Intracellular cross-talk between receptors coupled to phospholipase C via pertussis toxin sensitive and insensitive G-proteins

1993 ◽  
Vol 21 (3) ◽  
pp. 296S-296S
Author(s):  
JOHN M. DICKENSON ◽  
STEPHEN J. HILL
Keyword(s):  
Phospholipase C ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Cross Talk

scholarly journals Enkephalin activates the phospholipase C/Ca2+ system through cross-talk between opioid receptors and P2-purinergic or bradykinin receptors in NG 108–15 cells. A permissive role for pertussis toxin-sensitive G-proteins

1993 ◽  
Vol 290 (1) ◽  
pp. 241-247 ◽  
Author(s):  
F Okajima ◽  
H Tomura ◽  
Y Kondo
Keyword(s):  
Phospholipase C ◽  
G Proteins ◽  
Opioid Receptors ◽  
Pertussis Toxin ◽  
Cross Talk ◽  
Adenine Nucleotides ◽  
Single Cells ◽  
Hybrid Cell ◽  
Extracellular Atp ◽  
Permissive Role

In an NG 108-15 neuroblastoma x glioma hybrid cell suspension, extracellular ATP (via P2-purinergic receptors) and bradykinin stimulated Ins(1,4,5)P3 formation, which was accompanied by an increase in the cytosolic Ca2+ concentration ([Ca2+]i). Leucine enkephalin (EK) also slightly increased [Ca2+]i in the absence, but not in the presence, of apyrase, which hydrolyses extracellular ATP and ADP to AMP. When the cells were stimulated by P2-agonists or bradykinin prior to the application of EK, EK induces a remarkable rise in [Ca2+]i. This P2-agonist- or bradykinin-assisted EK action was also observed in single cells on a coverslip. A decrease in the extracellular Ca2+ concentration only slightly lowered the EK-induced rise in [Ca2+]i, but treatment of the cells with thapsigargin, an agent which depletes Ca2+ in the Ins(1,4,5)P3-sensitive pool, almost completely abolished EK action. The observed permissive stimulation by EK of Ins(1,4,5)P3 formation induced by a P2-agonist or bradykinin may be a primary event for the EK-induced [Ca2+]i rise. These actions of EK were antagonized by naloxone and completely reversed by prior treatment of the cells with pertussis toxin, whereas the toxin hardly affected the actions of P2-agonists and bradykinin themselves. Thus EK can induce phospholipase C activation and subsequent Ca2+ mobilization, provided that the cells have been previously or are simultaneously stimulated by endogenous adenine nucleotides or by externally applied P2-agonists or bradykinin. In this cross-talk mechanism between opioid receptors and these Ca(2+)-mobilizing agonist receptors, pertussis toxin-sensitive G-proteins play a permissive role.

Dual Regulation of Phospolipase C Activity by G Proteins

Physiology ◽  
1993 ◽  
Vol 8 (2) ◽  
pp. 61-63
Author(s):  
H Deckmyn ◽  
C Van Geet ◽  
J Vermylen
Keyword(s):  
Adenylate Cyclase ◽  
Phospholipase C ◽  
G Protein ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Inhibitory Pathway ◽  
Close Parallelism

Some subtypes of phosphatidylinositide-specific phospholipase C (PLC) are activated via pertussis toxin-sensitive or -insensitive G proteins. However, a G protein-dependent PLC inhibitory pathway also may exist. The resultant picture is of dual regulation of PLC, showing a close parallelism with the dual regulation of adenylate cyclase.

Modulation of phospholipase C pathway and level of Gq alpha/G11 alpha in rat myometrium during gestation

1996 ◽  
Vol 271 (3) ◽  
pp. C895-C904 ◽  
Author(s):  
S. Lajat ◽  
Z. Tanfin ◽  
G. Guillon ◽  
S. Harbon
Keyword(s):  
Phospholipase C ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Inositol Phosphates ◽  
Receptor Activation ◽  
Similar Increase ◽  
Inositol 1,4,5 Trisphosphate ◽  
M3 Subtype ◽  
Subtype A ◽  
Stimulation Of

The regulation of the receptor-G protein-phospholipase C (PLC) cascade was investigated in rat myometrium at midgestation (day 12) and at term (day 21) comparatively to the estrogen-treated tissue (day 0). Carbachol-mediated generation of [3H]inositol phosphates was insensitive to pertussis toxin and was enhanced at days 12 and 21 two- and threefold, respectively, with no alteration of muscarinic sites (M3 subtype). A similar increase could be detected in the production of inositol 1,4,5-trisphosphate, indicating the stimulation of a PLC degrading phosphatidylinositol 4,5-bisphosphate. AlF4- also enhanced PLC activation during gestation, suggesting pregnancy-related regulations that bypass receptor activation. Immunoreactive G proteins, Gq alpha and G11 alpha, and PLC-beta 3 were detected in all myometrial preparations. The amount of PLC-beta 3 was similar in day 0 and day 21 myometrium, although decreasing by 75% at midgestation. Of significance was the increased amount of Gq alpha in day 12 and day 21 myometrium (3- and 2-fold, respectively) which coincided with the enhanced phosphoinositide breakdown. The upregulation of Gq alpha may contribute to the enhanced PLC activity during pregnancy and at term.

scholarly journals Development of muscarinic-cholinergic stimulation of inositol phosphate production in cultured embryonic chick atrial cells. Evidence for a switch in guanine-nucleotide-binding protein coupling

1990 ◽  
Vol 271 (2) ◽  
pp. 443-448 ◽  
Author(s):  
J V Barnett ◽  
S M Shamah ◽  
B Lassegue ◽  
K K Griendling ◽  
J B Galper
Keyword(s):  
Phospholipase C ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Inositol Phosphate ◽  
In Ovo ◽  
Atrial Cells ◽  
Muscarinic Stimulation ◽  
Inositol Phosphate Production ◽  
Guanine Nucleotide Binding ◽  
Stimulation Of

We have demonstrated that muscarinic stimulation of inositol phosphate production in cultured atrial cells from chicks at 14 days in ovo is partially sensitive to inhibition by pertussis toxin. In these cells, muscarinic agonist binding is coupled to phospholipase C activity via at least two guanine-nucleotide-binding proteins (G-proteins), one sensitive to pertussis toxin and the other (Gp) insensitive to pertussis toxin [Barnett, Shamah, Lassegue, Griendling & Galper (1990) Biochem. J. 271, 437-442]. In the current study we demonstrate that during embryonic development of the chick heart, muscarinic stimulation of inositol phosphate production decreases by 50% between days 5 and 14 in ovo in cells cultured from both atrium and ventricle. In atrial cells, however, pertussis toxin-sensitive muscarinic stimulation of inositol phosphate production increased from undetectable levels at day 5 in ovo to 40% of total stimulation at day 12 in ovo. Muscarinic stimulation of inositol phosphate production in the ventricle did not become sensitive to pertussis toxin at any age studied. In permeabilized atrial cells from embryonic chicks at 5 days in ovo, guanosine 5′-[gamma-thio]triphosphate (GTP[S]) stimulated InsP1 levels by 40 +/- 10% (mean +/- S.E.M., n = 3), InsP2 levels by 117 +/- 18% and InsP3 levels by 51 +/- 8%, suggesting that at day 5 in ovo all of the muscarinic-stimulated inositol phosphate production was coupled to phospholipase C via Gp. H.p.l.c. analysis demonstrated that, in spite of these changes in coupling of phospholipase C to different G-proteins, no changes could be demonstrated in the isomers of InsP3 produced in response to carbamylcholine at both days 5 and 14 in ovo. These data demonstrate that embryonic development of the chick atrium is associated with a switch in coupling of muscarinic receptors to phospholipase C from Gp to a pertussis toxin substrate. This developmental switch in coupling of G-proteins may be related to possible developmental switches in levels of muscarinic receptor isoforms or switches in the subtype of phospholipase C.

scholarly journals Phospholipase C-β1 is regulated by a pertussis toxin-insensitive G-protein

1991 ◽  
Vol 280 (3) ◽  
pp. 753-760 ◽  
Author(s):  
T F J Martin ◽  
J E Lewis ◽  
J A Kowalchyk
Keyword(s):  
Phospholipase C ◽  
G Protein ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Gh3 Cells ◽  
Phospholipid Vesicles ◽  
Protein Tyrosine Phosphorylation ◽  
Gtp Binding ◽  
Gamma Subunits ◽  
Gh3 Cell

Regulation of phospholipase C (PLC) by receptors is mediated either through protein tyrosine phosphorylation or by activation of GTP-binding proteins (Gp). For the latter, pertussis toxin (PT)-sensitive and -insensitive pathways have been described, indicating PLC regulation by at least two types of G-proteins. The identity of PLC isoenzymes which are regulated by either type of Gp remains to be determined. Thyrotropin-releasing hormone stimulates a PLC in GH3 cells via a PT-insensitive Gp. Reconstitution methods for the assay of the GH3-cell Gp were developed. Previously, the membrane PLC was found to be reversibly extracted from membranes by high salt and to be activated by guanosine 5′-[gamma-thio]triphosphate (GTP[S]) only when membrane-associated, suggesting that Gp was retained in salt-extracted membranes. In the present work, Gp was cholate-solubilized from PLC-deficient membranes and incorporated into phospholipid vesicles, which were found to confer GTP[S]- and AlF4(-)-stimulated activity on a solubilized membrane PLC. The reconstitution provided a direct assay for the GH3-cell Gp which was shown to be distinct from Gi, Go and Gs proteins by immunodepletion studies. Incorporation of G-protein beta-gamma subunits into phospholipid vesicles with Gp inhibited GTP[S]-stimulated activity in the reconstitution. The results indicated that Gp is a heterotrimeric G-protein with the properties expected for the PT-insensitive GH3-cell Gp protein. PLC-beta 1 was fully purified and shown to be regulated by Gp in the reconstitution. In contrast, PT-sensitive G-proteins failed to affect the activity of PLC-beta 1. The results indicate (1) that a PT-insensitive Gp regulates PLC-beta 1 and (2) that PT-sensitive and -insensitive pathways of PLC regulation employ different PLC isoenzymes as well as different G-proteins.

scholarly journals Interferon-γ-stimulated and GTP-binding-proteins-mediated phospholipase A2 activation in human neuroblasts

1993 ◽  
Vol 294 (3) ◽  
pp. 893-898 ◽  
Author(s):  
M Ponzoni ◽  
P Cornaglia-Ferraris
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Ifn Gamma ◽  
Permeabilized Cells ◽  
Kinase C ◽  
Gtp Binding

Interferon-gamma (IFN-gamma) is a potent growth-inhibitory cytokine also endowed with differentiating activity on neural cells. Binding of IFN-gamma to its high-affinity receptor induces a rapid and transient activation of phospholipase A2 (PLA2). The mechanism coupling the IFN-gamma receptor (IFN-gamma-R) to PLA2 activation is not clearly defined, and no information is available on this mechanism in neuroblast cells. We have tested the hypothesis that GTP-binding proteins (G-proteins) may couple the IFN-gamma-R to PLA2 in the human neuroblastoma (NB) cell line LAN-5. Incubation of NB cells with IFN-gamma resulted in a rapid increase in [3H]arachidonic acid (AA) release, and this effect was blocked by pretreatment with anti-IFN-gamma antibodies. IFN-gamma-stimulated AA release was still observed in permeabilized cells that were blocked by pretreatment with anti-IFN-gamma-R antibodies. Exposure of permeabilized LAN-5 cells to guanosine 5′-[gamma-thio]triphosphate (GTP[S]), a non-hydrolysable GTP analogue, induced a dose-dependent release of [3H]AA. A non-specific nucleotide effect was excluded, since similar stimulatory effects on AA mobilization were not observed by GTP, ATP, CTP, ADP and GDP. IFN-gamma-stimulated AA release was completely blocked by the guanine nucleotide analogue that inhibits G-protein function, guanosine 5′-[beta-thio]diphosphate (GDP[S]). A role for G-proteins in IFN-gamma-R coupling to PLA2 was further supported by the inhibition of IFN-gamma-induced [3H]AA release by treatment of permeabilized cells with pertussis toxin and with the antiserum against the common alpha-subunits of G-proteins. To determine a possible contribution to AA mobilization by the phospholipase C and diacyglycerol lipase pathway or by protein kinase C activation, the effects of neomycin, a phospholipase C inhibitor, and PMA (phorbol 12-myristate 13-acetate), a direct activator of protein kinase C, were investigated. Neither neomycin nor PMA affected either basal or IFN-gamma-stimulated AA release. Ca2+ concentration, which has been shown to regulate the activity of some PLA2s, does not appear to play an important role in the regulation of the IFN-gamma-stimulated PLA2 activity, since incubating permeabilized cells in different concentrations of Ca2+ induced AA release without affecting the IFN-gamma response. Altogether, these findings suggest the existence of IFN-gamma-R, which couples a Ca(2+)-independent PLA2 activation via pertussis-toxin-sensitive G-proteins.

scholarly journals βγ Subunits of Pertussis Toxin-sensitive G Proteins Mediate A1Adenosine Receptor Agonist-induced Activation of Phospholipase C in Collaboration with Thyrotropin

1997 ◽  
Vol 272 (37) ◽  
pp. 23130-23137 ◽  
Author(s):  
Hideaki Tomura ◽  
Hiroshi Itoh ◽  
Kimie Sho ◽  
Koichi Sato ◽  
Motoshi Nagao ◽  
...  
Keyword(s):  
Phospholipase C ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Receptor Agonist

TSH activates macrophage inflammation by G13 and G15-dependent pathways

Endocrinology ◽  
2021 ◽  
Author(s):  
Chongbo Yang ◽  
Zhao He ◽  
Qunye Zhang ◽  
Ming Lu ◽  
Jiajun Zhao ◽  
...  
Keyword(s):  
Phospholipase C ◽  
G Protein ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Rho Gtpases ◽  
Thyroid Stimulating Hormone ◽  
Tsh Receptor ◽  
Sirna Interference ◽  
Inflammatory Effect ◽  
Stimulating Hormone

Abstract Thyroid-stimulating hormone (TSH) treatment activates IκB/NFκB (p65) and ERK, P38 in macrophages, but how these pathways are activated, and how they contribute to the pro-inflammatory effect of TSH on macrophages remain unknown. TSH receptor (TSHR) is coupled to four subfamilies of G proteins (Gs, Gi/o, Gq/11 and G12/13) for its downstream signalling. This study investigated the G protein subtypes responsible for the pro-inflammatory effect of TSH on macrophages. qPCR showed that Gi2, Gi3, Gas, Gq, G11, G12, G13, G15 are abundantly expressed by macrophages. The contribution of different G-protein pathways to the pro-inflammatory effect was studied by the corresponding inhibitors or siRNA interference. While TSH-induced IκB phosphorylation was not inhibited by Gs inhibitor NF449, Gi inhibitor pertussis toxin, Gq or G11 siRNA, it was blocked by phospholipase C inhibitor U73122 or G15 siRNA interference. TSH-induced ERK and P38 phosphorylation was blocked by G13 but not G12 siRNA interference. Interfering either G13 or G15 was able to block the pro-inflammatory effect of TSH on macrophages. The present study demonstrate that TSH activates macrophage inflammation by G13/ERK-P38/Rho GTPases and G15/PLC/PKCs/IκB pathways.

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