scholarly journals Differences in the regulation of endothelin-1- and lysophosphatidic-acid-stimulated Ins(1,4,5)P3 formation in rat-1 fibroblasts

1991 ◽  
Vol 280 (3) ◽  
pp. 609-615 ◽  
Author(s):  
R Plevin ◽  
E E MacNulty ◽  
S Palmer ◽  
M J O Wakelam
Keyword(s):  
Phospholipase C ◽  
Lysophosphatidic Acid ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Regulatory Protein ◽  
Permeabilized Cells ◽  
Endothelin 1 ◽  
Kinase C ◽  
Guanine Nucleotide Binding ◽  
Dose Dependent

Endothelin-1 (ET-1)- and lysophosphatidic acid (LPA)-stimulated PtdIns(4,5)P2 hydrolysis has been studied in Rat-1 fibroblasts. Although both agonists caused the dose-dependent accumulation of inositol phosphates, a number of differences were observed. LPA induced a transient increase in Ins(1,4,5)P3 mass which returned to basal levels within 90 s, whereas the response to ET-1 did not desensitize, with levels remaining at 3-4 times basal values for up to 15 min. Stimulated decreases in mass levels of PtdIns(4,5)P2 mirrored Ins(1,4,5)P3 formation for both agonists. Experiments with electropermeabilized cells demonstrated that the effects of both agonists are stimulated by a phospholipase C controlled by a guanine-nucleotide-binding regulatory protein; however, there are differences in the nature of these interactions. The inositol phosphate response to ET-1 is poorly potentiated by guanosine 5′-[gamma-thio]triphosphate (GTP[S]) and markedly inhibited by guanosine 5′-[beta-thio]diphosphate (GDP[S]), whereas that to LPA is potentiated by GTP[S] but is relatively insensitive to GDP[S]. In addition, LPA decreased the lag time for the onset of GTP[S]-stimulated [3H]InsP3 accumulation, whereas ET-1 was without effect. Phorbol 12-myristate 13-acetate treatment of the cells inhibited LPA-stimulated, but not ET-1-stimulated, inositol phosphate formation in both intact and permeabilized cells, suggesting that the site of protein kinase C-mediated phosphorylation may be blocked in ET-1-stimulated Rat-1 cells. The results indicate that the receptor-G-protein-phospholipase C interaction for the two agonists may not conform to the same model.

scholarly journals Amplification of fluoroaluminate-stimulated inositol phosphate generation in a cell line overexpressing the p21N-ras gene

1989 ◽  
Vol 259 (3) ◽  
pp. 737-741 ◽  
Author(s):  
M J O Wakelam
Keyword(s):  
Cell Line ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Regulatory Protein ◽  
Cell Types ◽  
Ras Gene ◽  
Cyclic Amp Accumulation ◽  
A Cell ◽  
Guanine Nucleotide Binding ◽  
Nih 3T3

The stimulation of inositol phosphate generation in NIH-3T3 cells and a derived transformant overexpressing the p21N-ras gene (T15+ cells) was examined. Incubation with NaF in the presence of Al3+ leads to the generation of inositol phosphates in each cell type, though the response in the T15+ cells is significantly amplified. The effect of fluoroaluminate is dose- and time-dependent. No differences were observed in fluoroaluminate-stimulated cyclic AMP accumulation among the cell types. In another NIH-3T3-derived cell line that expresses the transforming lys61 mutant of N-ras, no amplification of fluoroaluminate-stimulated inositol phosphate generation is observed. These results provide support for the proposal that, in the T15 cell line, p21N-ras can act in a guanine nucleotide-binding regulatory protein (G-protein)-like manner.

Inositol phosphate production in response to [Arg8]vasopressin, endothelin 1, and prostaglandin F2α in rat aorta and mesenteric arteries

1992 ◽  
Vol 70 (10) ◽  
pp. 1408-1416 ◽  
Author(s):  
Angèle Parent ◽  
Paul V. Nguyen ◽  
Xiao Ping Yang ◽  
Ernesto L. Schiffrin
Keyword(s):  
Phospholipase C ◽  
Blood Vessels ◽  
Time Course ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Prostaglandin F2α ◽  
Rat Aorta ◽  
Mesenteric Arteries ◽  
Phosphoinositide Metabolism ◽  
Endothelin 1

Vascular tissues such as rat aorta and mesenteric arteries are extensively used experimentally for the study of cardiovascular diseases. To further our understanding of the signal transduction mechanisms involved in responses to several potent vasoconstrictors, such as [Arg8]vasopressin (AVP), endothelin 1 (ET-1), and prostaglandin F2α (PGF2α), we have investigated the time course for production of inositol monophosphate (InsP1), bisphosphate (InsP2), and trisphosphate (InsP3) in response to these agonists as well as their relative potency for phosphatidylinositol hydrolysis. Time-course studies of production of the different inositol phosphates in response to AVP and PGF2α showed an early increase after 15–30 s of stimulation. Thereafter InsP3 declined towards baseline, with a secondary increase towards steady state after 5–10 min. Rapid turnover of InsP3 was reflected by accumulation of InsP1 and InsP2 in the presence of LiCl (20 mM) to inhibit monophosphatases. After 15–30 min of stimulation, there was accumulation of the Ins(1,3,4)P3 isomer. All three agonists induced greater accumulation of InsP2 in mesenteric arteries than in thoracic aorta, suggesting that turnover of Ins(1,4,5)P3 may be faster in the former than in the latter. The accumulation of total inositol phosphates induced by maximum concentrations of ET-1 was greater than in response to AVP or PGF2α. Dose–response curves showed that the rank order of potency for stimulation of production of inositol phosphates was AVP > ET-1 > PGF2α, similar to the sensitivity of blood vessels to these agents. Comparison of responses to ET-1 and ET-3 showed that the receptors stimulated by endothelins were of the isopeptide selective ETA subtype. In conclusion, all three agonists (AVP, ET-1, PGF2α) stimulate phospholipase C activity in rat aorta and in mesenteric arteries, although with different potencies. This study demonstrates that intact blood vessels allow a detailed investigation of inositol phosphate responses to different agonists of interest in cardiovascular research.Key words: phosphoinositide metabolism, phospholipase C, inositol trisphosphate, vasoconstrictors, blood vessels.

Regulation of oxytocin secretion by the ovine corpus luteum: effect of activators of protein kinase C

1990 ◽  
Vol 124 (2) ◽  
pp. 225-232 ◽  
Author(s):  
J. J. Hirst ◽  
G. E. Rice ◽  
G. Jenkin ◽  
G. D. Thorburn
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Corpus Luteum ◽  
Phospholipase C ◽  
Tissue Slices ◽  
Kinase C ◽  
Luteal Tissue ◽  
Dose Dependent ◽  
Stimulation Of

ABSTRACT The effect of protein kinase C activation and dibutyryl cyclic AMP on oxytocin secretion by ovine luteal tissue slices was investigated. Several putative regulators of luteal oxytocin secretion were also examined. Oxytocin was secreted by luteal tissue slices at a basal rate of 234·4 ± 32·8 pmol/g per h (n = 24) during 60-min incubations.Activators of protein kinase C: phorbol 12,13-dibutyrate (n = 8), phorbol 12-myristate,13-acetate (n = 4) and 1,2-didecanoylglycerol (n = 5), caused a dose-dependent stimulation of oxytocin secretion in the presence of a calcium ionophore (A23187; 0·2 μmol/l). Phospholipase C (PLC; 50–250 units/l) also caused a dose-dependent stimulation of oxytocin secretion by luteal slices. Phospholipase C-stimulated oxytocin secretion was potentiated by the addition of an inhibitor of diacylglycerol kinase (R59 022; n = 4). These data suggest that the activation of protein kinase C has a role in the stimulation of luteal oxytocin secretion. The results are also consistent with the involvement of protein kinase C in PLC-stimulated oxytocin secretion. The cyclic AMP second messenger system does not appear to be involved in the control of oxytocin secretion by the corpus luteum. Journal of Endocrinology (1990) 124, 225–232

Effect of glucocorticoid on prostaglandin F2α-induced prostaglandin E2 synthesis in osteoblast-like cells: inhibition of phosphoinositide hydrolysis by phospholipase C as well as phospholipase A2

1994 ◽  
Vol 131 (5) ◽  
pp. 510-515 ◽  
Author(s):  
Osamu Kozawa ◽  
Haruhiko Tokuda ◽  
Atsushi Suzuki ◽  
Jun Kotoyori ◽  
Yoshiaki Ito ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Phospholipase A ◽  
Phosphoinositide Hydrolysis ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Kinase C ◽  
Dose Dependent

Kozawa O, Tokuda H, Suzuki A, Kotoyori J, Ito Y, Oiso Y. Effect of glucocorticoid on prostaglandin F2α-induced prostaglandin E2 synthesis in osteoblast-like cells: inhibition of phosphoinositide hydrolysis by phospholipase C as well as phospholipase A2. Eur J Endocrinol 1994;131:510–15. ISSN 0804–4643 It is well known that osteoporosis is a common complication of patients with glucocorticoid excess. We showed previously that prostaglandin (PG) F2α stimulates the synthesis of PGE2, a potent bone resorbing agent, and that the activation of protein kinase C amplifies the PGF2α-induced PGE2 synthesis through the potentiation of phospholipase A2 activity in osteoblast-like MC3T3-E1 cells. In the present study, we examined the effect of dexamethasone on PGE2 synthesis induced by PGF2α in MC3T3-E1 cells. The pretreatment with dexamethasone significantly inhibited the PGE2 synthesis in a dose-dependent manner in the range between 0.1 and 10 nmol/l in these cells. This effect of dexamethasone was dependent on the time of pretreatment up to 8 h. Dexamethasone also inhibited PGE2 synthesis induced by melittin, known as a phospholipase A2 activator. Furthermore, dexamethasone significantly inhibited the enhancement of PGF2α- or melittin-induced PGE2 synthesis by 12-O-tetradecanoylphorbol-13-acetate, known as a protein kinase C activator. In addition, dexamethasone significantly inhibited PGF2α-induced formation of inositol phosphates in a dose-dependent manner between 0.1 and 10 nmol/l in MC3T3-E1 cells. These results strongly suggest that glucocorticoid inhibits PGF2α-induced PGE2 synthesis through the inhibition of phosphoinositide hydrolysis by phospholipase C as well as phospholipase A2 in osteoblast-like cells. Osamu Kozawa, Department of Biochemistry, Institute for Developmental Research, Aichi Prefectural Colony, Kasugai, Aichi 480-03, Japan

Carbachol-induced desensitization of PLC-β pathway in rat myometrium: downregulation of Gqα/G11α

1998 ◽  
Vol 275 (3) ◽  
pp. C636-C645 ◽  
Author(s):  
Sandrine Lajat ◽  
Simone Harbon ◽  
Zahra Tanfin
Keyword(s):  
Binding Sites ◽  
Prolonged Exposure ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Initial Period ◽  
Kinase C ◽  
Inositol Phosphate Production ◽  
Muscarinic Binding Sites ◽  
Heterologous Desensitization ◽  
Delayed Phase

In the estrogen-treated rat myometrium, carbachol increased the generation of inositol phosphates by stimulating the muscarinic receptor-Gq/G11-phospholipase C-β3 (PLC-β3) cascade. Exposure to carbachol resulted in a rapid and specific (homologous) attenuation of the subsequent muscarinic responses in terms of inositol phosphate production, PLC-β3 translocation to membrane, and contraction. Refractoriness was accompanied by a reduction of membrane muscarinic binding sites and an uncoupled state of residual receptors. Protein kinase C (PKC) altered the functionality of muscarinic receptors and contributed to the initial period of desensitization. A delayed phase of the muscarinic refractoriness was PKC independent and was associated with a downregulation of Gqα/G11α. Atropine failed to induce desensitization as well as Gqα/G11α downregulation, indicating that both events involve active occupancy of the receptor. Prolonged exposure to A[Formula: see text] reduced subsequent A[Formula: see text] as well as carbachol-mediated inositol phosphate responses and similarly induced downregulation of Gqα/G11α. Data suggest that a decrease in the level of Gqα/G11α is subsequent to its activation and may account for heterologous desensitization.

Mechanisms of action of endothelin 1 in maturing rabbit airway smooth muscle

1991 ◽  
Vol 260 (6) ◽  
pp. L434-L443 ◽  
Author(s):  
M. M. Grunstein ◽  
S. M. Rosenberg ◽  
C. M. Schramm ◽  
N. A. Pawlowski
Keyword(s):  
Smooth Muscle ◽  
Mechanisms Of Action ◽  
Maximal Response ◽  
Endothelin 1 ◽  
Kinase C ◽  
Adult Tissues ◽  
Age Dependent ◽  
Dose Dependent ◽  
Higher Doses ◽  
Pkc Activation

Maturational differences in the effects and mechanisms of action of endothelin 1 (ET-1) on airway contractility were investigated in tracheal smooth muscle (TSM) segments isolated from 2-wk-old and adult rabbits. In TSM under passive tension, ET-1 elicited dose-dependent contractions, with a potency of action that was significantly greater (P less than 0.001) in the 2-wk-old vs. adult tissues (i.e., mean +/- SE - log 50% of maximal response values: 8.59 +/- 0.17 vs. 7.79 +/- 0.15 - log M, respectively). In TSM half-maximally contracted with acetylcholine (ACh), however, ET-1 elicited dual and opposing dose-dependent effects. At lower doses (less than or equal to 10(-9) M), ET-1 induced TSM relaxation that was significantly greater in the adult vs. 2-wk-old TSM segments (i.e., approximately 100 vs. 26.5% decrease in active tension, respectively). The relaxant responses were associated with significantly enhanced (P less than 0.001) ET-1-induced release of prostaglandins E2 and I2 in the adult tissues. At higher doses (greater than 10(-9) M), ET-1 induced TSM contractions that were 1) attenuated to a relatively greater extent by the Ca2+ channel blocker, nifedipine (10(-5) M) in the 2-wk-old tissues and 2) associated with significantly (P less than 0.001) enhanced ET-1-stimulated accumulation of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in the immature TSM. Moreover, the TSM contractions were inhibited by the protein kinase C (PKC) antagonist, H-7, and the latter effect was more potent in the immature TSM. Collectively, these findings demonstrate that ET-1 exerts a potent duality of action in rabbit TSM which varies significantly with maturation, wherein 1) age-dependent differences in airway relaxation are associated with changes in the evoked release of bronchodilatory prostaglandins and 2) maturational differences in airway contraction are associated with changes in Ins(1,4,5)P3 accumulation and extracellular Ca2+ mobilization, coupled to differences in PKC activation.

scholarly journals G-proteins are not directly involved in the CD3-antigen-mediated production of inositol phosphates in HPB-ALL T-leukaemia cells expressing phospholipase C isoforms γ1 and β3

1993 ◽  
Vol 289 (2) ◽  
pp. 387-394 ◽  
Author(s):  
M Biffen ◽  
M Shiroo ◽  
D R Alexander
Keyword(s):  
Phospholipase C ◽  
Tyrosine Phosphorylation ◽  
G Protein ◽  
G Proteins ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Cross Linking ◽  
Protein Tyrosine Phosphorylation ◽  
Protein Tyrosine ◽  
Inositol Phosphate Production

The possible involvement of G-proteins in T cell antigen-receptor complex (TCR)-mediated inositol phosphate production was investigated in HPB-ALL T-cells, which were found to express the phospholipase C gamma 1 and beta 3 isoforms. Cross-linking the CD3 antigen on streptolysin-O-permeabilized cells stimulated a dose-dependent increase in inositol phosphate production, as did addition of guanosine 5′-[gamma-thio]triphosphate (GTP[S]) or vanadate, a phosphotyrosine phosphatase inhibitor. It was possible, therefore, that the CD3-antigen-mediated production of inositol phosphates was either via a G-protein-dependent mechanism or by stimulation of protein tyrosine phosphorylation. The CD3-induced inositol phosphate production was potentiated by addition of vanadate, but not by addition of GTP[S]. Guanosine 5′-[beta-thio]diphosphate (GDP[S]) inhibited the rise in inositol phosphates induced by GTP[S], vanadate or cross-linking the CD3 antigen. The increase in protein tyrosine phosphorylation stimulated by vanadate or the OKT3 monoclonal antibody was not observed in the presence of GDP[S], showing that in permeabilized HPB-ALL cells, GDP[S] inhibits the actions of tyrosine kinases as well as G-protein function. Addition of either ADP[S] or phenylarsine oxide inhibited CD3- and vanadate-mediated increases in both tyrosine phosphorylation and inositol phosphate production, but did not inhibit GTP[S]-stimulated inositol phosphate production. On the other hand, pretreatment of cells with phorbol 12,13-dibutyrate inhibited subsequent GTP[S]-stimulated inositol phosphate production but did not inhibit significantly inositol phosphate production stimulated by either OKT3 F(ab')2 fragments or vanadate. Our results are consistent with the CD3 antigen stimulating inositol phosphate production by increasing the level of protein tyrosine phosphorylation, but not by activating a G-protein.

Endothelin-1-Induced Phospholipase C-β and D and Protein Kinase C Isoenzyme Signaling Leading to Hypertrophy in Rat Cardiomyocytes

1995 ◽  
Vol 26 ◽  
pp. S100-103
Author(s):  
J. M. J. Lamers ◽  
Y. E. G. Eskildsen-Helmond ◽  
A. M. Resink ◽  
H. W. de Jonge ◽  
K. Bezstarosti ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase C ◽  
Rat Cardiomyocytes ◽  
Endothelin 1 ◽  
Kinase C

scholarly journals Relationships between the degree of cross-linking of surface immunoglobulin and the associated inositol 1,4,5-trisphosphate and Ca2+ signals in human B cells

1992 ◽  
Vol 284 (2) ◽  
pp. 447-455 ◽  
Author(s):  
F M McConnell ◽  
S B Shears ◽  
P J L Lane ◽  
M S Scheibel ◽  
E A Clark
Keyword(s):  
B Cells ◽  
Tyrosine Kinase ◽  
Phospholipase C ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Cross Linking ◽  
Immunoglobulin Receptor ◽  
Surface Immunoglobulin ◽  
Human B Cells ◽  
Inositol 1,4,5 Trisphosphate

Cross-linking of surface immunoglobulin (Ig) receptors on human B cells leads to the activation of a tyrosine kinase. The activated tyrosine kinase subsequently phosphorylates a number of substrates, including phospholipase C-gamma. This enzyme breaks down phosphoinositol bisphosphate to form two intracellular messengers, diacylglycerol and inositol 1,4,5-trisphosphate, leading to the activation of protein kinase C and the release of intracellular Ca2+ respectively. We have used h.p.l.c. and flow cytometry to measure accurately the inositol phosphate turnover and Ca2+ release in anti-Ig-stimulated human B cells. In particular, we have examined the effect of dose of the cross-linking antibody on the two responses. The identity of putative messenger inositol phosphates has been verified by structural analysis, and the amounts of both inositol phosphates and Ca2+ present have been quantified. In the Ramos Burkitt lymphoma, which is very sensitive to stimulus through its Ig receptors, both inositol phosphate production and Ca2+ release were found to be related to the dose of anti-Ig antibody applied. This suggests that phospholipase C-mediated signal transduction in human B cells converts the degree of cross-linking of the immunoglobulin receptor quantitatively into intracellular signals.

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