Coupling of the RAS-MAPK Pathway to Gene Activation by RSK2, a Growth Factor-Regulated CREB Kinase

Science ◽  
1996 ◽  
Vol 273 (5277) ◽  
pp. 959-963 ◽  
Author(s):  
J. Xing ◽  
D. D. Ginty ◽  
M. E. Greenberg
Keyword(s):  
Growth Factor ◽  
Mapk Pathway ◽  
Gene Activation ◽  
Creb Kinase

scholarly journals JNK and p38 Inhibitors Prevent Transforming Growth Factor-β1-Induced Myofibroblast Transdifferentiation in Human Graves’ Orbital Fibroblasts

2021 ◽  
Vol 22 (6) ◽  
pp. 2952
Author(s):  
Tzu-Yu Hou ◽  
Shi-Bei Wu ◽  
Hui-Chuan Kau ◽  
Chieh-Chih Tsai
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Mapk Pathway ◽  
Transforming Growth Factor Β1 ◽  
Tissue Growth ◽  
Mitogen Activated Protein Kinase ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Western Blots ◽  
Orbital Fibroblasts ◽  
Tgf Β1

Transforming growth factor-β1 (TGF-β1)-induced myofibroblast transdifferentiation from orbital fibroblasts is known to dominate tissue remodeling and fibrosis in Graves’ ophthalmopathy (GO). However, the signaling pathways through which TGF-β1 activates Graves’ orbital fibroblasts remain unclear. This study investigated the role of the mitogen-activated protein kinase (MAPK) pathway in TGF-β1-induced myofibroblast transdifferentiation in human Graves’ orbital fibroblasts. The MAPK pathway was assessed by measuring the phosphorylation of p38, c-Jun N-terminal kinase (JNK), and extracellular-signal-regulated kinase (ERK) by Western blots. The expression of connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), and fibronectin representing fibrogenesis was estimated. The activities of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) responsible for extracellular matrix (ECM) metabolism were analyzed. Specific pharmacologic kinase inhibitors were used to confirm the involvement of the MAPK pathway. After treatment with TGF-β1, the phosphorylation levels of p38 and JNK, but not ERK, were increased. CTGF, α-SMA, and fibronectin, as well as TIMP-1 and TIMP-3, were upregulated, whereas the activities of MMP-2/-9 were inhibited. The effects of TGF-β1 on the expression of these factors were eliminated by p38 and JNK inhibitors. The results suggested that TGF-β1 could induce myofibroblast transdifferentiation in human Graves’ orbital fibroblasts through the p38 and JNK pathways.

Cell type-specific requirement of the MAPK pathway for the growth factor action of gastrin

1999 ◽  
Vol 276 (6) ◽  
pp. G1363-G1372 ◽  
Author(s):  
Vinzenz M. Stepan ◽  
Chris J. Dickinson ◽  
John del Valle ◽  
Masashi Matsushima ◽  
Andrea Todisco
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Growth Factor ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Cell Type ◽  
Ar42j Cells ◽  
Cell Type Specific ◽  
Ar42j Cell ◽  
Stimulation Of

Gastrin (G17) has a CCKBreceptor-mediated growth-promoting effect on the AR42J rat acinar cell line that is linked to induction of both mitogen-activated protein kinase (MAPK) and c- fos gene expression. We investigated the mechanisms that regulate the growth factor action of G17 on the rat pituitary adenoma cell line GH3. Both AR42J and GH3cells displayed equal levels of CCKBreceptor expression and similar binding kinetics of125I-labeled G17. G17 stimulation of cell proliferation was identical in both cell lines. G17 stimulation of GH3cell proliferation was completely blocked by the CCKBreceptor antagonist D2 but not by the MEK inhibitor PD-98059 or the protein kinase C inhibitor GF-109203X, which completely inhibited G17 induction of AR42J cell proliferation. G17 induced a c- fos SRE-luciferase reporter gene plasmid more than fourfold in the AR42J cells, whereas it had no effect in the GH3cells. In contrast to what we observed in the AR42J cells, G17 failed to stimulate MAPK activation and Shc tyrosyl phosphorylation and association with the adapter protein Grb2. Epidermal growth factor induced the MAPK pathway in the GH3cells, demonstrating the integrity of this signaling system. G17 induced Ca2+mobilization in both the GH3and AR42J cells. The calmodulin inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide inhibited AR42J cell proliferation by 20%, whereas it completely blocked G17 induction of GH3cell growth. The Ca2+ionophore ionomycin stimulated GH3cell proliferation to a level similar to that observed in response to G17, but it had no effect on AR42J cell proliferation. Thus there are cell type specific differences in the requirement of the MAPK pathway for the growth factor action of G17. Whereas in the AR42J cells G17 stimulates cell growth through activation of MAPK and c- fos gene expression, in the GH3cells, G17 fails to activate MAPK, and it induces cell proliferation through Ca2+-dependent signaling pathways. Furthermore, induction of Ca2+mobilization in the AR42J cells appears not to be sufficient to sustain cell proliferation.

Cyclic stretch activates p38 SAPK2-, ErbB2-, and AT1-dependent signaling in bladder smooth muscle cells

2000 ◽  
Vol 279 (4) ◽  
pp. C1155-C1167 ◽  
Author(s):  
Hiep T. Nguyen ◽  
Rosalyn M. Adam ◽  
Samuel H. Bride ◽  
John M. Park ◽  
Craig A. Peters ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Protein Kinase ◽  
Smooth Muscle Cells ◽  
Dna Synthesis ◽  
Mapk Pathway ◽  
Muscle Cells ◽  
Cyclic Stretch ◽  
Bladder Smooth Muscle ◽  
Erk Mapk

Cyclic mechanical stretch of bladder smooth muscle cells (SMC) increases rates of DNA synthesis and stimulates transcription of the gene for heparin-binding epidermal growth factor-like growth factor (HB-EGF), an ErbB1/EGF receptor ligand that has been linked to hypertrophic bladder growth. In this study we sought to clarify the signaling pathways responsible for mechanotransduction of the stretch stimulus. HB-EGF mRNA levels, DNA synthesis, and AP-1/Ets DNA binding activities were induced by repetitive stretch of primary culture rat bladder SMC. Inhibitors of the p38 SAPK2 pathway, the angiotensin receptor type 1 (AT1), and the ErbB2 tyrosine kinase reduced each of these activities, while an inhibitor of the extracellular signal-regulated kinase mitogen-activated protein kinase (Erk-MAPK) pathway had no effect. Stretch rapidly activated stress-activated protein kinase 2 (p38 SAPK2) and Jun NH2-terminal kinase (JNK)/SAPK pathways but not the Erk-MAPK pathway and induced ErbB2 but not ErbB1 phosphorylation. Angiotensin II (ANG II) a bladder SMC mitogen previously linked to the stretch response, did not activate ErbB2, and ErbB2 activation occurred in response to stretch in the presence of an ANG receptor inhibitor, indicating that activation of the AT1-mediated pathway and the ErbB2-dependent pathway occurs by independent mechanisms. p38 SAPK2 and JNK/SAPK signaling also appeared to be independent of the ErbB2 and AT1 pathways. These findings indicate that stretch-stimulated DNA synthesis and gene expression in normal bladder SMC occur via multiple independent receptor systems (e.g., AT1 and ErbB2) and at least one MAPK pathway (p38 SAPK2). Further, we show that the Erk-MAPK pathway, which in most systems is linked to receptor-dependent cell growth responses, is not involved in progression to DNA synthesis or in the response of the HB-EGF gene to mechanical forces.

Epidermal growth factor upregulates β-adrenergic receptor signaling in a human salivary cell line

2003 ◽  
Vol 284 (5) ◽  
pp. C1164-C1175 ◽  
Author(s):  
Chih-Ko Yeh ◽  
Tazuko K. Hymer ◽  
April L. Sousa ◽  
Bin-Xian Zhang ◽  
Meyer D. Lifschitz ◽  
...  
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Adenylyl Cyclase ◽  
Adrenergic Receptor ◽  
Mapk Pathway ◽  
Receptor Density ◽  
Adenylyl Cyclase Activity ◽  
Adenylyl Cyclase System ◽  
Epidermal Growth ◽  
Salivary Cell

The effects of epidermal growth factor (EGF) on the β-adrenergic receptor-coupled adenylyl cyclase system were studied in a human salivary cell line (HSY). The β-adrenergic agonist isoproterenol (10−5 M) stimulated adenylyl cyclase activity by ∼2-fold, and the isoproterenol response was increased 1.8-fold after prolonged (48 h) exposure to EGF (5 × 10−10 M). In contrast, enzyme activation via stimulatory prostaglandin receptors and by agents acting on nonreceptor components of the adenylyl cyclase system was not enhanced by EGF. β-Adrenergic receptor density, assessed by binding of the β-adrenergic receptor antagonist (−)-[125I]iodopindolol, was increased threefold after EGF treatment. Competition binding studies with unlabeled antagonists selective for β1- and β2-adrenergic receptor subtypes indicated that the increase in (−)-[125I]iodopindolol binding sites induced by EGF reflected an increased number of β2-adrenergic receptors. Likewise, Northern blot analysis of RNA from EGF-treated cells revealed selective induction of β2-adrenergic receptor mRNA, which was blocked by the RNA synthesis inhibitor actinomycin D. The increase in β-adrenergic receptor density produced by EGF was unaltered after phorbol ester-induced downregulation of protein kinase C (PKC). Enhancement of isoproterenol-responsive adenylyl cyclase activity and phosphorylation of mitogen-activated protein kinase (MAPK) by EGF were both blocked by the MAPK pathway inhibitor PD-98059. The results suggest that in HSY cells EGF enhances β-adrenergic responsiveness by upregulating β2-adrenergic receptor expression at the transcriptional level. Moreover, the stimulatory effect of EGF on β2-adrenergic receptor signaling appears to be mediated by the MAPK pathway and independent of PKC activation.

Sprouty proteins: antagonists of endothelial cell signaling and more

2003 ◽  
Vol 90 (10) ◽  
pp. 586-590 ◽  
Author(s):  
Miguel Cabrita ◽  
Gerhard Christofori
Keyword(s):  
Growth Factor ◽  
Mapk Pathway ◽  
Medical Science ◽  
Receptor Activation ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Dual Function ◽  
Vegf Receptor ◽  
Mapk Activation ◽  
Binding Partners

SummaryAmong many signaling pathways, receptor tyrosine kinases (RTKs) can activate the mitogen-activated protein kinase (MAPK) signaling pathway that subsequently leads to a variety of cellular changes, including proliferation, differentiation and motility. The regulation of growth factor signaling is complex, and various cell types respond differently to the same stimulus for reasons not entirely understood. The recent discovery in Drosophila of Sprouty (dSpry), an inhibitor of RTK-induced MAPK activation, provides clues to how these signals are regulated. In mammals, four orthologues of dSpry, Spry1-4, have been described, and in this review we discuss their functional characteristics. Mammalian Sprys, like dSpry, are ligand-induced feedback inhibitors of a number of growth factor receptors. In endothelial cells, upon fibroblast growth factor (FGF) receptor and vascular endothelial growth factor (VEGF) receptor activation, Sprys translocate to the plasma membrane and inhibit cell growth and proliferation. However, in epidermal growth factor (EGF)-stimulated cells, Sprys can enhance MAPK activation. In addition, Sprys have many binding partners, including different effectors of the MAPK activation pathway. The intersection point where Sprys interfere in the MAPK pathway as well as their interactions with other proteins may partly explain the dual, yet opposing roles, on growth factor-induced MAPK activation. Moreover, Sprys require tyrosine phosphorylation to interact with their binding partners, a prerequisite for their dual function. Hence, Sprys add another layer of complexity to the regulation of RTK-mediated signal transduction that begins to explain the variation in cellular responses to growth factors.This publication was partially financed by Serono Foundation for the Advancement of Medical Science.Part of this paper was originally presented at the 2nd International Workshop on New Therapeutic Targets in Vascular Biology from February 6-9, 2003 in Geneva, Switzerland.

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