scholarly journals Stimulation of Protein Kinase C Inhibits Bursting in Disease-Linked Mutant Human Cardiac Sodium Channels

Circulation ◽  
2003 ◽  
Vol 107 (25) ◽  
pp. 3216-3222 ◽  
Author(s):  
M. Tateyama ◽  
J. Kurokawa ◽  
C. Terrenoire ◽  
I. Rivolta ◽  
R.S. Kass
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Sodium Channels ◽  
Kinase C ◽  
Cardiac Sodium Channels ◽  
Stimulation Of

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

scholarly journals Stimulation of protein kinase C and insulin release by 1-oleoyl-2-acetyl-glycerol

1985 ◽  
Vol 149 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Willy J. MALAISSE ◽  
Marjorie E. DUNLOP ◽  
Paulo C. F. MATHIAS ◽  
Francine MALAISSE-LAGAE ◽  
Abdullah SENER
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Release ◽  
Kinase C ◽  
Stimulation Of

scholarly journals Cytoplasmic [Ca2+] and intracellular pH in lymphocytes. Role of membrane potential and volume-activated Na+/H+ exchange.

1987 ◽  
Vol 89 (2) ◽  
pp. 185-213 ◽  
Author(s):  
S Grinstein ◽  
S Cohen
Keyword(s):  
Protein Kinase C ◽  
Membrane Potential ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Enzyme Treatment ◽  
Membrane Hyperpolarization ◽  
Kinase C ◽  
Free Media ◽  
Stimulation Of

The effect of elevating cytoplasmic Ca2+ [( Ca2+]i) on the intracellular pH (pHi) of thymic lymphocytes was investigated. In Na+-containing media, treatment of the cells with ionomycin, a divalent cation ionophore, induced a moderate cytoplasmic alkalinization. In the presence of amiloride or in Na+-free media, an acidification was observed. This acidification is at least partly due to H+ (equivalent) uptake in response to membrane hyperpolarization since: it was enhanced by pretreatment with conductive protonophores, it could be mimicked by valinomycin, and it was decreased by depolarization with K+ or gramicidin. In addition, activation of metabolic H+ production also contributes to the acidification. The alkalinization is due to Na+/H+ exchange inasmuch as it is Na+ dependent, amiloride sensitive, and accompanied by H+ efflux and net Na+ gain. A shift in the pHi dependence underlies the activation of the antiport. The effect of [Ca2+]i on Na+/H+ exchange was not associated with redistribution of protein kinase C and was also observed in cells previously depleted of this enzyme. Treatment with ionomycin induced significant cell shrinking. Prevention of shrinking largely eliminated the activation of the antiport. Moreover, a comparable shrinking produced by hypertonic media also activated the antiport. It is concluded that stimulation of Na+/H+ exchange by elevation of [Ca2+]i is due, at least in part, to cell shrinking and does not require stimulation of protein kinase C.

Role of protein kinase C in T-cell antigen receptor regulation of p21ras: evidence that two p21ras regulatory pathways coexist in T cells

1992 ◽  
Vol 12 (7) ◽  
pp. 3305-3312
Author(s):  
M Izquierdo ◽  
J Downward ◽  
J D Graves ◽  
D A Cantrell
Keyword(s):  
T Cells ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Kinase Inhibitor ◽  
Antigen Receptor ◽  
Permeabilized Cell ◽  
Regulatory Pathways ◽  
Kinase C ◽  
Stimulation Of

T-lymphocyte activation via the antigen receptor complex (TCR) results in accumulation of p21ras in the active GTP-bound state. Stimulation of protein kinase C (PKC) can also activate p21ras, and it has been proposed that the TCR effect on p21ras occurs as a consequence of TCR regulation of PKC. To test the role of PKC in TCR regulation of p21ras, a permeabilized cell system was used to examine TCR regulation of p21ras under conditions in which TCR activation of PKC was blocked, first by using a PKC pseudosubstrate peptide inhibitor and second by using ionic conditions that prevent phosphatidyl inositol hydrolysis and hence diacylglycerol production and PKC stimulation. The data show that TCR-induced p21ras activation is not mediated exclusively by PKC. Thus, in the absence of PKC stimulation, the TCR was still able to induce accumulation of p21ras-GTP complexes, and this stimulation correlated with an inactivation of p21ras GTPase-activating proteins. The protein tyrosine kinase inhibitor herbimycin could prevent the non-PKC-mediated, TCR-induced stimulation of p21ras. These data indicate that two mechanisms for p21ras regulation coexist in T cells: one PKC mediated and one not. The TCR can apparently couple to p21ras via a non-PKC-controlled route that may involve tyrosine kinases.

The protein kinase C inhibitor H-7 activates human neutrophils: effect on shape, actin polymerization, fluid pinocytosis and locomotion

1990 ◽  
Vol 96 (1) ◽  
pp. 99-106
Author(s):  
H.U. Keller ◽  
V. Niggli ◽  
A. Zimmermann ◽  
R. Portmann
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Actin Polymerization ◽  
Kinase Inhibitor ◽  
Human Neutrophils ◽  
Kinase C ◽  
Chemotactic Peptides ◽  
Protein Kinase C Inhibitor ◽  
Shape Changes ◽  
Stimulation Of

The present study demonstrates new properties of H-7. The protein kinase inhibitor H-7 is a potent activator of several neutrophil functions. Stimulation of initially spherical nonmotile neutrophils elicits vigorous shape changes within a few seconds, increases in cytoskeletal actin, altered F-actin distribution, increased adhesiveness and a relatively small increase in pinocytic activity. H-7 has also chemokinetic activities. Depending on the experimental condition, H-7 may elicit or inhibit neutrophil locomotion. It failed to induce chemotaxis. Thus, the response pattern elicited by H-7 is different from that of other leukocyte activators such as chemotactic peptides, PMA or diacylglycerols. The finding that H-7 can elicit shape changes, actin polymerization and pinocytosis suggests that these events can occur without activation of protein kinase C (PKC). PMA-induced shape changes and stimulation of pinocytosis were not inhibited by H-7.

scholarly journals Acceleration of Sodium-Calcium Exchange Activity during ATP-induced Calcium Release in Transfected Chinese Hamster Ovary Cells

1997 ◽  
Vol 109 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Melissa Vázquez ◽  
Yu Fang ◽  
John P. Reeves
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Chinese Hamster Ovary ◽  
Calcium Release ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Kinase C ◽  
Stimulation Of ◽  
Exchange Activity

The P2U purinergic agonist ATP (0.3 mM) elicited an increase in [Ca2+]i due to Ca2+ release from intracellular stores in transfected Chinese hamster ovary cells that express the bovine cardiac Na+/Ca2+ exchanger (CK1.4 cells). The following observations indicate that ATP-evoked Ca2+ release was accompanied by a Ca2+- dependent regulatory activation of Na+/Ca2+ exchange activity: Addition of extracellular Ca2+ (0.7 mM) 0–1 min after ATP evoked a dramatic rise in [Ca2+]i in Na+-free media (Li+ substitution) compared to Na+-containing media; no differences between Na+- and Li+-based media were observed with vector-transfected cells. In the presence of physiological concentrations of extracellular Na+ and Ca2+, the ATP-evoked rise in [Ca2+]i declined more rapidly in CK1.4 cells compared to control cells, but then attained a long-lived plateau of elevated [Ca2+]i which eventually came to exceed the declining [Ca2+]i values in control cells. ATP elicited a transient acceleration of exchange-mediated Ba2+ influx, consistent with regulatory activation of the Na+/Ca2+ exchanger. The acceleration of Ba2+ influx was not observed in vector-transfected control cells, or in CK1.4 cells in the absence of intracellular Na+ or when the Ca2+ content of the intracellular stores had been reduced by prior treatment with ionomycin. The protein kinase C activator phorbol 12-myristate 13-acetate attenuated the exchange-mediated rise in [Ca2+]i under Na+-free conditions, but did not inhibit the ATP-evoked stimulation of Ba2+ influx. The effects of PMA are therefore not due to inhibition of exchange activity, but probably reflect the influence of protein kinase C on other Ca2+ homeostatic mechanisms. We conclude that exchange activity is accelerated during ATP-evoked Ca2+ release from intracellular stores through regulatory activation by increased [Ca2+]i. In the absence of extracellular Ca2+, the stimulation of exchange activity is short-lived and follows the time course of the [Ca2+]i transient; in the presence of extracellular Ca2+, we suggest that the exchanger remains activated for a longer period of time, thereby stabilizing and prolonging the plateau phase of store-dependent Ca2+ entry.

scholarly journals Nuclear diacylglycerol is increased during cell proliferation in vivo

1993 ◽  
Vol 290 (3) ◽  
pp. 633-636 ◽  
Author(s):  
H Banfić ◽  
M Žižak ◽  
N Divecha ◽  
R F Irvine
Keyword(s):  
Cell Proliferation ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Nuclear Membrane ◽  
Cellular Proliferation ◽  
Detectable Change ◽  
Renal Growth ◽  
Kinase C ◽  
Stimulation Of

Highly purified nuclei were prepared from livers and kidneys of rats undergoing compensatory hepatic or renal growth, the former being predominantly by cellular proliferation, and the latter mostly by cellular enlargement. In liver, an increase in nuclear diacylglycerol (DAG) concentration occurred between 16 and 30 h, peaking at around 20 h. At the peak of nuclear DAG production a specific translocation of protein kinase C to the nucleus could be detected; no such changes occurred in kidney. There was no detectable change in whole-cell DAG levels in liver, and the increase in DAG was only measurable in nuclei freed of their nuclear membrane. Overall, these results suggest that there is a stimulation of intranuclear DAG production, possibly through the activation of an inositide cycle [Divecha, Banfić and Irvine (1991) EMBO J. 10, 3207-3214] during cell proliferation in vivo.

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