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.

Prolactin stimulation of ornithine decarboxylase and mitogenesis in Nb2 node lymphoma cells: The role of protein kinase C and calcium mobilization

1986 ◽  
Vol 12 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Arthur R. Buckley ◽  
David W. Montgomery ◽  
Ruthann Kibler ◽  
Charles W. Putnam ◽  
Charles F. Zukoski ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Ornithine Decarboxylase ◽  
Calcium Mobilization ◽  
Lymphoma Cells ◽  
Kinase C ◽  
Stimulation Of

PROTEIN KINASE C CONTROLS CA2+ MOBILIZATION IN HUMAN PLATELETS

1987 ◽  
Author(s):  
W Siffert ◽  
P Scheid ◽  
JW N Akkerman
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Human Platelets ◽  
Cytosolic Ph ◽  
Fluorescent Indicators ◽  
Kinase C ◽  
Deutsche Forschungsgemeinschaft ◽  
Ionophore Monensin ◽  
Stimulation Of

Platelet stimulation has been shown to result in a rise of cytosolic pH (pHi) as a result of an activation of a Na+/H+ antiport. We have investigated the role of pH in Ca2+ mobilization in human platelets. pHi and free Ca2+, {Ca2+)i, were measured in platelets loaded with the fluorescent indicators BCECF and quin2, respectively. Stimulation of platelets by either thrombin or OAG, an activator of protein kinase C (Pk-C), increased pHi. Pretreatment of platelets with inhibitors of Pk-C, trifluoperazine (TFP) or sphingosine (SPH), blocked the stimulus-induced rise in pHi, suggesting a role of Pk-C in the activation of Na+/H+ exchange. Blocking Na+/H+ exchange by an amiloride analogue or by TFP similarly suppressed the thrombin-induced increase in {Ca2*}i. This effect could be prevented by increasing pHi with the Na+/H+ ionophore monensin or with NH4Cl. The thrombin-induced (0.05 U/ml) rise in {Ca2+}i was more than 3-fold enhanced when the pH was raised from 6.8 to 7.4.Our results demonstrate that pHi controls Ca2+ mobilization in human platelets and suggest that Pk-C contributes to this control by activating the Na+/H+ exchanger.Supported by the Deutsche Forschungsgemeinschaft. No Sche 46/5-2.

Evidence for a Role of Protein Kinase C in the Stimulation of Lipolysis by Growth Hormone and Isoproterenol*

Endocrinology ◽  
1990 ◽  
Vol 126 (6) ◽  
pp. 2973-2982 ◽  
Author(s):  
ERELA GORIN ◽  
LIH-RUEY TAI ◽  
THOMAS W. HONEYMAN ◽  
H. MAURICE GOODMAN
Keyword(s):  
Growth Hormone ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Kinase C ◽  
Stimulation Of

Alpha 1-adrenergic stimulation of Na-H exchange in cardiac myocytes

1992 ◽  
Vol 263 (5) ◽  
pp. C1096-C1102 ◽  
Author(s):  
M. A. Wallert ◽  
O. Frohlich
Keyword(s):  
Protein Kinase C ◽  
Steady State ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Ph Dependence ◽  
Adrenergic Stimulation ◽  
Adult Rat ◽  
Kinase C ◽  
Rat Heart Myocytes ◽  
Stimulation Of

The activation of Na-H exchange in adult rat heart myocytes was characterized in response to a phorbol ester (phorbol 12-myristate 13-acetate) and an alpha 1-adrenergic agonist [6-fluoronorepinephrine (6F-NE)]. Transport activation was assessed by determining the initial rate with which intracellular pH (pHi) was returned from an acid pulse and by following changes in steady-state pHi; pHi was determined by a pH-sensitive fluorescent dye. Both agonists shifted the intracellular pH dependence of Na-H exchange by 0.10-0.15 pH units in the alkaline direction. This shift was prevented by the presence of sphingosine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), inhibitors of protein kinase C. The agonists also alkalinized pHi at steady state. The alkalinization by 6F-NE was blocked by prazosin and H-7. This indicates that the adrenergic stimulation of cardiac Na-H exchange is mediated by an alpha 1-adrenergic mechanism and very likely involves the activation of protein kinase C.

Role of Protein Kinase C in Stimulation of Interleukin 2 Production

2020 ◽  
pp. 279-308
Author(s):  
Julianne J. Sando ◽  
Caroline M. Kramer ◽  
Janet R. Harrison ◽  
David E. Jensen
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Interleukin 2 ◽  
Kinase C ◽  
Stimulation Of
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