ATP- and EGF-stimulated phosphatidylinositol synthesis by two different pathways, phospholipase D and diacylglycerol kinase, in A-431 epidermoid carcinoma cells

1996 ◽  
Vol 74 (2) ◽  
pp. 197-209 ◽  
Author(s):  
Kazuo Hosoi ◽  
Yoshimi Shioda ◽  
Takao Ueha ◽  
Toshiko Atsumi ◽  
Kenji Sugita ◽  
...  
Keyword(s):  
Phosphatidic Acid ◽  
Purinergic Receptors ◽  
Calcium Ionophore ◽  
Butyl Alcohol ◽  
Carcinoma Cells ◽  
Epidermoid Carcinoma ◽  
Ionophore A23187 ◽  
Acetoxymethyl Ester ◽  
Calmodulin Antagonist ◽  
Stimulation Of

The [3H]inositol incorporation into the membrane fraction of A-431 human epidermoid carcinoma cells was markedly increased by stimulation of the cells with either epidermal growth factor (EGF), ATP, bradykinin, or a calcium ionophore A23187 in the presence of 1 mM extracellular calcium ions; most incorporated [3H]inositol was found to have accumulated as phosphatidylinositol (PI). The EGF- and ATP-stimulated PI synthesis was inhibited by two protein kinase C inhibitors, staurosporine and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7), and an intracellular calcium chelator, 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester (BAPTA/AM), but not by the calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7). Pretreatment of cells with pertussis toxin (IAP, islet-activating protein) inhibited the PI synthesis, [Ca2+]i elevation, and inositol trisphosphate (IP3) production by ATP, suggesting that the phospholipase C (PLC) system coupled with IAP-sensitive G protein is involved in the ATP-stimulated PI synthesis. On the other hand, the ATP stimulation increased the release of [3H]choline and [32P]phosphatidic acid (PA) from radiolabeled cells, and such release was not inhibited by IAP. In the presence of n-butyl alcohol, which prevents the production of PA by generation of phosphatidylbutanol, the ATP-stimulated PI synthesis was reduced. Because n-butyl alcohol did not inhibit IP3 production and [Ca2+]i elevation, this fact suggests that the IAP-insensitive PLD system is involved in the ATP-stimulated PI synthesis. In A-431 cells, the stimulation of P2-purinergic receptors appears to activate the IAP-sensitive PLC system and IAP-insensitive PLD system, both of which are essential for the stimulation of PI synthesis. The present results imply the general prospect that ligand stimulation, which mobilizes second messengers and consumes their precursors, simultaneously provokes the pathway to synthesize and salvage the second messenger precursors as well.Key words: P2-purinergic receptors, phosphatidylinositol, EGF receptors, phosphatidic acid, A-431 cells.

scholarly journals Stimulation of CEACAM1 expression by 12- O -tetradecanoylphorbol-13-acetate (TPA) and calcium ionophore A23187 in endometrial carcinoma cells

2005 ◽  
Vol 27 (3) ◽  
pp. 483-490 ◽  
Author(s):  
Ana-Maria Bamberger ◽  
Juliane Briese ◽  
Julica Götze ◽  
Insa Erdmann ◽  
Heinrich M. Schulte ◽  
...  
Keyword(s):  
Endometrial Carcinoma ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Carcinoma Cells ◽  
Ionophore A23187 ◽  
Stimulation Of

Differential control of type-I iodothyronine deiodinase expression by the activation of the cyclic AMP and phosphoinositol signalling pathways in cultured human thyrocytes

1995 ◽  
Vol 14 (2) ◽  
pp. 171-177 ◽  
Author(s):  
S G Beech ◽  
S W Walker ◽  
J R Arthur ◽  
D Lee ◽  
G J Beckett
Keyword(s):  
Cyclic Amp ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Signalling Pathways ◽  
Cell Labelling ◽  
Ionophore A23187 ◽  
Type I ◽  
Iodothyronine Deiodinase ◽  
Differential Control ◽  
Stimulation Of

ABSTRACT The effects of TSH and the activation of the cyclic AMP (cAMP) and Ca2+-phosphatidylinositol (Ca2+-PI) cascades on the activity and expression of the selenoenzyme thyroidal type-I iodothyronine deiodinase (ID-I) have been studied using human thyrocytes grown in primary culture. Stimulation of ID-I activity and expression was obtained with TSH and an analogue of cAMP, 8-bromo-cAMP. In the presence or absence of TSH, the addition of the phorbol ester, phorbol 12-myristate 13-acetate (PMA) together with the calcium ionophore A23187, caused a decrease in ID-I activity; a decrease in ID-I expression was also observed as assessed by cell labelling with [75 Se]selenite. PMA alone had no effect on ID-I activity in the presence or absence of TSH. A23187 alone produced a small but significant reduction in ID-I activity, but only in TSH-stimulated cells. These data provide evidence that the expression of thyroidal ID-I is negatively regulated by the Ca2+-PI cascade, and positively regulated by the cAMP cascade.

Ca2+-dependent Activation of the 33-kDa Protein Kinase Transmits Thrombin Receptor Signals in Human Platelets

1996 ◽  
Vol 76 (03) ◽  
pp. 439-443 ◽  
Author(s):  
Masaru Ido ◽  
Shinya Kato ◽  
Hiroyuki Ogawa ◽  
Kenji Hayashi ◽  
Yoshihiro Komada ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Calcium Ionophore ◽  
Structural Analog ◽  
Human Platelets ◽  
Calcium Ionophore A23187 ◽  
Similar Degree ◽  
Ionophore A23187 ◽  
Dependent Manner ◽  
Serine Threonine Kinase ◽  
Acetoxymethyl Ester

SummaryThrombin stimulation induces a dramatic increase in the activity of the 33-kDa serine/threonine kinase (PK33) in human platelets (10). The Arg-Gly-Asp (RGD) peptide, an inhibitor of the thrombin-mediated aggregation of platelets, did not affect the PK33 activation induced by thrombin suggesting that the activation of this kinase occurs independently from platelet aggregation. To identify a potential role of Ca2+ and calmodulin in the regulation of PK33, the effect of several Ca2+/calmodulin inhibitors on the thrombin-induced activation of PK33 was assessed using denaturation/renaturation method. Pretreatment of platelets with EGTA decreased the maximum PK33 activity induced by thrombin. The chelation of both the extra- and the intracellular Ca2+ by EGTA and by acetoxymethyl ester of 5,5′ -dimethyl-bis-(<9-aminophen-oxy) ethane-N,N,N′,N′-tetraacetic acid (BAPTA-AM) decreased further the PK33 activation by thrombin. Preincubation of platelets with the anticalmodulin agent, N-(4-aminobutyl)-5-chloro-2-naphtha-lenesulfonamide (W13), inhibited markedly the activation of PK33 by thrombin, whereas the inactive structural analog N-(4-aminobutyl)-2-naphthalenesulfonamide (W12) and the myosin light chain kinase inhibitor 1 -(5-chloronaphthalene-1 -sulfonyl)-1 H-hexahydro-1,4-diaze-pine (ML9) showed very weak inhibitory effects. Treatment of resting platelets with the calcium ionophore, A23187, activated PK33 in a dose-dependent manner; phorbol 12-myristate 13-acetate enhanced this effect. However, the two foregoing agents did not induce similar degree of PK33 activities as thrombin. These results indicate that the activation of PK33 is independent of the formation of the GPIIb/IIIa-fibrinogen complex and that it might be regulated by a Ca2+-dependent pathway.

Oxygen Uptake of Rainbow Trout Oncorhynchus Mykiss Phagocytes Following Stimulation of the Respiratory Burst

1990 ◽  
Vol 154 (1) ◽  
pp. 339-353
Author(s):  
L. A. J. NAGELKERKE ◽  
M. C. PANNEVIS ◽  
D. F. HOULIHAN ◽  
C. J. SECOMBES
Keyword(s):  
Rainbow Trout ◽  
Oxygen Uptake ◽  
Respiratory Burst ◽  
Biological Significance ◽  
Calcium Ionophore ◽  
Head Kidney ◽  
Oxidase Inhibitor ◽  
Ionophore A23187 ◽  
Stimulation Of

The in vitro oxygen uptake of rainbow trout phagocyte-enriched head kidney leucocyte and head kidney macrophage suspensions was monitored. Stimulation of these cells with zymosan or phorbol myristate acetate induced a two-to 10-fold increase in oxygen uptake, the so-called respiratory burst. This respiratory burst activity was markedly enhanced in the presence of the calcium ionophore A23187 and inhibited in the presence of the NADPH oxidase inhibitor diphenyl iodonium or when glucose was absent from the buffer. The presence of sodium azide also inhibited the response of phagocyte-enriched suspensions by approximately 36 %, but only by 16 % for macrophage suspensions. The possible pathways responsible for the respiratory burst in fish phagocytes and its biological significance are discussed.

The role of calcium and calmodulin in mediating release of thyrotrophin-releasing hormone by cultured hypothalamic cells

1987 ◽  
Vol 115 (2) ◽  
pp. 255-262 ◽  
Author(s):  
M. D. Lewis ◽  
S. M. Foord ◽  
M. F. Scanlon
Keyword(s):  
Cell Cultures ◽  
Calcium Influx ◽  
Calcium Ionophore ◽  
Reversed Phase ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Calmodulin Antagonist ◽  
Thyrotrophin Releasing Hormone ◽  
Fetal Rat ◽  
Basal Release

ABSTRACT We have developed a fetal rat hypothalamic cell culture system for the study of factors controlling the acute release of TRH. Release of TRH by the cells has been characterized by reversed-phase high pressure liquid chromatography and about 86% of the total immunoreactivity in the medium co-eluted with synthetic TRH. Release of TRH by the cells in response to 56 mmol K+/l increased between days 5 and 9 of culture but reached a plateau thereafter. Cell contents of TRH did not change significantly between days 5 and 14 of culture. Release of TRH from the cells was stimulated by K+ (56 mmol/l), veratridine (100 μmol/l) and ouabain (100 μmol/l) to 550, 480 and 335% of basal release respectively over a 1-h period. Release of TRH was dependent upon calcium in that it was absent when calcium-free medium was used and could be blocked by verapamil (20 μmol/l); however it could not be blocked by nifedipine (50 μmol/l). The calcium ionophore A23187 (1 μmol/l) stimulated TRH release to 340% of basal release. Tetrodotoxin (1 μmol/l) completely abolished the release in response to veratridine but had no effect on the release stimulated by K+ (56 mmol/l). The calmodulin antagonists trifluoperazine and triflupromazine (50 μmol/l) inhibited veratridine-stimulated TRH release. This was at a site after calcium influx as they also inhibited A23187-stimulated TRH release. The highly specific calmodulin antagonist W7 (10 μmol/l) also inhibited both veratridine and A23187-stimulated TRH release whereas, at the same concentration, its inactive analogue W5 did not significantly inhibit TRH release in response to either stimulus. These results confirm that fetal rat hypothalamic cell cultures release authentic TRH which can be stimulated by a number of depolarizing agents. Calcium is essential for depolarization-induced release which is also dependent on calmodulin. Fetal rat hypothalamic cell cultures are a valid model for the study of factors controlling the release of TRH. J. Endocr. (1987) 115, 255–262

Cholinergic stimulation of ouabain-sensitive respiration in rat submandibular gland

1983 ◽  
Vol 245 (3) ◽  
pp. G364-G368 ◽  
Author(s):  
D. J. Stewart ◽  
D. J. Pon ◽  
A. K. Sen
Keyword(s):  
Oxygen Consumption ◽  
Submandibular Gland ◽  
Sodium Pump ◽  
Calcium Ionophore ◽  
Sodium Reabsorption ◽  
Tissue Respiration ◽  
Ionophore A23187 ◽  
Cholinergic Stimulation ◽  
Rat Submandibular Gland ◽  
Stimulation Of

Oxygen consumption of slices of rat submandibular gland was monitored with an oxygen electrode method. Carbachol stimulated an immediate increase in tissue respiration that was inhibitable by ouabain. The stimulation required the presence of calcium in the incubation medium and was blocked by atropine. The calcium ionophore A23187 also stimulated ouabain-sensitive oxygen consumption in the tissue slices. The results show that the mechanism using the extra energy during cholinergic stimulation is the sodium pump. Amiloride at a 1, 10, or 100 microM concentration had no effect on stimulation of ouabain-sensitive respiration by carbachol. Since amiloride, which is known to block the sodium reabsorption process in the ductal segment, has no effect on the stimulation, the increased sodium pump activity is probably located in the acinar region and is associated with the primary fluid secretion process.

scholarly journals Calcium ionophore A23187 as a regulator of gene expression in mammalian cells.

1986 ◽  
Vol 103 (6) ◽  
pp. 2145-2152 ◽  
Author(s):  
E Resendez ◽  
J Ting ◽  
K S Kim ◽  
S K Wooden ◽  
A S Lee
Keyword(s):  
Mammalian Cells ◽  
De Novo ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Similar Response ◽  
Calmodulin Antagonist ◽  
Induction Process ◽  
Continuous Presence ◽  
Lower Magnitude

The calcium ionophore A23187 can reversibly induce the expression of two glucose-regulated genes, p3C5 and p4A3. This induction requires a continuous presence of the ionophore for over 2 h. Although extracellular Ca2+ is important for the optimal effect of A23187, it is not necessary for the induction, since a similar response with a lower magnitude can be triggered in cells cultured in low Ca2+ medium buffered with EGTA. Both the basal and induced levels of p3C5 and p4A3 transcripts can be modulated by the calmodulin antagonist W-7, indicating the involvement of Ca2+/calmodulin-associated pathways. In addition, the sensitivity of the A23187 induction to cycloheximide suggests that the induction process is dependent on de novo protein synthesis.

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