Defining the role of protein kinase c in calcium-ionophore-(A23187)-mediated activation of phospholipase A2 in pulmonary endothelium

Abstract The addition of 1-oleoyl-2-acetylglycerol (OAG), or phorbol-12- myristate-13-acetate (PMA) to platelets induced the phosphorylation of a 47,000 dalton protein (47 Kd), fusion of granule membranes with membranes of the surface connected canalicular system, the formation of large vesicles and the secretion of serotonin. 1-(5- isoquinolinesulfonyl)-2-methyl-piperazine (H7), and sphingosine, inhibitors of protein kinase C, significantly inhibited the ultrastructural changes and the phosphorylation of 47 Kd. N-(2- guanidinoethyl)-5-isoquinolinesulfonamide (HA1004), structurally similar to H7, but a weaker inhibitor of protein kinase C, did not attenuate these responses to OAG or to PMA. H7, but not HA1004, also markedly inhibited secretion induced by the synergistic combination of OAG and the calcium ionophore A23187. Amiloride and 5-(N,N dimethyl)- amiloride, inhibitors of the Na+/H+ transporter, did not inhibit the ultrastructural response and the protein phosphorylation induced by OAG, or the secretion induced by the combination of A23187 and OAG. The results link the activation of protein kinase C by diglycerides to the labilization and fusion of granule membranes important for secretion.

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Protein kinase C activation and calcium mobilization decrease prolactin release from human decidual cells in early pregnancy

Journal of Endocrinology ◽

10.1677/joe.0.1370335 ◽

1993 ◽

Vol 137 (2) ◽

pp. 335-340 ◽

Cited By ~ 3

Author(s):

T. Kubota ◽

S. Kamada ◽

M. Taguchi ◽

S. Sakamoto ◽

T. Aso

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Early Pregnancy ◽

Calcium Ionophore ◽

Calcium Ionophore A23187 ◽

Calcium Mobilization ◽

Ionophore A23187 ◽

Prolactin Release ◽

Kinase C ◽

Decidual Cells

ABSTRACT The present study was undertaken to investigate the effects of protein kinase C (PKC) activation and calcium mobilization on the release of prolactin from human decidual cells in early pregnancy. Decidua obtained from patients in early pregnancy was enzymatically dispersed and cultured with phorbol myristate acetate (PMA) and calcium ionophore A23187 in a cell culture system. Prolactin in the medium was measured by enzyme-immunoassay. PMA, a PKC activator, dose-dependently attenuated the release of prolactin from cultured decidual cells, while a PKC inhibitor, H7, significantly (P < 0·001) diminished the effect of PMA on prolactin release. PMA had no effect on cell numbers or DNA synthesis in the decidual cells during culture. It did not significantly increase the generation of inositol phosphate in decidual cells prelabelled with myo[3H]inositol and it had no effect on intracellular calcium concentration ([Ca2 + ]i). Calcium ionophore A23187, a Ca2 +-mobilizing agent, also significantly (P<0·001) attenuated the release of prolactin and potentiated the PMA-induced suppression of prolactin release from decidual cells. These findings suggest that activation of PKC and mobilization of Ca2+ may be involved in regulating prolactin release from human decidual cells. The PMA-induced suppression of prolactin release is not triggered by phosphoinositide hydrolysis nor by the increase in [Ca2 + ]i in decidual cells. Journal of Endocrinology (1993) 137, 335–340

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Protein kinase C dependent and independent activation of phospholipase A2under calcium ionophore (A23187) exposure in rabbit pulmonary arterial smooth muscle cells

FEBS Letters ◽

10.1016/0014-5793(91)80735-l ◽

1991 ◽

Vol 285 (1) ◽

pp. 104-107 ◽

Cited By ~ 20

Author(s):

Sajal Chakraborti ◽

John R. Michael ◽

Samir K. Patra

Keyword(s):

Smooth Muscle ◽

Protein Kinase C ◽

Protein Kinase ◽

Calcium Ionophore ◽

Calcium Ionophore A23187 ◽

Ionophore A23187 ◽

Kinase C ◽

Pulmonary Arterial ◽

Arterial Smooth Muscle Cells ◽

Pulmonary Arterial Smooth Muscle

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Protein kinase C regulates proliferation of mast cells and the expression of the mRNAs of fos and jun proto-oncogenes during activation by IgE-Ag or calcium ionophore A23187

Blood ◽

10.1182/blood.v78.9.2354.bloodjournal7892354 ◽

1991 ◽

Vol 78 (9) ◽

pp. 2354-2364

Author(s):

D Baranes ◽

E Razin

Keyword(s):

Protein Kinase C ◽

Mast Cells ◽

Protein Kinase ◽

Calcium Ionophore ◽

Calcium Ionophore A23187 ◽

Prolonged Treatment ◽

Ionophore A23187 ◽

Short Term ◽

Kinase C ◽

Short Term Exposure

Short-term stimulation (up to 16 hours) of interleukin-3 (IL-3)- dependent mouse bone marrow-derived mast cells, Abelson transformed mouse liver-derived mast cells, or rat basophilic leukemia cells by either IgE-Ag or calcium ionophore A23187 resulted in inhibition of their proliferation as measured by 3H-thymidine incorporation and MTT (tetrazolium) assays, and in accumulation of the mRNAs of c-fos, c-jun, junB and slightly of junD proto-oncogenes. The involvement of protein kinase C (PKC) in these responses was investigated by using several approaches of enzyme activity regulation. Direct activation of the PKC was achieved by short-term exposure of the cells to the PKC-specific activator phorbol 12-myristate-13-acetate (PMA). Inhibition of PKC activity was obtained by either prolonged treatment of the cells with PMA or by exposure of the cells to the PKC inhibitors H-7 and staurosporine. The results showed the following: (1) Short-term exposure of mast cells to PMA was sufficient to induce inhibition of proliferation. (2) An increase in PKC activity was associated with a decrease in the proliferation of IgE-dinitrophenol (DNP) or calcium ionophore A23187-stimulated cells. (3) A direct correlation was found between the increase in PKC activity and the increase in the level of the mRNAs of the jun proto-oncogenes in cells activated by both stimuli mentioned. (4) While an increase in PKC activity was associated with the upregulation of the level of c-fos mRNA during calcium ionophore A23187 stimulation, it showed the opposite effect on the expression of the mRNA of this proto-oncogene when the cells were triggered by IgE- DNP. Therefore, we concluded that PKC plays various roles in the expression of the mRNA of c-fos in activated mast cells depending on the stimulus involved. In addition, the expression of the mRNA of c-jun and junB proto-onogenes is not coordinately regulated with that of c- fos during immunologic stimulation. This discordancy, which is associated with the increase in PKC activity in mast cells, may play a role in the regulation of the transcription of AP-1-responsive genes, and therefore could be associated with the regulation of proliferation of these cells.

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Diradylglycerols stimulate phospholipase A2 and subsequent exocytosis in ram spermatozoa. Evidence that the effect is not mediated via protein kinase C

Biochemical Journal ◽

10.1042/bj2970225 ◽

1994 ◽

Vol 297 (1) ◽

pp. 225-232 ◽

Cited By ~ 28

Author(s):

E R S Roldan ◽

C Fragio

Keyword(s):

Arachidonic Acid ◽

Protein Kinase C ◽

Protein Kinase ◽

Phospholipase A2 ◽

Kinase Inhibitor ◽

Ionophore A23187 ◽

Kinase C ◽

Acrosomal Exocytosis ◽

Phospholipase A2 Activity

We tested the hypothesis that the role of diacylglycerol (DAG) in sperm acrosomal exocytosis is related to the activation of phospholipase A2, and that this effect is not mediated via protein kinase C. Treatment of [14C]arachidonic acid-labelled ram spermatozoa with Ca2+ and the ionophore A23187 stimulated both liberation of arachidonic acid and acrosomal exocytosis. No changes in [14C]DAG or [14C]monoacylglycerol were found after stimulation of spermatozoa, thus suggesting that arachidonic acid may be released exclusively via phospholipase A2. An increase in the endogenous levels of diradylglycerols (DRGs), resulting from exposure either to the DAG kinase inhibitor R 59022 or to exogenous 1-oleoyl-2-acetyl-sn-glycerol or 1,2-dioctanoyl-sn-glycerol, led to an increase in both phospholipase A2 activity and exocytosis when cells were stimulated with A23187 and Ca2+. Addition of DRGs that do not stimulate protein kinase C(1,3-dioctanoylglycerol, 1-O-hexadecyl-2-acetyl-rac-glycerol) also resulted in an increase in phospholipase A2 activity and exocytosis. On the other hand, phorbol esters (phorbol 12,13-dibutyrate; phorbol 12-myristate 13-acetate) did not enhance enzyme activity or exocytosis. Finally, exposure to 1-O-hexadecyl-2-O-methyl-rac-glycerol, a compound known to inhibit protein kinase C, did not affect phospholipase A2 activity or acrosomal exocytosis. We therefore conclude that in spermatozoa the messenger role of DAG is related to the activation of phospholipase A2, which in turn would generate an array of metabolites directly or indirectly involved in bringing about exocytosis of the acrosome.

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Involvement of protein kinase C in mouse mammary gland development

Journal of Endocrinology ◽

10.1677/joe.0.1090029 ◽

1986 ◽

Vol 109 (1) ◽

pp. 29-34 ◽

Cited By ~ 29

Author(s):

J. J. Caulfield ◽

F. F. Bolander

Keyword(s):

Protein Kinase C ◽

Mammary Gland ◽

Protein Kinase ◽

Milk Protein ◽

Calcium Ionophore ◽

Calcium Ionophore A23187 ◽

Ionophore A23187 ◽

Kinase C ◽

Protein Kinase C Activity ◽

Biochemical Differentiation

ABSTRACT The relationship between kinase C activity and mammary gland differentiation was investigated by following kinase activity throughout the mouse reproductive cycle and by pharmacologically perturbing the kinase, while monitoring biochemical differentiation. Protein kinase C activity declined during pregnancy and remained low throughout lactation, suggesting an inverse relationship with milk protein expression. This negative association was further supported by the use of quercetin (50–100 μmol/l) and gossypol (50 μmol/l), which are both protein kinase C inhibitors. These compounds doubled α-lactalbumin levels in mammary explants cultured with hormones. However, a phorbol ester, known to activate protein kinase C, had no effect on α-lactalbumin production, although it did stimulate this milk protein 2·5-fold in the presence of the calcium ionophore, A23187. In the absence of raised calcium levels, protein kinase C activity therefore appeared to be inversely correlated with biochemical differentiation; but, in the presence of increased calcium concentrations, both calcium and the kinase acted synergistically to augment hormone-induced α-lactalbumin expression. J. Endocr. (1986) 109, 29–34

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A role for protein kinase C in the membrane fusion necessary for platelet granule secretion

Blood ◽

10.1182/blood.v74.7.2405.bloodjournal7472405 ◽

1989 ◽

Vol 74 (7) ◽

pp. 2405-2413 ◽

Cited By ~ 1

Author(s):

JM Gerrard ◽

LL Beattie ◽

J Park ◽

SJ Israels ◽

A McNicol ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Membrane Fusion ◽

Calcium Ionophore ◽

Calcium Ionophore A23187 ◽

Ultrastructural Changes ◽

Ionophore A23187 ◽

Kinase C ◽

Granule Secretion ◽

Dimethyl Amiloride

The addition of 1-oleoyl-2-acetylglycerol (OAG), or phorbol-12- myristate-13-acetate (PMA) to platelets induced the phosphorylation of a 47,000 dalton protein (47 Kd), fusion of granule membranes with membranes of the surface connected canalicular system, the formation of large vesicles and the secretion of serotonin. 1-(5- isoquinolinesulfonyl)-2-methyl-piperazine (H7), and sphingosine, inhibitors of protein kinase C, significantly inhibited the ultrastructural changes and the phosphorylation of 47 Kd. N-(2- guanidinoethyl)-5-isoquinolinesulfonamide (HA1004), structurally similar to H7, but a weaker inhibitor of protein kinase C, did not attenuate these responses to OAG or to PMA. H7, but not HA1004, also markedly inhibited secretion induced by the synergistic combination of OAG and the calcium ionophore A23187. Amiloride and 5-(N,N dimethyl)- amiloride, inhibitors of the Na+/H+ transporter, did not inhibit the ultrastructural response and the protein phosphorylation induced by OAG, or the secretion induced by the combination of A23187 and OAG. The results link the activation of protein kinase C by diglycerides to the labilization and fusion of granule membranes important for secretion.

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Generation of hydrogen peroxide in cultured porcine thyroid cells: synergistic regulation by cytoplasmic free calcium and protein kinase C

Journal of Endocrinology ◽

10.1677/joe.0.1200503 ◽

1989 ◽

Vol 120 (3) ◽

pp. 503-508 ◽

Cited By ~ 15

Author(s):

N. Takasu ◽

T. Yamada ◽

Y. Shimizu ◽

Y. Nagasawa ◽

I. Komiya

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Calcium Ionophore ◽

Calcium Ionophore A23187 ◽

Free Calcium ◽

Ionophore A23187 ◽

Thyroid Cells ◽

Kinase C ◽

Synergistic Regulation ◽

Cytoplasmic Free Calcium

ABSTRACT This study set out to elucidate the mechanism by which H2O2 generation is regulated in cultured porcine thyroid cells. We monitored continuously the effects of the calcium ionophore A23187 and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) on H2O2 generation, using homovanillic acid and horseradish peroxidase. A23187 and TPA stimulated H2O2 generation. A23187 increased cytoplasmic free calcium and TPA activated protein kinase C. Generation of H2O2 is therefore regulated by cytoplasmic free calcium and protein kinase C. Exposure to A23187 or TPA augmented further the stimulation of H2O2 generation by TPA or A23187 respectively. Thus A23187 and TPA, by increasing cytoplasmic free calcium and activating protein kinase C respectively, synergistically activate H2O2 generation. Journal of Endocrinology (1989) 120, 503–508

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