scholarly journals Rapid activation of sodium–proton exchange and extracellular signal-regulated protein kinase in fibroblasts by G protein-coupled 5-HT1A receptor involves distinct signalling cascades

1998 ◽  
Vol 330 (1) ◽  
pp. 489-495 ◽  
Author(s):  
N. Maria GARNOVSKAYA ◽  
Yurii MUKHIN ◽  
R. John RAYMOND
Keyword(s):  
Protein Kinase ◽  
G Protein ◽  
Tyrosine Kinases ◽  
Proton Exchange ◽  
Response Curves ◽  
Extracellular Signal ◽  
Sodium Proton Exchange ◽  
Time Courses ◽  
Rapid Activation ◽  
G Protein Coupled

These experiments tested the hypothesis that signalling elements involved in the activation of the extracellular signal-regulated protein kinase (ERK) mediate rapid activation of sodium-proton exchange (NHE) in fibroblasts when both signals are initiated by a single G protein-coupled receptor, the 5-HT1A receptor. Similarities between the two processes were comparable concentration-response curves and time-courses, and overlapping sensitivity to some pharmacological inhibitors of tyrosine kinases (staurosporine and genistein), and phosphoinositide 3ʹ-kinase (wortmannin and LY204002). Activation of NHE was much more sensitive to the phosphatidylcholine-specific phospholipase inhibitor (D609) than was ERK. Neither pathway was sensitive to manoeuvres designed to block PKC. In contrast, Src or related kinases appear to be required to activate ERK, but not NHE. Transfection of cDNA constructs encoding inactive mutant phosphoinositide 3ʹ-kinase, Grb2, Sos, Ras, and Raf molecules were successful in attenuating ERK, but had essentially no effect upon NHE activation. Finally, PD98059, an inhibitor of mitogen activated/extracellular signal regulated kinase kinase, blocked ERK but not NHE activation. Thus, in CHO fibroblast cells, activation by the 5-HT1A receptor of ERK and NHE share a number of overlapping features. However, our studies do not support a major role for ERK, when activated by the 5-HT1A receptor, as a short-term upstream regulator of NHE activity.

scholarly journals G Protein-Coupled Receptor-Mediated Mitogen-Activated Protein Kinase Activation through Cooperation of Gαq and Gαi Signals

2000 ◽  
Vol 20 (18) ◽  
pp. 6837-6848 ◽  
Author(s):  
Andree Blaukat ◽  
Ana Barac ◽  
Michael J. Cross ◽  
Stefan Offermanns ◽  
Ivan Dikic
Keyword(s):  
Protein Kinase ◽  
G Protein ◽  
Tyrosine Kinases ◽  
Synergistic Effects ◽  
Mitogen Activated Protein Kinase ◽  
General Mechanism ◽  
Mitogen Activated Protein ◽  
Novel Concept ◽  
G Protein Coupled ◽  
Stimulation Of

ABSTRACT G protein-coupled receptors (GPCRs) have been shown to stimulate extracellular regulated kinases (ERKs) through a number of linear pathways that are initiated by Gq/11 or Giproteins. We studied signaling to the ERK cascade by receptors that simultaneously activate both G protein subfamilies. In HEK293T cells, bradykinin B2 receptor (B2R)-induced stimulation of ERK2 and transcriptional activity of Elk1 are dependent on Gαq-mediated protein kinase C (PKC) and on Gαi-induced Ras activation, while they are independent of Gβγ subunits, phosphatidylinositol 3-kinase, and tyrosine kinases. Similar results were obtained with m1 and m3muscarinic receptors in HEK293T cells and with the B2R in human and mouse fibroblasts, indicating a general mechanism in signaling toward the ERK cascade. Furthermore, the bradykinin-induced activation of ERK is strongly reduced in Gαq/11-deficient fibroblasts. In addition, we found that constitutively active mutants of Gαq/11 or Gαi proteins alone poorly stimulate ERK2, whereas a combination of both led to synergistic effects. We conclude that dually coupled GPCRs require a cooperation of Gαi- and Gq/11-mediated pathways for efficient stimulation of the ERK cascade. Cooperative signaling by multiple G proteins thus might represent a novel concept implicated in the regulation of cellular responses by GPCRs.

scholarly journals Rho Family GTPases Are Required for Activation of Jak/STAT Signaling by G Protein-Coupled Receptors

2003 ◽  
Vol 23 (4) ◽  
pp. 1316-1333 ◽  
Author(s):  
Stéphane Pelletier ◽  
François Duhamel ◽  
Philippe Coulombe ◽  
Michel R. Popoff ◽  
Sylvain Meloche
Keyword(s):  
Tyrosine Phosphorylation ◽  
G Protein ◽  
Tyrosine Kinases ◽  
Rho Gtpases ◽  
G Protein Coupled Receptors ◽  
Dependent Manner ◽  
Signal Transducers ◽  
Regulatory Effects ◽  
Rapid Activation ◽  
G Protein Coupled

ABSTRACT As do cytokine receptors and receptor tyrosine kinases, G protein-coupled receptors (GPCRs) signal to Janus kinases (Jaks) and signal transducers and activators of transcription (STATs). However, the early biochemical events linking GPCRs to this signaling pathway have been unclear. Here we show that GPCR-stimulated Rac activity and the subsequent generation of reactive oxygen species are necessary for activating tyrosine phosphorylation of Jaks and STAT-dependent transcription. The requirement for Rac activity can be overcome by addition of hydrogen peroxide. Expression of activated mutants of Rac1 is sufficient to activate Jak2 and STAT-dependent transcription, and the activation of Jak2 correlates with the ability of Rac1 to bind to NADPH oxidase subunit p67phox. We further show that GPCR agonists stimulate tyrosine phosphorylation of STAT1 and STAT3 proteins in a Rac-dependent manner. The tyrosine phosphorylation of STAT3 is biphasic; the first peak of phosphorylation is weak and correlates with rapid activation of Jaks by GPCRs, whereas the second peak is stronger and requires the synthesis of an autocrine factor. Rho also plays an essential role in the induction of STAT transcriptional activity. Our results highlight a novel role for Rho GTPases in mediating the regulatory effects of GPCRs on STAT-dependent gene expression.

Src-family tyrosine kinases, phosphoinositide 3-kinase and Gab1 regulate extracellular signal-regulated kinase 1 activation induced by the type A endothelin-1 G-protein-coupled receptor

2001 ◽  
Vol 360 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Sandra BISOTTO ◽  
Elizabeth D. FIXMAN
Keyword(s):  
Tyrosine Phosphorylation ◽  
G Protein ◽  
Tyrosine Kinases ◽  
Type A ◽  
Extracellular Signal Regulated Kinase ◽  
Endothelin 1 ◽  
Extracellular Signal ◽  
Phosphoinositide 3 Kinase ◽  
Src Family Tyrosine Kinases ◽  
G Protein Coupled

The multisubstrate docking protein, growth-factor-receptor-bound protein 2-associated binder 1 (Gab1), which is phosphorylated on tyrosine residues following activation of receptor tyrosine kinases and cytokine receptors, regulates cell proliferation, survival and epithelial morphogenesis. Gab1 is also tyrosine phosphorylated following activation of G-protein-coupled receptors (GPCRs) where its function is poorly understood. To elucidate the role of Gab1 in GPCR signalling, we investigated the mechanism by which the type A endothelin-1 (ET-1) GPCR induced tyrosine phosphorylation of Gab1. Tyrosine phosphorylation of Gab1 induced by endothelin-1 was inhibited by PP1, a pharmacological inhibitor of Src-family tyrosine kinases. ET-1-induced Gab1 tyrosine phosphorylation was also inhibited by LY294002, which inhibits phosphoinositide 3-kinase (PI 3-kinase) enzymes. Inhibition of Src-family tyrosine kinases or PI 3-kinase also inhibited ET-1-induced activation of the mitogen activated protein kinase family member, extracellular signal-regulated kinase (ERK) 1. Thus we determined whether Gab1 regulated ET-1-induced ERK1 activation. Overexpression of wild-type Gab1 potentiated ET-1-induced activation of ERK1. Structure–function analyses of Gab1 indicated that mutant forms of Gab1 that do not bind the Src homology (SH) 2 domains of the p85 adapter subunit of PI 3-kinase or the SH2-domain-containing protein tyrosine phosphatase 2 (SHP-2) were impaired in their ability to potentiate ET-1-induced ERK1 activation. Taken together, our data indicate that PI 3-kinase and Src-family tyrosine kinases regulate ET-1-induced Gab1 tyrosine phosphorylation, which, in turn, induces ERK1 activation via PI 3-kinase- and SHP-2-dependent pathways.

scholarly journals Protein Kinase A-mediated Phosphorylation of the Gα13Switch I Region Alters the Gαβγ13-G Protein-coupled Receptor Complex and Inhibits Rho Activation

2002 ◽  
Vol 278 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Jeanne M. Manganello ◽  
Jin-Sheng Huang ◽  
Tohru Kozasa ◽  
Tatyana A. Voyno-Yasenetskaya ◽  
Guy C. Le Breton
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
G Protein ◽  
Receptor Complex ◽  
G Protein Coupled Receptor ◽  
G Protein Coupled ◽  
Kinase A

G-protein-coupled-receptor activation of the smooth muscle calponin gene

2001 ◽  
Vol 357 (2) ◽  
pp. 587-592 ◽  
Author(s):  
Nickolai O. DULIN ◽  
Sergei N. ORLOV ◽  
Chad M. KITCHEN ◽  
Tatyana A. VOYNO-YASENETSKAYA ◽  
Joseph M. MIANO
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
G Protein ◽  
Transcriptional Activation ◽  
Fold Increase ◽  
Receptor Activation ◽  
G Protein Coupled Receptors ◽  
Mitogen Activated Protein Kinase ◽  
G Protein Coupled

A hallmark of cultured smooth muscle cells (SMCs) is the rapid down-regulation of several lineage-restricted genes that define their in vivo differentiated phenotype. Identifying factors that maintain an SMC differentiated phenotype has important implications in understanding the molecular underpinnings governing SMC differentiation and their subversion to an altered phenotype in various disease settings. Here, we show that several G-protein coupled receptors [α-thrombin, lysophosphatidic acid and angiotensin II (AII)] increase the expression of smooth muscle calponin (SM-Calp) in rat and human SMC. The increase in SM-Calp protein appears to be selective for G-protein-coupled receptors as epidermal growth factor was without effect. Studies using AII showed a 30-fold increase in SM-Calp protein, which was dose- and time-dependent and mediated by the angiotensin receptor-1 (AT1 receptor). The increase in SM-Calp protein with AII was attributable to transcriptional activation of SM-Calp based on increases in steady-state SM-Calp mRNA, increases in SM-Calp promoter activity and complete abrogation of protein induction with actinomycin D. To examine the potential role of extracellular signal-regulated kinase (Erk1/2), protein kinase B, p38 mitogen-activated protein kinase and protein kinase C in AII-induced SM-Calp, inhibitors to each of the signalling pathways were used. None of these signalling molecules appears to be crucial for AII-induced SM-Calp expression, although Erk1/2 may be partially involved. These results identify SM-Calp as a target of AII-mediated signalling, and suggest that the SMC response to AII may incorporate a novel activity of SM-Calp.

scholarly journals Modulation of human erg K+channel gating by activation of a G protein-coupled receptor and protein kinase C

1998 ◽  
Vol 511 (2) ◽  
pp. 333-346 ◽  
Author(s):  
Francisco Barros ◽  
David Gómez-Varela ◽  
Cristina G. Viloria ◽  
Teresa Palomero ◽  
Teresa Giráldez ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
G Protein ◽  
Channel Gating ◽  
K Channel ◽  
G Protein Coupled Receptor ◽  
Kinase C ◽  
G Protein Coupled

scholarly journals G-protein–coupled formyl peptide receptors play a dual role in neutrophil chemotaxis and bacterial phagocytosis

2019 ◽  
Vol 30 (3) ◽  
pp. 346-356 ◽  
Author(s):  
Xi Wen ◽  
Xuehua Xu ◽  
Wenxiang Sun ◽  
Keqiang Chen ◽  
Miao Pan ◽  
...  
Keyword(s):  
G Protein ◽  
Receptor Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Actin Polymerization ◽  
G Protein Coupled Receptors ◽  
Peptide Receptors ◽  
Tyrosine Kinase Signaling ◽  
Formyl Peptide Receptors ◽  
Formyl Peptide ◽  
G Protein Coupled

A dogma of innate immunity is that neutrophils use G-protein–coupled receptors (GPCRs) for chemoattractant to chase bacteria through chemotaxis and then use phagocytic receptors coupled with tyrosine kinases to destroy opsonized bacteria via phagocytosis. Our current work showed that G-protein–coupled formyl peptide receptors (FPRs) directly mediate neutrophil phagocytosis. Mouse neutrophils lacking formyl peptide receptors (Fpr1/2–/–) are defective in the phagocytosis of Escherichia coli and the chemoattractant N-formyl-Met-Leu-Phe (fMLP)-coated beads. fMLP immobilized onto the surface of a bead interacts with FPRs, which trigger a Ca2+response and induce actin polymerization to form a phagocytic cup for engulfment of the bead. This chemoattractant GPCR/Gi signaling works independently of phagocytic receptor/tyrosine kinase signaling to promote phagocytosis. Thus, in addition to phagocytic receptor-mediated phagocytosis, neutrophils also utilize the chemoattractant GPCR/Gi signaling to mediate phagocytosis to fight against invading bacteria.

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