‡Department of Morphological and Biomedical Sciences, University of Verona, Verona, Italy
| | - Chiara Cavallini
- ‡Department of Morphological and Biomedical Sciences, University of Verona, Verona, Italy
| | - Anna Lecchi
- §Angelo Bianchi Bonomi Haemophila and Thrombosis Centre, IRCCS Maggiore Hospital, University of Milan, Milan, Italy
| | - Marco Cattaneo
- ∥Unit of Haematology and Thrombosis, San Paolo Hospital, DMCO-University of Milan, Milan, Italy
| | | | - Giorgio Berton
- †Department of Pathology, Section of General Pathology, University of Verona, Verona, Italy
- To whom correspondence should be addressed (email )
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21
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Wu EHT, Tam BHL, Wong YH. Constitutively active alpha subunits of G(q/11) and G(12/13) families inhibit activation of the pro-survival Akt signaling cascade. FEBS J 2006; 273:2388-98. [PMID: 16704413 DOI: 10.1111/j.1742-4658.2006.05245.x] [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: 11/30/2022]
Abstract
Accumulating evidence indicates that G protein signaling plays an active role in the regulation of cell survival. Our previous study demonstrated the regulatory effects of G(i/o) proteins in nerve growth factor-induced activation of pro-survival Akt kinase. In the present study we explored the role of various members of the G(s), G(q/11) and G(12/13) subfamilies in the regulation of Akt in cultured mammalian cells. In human embryonic kidney 293 cells transiently expressing constitutively active mutants of G alpha11, G alpha14, G alpha16, G alpha12, or G alpha13 (G alpha11QL, G alpha14QL, G alpha16QL, G alpha12QL and G alpha13QL, respectively), basal phosphorylation of Akt was attenuated, as revealed by western blotting analysis using a phosphospecific anti-Akt immunoglobulin. In contrast, basal Akt phosphorylation was unaffected by the overexpression of a constitutively active G alpha(s) mutant (G alpha(s)QL). Additional experiments showed that G alpha11QL, G alpha14QL, G alpha16QL, G alpha12QL and G alpha13QL, but not G alpha(s)QL, attenuated phosphorylation of the Akt-regulated translation regulator tuberin. Moreover, they were able to inhibit the epidermal growth factor-induced Akt activation and tuberin phosphorylation. The inhibitory mechanism of Gq family members was independent of phospholipase Cbeta activation and calcium signaling because G alpha11QL, G alpha14QL and G alpha16QL remained capable of inhibiting epidermal growth factor-induced Akt activation in cells pretreated with U73122 and the intracellular calcium chelator, BAPTA/AM. Finally, overexpression of the dominant negative mutant of RhoA blocked G alpha12QL- and G alpha13QL-mediated inhibition, suggesting that activated G alpha12 and G alpha13 inhibit Akt signaling via RhoA. Collectively, this study demonstrated the inhibitory effect of activated G alpha11, G alpha14, G alpha16, G alpha12 and G alpha13 on pro-survival Akt signaling.
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Affiliation(s)
- Eddy H T Wu
- Department of Biochemistry, the Molecular Neuroscience Center, and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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22
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Lallemend F, Hadjab S, Hans G, Moonen G, Lefebvre PP, Malgrange B. Activation of protein kinase CbetaI constitutes a new neurotrophic pathway for deafferented spiral ganglion neurons. J Cell Sci 2006; 118:4511-25. [PMID: 16179609 DOI: 10.1242/jcs.02572] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In mammals, degeneration of peripheral auditory neurons constitutes one of the main causes of sensorineural hearing loss. Unfortunately, to date, pharmacological interventions aimed at counteracting this condition have not presented complete effectiveness in protecting the integrity of cochlear neural elements. In this context, the protein kinase C (PKC) family of enzymes are important signalling molecules that play a role in preventing neurodegeneration after nervous system injury. The present study demonstrates, for the first time, that the PKC signalling pathway is directly neurotrophic to axotomised spiral ganglion neurons (SGNs). We found that PKCbetaI was strictly expressed by postnatal and adult SGNs both in situ and in vitro. In cultures of SGNs, we observed that activators of PKC, such as phorbol esters and bryostatin 1, induced neuronal survival and neurite regrowth in a manner dependent on the activation of PKCbetaI. The neuroprotective effects of PKC activators were suppressed by pre-treatment with LY294002 (a PI3K inhibitor) and with U0126 (a MEK inhibitor), indicating that PKC activators promote the survival and neurite outgrowth of SGNs by both PI3K/Akt and MEK/ERK-dependent mechanisms. In addition, whereas combining the neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) was shown to provide only an additive effect on SGN survival, the interaction between PKC and neurotrophin signalling gave rise to a synergistic increase in SGN survival. Taken together, the data indicate that PKCbetaI activation represents a key factor for the protection of the integrity of neural elements in the cochlea.
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Affiliation(s)
- François Lallemend
- Research Centre for Cellular and Molecular Neurobiology, Developmental Neurobiology Unit, University of Liège, Av. de l'Hopital 1 B36, 4000 Liège, Belgium.
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Shen G, Jeong WS, Hu R, Kong ANT. Regulation of Nrf2, NF-kappaB, and AP-1 signaling pathways by chemopreventive agents. Antioxid Redox Signal 2005; 7:1648-63. [PMID: 16356127 DOI: 10.1089/ars.2005.7.1648] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The inhibition of carcinogenesis by chemopreventive agents has been demonstrated in many tumorigenesis animal models. The chemopreventive mechanisms of those phytochemicals have been investigated extensively, though mostly in in vitro cell culture systems. The cellular signaling cascades mediated by transcription factors, including nuclear factor E2-related factor 2 (Nrf2), nuclear factor-kappaB (NF-kappaB), and activator protein-1 (AP-1), have been shown to play pivotal roles in tumor initiation, promotion, and progression processes. Thus, as demonstrated by previous substantive mechanistic studies, they appear to be ideal targets for cancer chemoprevention. In this review, we discuss the current progress and future challenges on our understanding of the molecular mechanisms in cancer chemoprevention by phytochemicals, focusing on the regulation of Nrf2, NF-kappaB, and AP-1 signaling pathways.
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Affiliation(s)
- Guoxiang Shen
- Department of Pharmaceutics and Graduate Program in Pharmaceutical Science, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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24
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Macfarlane SR, Sloss CM, Cameron P, Kanke T, McKenzie RC, Plevin R. The role of intracellular Ca2+ in the regulation of proteinase-activated receptor-2 mediated nuclear factor kappa B signalling in keratinocytes. Br J Pharmacol 2005; 145:535-44. [PMID: 15821758 PMCID: PMC1576156 DOI: 10.1038/sj.bjp.0706204] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1 In this study, we examined the role of Ca2+ in linking proteinase-activated receptor-2 (PAR2) to the nuclear factor kappa B (NFkappaB) pathway in a skin epithelial cell line NCTC2544 stably expressing PAR2 (clone G). 2 In clone G, PAR2-mediated NFkappaB luciferase reporter activity and NFkappaB DNA-binding activity was reduced by preincubation with BAPTA-AM but not BAPTA. Trypsin stimulation of inhibitory kappa B kinases, IKKalpha and IKKbeta, was also inhibited following pretreatment with BAPTA-AM. 3 BAPTA/AM also prevented PAR2-mediated IKKalpha activation in cultured primary human keratinocytes. 4 The effect of BAPTA-AM was also selective for the IKK/NFkappaB signalling axis; PAR2 coupling to ERK, or p38 MAP kinase was unaffected. 5 Pharmacological inhibition of the Ca2+-dependent regulatory protein calcineurin did not inhibit trypsin-stimulated IKK activity or NFkappaB-DNA binding; however, inhibition of Ca2+-dependent protein kinase C isoforms or InsP3 formation using GF109203X or the phospholipase C inhibitor U73122, respectively, reduced both IKK activity and NFkappaB-DNA binding. 6 Mutation of PAR2 within the C-terminal to produce a mutant receptor, which does not couple to Ca2+ signalling, but is able to activate ERK, abrogated NFkappaB-DNA binding and IKK activity stimulated by trypsin. 7 These results suggest a predominant role for the InsP3/Ca2+ axis in the regulation of IKK signalling and NFkappaB transcriptional activation.
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Affiliation(s)
- Scott R Macfarlane
- Department of Physiology & Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR, Scotland
| | - Callum M Sloss
- Department of Physiology & Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR, Scotland
| | - Pamela Cameron
- Department of Physiology & Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR, Scotland
| | - Toru Kanke
- Department of Physiology & Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR, Scotland
| | - Roderick C McKenzie
- Epidermal Infection and Protection Group, Laboratory for Clinical and Molecular Virology, Royal Dick Veterinary School, University of Edinburgh, Summerhall, Edinburgh EH9 1QH
| | - Robin Plevin
- Department of Physiology & Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR, Scotland
- Author for correspondence:
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Harenberg A, Girkontaite I, Giehl K, Fischer KD. The Lsc RhoGEF mediates signaling from thromboxane A2 to actin polymerization and apoptosis in thymocytes. Eur J Immunol 2005; 35:1977-86. [PMID: 15884057 DOI: 10.1002/eji.200425769] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Lsc RhoGEF (also known as p115-RhoGEF) is a GTP exchange factor (GEF), an activator of GTPases of the Rho family. Lsc has a RhoGEF domain specific for Rho GTPase and a regulator of G protein signaling (RGS) domain specific for Galpha(12/13) subunits. One G protein receptor that can couple to Galpha(12/13) subunits is the receptor for thromboxane A(2 )(TXA(2)), thromboxane-prostanoid (called TP), which is highly expressed in immature thymocytes. TXA(2) has been implicated in thymocyte apoptosis. We found that Lsc(-/-) mice on a BALB/c background show thymic hyperplasia due to increased numbers of thymocytes and that these numbers further increase with the age of the mice. To investigate a role for Lsc in TXA(2) signaling, we analyzed activation of primary thymocytes by TXA(2) in vitro. TXA(2)-induced apoptosis of double-positive thymocytes and Rho activation required Lsc, and TXA(2) stimulation of actin polymerization and cofilin phosphorylation required both Lsc and Rho kinase (ROCK). Additionally, in the absence of Lsc, phosphorylation of the survival kinase Akt in response to TXA(2) was greatly enhanced. Together, these data demonstrate that Lsc is essential for mediating TXA(2 )signaling involved in apoptosis and actin organization and suggest that TXA(2) regulates thymic cellularity via Lsc.
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Affiliation(s)
- Anke Harenberg
- Department of Physiological Chemistry, University of Ulm, Ulm, Germany
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Shah BH, Neithardt A, Chu DB, Shah FB, Catt KJ. Role of EGF receptor transactivation in phosphoinositide 3-kinase-dependent activation of MAP kinase by GPCRs. J Cell Physiol 2005; 206:47-57. [PMID: 15920762 DOI: 10.1002/jcp.20423] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many G protein coupled receptors (GPCRs) cause phosphorylation of MAP kinases through transactivation of the epidermal growth factor receptor (EGF-R), leading to increased cell survival and growth, motility, and migration. Phosphoinositide 3-kinase (PI3K) is one of the important cell survival signaling molecules activated by EGF-R stimulation. However, the extent to which EGF-R transactivation is essential for GPCR agonist-stimulated PI3K activation is not known. Here we examined the mechanism of PI3K activation that elicits GPCR-mediated ERK1/2 activation by pathways dependent and/or independent of EGF-R transactivation in specific cell types. Immortalized hypothalamic neurons (GT1-7 cells) express endogenous gonadotropin-releasing hormone receptors (GnRH-R) and their stimulation causes marked phosphorylation of ERK1/2 and Akt (Ser 473) through transactivation of the EGF-R and recruitment of PI3K. In C9 hepatocytes, agonist activation of AT1 angiotensin II (AT1-R), lysophosphatidic acid (LPA), and EGF receptors caused phosphorylation of Akt through activation of the EGF-R in a PI3K-dependent manner. However, ERK1/2 activation by these agonists in these cells was independent of PI3K activation. In contrast, agonist stimulation of HEK 293 cells stably expressing AT1-R caused ERK1/2 phosphorylation that was independent of EGF-R transactivation but required PI3K activation. LPA signaling in these cells showed partial and complete dependence on EGF-R and PI3K, respectively. These data indicate that GPCR-induced ERK1/2 phosphorylation is dependent or independent of PI3K in specific cell types, and that the involvement of PI3K during ERK1/2 activation is not dependent solely on agonist-induced transactivation of the EGF-R.
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Affiliation(s)
- Bukhtiar H Shah
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4510, USA.
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Melikova S, Dylla SJ, Verfaillie CM. Phosphatidylinositol-3-kinase activation mediates proline-rich tyrosine kinase 2 phosphorylation and recruitment to β1-integrins in human CD34+ cells. Exp Hematol 2004; 32:1051-6. [PMID: 15539082 DOI: 10.1016/j.exphem.2004.07.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Revised: 07/22/2004] [Accepted: 07/23/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE beta1-integrins mediate hematopoietic stem and progenitor cell homing and retention in the bone marrow (BM) and inhibit hematopoietic proliferation and differentiation. Having no intrinsic kinase activity, integrins recruit intracellular kinases, such as the focal adhesion kinase (FAK) or the related proline-rich tyrosine kinase 2 (PYK2), to initiate signal transduction. Phosphatidylinositol-3-kinase (PI3K), which is involved in beta1-integrin signaling in many cell types, is physically and functionally associated with FAK in anchorage-dependent cells. Because PYK2 is the principal focal adhesion kinase expressed in primary human CD34+ cells, we assessed its functional relationship with PI3K in CD34+ cells in response to integrin engagement. METHODS beta1-integrins on primary mobilized peripheral blood CD34+ cells and CD34+ KG1A cells were engaged by adhesion to fibronectin (FN) or by cross-linking with an anti-beta1 integrin antibody, respectively. PI3K activity and PYK2 phosphorylation were then assessed in the presence or absence of the PI3K inhibitor, wortmannin. Association between PI3K, PYK2, and the beta1-integrin subunit were also evaluated in co-immunoprecipitation experiments. RESULTS beta1-integrin engagement induced PI3K activation, which was required for, and temporally preceded, PYK2 phosphorylation, indicating that PI3K lies upstream of PYK2 in CD34+ cells. Furthermore, although PYK2 and PI3K were constitutively associated, interaction of the PYK2/PI3K complex with beta1-integrins required prior integrin engagement and PI3K activation. CONCLUSION Activation of PI3K following beta1-integrin engagement on human CD34+ cells results in subsequent phosphorylation of PYK2, and is required for the recruitment of the PI3K/PYK2 complex to beta1-integrins at the cell surface.
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Affiliation(s)
- Sofya Melikova
- Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, USA
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Takada Y, Aggarwal BB. TNF activates Syk protein tyrosine kinase leading to TNF-induced MAPK activation, NF-kappaB activation, and apoptosis. THE JOURNAL OF IMMUNOLOGY 2004; 173:1066-77. [PMID: 15240695 DOI: 10.4049/jimmunol.173.2.1066] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Spleen tyrosine kinase (Syk), a nonreceptor protein kinase initially found to be expressed only in hemopoietic cells, has now been shown to be expressed in nonhemopoietic cells and to mediate signaling of various cytokines. Whether Syk plays any role in TNF signaling was investigated. Treatment of Jurkat T cells with TNF activated Syk kinase but not ZAP70, another member of Syk kinase family, and the optimum activation occurred at 10 s and with 1 nM TNF. TNF also activated Syk in myeloid and epithelial cells. TNF-induced Syk activation was abolished by piceatannol (Syk-selective inhibitor), which led to the suppression of TNF-induced activation of c- JNK, p38 MAPK, and p44/p42 MAPK. Jurkat cells that did not express Syk (JCaM1, JCaM1/lck) showed lack of TNF-induced Syk, JNK, p38 MAPK, and p44/p42 MAPK activation, as well as TNF-induced IkappaBalpha phosphorylation, IkappaBalpha degradation, and NF-kappaB activation. TNF-induced NF-kappaB activation was enhanced by overexpression of Syk by Syk-cDNA and suppressed when Syk expression was down-regulated by expression of Syk-small interfering RNA (siRNA-Syk). The apoptotic effects of TNF were reduced by up-regulation of NF-kappaB by Syk-cDNA, and enhanced by down-regulation of NF-kappaB by siRNA-Syk. Immunoprecipitation of cells with Syk Abs showed TNF-dependent association of Syk with both TNFR1 and TNFR2; this association was enhanced by up-regulation of Syk expression with Syk-cDNA and suppressed by down-regulation of Syk using siRNA-Syk. Overall, our results demonstrate that Syk activation plays an essential role in TNF-induced activation of JNK, p38 MAPK, p44/p42 MAPK, NF-kappaB, and apoptosis.
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Affiliation(s)
- Yasunari Takada
- Cytokine Research Laboratory, Department of Bioimmunotherapy, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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29
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Shi GX, Harrison K, Han SB, Moratz C, Kehrl JH. Toll-Like Receptor Signaling Alters the Expression of Regulator of G Protein Signaling Proteins in Dendritic Cells: Implications for G Protein-Coupled Receptor Signaling. THE JOURNAL OF IMMUNOLOGY 2004; 172:5175-84. [PMID: 15100254 DOI: 10.4049/jimmunol.172.9.5175] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Conserved structural motifs on pathogens trigger pattern recognition receptors present on APCs such as dendritic cells (DCs). An important class of such receptors is the Toll-like receptors (TLRs). TLR signaling triggers a cascade of events in DCs that includes modified chemokine and cytokine production, altered chemokine receptor expression, and changes in signaling through G protein-coupled receptors (GPCRs). One mechanism by which TLR signaling could modify GPCR signaling is by altering the expression of regulator of G protein signaling (RGS) proteins. In this study, we show that human monocyte-derived DCs constitutively express significant amounts of RGS2, RGS10, RGS14, RGS18, and RGS19, and much lower levels of RGS3 and RGS13. Engagement of TLR3 or TLR4 on monocyte-derived DCs induces RGS16 and RGS20, markedly increases RGS1 expression, and potently down-regulates RGS18 and RGS14 without modifying other RGS proteins. A similar pattern of Rgs protein expression occurred in immature bone marrow-derived mouse DCs stimulated to mature via TLR4 signaling. The changes in RGS18 and RGS1 expression are likely important for DC function, because both proteins inhibit G alpha(i)- and G alpha(q)-mediated signaling and can reduce CXC chemokine ligand (CXCL)12-, CC chemokine ligand (CCL)19-, or CCL21-induced cell migration. Providing additional evidence, bone marrow-derived DCs from Rgs1(-/-) mice have a heightened migratory response to both CXCL12 and CCL19 when compared with similar DCs prepared from wild-type mice. These results indicate that the level and functional status of RGS proteins in DCs significantly impact their response to GPCR ligands such as chemokines.
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MESH Headings
- Animals
- Bone Marrow Cells/metabolism
- CHO Cells
- COS Cells
- Cells, Cultured
- Chemotaxis, Leukocyte/genetics
- Chemotaxis, Leukocyte/immunology
- Cricetinae
- Dendritic Cells/cytology
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Female
- GTP-Binding Protein alpha Subunits/biosynthesis
- HeLa Cells
- Humans
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred C57BL
- Monocytes/immunology
- Monocytes/metabolism
- RGS Proteins/antagonists & inhibitors
- RGS Proteins/biosynthesis
- RGS Proteins/deficiency
- RGS Proteins/genetics
- RGS Proteins/physiology
- Receptors, CCR4
- Receptors, Cell Surface/physiology
- Receptors, Chemokine/metabolism
- Receptors, Chemokine/physiology
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Signal Transduction/immunology
- Toll-Like Receptor 3
- Toll-Like Receptor 4
- Toll-Like Receptors
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Affiliation(s)
- Geng-Xian Shi
- B Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Guo J, Meng F, Fu X, Song B, Yan X, Zhang G. N-methyl-D-aspartate receptor and L-type voltage-gated Ca2+ channel activation mediate proline-rich tyrosine kinase 2 phosphorylation during cerebral ischemia in rats. Neurosci Lett 2004; 355:177-80. [PMID: 14732460 DOI: 10.1016/j.neulet.2003.10.076] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cerebral ischemia induces rapid efflux of glutamate into the extracellular space contributing to excessive activation of glutamate receptors in postsynaptic cells, particularly N-methyl-D-aspartate (NMDA) receptors, which triggers the neuron lesion through calcium overload. Our studies indicated that cerebral ischemia stimulated the rapid activation of nonreceptor tyrosine kinases proline-rich tyrosine kinase 2 (Pyk2) and Src and the binding to Pyk2 activated the latter. Pyk2 activation significantly depends on the increase of the intracellular calcium level; blockage of both calcium ion channel NMDA receptors and L-type voltage-gated Ca2+ channel (L-VGCC), respectively, could effectively inhibit phosphorylation of Pyk2 in early ischemia episodes. Moreover, pretreatment with the protein kinase C inhibitor (chelerythrine chloride) reduced the ischemia-induced activation of Pyk2. Noticeably, CaMKII, a family of calcium/calmodulin-dependent kinases, also may be involved in the regulation of Pyk2 activity because its inhibitor KN62 attenuated Pyk2 phosphorylation during ischemia. Together with previous studies, these results indicate that calcium influx elicited by active NMDA receptors and L-VGCC triggers the Pyk2-Src signaling pathway mediated by PKC, which aggravates cerebral ischemia lesions through up-regulating the function of NMDA receptors after the onset of ischemia, and also could be regulated partly by CaM-dependent kinases like CaMKII.
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Affiliation(s)
- Jun Guo
- Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, 84 West Huai-hai Road, Xuzhou, Jiangsu, 221002, PR China
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31
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Zhao X, Vainshtein I, Gellibolian R, Shu Y, Dotimas H, Wang XM, Fung P, Horecka J, Bosano BL, Eglen RM. Homogeneous Assays for Cellular Protein Degradation Usingβ-Galactosidase Complementation: NF-κB/IκB Pathway Signaling. Assay Drug Dev Technol 2003; 1:823-33. [PMID: 15090228 DOI: 10.1089/154065803772613453] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Activation of cells by the tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) cytokines results in activation of the nuclear factor-kappaB (NF-kappaB) via proteasomal degradation of an associated IkappaB molecule. To monitor cellular IkappaB, the protein was recombinantly expressed as a fusion protein with a novel enzymatic tag, ProLabel (PL). ProLabel is a small 5.5-kDa sequence from the amino-terminal amino acids of beta-galactosidase, possesses a simple ribbon structure, and can be fused to many proteins via the amino or carboxyl terminus. Expression of this construct allows quantitative detection of the recombinant protein in crude lysates by using a method based on beta-galactosidase enzyme fragment complementation (EFC). Transient transfection of IkappaB-PL in HeLa cells generated an EFC signal that was highly correlated with a western analysis of the protein construct. ProLabel expressed alone in the cells did not show any EFC activity, due to rapid proteolytic degradation, indicating a very low background signal from the protein tag. TNF-alpha and IL-1 treatment induced a concentration-dependent degradation of IkappaB-PL, with potency values similar to those reported using other methods. IkappaBM-PL (mutant of IkappaB-PL), in contrast, did not undergo degradation for concentrations up to and including 10 ng/ml TNF-alpha or IL-1, demonstrating that degradation of IkappaB-PL was specific to the NF-kappaB pathway activation. TNF-alpha and IL-1 induced maximal IkappaB-PL degradation within 30 min of induction. This was reversed by several agents that ablate this pathway, including anti-TNF-alpha antibodies and the proteasome inhibitor, MG-132. The assay was amenable to HTS systems, with good precision and reproducibility. Z' values and coefficients of variance for IkappaB-PL degradation were 0.6 and <9%, respectively.
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Uhlig U, Fehrenbach H, Lachmann RA, Goldmann T, Lachmann B, Vollmer E, Uhlig S. Phosphoinositide 3-OH kinase inhibition prevents ventilation-induced lung cell activation. Am J Respir Crit Care Med 2003; 169:201-8. [PMID: 14578214 DOI: 10.1164/rccm.200303-343oc] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In acute respiratory distress syndrome patients, protective ventilation strategies reduce mortality and proinflammatory mediator levels. It has been suggested that some of the side effects of mechanical ventilation are caused by the excessive release of mediators capable of causing pulmonary inflammation and tissue destruction (biotrauma). Selective inhibition of this process might be used to minimize the side effects of artificial mechanical ventilation. This study was designed to identify the cell types and specific signaling mechanisms that are activated by ventilation with increased pressure/volume (overventilation). In isolated perfused mouse lungs, overventilation caused nuclear translocation of nuclear factor-kappaB (NF-kappaB) and enhanced expression of interleukin-6 mRNA in alveolar macrophages and alveolar epithelial type II cells. The phosphoinositide 3-OH kinase inhibitor Ly294002 prevented nuclear translocation of NF-kappaB and the subsequent release of interleukin-6 and macrophage inflammatory protein-2alpha in overventilated but not in endotoxic lungs. Similar results were obtained in rats in vivo, where Ly294002 prevented NF-kappaB activation by overventilation but not by endotoxin. These findings show that alveolar macrophages and alveolar epithelial type II cells contribute to the ventilation-induced release of proinflammatory mediators and that selective inhibition of this process is possible without inhibiting the activation of NF-kappaB by endotoxin.
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33
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Nicholas J. Human herpesvirus-8-encoded signalling ligands and receptors. J Biomed Sci 2003; 10:475-89. [PMID: 12928588 DOI: 10.1007/bf02256109] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2003] [Accepted: 05/15/2003] [Indexed: 01/26/2023] Open
Abstract
Analysis of the genome of human herpesvirus 8 (HHV-8) led to the discovery of several novel genes, unique among the characterized gammaherpesviruses. These include cytokines (interleukin-6 and chemokine homologues), two putative signal-transducing transmembrane proteins encoded by genes K1 and K15 at the genome termini, and an OX-2 (CD200) receptor homologue that had not previously been identified in a gammaherpesvirus. HHV-8 also specifies a diverged version of the gammaherpesvirus-conserved G protein-coupled chemokine receptor (vGCR) and a latently expressed protein unique to HHV-8 specified by open reading frame (ORF) K12. These cytokine and receptor homologues mediate signal transduction or modulate the activities of other endogenous cytokines and receptors to enhance viral productive replication, regulate latent-lytic switching, evade host attack, or mediate cell survival. The viral signalling ligands and receptors are also potential contributors to virus-associated diseases, Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease, and so represent potentially important targets for therapeutic and antiviral drugs. Understanding these proteins' modes of action and functions in viral biology and disease is therefore of considerable importance, and the subject of this review.
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Affiliation(s)
- John Nicholas
- Molecular Virology Laboratories, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Md. 21231, USA.
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Yang M, Zhang H, Voyno-Yasenetskaya T, Ye RD. Requirement of Gbetagamma and c-Src in D2 dopamine receptor-mediated nuclear factor-kappaB activation. Mol Pharmacol 2003; 64:447-55. [PMID: 12869650 DOI: 10.1124/mol.64.2.447] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The D2 dopamine receptor (D2R) was examined for its ability to mediate nuclear factor-kappaB (NF-kappaB) activation through G proteins. Stimulation of D2R-transfected HeLa cells with its agonist quinpirole induced the expression of a NF-kappaB luciferase reporter and formation of NF-kappaB-DNA complex. This response was blocked by pertussis toxin, and by the Gbetagamma scavengers transducin and beta-adrenergic receptor kinase 1 carboxyl-terminal fragment. Unlike Gi-coupled chemoattractant receptors, D2R activated NF-kappaB without an increase in phospholipase C-beta activity, and the response was only slightly affected by the phosphoinositide 3-kinase inhibitor 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002). In contrast, treatment with genistein and 4-amino-1-tert-butyl-3-(p-methylphenyl)pyrazolo[3,4-d] pyrimidine abolished the induced NF-kappaB activation, suggesting involvement of protein tyrosine kinases. Activation of D2R led to phosphorylation of c-Src at Tyr-418, and expression of a kinase-deficient c-Src inhibited D2R-mediated NF-kappaB activation. The D2R-mediated NF-kappaB activation was not dependent on epidermal growth factor (EGF) receptor transactivation since 4-(3'-chloroanilino)-6,7-dimethoxyquinazoline (AG1478), an EGF receptor-selective tyrphostin used at 1 microM, blocked EGF-induced NF-kappaB activation but not the quinpirole-induced response. In addition, the D2R-mediated NF-kappaB activation was enhanced by over-expression of beta-arrestin 1. These results suggest that D2R-mediated NF-kappaB activation requires Gbetagamma and c-Src, and possibly involves beta-arrestin 1.
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Affiliation(s)
- Ming Yang
- Department of Pharmacology, M/C 868, University of Illinois at Chicago, 835 S. Wolcott Avenue, Chicago, IL 60612, USA
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35
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Zhu YM, Bradbury DA, Pang L, Knox AJ. Transcriptional regulation of interleukin (IL)-8 by bradykinin in human airway smooth muscle cells involves prostanoid-dependent activation of AP-1 and nuclear factor (NF)-IL-6 and prostanoid-independent activation of NF-kappaB. J Biol Chem 2003; 278:29366-75. [PMID: 12748173 DOI: 10.1074/jbc.m301785200] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bradykinin (BK) is a potent neutrophil chemotractant, proinflammatory mediator, and angiogenic factor, which acts through G protein-coupled receptors (GPCRs). Here we studied the mechanisms involved in IL-8 generation by BK in human airway smooth muscle cells focusing on the transcription factors involved and role of endogenous prostanoids in transcription factor activation. Transfection experiments with wild-type IL-8 promoter constructs or constructs with NF-kappaB, AP-1, and NF-IL-6 binding site mutations suggested that all three transcription factors were necessary for optimal IL-8 expression. BK increased NF-kappaB, AP-1, and NF-IL-6 binding to the IL-8 promoter by electrophoretic mobility shift assay. NF-kappaB, the most important transcription factor in the current study, was translocated to the nucleus after BK stimulation. Indomethacin, a cyclooxygenase inhibitor, partially inhibited IL-8 release and the promoter binding of AP-1 and NF-IL-6, but not NF-kappaB. Furthermore, exogenous prostaglandin E2 stimulated AP-1 and NF-IL-6 binding to the IL-8 promoter. The anti-inflammatory glucocorticoid dexamethasone inhibited NF-kappaB translocation and the promoter binding of NF-kappaB, AP-1, and NF-IL-6. These results are the first to delineate the transcription factors involved in BK induced IL-8 release. Transcriptional activation of the IL-8 promoter by BK involves the prostanoid-independent activation of NF-kappaB, and prostanoid-dependent activation of AP-1 and NF-IL-6 plays a key role in augmenting the response. Endogenous prostanoid generation in response to GPCR ligands such as BK may be an important mechanism whereby GPCRs signal to the nucleus to maximize the transcription of inflammatory response genes.
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Affiliation(s)
- Yong M Zhu
- Division of Respiratory Medicine, School of Medical and Surgical Sciences, University of Nottingham, Nottingham NG5 1PB, United Kingdom
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Holmes CL, Landry DW, Granton JT. Science review: Vasopressin and the cardiovascular system part 1--receptor physiology. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2003; 7:427-34. [PMID: 14624682 PMCID: PMC374366 DOI: 10.1186/cc2337] [Citation(s) in RCA: 223] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Vasopressin is emerging as a rational therapy for vasodilatory shock states. Unlike other vasoconstrictor agents, vasopressin also has vasodilatory properties. The goal of the present review is to explore the vascular actions of vasopressin. In part 1 of the review we discuss structure, signaling pathways, and tissue distributions of the classic vasopressin receptors, namely V1 vascular, V2 renal, V3 pituitary and oxytocin receptors, and the P2 class of purinoreceptors. Knowledge of the function and distribution of vasopressin receptors is key to understanding the seemingly contradictory actions of vasopressin on the vascular system. In part 2 of the review we discuss the effects of vasopressin on vascular smooth muscle and the heart, and we summarize clinical studies of vasopressin in shock states.
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Affiliation(s)
- Cheryl L Holmes
- Staff intensivist, Department of Medicine, Division of Critical Care, Kelowna General Hospital, Kelowna BC, Canada
| | - Donald W Landry
- Associate Professor, Department of Medicine, Columbia University, New York, New York, USA
| | - John T Granton
- Assistant Professor of Medicine, Faculty of Medicine, and Program Director, Critical Care Medicine, University of Toronto, and Consultant in Pulmonary and Critical Care Medicine, Director Pulmonary Hypertension Program, University Health Network, Toronto, Ontario, Canada
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Lin P, Ye RD. The lysophospholipid receptor G2A activates a specific combination of G proteins and promotes apoptosis. J Biol Chem 2003; 278:14379-86. [PMID: 12586833 DOI: 10.1074/jbc.m209101200] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
G2A, a G protein-coupled receptor for which lysophosphatidylcholine (LPC) is a high affinity ligand, belongs to a newly defined lysophospholipid receptor subfamily. Expression of G2A is transcriptionally up-regulated by stress-inducing and cell-damaging agents, and ectopic expression of G2A leads to growth inhibition. However, the G proteins that functionally couple to G2A have not been elucidated in detail. We report here that G2A ligand independently stimulates the accumulation of both inositol phosphates and cAMP. LPC does not further enhance inositol phosphate accumulation but dose-dependently augments intracellular cAMP concentration. Expression of G alpha(q) and G alpha(13) with G2A potentiates G2A-mediated activation of a NF-kappa B-luciferase reporter. These results demonstrate that G2A differentially couples to multiple G proteins including G alpha(s), G alpha(q), and G alpha(13), depending on whether it is bound to ligand. G2A-transfected HeLa cells display apoptotic signs including membrane blebbing, nuclear condensation, and reduction of mitochondrial membrane potential. Furthermore, G2A-induced apoptosis can be rescued by the caspase inhibitors, z-vad-fmk and CrmA. Although apoptosis occurs without LPC stimulation, LPC further enhances G2A-mediated apoptosis and correlates with its ability to induce cAMP elevation in both HeLa cells and primary lymphocytes. Rescue from G2A-induced apoptosis was achieved by co-expression of a G alpha(12/13)-specific inhibitor, p115RGS (regulator of G protein signaling), in combination with 2',5'-dideoxyadenosine treatment. These results demonstrate the ability of G2A to activate a specific combination of G proteins, and that G2A/LPC-induced apoptosis involves both G alpha(13)- and G alpha(s)-mediated pathways.
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Affiliation(s)
- Phoebe Lin
- Department of Pharmacology, College of Medicine, University of Illinois, Chicago 60612, USA
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Abstract
Metastatic disease is the most critical impediment to cancer patient survival. However, comparatively little is known concerning the intricate pathways which govern the complex phenotypes associated with metastasis. The KISS1 metastasis suppressor gene inhibits metastasis in both in vivo melanoma and breast carcinoma models. Despite its clear physiological activity, the mechanism of KISS1 remains unclear. Recent identification of a 54 amino acid peptide of KISS1, termed metastin or kisspeptin-54, and its cognate G-protein coupled receptor (hOT7T175, AXOR12, GPR54) have provided additional clues and avenues of research. While studies have attributed KISS1 with modulation of NFkappaB regulation, experiments with metastin and its receptor implicate MAP kinase pathways and also suggest the potential of autocrine, paracrine and endocrine roles. Impacts on motility, chemotaxis, adhesion and invasion have each been documented in disparate cell lines and conflicting observations require resolution. Nevertheless, mounting clinical evidence, particularly the loss of KISS1 in metastases, correlates KISS1 and metastin receptor expression with human tumor progression. Together, the data substantiate roles for these molecules in metastasis regulation.
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Affiliation(s)
- John F Harms
- Jake Gittlen Cancer Research Institute, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
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Ivey K, Tyson B, Ukidwe P, McFadden DG, Levi G, Olson EN, Srivastava D, Wilkie TM. Galphaq and Galpha11 proteins mediate endothelin-1 signaling in neural crest-derived pharyngeal arch mesenchyme. Dev Biol 2003; 255:230-7. [PMID: 12648486 DOI: 10.1016/s0012-1606(02)00097-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Endothelin-A (ET(A)) is a G-protein-coupled receptor expressed in the neural crest-derived mesenchyme of the pharyngeal arches during craniofacial development. Targeted deletion of the ET(A) receptor or its ligand endothelin-1 (ET-1) causes cleft palate and hypoplasia of the mandible, otic cup, and tympanic ring. Previously we showed that Galpha(q)/Galpha(11)-null mice die around E11.0, whereas Galpha(q)((-/-))Galpha(11)((+/-)) mice survive to birth with hypomorphic phenotypes similar to, but less severe than, ET(A) or ET-1-null mice. To determine whether ET-1 signaling is transduced by Galpha(q)/Galpha(11) proteins, we examined the expression patterns of several ET-1 dependent and independent transcription factors in Galpha(q)/Galpha(11)-deficient embryos. Expression of genes encoding the ET-1-dependent transcription factors Dlx3, Dlx6, dHAND, and eHAND was specifically downregulated in the pharyngeal arches of Galpha(q)/Galpha(11)-deficient mice. In contrast, pharyngeal arch expression of the homeobox gene Msx1, which is not regulated by ET-1 signaling, was maintained in these embryos. We conclude that the Galpha(q) and Galpha(11) proteins serve as the intracellular mediators of ET-1 signaling in the pharyngeal arch mesenchyme.
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Affiliation(s)
- Kathryn Ivey
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, , Dallas, TX 75390-9104, USA
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Wieland T, Mittmann C. Regulators of G-protein signalling: multifunctional proteins with impact on signalling in the cardiovascular system. Pharmacol Ther 2003; 97:95-115. [PMID: 12559385 DOI: 10.1016/s0163-7258(02)00326-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Regulator of G-protein signalling (RGS) proteins form a superfamily of at least 25 proteins, which are highly diverse in structure, expression patterns, and function. They share a 120 amino acid homology domain (RGS domain), which exhibits GTPase accelerating activity for alpha-subunits of heterotrimeric G-proteins, and thus, are negative regulators of G-protein-mediated signalling. Based on the organisation of the Rgs genes, structural similarities, and differences in functions, they can be divided into at least six subfamilies of RGS proteins and three more families of RGS-like proteins. Many of these proteins regulate signalling processes within cells, not only via interaction with G-protein alpha-subunits, but are G-protein-regulated effectors, Gbetagamma scavenger, or scaffolding proteins in signal transduction complexes as well. The expression of at least 16 different RGS proteins in the mammalian or human myocardium have been described. A subgroup of at least eight was detected in a single atrial myocyte. The exact functions of these proteins remain mostly elusive, but RGS proteins such as RGS4 are involved in the regulation of G(i)-protein betagamma-subunit-gated K(+) channels. An up-regulation of RGS4 expression has been consistently found in human heart failure and some animal models. Evidence is increasing that the enhanced RGS4 expression counter-regulates the G(q/11)-induced signalling caused by hypertrophic stimuli. In the vascular system, RGS5 seems to be an important signalling regulator. It is expressed in vascular endothelial cells, but not in cultured smooth muscle cells. Its down-regulation, both in a model of capillary morphogenesis and in an animal model of stroke, render it a candidate gene, which may be involved in the regulation of capillary growth, angiogenesis, and in the pathophysiology of stroke.
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Affiliation(s)
- Thomas Wieland
- Institut für Pharmakologie und Toxikologie, Fakultät für Klinische Medizin Mannheim der Universität Heidelberg, Maybachstrasse 14-16, D-68169 Mannheim, Germany.
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Cheng JJ, Chao YJ, Wang DL. Cyclic strain activates redox-sensitive proline-rich tyrosine kinase 2 (PYK2) in endothelial cells. J Biol Chem 2002; 277:48152-7. [PMID: 12368297 DOI: 10.1074/jbc.m110937200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proline-rich tyrosine kinase 2 (PYK2), structurally related to focal adhesion kinase, has been shown to play a role in signaling cascades. Endothelial cells (ECs) under hemodynamic forces increase reactive oxygen species (ROS) that modulate signaling pathways and gene expression. In the present study, we found that bovine ECs subjected to cyclic strain rapidly induced phosphorylation of PYK2 and Src kinase. This strain-induced PYK2 and Src phosphorylation was inhibited by pretreating ECs with an antioxidant N-acetylcysteine. Similarly, ECs exposed to H(2)O(2) increased both PYK2 and Src phosphorylation. An increased association of Src to PYK2 was observed in ECs after cyclic strain or H(2)O(2) exposure. ECs treated with an inhibitor to Src (PPI) greatly reduced Src and PYK2 phosphorylation, indicating that Src mediated PYK2 activation. Whereas the protein kinase C (PKC) inhibitor (calphostin C) pretreatment was shown to inhibit strain-induced NADPH oxidase activity, ECs treated with either calphostin C or the inhibitor to NADPH oxidase (DPI) reduced strain-induced ROS levels and then greatly inhibited the Src and PYK2 activation. In contrast to the activation of PYK2 and Src with calcium ionophore (ionomycin), ECs treated with a Ca(2+) chelator inhibited both phosphorylation, indicating that PYK2 and Src activation requires Ca(2+). ECs transfected with antisense to PKCalpha, but not antisense to PKCepsilon(,) reduced cyclic strain-induced PYK2 activation. These data suggest that cyclic strain-induced PYK2 activity is mediated via Ca(2+)-dependent PKCalpha that increases NADPH oxidase activity to produce ROS crucial for Src and PYK2 activation. ECs under cyclic strain thus activate redox-sensitive PYK2 via Src and PKC, and this PYK2 activation may play a key role in the signaling responses in ECs under hemodynamic influence.
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Affiliation(s)
- Jing-Jy Cheng
- Cardiovascular Division, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan 11529
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Yowell CW, Daaka Y. G Protein–Coupled Receptors Provide Survival Signals in Prostate Cancer. ACTA ACUST UNITED AC 2002; 1:177-81. [PMID: 15046693 DOI: 10.3816/cgc.2002.n.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Prostate cancer is the leading cause for noncutaneous cancer-related deaths among men in the United States. The disease is biologically characterized as being either androgen dependent or androgen independent. Whereas androgen-dependent prostate cancer can be successfully treated with androgen ablative therapy, to date no cure exists for androgen-independent disease. Mechanisms involved in the progression of prostate cancer to androgen independence are not known. Here we present evidence that in addition to growth factor receptor tyrosine kinases, G protein- coupled receptors can mediate survival signals in prostate cancer cells. The G protein- coupled receptors exert their effects by activating multiple intracellular signal transduction networks that promote prostate cancer cell survival, including the activation of c-Jun N-terminal kinase, protein kinase B (Akt) and nuclear factor-kB. Prostate-expressed G protein- coupled receptors and their downstream effectors may prove to be effective targets in the treatment of advanced prostate cancer.
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Affiliation(s)
- Charles W Yowell
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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43
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Davies PF. Multiple signaling pathways in flow-mediated endothelial mechanotransduction: PYK-ing the right location. Arterioscler Thromb Vasc Biol 2002; 22:1755-7. [PMID: 12426200 DOI: 10.1161/01.atv.0000034391.00347.71] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Wu SS, Chiu T, Rozengurt E. ANG II and LPA induce Pyk2 tyrosine phosphorylation in intestinal epithelial cells: role of Ca2+, PKC, and Rho kinase. Am J Physiol Cell Physiol 2002; 282:C1432-44. [PMID: 11997258 DOI: 10.1152/ajpcell.00323.2001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The G protein-coupled receptor agonists angiotensin II (ANG II) and lysophosphatidic acid (LPA) rapidly induce tyrosine phosphorylation of the cytosolic proline-rich tyrosine kinase 2 (Pyk2) in IEC-18 intestinal epithelial cells. The combined Pyk2 tyrosine phosphorylation induced by phorbol 12,13-dibutyrate, a direct agonist of protein kinase C (PKC), and ionomycin, a Ca2+ ionophore, was equal to that induced by ANG II. Inhibition of either PKC or Ca2+ signaling attenuated the effect of ANG II and LPA, although simultaneous inhibition of both pathways failed to completely abolish Pyk2 tyrosine phosphorylation. Cytochalasin D, which disrupts stress fibers, strongly inhibited the response of Pyk2 to ANG II or LPA. The distinct Rho-associated kinase (ROK) inhibitors HA-1077 and Y-27632, as well as the Rho inhibitor Clostridium botulinum C3 exoenzyme, also significantly attenuated ANG II- and LPA-stimulated Pyk2 tyrosine phosphorylation. Simultaneous inhibition of PKC, Ca2+, and either actin assembly or ROK completely abolished the Pyk2 response. Together, these results show that ANG II and LPA rapidly induce Pyk2 tyrosine phosphorylation in intestinal epithelial cells via separate Ca2+-, PKC-, and Rho-mediated pathways.
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Affiliation(s)
- Steven S Wu
- Department of Pediatrics, School of Medicine and Molecular Biology Institute, University of California, Los Angeles, California 90095-1786, USA
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45
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Abstract
The heterotrimeric guanine nucleotide-binding proteins (G proteins) are signal transducers that communicate signals from many hormones, neurotransmitters, chemokines, and autocrine and paracrine factors. The extracellular signals are received by members of a large superfamily of receptors with seven membrane-spanning regions that activate the G proteins, which route the signals to several distinct intracellular signaling pathways. These pathways interact with one another to form a network that regulates metabolic enzymes, ion channels, transporters, and other components of the cellular machinery controlling a broad range of cellular processes, including transcription, motility, contractility, and secretion. These cellular processes in turn regulate systemic functions such as embryonic development, gonadal development, learning and memory, and organismal homeostasis.
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Affiliation(s)
- Susana R Neves
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, NY 10029, USA
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Yamakaw K, Kitamura K, Nonoguchi H, Takasu N, Miller RT, Tomita K. Galpha13 induces preproET-1 gene expression via JNK. Hypertens Res 2002; 25:427-32. [PMID: 12135322 DOI: 10.1291/hypres.25.427] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The endothelin B receptor (ETBR) has been shown to mediate autoinduction of endothelin-1 (ET-1). We previously reported that the ET(B)R interacts with Galpha13, a member of the heterotrimeric GTP-binding protein family. In the present study, we examined whether Galpha13 induces preproET-1 (ppET-1) gene transcription, which could result in ET-1 autoinduction in a renal epithelial cell line. We generated a reporter gene construct under control of the ppET-1 promoter region. The construct was transiently expressed in COS-7 cells. Transient expression of ETBR increased the promoter activity of ppET-1 following treatment with 100 nmol/l of ET-1. Expression of Galpha13Q226L or Galpha9209L, constitutively active forms of Galpha13 and Galpha9, also activated the ppET-1 promoter. ETBR-stimulated ppET-1 promoter activity was partially diminished by the expression of dominant negative forms of c-Jun N-terminal kinase (JNK1APF) or MAPK/ERK kinase (MEKK97M). Expression of JNK1APF also inhibited Galpha13Q226L-induced ppET-1 promoter activation. These findings indicate that Galpha13 can induce ppET-1 gene expression through a JNK-mediated pathway. Our results also suggest that this Galpha13-coupled signaling pathway may play an important role in a sustained ET-1 autoinduction loop in various pathophysiological conditions.
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Affiliation(s)
- Ken Yamakaw
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Japan
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Abstract
Recent advances in genomics and proteomics, combined with the facilitated generation and analysis of transgenic and gene-knockout animals, have revealed new complexities in classical biological systems, including the B-cell compartment. Studies on an 'old', but poorly characterized, B-cell subset--the naive, marginal-zone (MZ) B-cell subset--over the past two years have spawned an avalanche of data that encompass the generation and function of these cells. Now that the initial 'infatuation' is over, it is time to reconsider these data and generate some conclusions that can be incorporated into a working model of the B-cell system.
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Affiliation(s)
- Flavius Martin
- Department of Microbiology, University of Alabama at Birmingham, 35294-3300, USA
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Siehler S, Wang Y, Fan X, Windh RT, Manning DR. Sphingosine 1-phosphate activates nuclear factor-kappa B through Edg receptors. Activation through Edg-3 and Edg-5, but not Edg-1, in human embryonic kidney 293 cells. J Biol Chem 2001; 276:48733-9. [PMID: 11673450 DOI: 10.1074/jbc.m011072200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Sphingosine 1-phosphate (S1P) exerts a variety of actions as a second messenger or as an agonist that binds to one or more members of the Edg family of G protein-coupled receptors. By using human embryonic kidney 293 cells, we show that S1P activates nuclear factor-kappa B (NF-kappa B) in a receptor-dependent fashion. Edg-3 and Edg-5, which are coupled to G(i), G(q), and G(13), affect activation of NF-kappa B, whereas Edg-1, which is coupled to G(i) alone, does not. We find that the activation of NF-kappa B requires protein kinase C and Ca(2+), probably downstream of G(q), but that the activation of Rho alone by S1P, whether through G(q) or G(13), does not translate into the activation of NF-kappa B. G beta gamma has little effect of its own but potentiates the activation of NF-kappa B achieved through other G proteins. We conclude that the activation of NF-kappa B by S1P is a receptor-mediated process that relies primarily on the activation of a phospholipase C by G(q) and secondarily on effector regulation through other G proteins.
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Affiliation(s)
- S Siehler
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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