EGF receptor transactivation is obligatory for protein  synthesis stimulation by G protein-coupled receptors

Voisin, Laure; Foisy, Sylvain; Giasson, Edith; Lambert, Chantal; Moreau, Pierre; Meloche, Sylvain

doi:10.1152/ajpcell.00261.2001

Cited by 70 publications

(53 citation statements)

References 43 publications

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“…In fact, we show that the blockade of a-PDGFR binding site exerted only a negligible effect on the downstream signaling, whereas receptor internalization inhibited the vast majority of Akt activation (Supplementary Data 2C). Transactivation of multiple tyrosine kinase receptors, including PDGFR (22), has been described in a wide range of normal and malignant cell types (23)(24)(25)(26). Here we provide the first evidence that the soluble fraction of human bone marrow activates the PI3K/Akt pathway in bone-metastatic prostate cells predominantly through a-PDGFR transactivation.…”

Section: Resultsmentioning

confidence: 99%

Human Bone Marrow Activates the Akt Pathway in Metastatic Prostate Cells through Transactivation of the α-Platelet–Derived Growth Factor Receptor

Dolloff

Russell²,

Loizos³

et al. 2007

Cancer Research

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Section: Resultsmentioning

confidence: 99%

Human Bone Marrow Activates the Akt Pathway in Metastatic Prostate Cells through Transactivation of the α-Platelet–Derived Growth Factor Receptor

Dolloff

Russell²,

Loizos³

et al. 2007

Cancer Research

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“…Since TRH does not directly bind to EGF receptor (Luo et al 2003), the signal transduction amplificatory effect might explain why EGF receptor transactivation has a relevant action of G protein-coupled receptors linked to Ras/MAP kinase activation (Daub et al 1996) and protein synthesis (Voisin et al 2002). Although the specific effects of EGF on insulin synthesis have not been identified, TRH activation of EGF receptor phosphorylation influencing the relative pathways cannot be excluded.…”

Section: Discussionmentioning

confidence: 99%

Expression of thyrotropin-releasing hormone receptor in immortalized beta-cell lines and rat pancreas

Luo

Yano²

2004

Journal of Endocrinology

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Thyrotropin-releasing hormone (TRH), a hypothalamic tripeptide, is expressed in pancreatic islets at peak levels during the late gestation and early neonate period. TRH increases insulin production in cultured -cells, suggesting that it might play a role in regulating pancreatic -cell function. However, there is limited information on TRH receptor expression in the pancreas. The aim of the present study was to explore the distribution of the TRH receptor in the pancreas and its function in pancreatic -cells. TRH receptor type 1 (TRHR1) gene expression was detected by RT-PCR and verified by Northern blotting and immunoblotting in the -cell lines, INS-1 and TC-6, and the rat pancreatic organ. The absence of TRH receptor type 2 expression in the tissue and cells indicated the tissue specificity of TRH receptor expression in the pancreas. The TRHR1 signals (detected by in situ hybridization) were distributed not only in islets but also in the surrounding areas of the pancreatic ductal and vasal epithelia. The apparent dissociation constant value for the affinity of [ 3 H]3-methyl-histidine TRH (MeTRH) is 4·19 in INS-1 and 3·09 nM in TC-6. In addition, TRH induced epidermal growth factor (EGF) receptor phosphorylation with a half-maximum concentration of approximately 50 nM, whereas the high affinity analogue of TRH, MeTRH, was 1 nM. This suggested that the affinity of TRH ligands for the TRH receptor influences the activation of EGF receptor phosphorylation in TC-6 cells. Our observations suggested that the biological role of TRH in pancreatic -cells is via the activation of TRHR1. Further research is required to identify the role of TRHR1 in the pancreas aside from the islets.

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“…Gene Induction and Semi-quantification of iNOS and COX-2 mRNApCMVEC seeded into 10-cm dishes were treated for 2 h at 37°C with either the vehicle (sterile bidistilled and deionized water), sLPA (1-10 M), or human IL-1␤ (10 ng/ml) in the presence or absence of caveolae-disrupting agents filipin (5 g/ml) and methyl-␤-cyclodextrin (5 mM), non-selective phospholipase (27,(36)(37)(38)(39). Inhibitors were incubated 1 h prior to LPA stimulation.…”

Section: Methodsmentioning

confidence: 99%

Modulation of Pro-inflammatory Gene Expression by Nuclear Lysophosphatidic Acid Receptor Type-1

Gobeil

Bernier

Vazquez-Tello

et al. 2003

Journal of Biological Chemistry

128

155

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Lysophosphatidic acid (LPA) is a bioactive molecule involved in inflammation, immunity, wound healing, and neoplasia. Its pleiotropic actions arise presumably by interaction with their cell surface G protein-coupled receptors. Herein, the presence of the specific nuclear lysophosphatidic acid receptor-1 (LPA 1 R) was revealed in unstimulated porcine cerebral microvascular endothelial cells (pCMVECs), LPA 1 R stably transfected HTC4 rat hepatoma cells, and rat liver tissue using complementary approaches, including radioligand binding experiments, electron-and cryomicroscopy, cell fractionation, and immunoblotting with three distinct antibodies. Coimmunoprecipitation studies in enriched plasmalemmal fractions of unstimulated pCMVEC showed that LPA 1 Rs are dually sequestrated in caveolin-1 and clathrin subcompartments, whereas in nuclear fractions LPA 1 R appeared primarily in caveolae. Immunofluorescent assays using a cell-free isolated nuclear system confirmed LPA 1 R and caveolin-1 co-localization. In pCMVEC, LPA-stimulated increases in cyclooxygenase-2 and inducible nitricoxide synthase RNA and protein expression were insensitive to caveolea-disrupting agents but sensitive to LPAgenerating phospholipase A 2 enzyme and tyrosine kinase inhibitors. Moreover, LPA-induced increases in Ca 2؉ transients and/or iNOS expression in highly purified rat liver nuclei were prevented by pertussis toxin, phosphoinositide 3-kinase/Akt inhibitor wortmannin and Ca 2؉ chelator and channel blockers EGTA and SK&F96365, respectively. This study describes for the first time the nucleus as a potential organelle for LPA intracrine signaling in the regulation of pro-inflammatory gene expression.In the mammalian system, LPA 1 signaling cascades regulate important cellular processes, including gene expression, cell proliferation and growth, cell survival and death, and cell motility and secretion (1-3). These plethora of activities are characteristic features of inflammation that occur in various physiological as well as pathological states (e.g. ontogenic change, wound healing, cancer, etc.) (1-3). In humans, physiological responses induced by LPA arise from specific interactions with at least three genetically identified receptors designated LPA 1 , LPA 2 , and LPA 3 (formerly referred to as EDG 2 , EDG 4 , and EDG 7 receptors, respectively), which belong to the heptahelical transmembrane-spanning G protein-coupled receptor (GPCR) superfamily (4). These receptors show a broad, virtually distinct distribution and may couple in a cell-dependent manner to numerous heterotrimeric G proteins. In this context, LPA 1 and LPA 2 receptors have been shown to interact with G i/o , G q/11/14 , and G 12/13 proteins, whereas the LPA 3 receptor combines with G i/o and G q/11/14 proteins (5). Although many responses induced by extracellular LPA can result from its interaction with plasma membrane GPCRs, there is circumstantial evidence for an intracrine mode of action of LPA. For instance, putative biogenesis (e.g. secretory and cytosolic calcium-depen...

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EGF receptor transactivation is obligatory for protein synthesis stimulation by G protein-coupled receptors

Cited by 70 publications

References 43 publications

Human Bone Marrow Activates the Akt Pathway in Metastatic Prostate Cells through Transactivation of the α-Platelet–Derived Growth Factor Receptor

Human Bone Marrow Activates the Akt Pathway in Metastatic Prostate Cells through Transactivation of the α-Platelet–Derived Growth Factor Receptor

Expression of thyrotropin-releasing hormone receptor in immortalized beta-cell lines and rat pancreas

Modulation of Pro-inflammatory Gene Expression by Nuclear Lysophosphatidic Acid Receptor Type-1

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