scholarly journals Natural polyamines stimulate G-proteins

1992 ◽  
Vol 282 (2) ◽  
pp. 545-550 ◽  
Author(s):  
J L Bueb ◽  
A Da Silva ◽  
M Mousli ◽  
Y Landry
Keyword(s):  
Mast Cells ◽  
Pertussis Toxin ◽  
Inositol Phosphates ◽  
Second Messengers ◽  
G Protein Coupled Receptors ◽  
Extracellular Signals ◽  
Physiological Relevance ◽  
G Protein Coupled ◽  
Stimulation Of ◽  
Rat Mast Cells

The natural polyamines spermine and spermidine, the biosynthetic precursor putrescine and their analogues cadaverine and tyramine stimulate the GTPase activity of purified GTP-binding proteins (Go/Gi) from calf brain reconstituted into phospholipid vesicles. The order of potency was spermine greater than spermidine greater than putrescine = cadaverine greater than tyramine. The physiological relevance of this observation was assessed, showing the same order of potency of polyamines in the stimulation of peritoneal and tracheal rat mast cells. The activation of rat mast cells by polyamines was inhibited by benzalkonium chloride or by a 2 h pretreatment of the cells with pertussis toxin. The increase in inositol phosphates evoked by polyamines was also inhibited by pertussis toxin. Therefore we propose that intracellular polyamines might control the basal level of second messengers and modulate extracellular signals transduced through G-protein-coupled receptors.

scholarly journals Heterodimerization Between the Lutropin and Follitropin Receptors is Associated With an Attenuation of Hormone-Dependent Signaling

Endocrinology ◽  
2013 ◽  
Vol 154 (10) ◽  
pp. 3925-3930 ◽  
Author(s):  
Xiuyan Feng ◽  
Meilin Zhang ◽  
Rongbin Guan ◽  
Deborah L. Segaloff
Keyword(s):  
Protein Interactions ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
G Protein Coupled Receptors ◽  
Fsh Receptor ◽  
Bioluminescence Resonance Energy Transfer ◽  
Protein Protein Interactions ◽  
Lh Receptor ◽  
G Protein Coupled ◽  
Stimulation Of

The LH receptor (LHR) and FSH receptor (FSHR) are each G protein-coupled receptors that play critical roles in reproductive endocrinology. Each of these receptors has previously been shown to self-associate into homodimers and oligomers shortly after their biosynthesis. As shown herein using bioluminescence resonance energy transfer to detect protein-protein interactions, our data show that the LHR and FSHR, when coexpressed in the same cells, specifically heterodimerize with each other. Further experiments confirm that at least a portion of the cellular LHR/FSHR heterodimers are present on the cell surface and are functional. We then sought to ascertain what effects, if any, heterodimerization between the LHR and FSHR might have on signaling. It was observed that when the LHR was expressed under conditions promoting the heterodimerization with FSHR, LH or human chorionic gonadotropin (hCG) stimulation of Gs was attenuated. Conversely, when the FSHR was expressed under conditions promoting heterodimerization with the LHR, FSH-stimulated Gs activation was attenuated. These results demonstrate that the coexpression of the LHR and FSHR enables heterodimerizaton between the 2 gonadotropin receptors and results in an attenuation of signaling through each receptor.

scholarly journals Rescue of defective G protein–coupled receptor function in vivo by intermolecular cooperation

2010 ◽  
Vol 107 (5) ◽  
pp. 2319-2324 ◽  
Author(s):  
Adolfo Rivero-Müller ◽  
Yen-Yin Chou ◽  
Inhae Ji ◽  
Svetlana Lajic ◽  
Aylin C. Hanyaloglu ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Luteinizing Hormone Receptor ◽  
Wild Type ◽  
Gpcr Signaling ◽  
Physiological Relevance ◽  
Biosynthesis Activation ◽  
Mutant Receptors ◽  
G Protein Coupled

G protein–coupled receptors (GPCRs) are ubiquitous mediators of signaling of hormones, neurotransmitters, and sensing. The old dogma is that a one ligand/one receptor complex constitutes the functional unit of GPCR signaling. However, there is mounting evidence that some GPCRs form dimers or oligomers during their biosynthesis, activation, inactivation, and/or internalization. This evidence has been obtained exclusively from cell culture experiments, and proof for the physiological significance of GPCR di/oligomerization in vivo is still missing. Using the mouse luteinizing hormone receptor (LHR) as a model GPCR, we demonstrate that transgenic mice coexpressing binding-deficient and signaling-deficient forms of LHR can reestablish normal LH actions through intermolecular functional complementation of the mutant receptors in the absence of functional wild-type receptors. These results provide compelling in vivo evidence for the physiological relevance of intermolecular cooperation in GPCR signaling.

Adrenergic stimulation of inositol phosphate accumulation in tracheal epithelium

1989 ◽  
Vol 66 (1) ◽  
pp. 504-508 ◽  
Author(s):  
T. Bainbridge ◽  
R. D. Feldman ◽  
M. J. Welsh
Keyword(s):  
Adrenergic Receptor ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Second Messengers ◽  
Receptor Activation ◽  
Adrenergic Stimulation ◽  
Cl Secretion ◽  
Phosphate Accumulation ◽  
Inositol Phosphate Accumulation ◽  
Stimulation Of

To determine whether inositol phosphates are important second messengers in the regulation of Cl- secretion by airway epithelia, we examined the relationship between inositol phosphate accumulation and Cl- secretion in response to adrenergic agonists. We found that epinephrine stimulated Cl- secretion and inositol phosphate accumulation with similar concentration dependence. Although isoproterenol stimulated Cl- secretion, there was no effect of beta-adrenergic receptor activation on inositol phosphate accumulation. In contrast, alpha 1-adrenergic receptor activation stimulated inositol phosphate accumulation but failed to induce Cl- secretion. Another Cl- secretagogue, prostaglandin E1, also failed to stimulate inositol phosphate accumulation. These data suggest that inositol phosphate accumulation is neither sufficient nor required for stimulation of Cl- secretion in cultured canine tracheal epithelial cells.

scholarly journals Effects of pertussis toxin on growth factor-stimulated inositol phosphate formation and DNA synthesis in Swiss 3T3 cells

1988 ◽  
Vol 249 (3) ◽  
pp. 917-920 ◽  
Author(s):  
C W Taylor ◽  
D M Blakeley ◽  
A N Corps ◽  
M J Berridge ◽  
K D Brown
Keyword(s):  
Growth Factor ◽  
Dna Synthesis ◽  
Pertussis Toxin ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Phosphoinositide Hydrolysis ◽  
Polypeptide Growth Factors ◽  
Swiss 3T3 ◽  
Swiss 3T3 Cell ◽  
Stimulation Of

We have compared the effects of pretreatment of Swiss 3T3 cell with pertussis toxin on the stimulation of DNA synthesis and phosphoinositide hydrolysis in response to a wide variety of mitogens. The toxin substantially inhibited the stimulation of DNA synthesis in response to a phorbol ester or various peptide and polypeptide growth factors irrespective of their ability to activate phosphoinositidase C. Production of inositol phosphates in response to platelet-derived growth factor, fibroblast growth factor and prostaglandin F2 alpha were unaffected by the toxin while bombesin- and vasopressin-stimulated formation of inositol phosphates were inhibited by only 27 and 23% respectively. These results argue against a major role for a pertussis toxin-sensitive G protein in coupling any of these mitogen receptors to activation of a phosphoinositidase C. Furthermore, the results suggest that the widespread inhibitory effects of pertussis toxin on mitogen-stimulated DNA synthesis may be unrelated to the toxin's limited actions on phosphoinositide hydrolysis.

Cholinergic stimulation of phosphoinositide metabolism in isolated rat glomeruli

1992 ◽  
Vol 262 (2) ◽  
pp. F256-F266 ◽  
Author(s):  
P. Meneton ◽  
M. Bloch-Faure ◽  
G. Guillon ◽  
D. Chabardes ◽  
F. Morel ◽  
...  
Keyword(s):  
Pertussis Toxin ◽  
Maximum Dose ◽  
Inositol Phosphates ◽  
Effective Concentration ◽  
Phosphoinositide Metabolism ◽  
Cholinergic Stimulation ◽  
Cellular Mechanisms ◽  
Isolated Rat ◽  
Cholinergic Effects ◽  
Stimulation Of

Cholinergic effects on kidney function have been observed in some mammals but the intrarenal localization and the cellular mechanisms of these effects are poorly defined to date. The aim of this work was to study the effects of carbachol on phosphoinositide metabolism in freshly isolated rat glomeruli labeled with myo-[3H]inositol. Carbachol rapidly and markedly stimulates phosphoinositide metabolism with a 50% effective concentration of 3 microM. The enormous magnitude of the response is enlightened by the use of 10 mM lithium, which provokes in the presence of the agonist a large accumulation of inositol phosphates and a corresponding depletion of cellular free inositol. The response is inhibited by 85% by pirenzepine, is pertussis toxin insensitive, and shows no desensitization at maximum dose of carbachol up to 40 min of stimulation.

scholarly journals The metalloprotease Kuzbanian (ADAM10) mediates the transactivation of EGF receptor by G protein–coupled receptors

2002 ◽  
Vol 158 (2) ◽  
pp. 221-226 ◽  
Author(s):  
Yibing Yan ◽  
Kyoko Shirakabe ◽  
Zena Werb
Keyword(s):  
Signaling Pathways ◽  
G Protein ◽  
Egf Receptor ◽  
Critical Role ◽  
G Protein Coupled Receptors ◽  
Heparin Binding ◽  
Egf Receptors ◽  
Gpcr Activation ◽  
G Protein Coupled ◽  
Stimulation Of

Communication between different signaling pathways enables cells to coordinate the responses to diverse environmental signals. Activation of the transmembrane growth factor precursors plays a critical role in this communication and often involves metalloprotease-mediated proteolysis. Stimulation of G protein–coupled receptors (GPCR) transactivates the EGF receptors (EGFRs), which occurs via a metalloprotease-dependent cleavage of heparin-binding EGF (HB-EGF). However, the metalloprotease mediating the transactivation remains elusive. We show that the integral membrane metalloprotease Kuzbanian (KUZ; ADAM10), which controls Notch signaling in Drosophila, stimulates GPCR transactivation of EGFR. Upon stimulation of the bombesin receptors, KUZ increases the docking and activation of adaptors Src homology 2 domain–containing protein and Gab1 on the EGFR, and activation of Ras and Erk. In contrast, transfection of a protease domain–deleted KUZ, or blocking endogenous KUZ by morpholino antisense oligonucleotides, suppresses the transactivation. The effect of KUZ on shedding of HB-EGF and consequent transactivation of the EGFR depends on its metalloprotease activity. GPCR activation enhances the association of KUZ and its substrate HB-EGF with tetraspanin CD9. Thus, KUZ regulates the relay between the GPCR and EGFR signaling pathways.

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