Protein kinase C and intracellular pH regulate zymosan-induced lysosomal enzyme secretion in macrophages

1995 ◽  
Vol 58 (4) ◽  
pp. 485-494 ◽  
Author(s):  
Hans Tapper ◽  
Roger Sundler
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Lysosomal Enzyme ◽  
Enzyme Secretion ◽  
Kinase C

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.

Phorbol ester inhibition of Na-H exchange in rabbit proximal colon

1985 ◽  
Vol 249 (5) ◽  
pp. C527-C530 ◽  
Author(s):  
J. Ahn ◽  
E. B. Chang ◽  
M. Field
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Phorbol Ester ◽  
Proximal Colon ◽  
Bathing Medium ◽  
Two Agents ◽  
Luminal Membrane ◽  
Kinase C

In rabbit proximal colon, in vitro addition of phorbol 12,13-dibutyrate (PDB, 10(-7) M) to the serosal bathing medium inhibits mucosal (m)-to-serosal (s) unidirectional Na flux (JsmNa) without altering JsmNa or unidirectional Cl fluxes. Similar results were obtained when amiloride (2 X 10(-4) M) was added to the mucosal bathing medium. No additivity of effect was seen when tissues were exposed to both agents. Measurements with carboxyfluorescein reveal that the two agents cause equal decreases of intracellular pH (pHi), an effect that is dependent on the presence of extracellular Na (Na replacement also decreases pHi). No additivity of pHi effects is seen when both agents are added together. To determine the membrane site of this PDB-inhibitable Na-H exchange, Na influx across the luminal border of proximal colon was measured and was found to be inhibited equally by PDB and amiloride. We conclude that PDB, by activation of protein kinase C, inhibits electro-neutral amiloride-sensitive Na-H exchange in the luminal membrane of proximal colon.

Ca2+-, phorbol ester-, and cAMP-stimulated enzyme secretion from permeabilized rat pancreatic acini

1986 ◽  
Vol 250 (5) ◽  
pp. G698-G708 ◽  
Author(s):  
T. Kimura ◽  
K. Imamura ◽  
L. Eckhardt ◽  
I. Schulz
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Protein Release ◽  
Enzyme Secretion ◽  
Dependent Manner ◽  
Intact Cells ◽  
Pancreatic Acini ◽  
Kinase C ◽  
Kinase A

Enzyme secretion from the exocrine pancreas is stimulated by receptor-activated breakdown of phosphatidylinositol 4,5-bisphosphate and consequent rise of both inositol 1,4,5-trisphosphate (IP3) and diacylglycerol, which leads to Ca2+ release and to activation of protein kinase C, respectively. Another way involves receptor-mediated stimulation of adenylate cyclase and consequent rise of cAMP and activation of protein kinase A. In the present work we have studied direct stimulation, inhibition, and mutual interaction of these pathways on enzyme secretion from isolated rat pancreatic acini that had been permeabilized by treatment with saponin or digitonin. The data were compared with those obtained in isolated intact acini. The data show that with increasing free Ca2+ concentrations greater than 10(-6) M protein release increases in "leaky" but not in "intact" cells and is maximal at approximately 10(-3) M, increasing about twofold compared with that in the absence of Ca2+. In the presence of the acetylcholine analogue carbachol, this effect of Ca2+ is enhanced by about threefold in leaky cells and is also present in intact cells to a similar extent. cAMP and its analogues, dibutyryl cAMP (dbcAMP) and 8-bromo-cAMP stimulate protein release by about twofold in the presence of Ca2+ in leaky cells. In intact acini cAMP has no effect, and cAMP analogues stimulate enzyme secretion by about twofold in some but not all experiments. Similarly, forskolin, an activator of adenylate cyclases and inhibitors of cyclic nucleotide-dependent phosphodiesterases, such as 3-isobutyl-1-methylxanthine (IBMX) and R0 201724, stimulate protein release in permeabilized acini. The Ca2+-binding protein calmodulin has no effect on enzyme secretion, whereas the calmodulin antagonist trifluoperazine dihydrochloride stimulates protein release in leaky but not in intact acini. The activator of protein kinase C, 12-O-tetradecanoylphorbol 13-acetate (TPA) stimulates protein release in a Ca2+-dependent manner and enhances cAMP-induced secretion. The effects of carbachol, TPA, cAMP, and a combination of both TPA and cAMP are inhibited by the polyamine spermine in permeabilized cells. Spermine has no effect on carbachol-induced enzyme secretion in intact cells. The data suggest that enzyme secretion from pancreatic acinar cells is mediated by cAMP protein kinase A and by Ca2+ phospholipid protein kinase C in a Ca2+-dependent way and that interaction occurs between both pathways.

Modulation of Na+/H+ exchange and intracellular pH by protein kinase C and protein phosphatase in blood platelets

1991 ◽  
Vol 1068 (2) ◽  
pp. 161-166 ◽  
Author(s):  
Avinoam A. Livne ◽  
Orit Aharonovitz ◽  
Hagit Fridman ◽  
Yasumasa Tsukitani ◽  
Stefanie Markus
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Protein Phosphatase ◽  
Blood Platelets ◽  
Kinase C

scholarly journals Interleukin-3-stimulated haemopoietic stem cell proliferation. Evidence for activation of protein kinase C and Na+/H+ exchange without inositol lipid hydrolysis

1988 ◽  
Vol 256 (2) ◽  
pp. 585-592 ◽  
Author(s):  
A D Whetton ◽  
S J Vallance ◽  
P N Monk ◽  
E J Cragoe ◽  
T M Dexter ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Proliferation ◽  
Stem Cell ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Stem Cell Proliferation ◽  
Interleukin 3 ◽  
Haemopoietic Stem Cell ◽  
Kinase C

Interleukin 3 (IL-3) is an important regulator of haemopoietic stem cell proliferation both in vivo and in vitro. Little is known about the possible mechanisms whereby this growth factor acts on stem cells to stimulate cell survival and proliferation. Here we have investigated the role of intracellular pH and the Na+/H+ antiport in stem cell proliferation using the multipotential IL-3-dependent stem cell line, FDCP-Mix 1. Evidence is presented that IL-3 can stimulate the activation of an amiloride-sensitive Na+/H+ exchange via protein kinase C activation. IL-3-mediated activation of the Na+/H+ exchange is not observed in FDCP-Mix 1 cells where protein kinase C levels have been down-modulated by treatment with phorbol esters. Also the protein kinase C inhibitor H7 can inhibit IL-3-mediated increases in intracellular pH. This activation of Na+/H+ exchange via protein kinase C has been shown to occur with no measurable effects of IL-3 on inositol lipid hydrolysis or on cytosolic Ca2+ levels. Evidence is also presented that this IL-3-stimulated alkalinization acts as a signal for cellular proliferation in stem cells.

scholarly journals Ca2+ and pH determine the interaction of chromaffin cell scinderin with phosphatidylserine and phosphatidylinositol 4,5,-biphosphate and its cellular distribution during nicotinic-receptor stimulation and protein kinase C activation.

1992 ◽  
Vol 119 (4) ◽  
pp. 797-810 ◽  
Author(s):  
A Rodríguez Del Castillo ◽  
M L Vitale ◽  
J M Trifaró
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Nicotinic Receptor ◽  
Dependent Manner ◽  
Filamentous Actin ◽  
Membrane Phospholipids ◽  
Receptor Stimulation ◽  
Actin Networks ◽  
Kinase C

Nicotinic stimulation and high K(+)-depolarization of chromaffin cells cause disassembly of cortical filamentous actin networks and redistribution of scinderin, a Ca(2+)-dependent actin filament-severing protein. These events which are Ca(2+)-dependent precede exocytosis. Activation of scinderin by Ca2+ may cause disassembly of actin filaments leaving cortical areas of low cytoplasmic viscosity which are the sites of exocytosis (Vitale, M. L., A. Rodríguez Del Castillo, L. Tchakarov, and J.-M. Trifaró. 1991. J. Cell. Biol. 113:1057-1067). It has been suggested that protein kinase C (PKC) regulates secretion. Therefore, the possibility that PKC activation might modulate scinderin redistribution was investigated. Here we report that PMA, a PKC activator, caused scinderin redistribution, although with a slower onset than that induced by nicotine. PMA effects were independent of either extra or intracellular Ca2+ as indicated by measurements of Ca2+ transients, and they were likely to be mediated through direct activation of PKC because inhibitors of the enzyme completely blocked the response to PMA. Scinderin was not phosphorylated by the kinase and further experiments using the Na+/H+ antiport inhibitors and intracellular pH determinations, demonstrated that PKC-mediated scinderin redistribution was a consequence of an increase in intracellular pH. Moreover, it was shown that scinderin binds to phosphatidylserine and phosphatidylinositol 4,5-biphosphate liposomes in a Ca(2+)-dependent manner, an effect which was modulated by the pH. The results suggest that under resting conditions, cortical scinderin is bound to plasma membrane phospholipids. The results also show that during nicotinic receptor stimulation both a rise in intracellular Ca2+ and pH are observed. The rise in intracellular pH might be the result of the translocation and activation of PKC produced by Ca2+ entry. This also would explain why scinderin redistribution induced by nicotine is partially (26-40%) inhibited by inhibitors of either PKC or the Na+/H+ antiport. In view of these findings, a model which can explain how scinderin redistribution and activity may be regulated by pH and Ca2+ in resting and stimulated conditions is proposed.

Protein kinase C in intracellular pH regulation in alveolar type II cells

1996 ◽  
Vol 271 (1) ◽  
pp. L106-L113 ◽  
Author(s):  
S. Wadsworth ◽  
A. M. Wu ◽  
A. Spitzer ◽  
A. Chander
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Dependent Manner ◽  
Type Ii ◽  
Alveolar Type Ii Cells ◽  
Kinase C ◽  
Acid Load

The Na+/H+ exchanger and Na(+)-HCO3- cotransporter have been implicated in regulation of intracellular pH (pHi) in alveolar type II cells. This study demonstrates that activation of protein kinase C (PKC) stimulates both of these ion transporters in type II cells. Treatment of type II cells with 80 nM phorbol 12-myristate 13-acetate (PMA) increased the resting pHi in a time-dependent manner. Compared with control cells, the rates of recovery from an acid load increased with PMA treatment, reaching a maximum at 15 min, and returned to control levels by 3 h. The PMA-stimulated changes in recovery rate were sensitive to H-7, a PKC inhibitor. For PMA treatment up to 2 h, these recoveries were also sensitive to dimethylamiloride (DMA), an inhibitor of Na+/H+ exchanger activity, and to HCO3-, suggesting activation of both the Na+/H+ exchanger and the Na(+)-HCO3- cotransporter. After prolonged (3 h) treatment with PMA, however, the recovery was insensitive to DMA but was sensitive to HCO3-, suggesting that the Na+/H+ exchanger was no longer active and that most of the recovery was mediated by the Na(+)-HCO3- cotransporter. PMA treatment also altered the Na+ kinetics of the recovery from an acid load with respect to the Michaelis constant (Km) and maximal ion flux (Vmax), suggesting protein modifications of each transporter. We suggest that PKC activation in type II cells results in acute and long-term changes in pHi regulatory mechanisms mediated by the Na+/H+ exchanger and by the Na(+)-HCO3- cotransporter.

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