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Birkeland ES, Koch LM, Dechant R. Another Consequence of the Warburg Effect? Metabolic Regulation of Na +/H + Exchangers May Link Aerobic Glycolysis to Cell Growth. Front Oncol 2020; 10:1561. [PMID: 32974190 PMCID: PMC7462004 DOI: 10.3389/fonc.2020.01561] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022] Open
Abstract
To adjust cell growth and proliferation to changing environmental conditions or developmental requirements, cells have evolved a remarkable network of signaling cascades that integrates cues from cellular metabolism, growth factor availability and a large variety of stresses. In these networks, cellular information flow is mostly mediated by posttranslational modifications, most notably phosphorylation, or signaling molecules such as GTPases. Yet, a large body of evidence also implicates cytosolic pH (pHc) as a highly conserved cellular signal driving cell growth and proliferation, suggesting that pH-dependent protonation of specific proteins also regulates cellular signaling. In mammalian cells, pHc is regulated by growth factor derived signals and responds to metabolic cues in response to glucose stimulation. Importantly, high pHc has also been identified as a hall mark of cancer, but mechanisms of pH regulation in cancer are only poorly understood. Here, we discuss potential mechanisms of pH regulation with emphasis on metabolic signals regulating pHc by Na+/H+-exchangers. We hypothesize that elevated NHE activity and pHc in cancer are a direct consequence of the metabolic adaptations in tumor cells including enhanced aerobic glycolysis, generally referred to as the Warburg effect. This hypothesis not only provides an explanation for the growth advantage conferred by a switch to aerobic glycolysis beyond providing precursors for accumulation of biomass, but also suggests that treatments targeting pH regulation as a potential anti-cancer therapy may effectively target the result of altered tumor cell metabolism.
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Affiliation(s)
- Eivind Salmorin Birkeland
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zurich, Switzerland.,Life Science Zurich, Ph.D. Program for Molecular Life Sciences, Zurich, Switzerland
| | - Lisa Maria Koch
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zurich, Switzerland.,Life Science Zurich, Ph.D. Program for Molecular Life Sciences, Zurich, Switzerland
| | - Reinhard Dechant
- Institute of Biochemistry, Department of Biology, ETH Zürich, Zurich, Switzerland
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Loucks K, Waddell D, Ross C. Lipopolysaccharides elicit an oxidative burst as a component of the innate immune system in the seagrass Thalassia testudinum. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2013; 70:295-303. [PMID: 23807482 DOI: 10.1016/j.plaphy.2013.05.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/20/2013] [Indexed: 06/02/2023]
Abstract
This study represents the first report characterizing the biological effects of a lipopolysaccharide (LPS) immune modulator on a marine vascular plant. LPS was shown to serve as a strong elicitor of the early defense response in the subtropical seagrass Thalassia testudinum Banks ex König and was capable of inducing an oxidative burst identified at the single cell level. The formation of reactive oxygen species (ROS), detected by a redox-sensitive fluorescent probe and luminol-based chemiluminescence, included a diphenyleneiodonium sensitive response, suggesting the involvement of an NADPH oxidase. A 900 bp cDNA fragment coding for this enzyme was sequenced and found to encode a NAD binding pocket domain with extensive homology to the Arabidopsis thaliana rbohF (respiratory burst oxidase homolog) gene. The triggered release of ROS occurred at 20 min post-elicitation and was dose-dependent, requiring a minimal threshold of 50 μg/mL LPS. Pharmacological dissection of the early events preceding ROS emission indicated that the signal transduction chain of events involved extracellular alkalinization, G-proteins, phospholipase A2, as well as K(+), Ca(2+), and anion channels. Despite exclusively thriving in a marine environment, seagrasses contain ROS-generating machinery and signal transduction components that appear to be evolutionarily conserved with the well-characterized defense response systems found in terrestrial plants.
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Affiliation(s)
- Kyle Loucks
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA
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Rothstein A. The Na+/H+ exchange system in cell pH and volume control. Rev Physiol Biochem Pharmacol 2005; 112:235-57. [PMID: 2682966 DOI: 10.1007/bfb0027498] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Takaichi K, Balkovetz DF, Van Meir E, Warnock DG. Cytosolic pH sensitivity of an expressed human NHE-1 Na(+)-H+ exchanger. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 264:C944-50. [PMID: 8476023 DOI: 10.1152/ajpcell.1993.264.4.c944] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
These studies examined the effects of protein kinase C activation and calmodulin inhibition on the amiloride-sensitive NHE-1 isoform of the Na(+)-H+ exchanger in defined host cells. Our objective was to define differences in the cellular regulatory responses using a specified isoform of the Na(+)-H+ exchanger. Suspended cells were loaded with 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF) and preacidified to a cytosolic pH of 6.2. Wild-type mouse Ltk- cells, human A-431 cells, and mutant mouse fibroblasts stably transfected with the human NHE-1 isoform (LAP+ cells) were examined to define the maximal rate of transport (Vmax) in response to 140 mM external Na+, the Hill stoichiometric coefficient, and the cytosolic pH at which the NHE-1 isoform was half-maximally stimulated (pH50). The mouse NHE-1 isoform had a greater affinity for cytosolic H+ than the human NHE-1 isoforms. Calmodulin antagonism with N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide reduced the Vmax and shifted the pH50 in the acidic direction, especially in the A-431 cells. Protein kinase C stimulation had a similar effect in A-431 cells and little effect in the wild-type (Ltk-) and transfected (LAP+) mouse cells. While the NHE-1 isoform contains several potential phosphorylation sites, the cellular milieu in which the isoform is expressed has an important effect on the modulation of NHE-1 activity.
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Affiliation(s)
- K Takaichi
- Department of Medicine, University of Alabama, Birmingham 35294
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Stith BJ, Goalstone ML, Kirkwood AJ. Protein kinase C initially inhibits the induction of meiotic cell division in Xenopus oocytes. Cell Signal 1992; 4:393-403. [PMID: 1419482 DOI: 10.1016/0898-6568(92)90034-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have used one activator and two inhibitors of protein kinase C (PKC) to examine the role of this enzyme in the induction of meiotic cell division. At 1 U/ml, phosphatidylcholine-specific phospholipase C increases DAG, alters intracellular pH and inhibits the induction of meiosis by insulin or progesterone. However, when added about 1.6 h after progesterone, the enzyme speeds the induction of cell division. Microinjection of inhibitor peptide (19-36) of PKC has little effect on progesterone action but stimulates the induction of meiosis by insulin. When the inhibitor peptide is injected about 2h after insulin addition, the peptide inhibits. A second PKC inhibitor, staurosporine, decreases PKC-dependent intracellular pH and in vitro oocyte PKC activity. At similar concentrations, staurosporine stimulates insulin or progesterone action, but, when added after about 2 h, the drug inhibits induction by insulin. We conclude that PKC is initially inhibitory to the induction of meiotic cell division but then may become synergistic.
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Affiliation(s)
- B J Stith
- Department of Biology, University of Colorado, Denver 80217-3364
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MacLeod KT, Harding SE. Effects of phorbol ester on contraction, intracellular pH and intracellular Ca2+ in isolated mammalian ventricular myocytes. J Physiol 1991; 444:481-98. [PMID: 1822559 PMCID: PMC1179944 DOI: 10.1113/jphysiol.1991.sp018889] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
1. We have investigated the actions of certain phorbol esters on the intracellular pH, intracellular Ca2+ and contractility of isolated rat and guinea-pig cardiac myocytes. Intracellular pH was measured using 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF) and intracellular Ca2+ was measured using Fura-2. 2. Application of the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (also called phorbol 12-myristate 13-acetate) (TPA) (which activates protein kinase C) to rat cardiac myocytes significantly increased cell shortening by 116 +/- 34% (n = 8) (p less than 0.02). The rate of change of cell length during contraction (i.e. +dL/dt) increased from 67.2 +/- 8.7 microns/s to 127.7 +/- 14.1 microns/s (n = 7). The rate of change of cell length during relaxation (-dL/dt) increased from 55.8 +/- 7.4 microns/s to 118.9 +/- 12.1 microns/s (n = 7). Time to peak shortening was unchanged. 3. Application of 4 alpha-phorbol 12,13-didecanoate, which does not activate protein kinase C, did not affect rat myocyte contractility. An insignificant decrease in contractility (by 7.5 +/- 7.5%) was observed (n = 5). The positive inotropic effect of TPA may therefore be evoked through an activation of protein kinase C. 4. In rat myocytes we have measured the changes of pHi and contractility (cell shortening) during an alkalosis and acidosis induced by exposure to and subsequent removal of NH4Cl both in the presence and absence of TPA. Recovery times from an acid load were significantly (p less than 0.05) enhanced by 15.1 +/- 6.9% (n = 13) in the presence of TPA. Recovery times of cell shortening were also more rapid (p less than 0.05) by an average of 59.1 +/- 10.6% (n = 5) in the presence of TPA. Recovery times were unchanged in the presence of 4-phorbol 12,13-didecanoate (which does not activate protein kinase C). 5. Since pHi recovery of an isolated myocyte from an acid load is partially inhibited by the presence of 1 mM-amiloride and inhibited by removing extracellular Na+ then it is suggested that, like pHi regulation in sheep heart Purkinje fibres, pHi recovery in rat cardiac ventricular myocytes is mainly through sarcolemmal Na(+)-H+ exchange. We suggest that in the presence of TPA the Na(+)-H+ exchange is stimulated. 6. The relationship between pHi and cell shortening is non-linear as has been observed by others in whole tissue preparations. The presence of TPA shifts the relationship upwards such that at any one pHi, cell shortening is greater.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- K T MacLeod
- Department of Cardiac Medicine, National Heart and Lung Institute, London
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Northwood IC, Davis RJ. Signal transduction by the epidermal growth factor receptor after functional desensitization of the receptor tyrosine protein kinase activity. Proc Natl Acad Sci U S A 1990; 87:6107-11. [PMID: 2166944 PMCID: PMC54481 DOI: 10.1073/pnas.87.16.6107] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Previous work identified a protein kinase activity that phosphorylates the epidermal growth factor (EGF) receptor at Thr669. An assay for this protein kinase activity present in homogenates prepared from A431 human epidermoid carcinoma cells was developed using a synthetic peptide substrate corresponding to residues 663-681 of the EGF receptor (peptide T669). Here we report that a greater initial rate of T669 phosphorylation was observed in experiments using homogenates prepared from EGF- or phorbol ester-treated cells compared with control cells. EGF and 4 beta-phorbol 12-myristate 13-acetate (PMA) caused a 6-fold and a 2-fold increase in protein kinase activity, respectively. A kinetic analysis of T669 phosphorylation demonstrated that the increase in protein kinase activity observed was accounted for by an increase in Vmax. To examine the interaction between protein kinase C and signal transduction by the EGF receptor, the effect of pretreatment of cells with PMA on the subsequent response to EGF was investigated. Treatment of cells with PMA caused greater than 90% inhibition of the EGF-stimulated tyrosine phosphorylation of the EGF receptor and abolished the EGF-stimulated formation of soluble inositol phosphates. In contrast, PMA was not observed to inhibit the stimulation of T669 protein kinase activity caused by EGF. Thus, the apparent functional desensitization of the EGF receptor caused by PMA does not inhibit signal transduction mediated by the T669 protein kinase. Our results demonstrate that EGF receptor transmodulation alters the pattern of signal-transduction pathways that are utilized by the EGF receptor.
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Affiliation(s)
- I C Northwood
- Howard Hughes Medical Institute, Program in Molecular Medicine, Worcester, MA
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Heisermann GJ, Wiley HS, Walsh BJ, Ingraham HA, Fiol CJ, Gill GN. Mutational removal of the Thr669 and Ser671 phosphorylation sites alters substrate specificity and ligand-induced internalization of the epidermal growth factor receptor. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38233-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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10
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Effects of substitution of threonine 654 of the epidermal growth factor receptor on epidermal growth factor-mediated activation of phospholipase C. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39251-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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11
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Holsey C, Cragoe EJ, Nair CN. Evidence for poliovirus-induced cytoplasmic alkalinization in HeLa cells. J Cell Physiol 1990; 142:586-91. [PMID: 2155910 DOI: 10.1002/jcp.1041420319] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
During the early period after poliovirus infection of HeLa cells, cellular Na+/K+ ATPase activity is transiently activated. We investigated the possibility that Na+/K+ ATPase activation is a consequence of Na+/H+ antiporter activation. Increased uptake of the weak organic acid 5,5-dimethyloxazolidine-2,4-dione by infected cells around 2 h after infection suggested cytoplasmic alkalinization equivalent to pH 7.7 during the biosynthetic phase of viral replication. Consistent with the involvement of Na+/H+ antiporter activation in this phenomenon, it was found to be [Na+]-dependent and inhibited by 5-(N-ethyl-N-isopropyl)amiloride (EIPA). However, the pH increase was not associated with an increase in amiloride-sensitive Na+ uptake by infected cells predicted by this mechanism. By contrast, the alkalinization could be abolished with the anion-exchange inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), implicating an anion-exchange mechanism, such as Cl-/HCO3- exchange, in this process. In addition to abolishing virus-induced intracellular alkalinization, both EIPA and DIDS moderately inhibited viral replication. Manipulation of intracellular pH with nigericin in the incubation medium revealed that maximum viral replication required a pH of about 7.7 and that replication was significantly inhibited even at pH 7.3. Thus, the pH increase in infected cells appeared to be physiologically relevant. These findings represent the first demonstration of a biologically meaningful pH increase in cells infected with a lytic virus.
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Affiliation(s)
- C Holsey
- Department of Cell and Molecular Biology, Medical College of Georgia, Augusta 30912-2100
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12
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Ackerman P, Osheroff N. Regulation of casein kinase II activity by epidermal growth factor in human A-431 carcinoma cells. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)80160-0] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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13
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Saunders RD, Brandon YW, DeVries GH. Role of intracellular pH in the axolemma- and myelin-induced proliferation of Schwann cells. J Neurochem 1989; 52:1576-81. [PMID: 2540277 DOI: 10.1111/j.1471-4159.1989.tb09211.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In order to provide additional information on the biochemical events that interact to cause Schwann cells to proliferate, we have monitored the intracellular pH of Schwann cells that have been stimulated to divide with myelin-enriched fractions (MEF) or axolemma-enriched fractions (AEF). The intracellular pH of Schwann cells was monitored using 2',7'-bis(carboxymethyl)-5(6)-carboxyfluorescein (BCECF), which displays an increase in fluorescence upon alkalinization. Both AEF and MEF caused dose-dependent increases in the intracellular fluorescence of the Schwann cell cultures. At their maximum doses, AEF and MEF stimulation resulted in a 260 and 300% increase in intracellular fluorescence, respectively. The increase in intracellular fluorescence was abolished when cells were stimulated in Na+-free media, suggesting a role for the Na+/H+ exchanger. Mitotic stimulation required integrity of the Na+/H+ exchanger, as inhibition of the Na+/H+ exchanger for periods up to 1 h after addition of mitogen caused a significant inhibition of subsequent mitosis. Phorbol esters, which can potentiate AEF- and MEF-induced Schwann cell proliferation, increased intracellular fluorescence fivefold, an effect which was also dependent upon the presence of Na+ in the culture media. The specificity of the increase in intracellular pH for AEF and MEF was tested by incubating Schwann cells with liver microsomes and a biologically inactive phorbol alcohol, neither of which is significantly mitogenic for Schwann cells. Neither liver microsomes nor phorbol alcohol had a significant effect on intracellular pH. The implications of the increase in intracellular pH in Schwann cells with respect to inositol phospholipid metabolism, protein kinase C activation, and cellular proliferation are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R D Saunders
- Department of Biochemistry and Molecular Biophysics, Virginia Commonwealth University, Medical College of Virginia, Richmond
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Ernst LK, Rajan VP, Larsen RD, Ruff MM, Lowe JB. Stable Expression of Blood Group H Determinants and GDP-L-fucose: β-D-galactoside 2-α-L-Fucosyltransferase in Mouse Cells After Transfection with Human DNA. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)94086-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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15
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Grinstein S, Rotin D, Mason MJ. Na+/H+ exchange and growth factor-induced cytosolic pH changes. Role in cellular proliferation. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 988:73-97. [PMID: 2535787 DOI: 10.1016/0304-4157(89)90004-x] [Citation(s) in RCA: 547] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- S Grinstein
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
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Decker SJ, Dorai B, Russell S. Mutation of a protein kinase C phosphorylation site in the erbB protein of avian erythroblastosis virus. J Virol 1988; 62:3649-54. [PMID: 2901498 PMCID: PMC253506 DOI: 10.1128/jvi.62.10.3649-3654.1988] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Tumor promoter-stimulated phosphorylation of threonine 98 of the erbB protein of avian erythroblastosis virus (AEV) correlates with inhibition of erbB-dependent mitogenesis. To more clearly define the role of phosphorylation of this residue in regulation of the activity of the erbB protein, we have constructed erbB mutations which encode alanine (Ala-98), tyrosine (Tyr-98), or serine (Ser-98) at position 98. The biosynthesis and stability of the three mutant proteins were similar to those of the wild-type erbB protein, and all three retained the ability to transform chicken embryo fibroblasts. Treatment of transformed CEF with 12-tetradecanoylphorbol-13-acetate (TPA) stimulated incorporation of 32Pi into wild-type and mutant erbB proteins and resulted in a slight decrease in the electrophoretic mobilities of all the erbB proteins. Tryptic maps of erbB phosphopeptides showed no endogenous or TPA-stimulated phosphorylation of alanine 98 or tyrosine 98 in cells transformed by the Ala-98 and Tyr-98 mutants. Analysis of tryptic phosphopeptides by high-pressure liquid chromatography revealed that TPA treatment of cells stimulated phosphorylation of other sites of the erbB protein in addition to threonine 98. A high endogenous level of phosphorylation of serine 98 of the Ser-98 mutant protein was found, and TPA treatment of cells did not result in further phosphorylation of this residue. Cells transformed by wild-type and mutant AEV were equally sensitive to TPA-dependent inhibition of growth in soft agar and TPA-dependent inhibition of [3H]thymidine incorporation. TPA treatment inhibited tyrosine phosphorylation to a similar extent in cells transformed by wild-type or Ala-98 AEV. These data indicate that phosphorylation of threonine 98 of the erbB protein is not responsible for TPA-dependent inhibition of growth of AEV-transformed cells or TPA-induced inhibition of erbB-dependent tyrosine phosphorylation. TPA-stimulated phosphorylation of the erbB protein at other sites may mediate these effects. The data also show that subtle changes in a phosphorylation site (i.e., changing threonine to serine) can drastically alter recognition by protein kinases.
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Affiliation(s)
- S J Decker
- Rockefeller University, New York, New York 10021-6399
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Tilly BC, van Paridon PA, Verlaan I, de Laat SW, Moolenaar WH. Epidermal-growth-factor-induced formation of inositol phosphates in human A431 cells. Differences from the effect of bradykinin. Biochem J 1988; 252:857-63. [PMID: 3138977 PMCID: PMC1149226 DOI: 10.1042/bj2520857] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In human A431 epidermoid carcinoma cells, epidermal growth factor (EGF) rapidly stimulates the breakdown of inositol phospholipids and raises cytoplasmic free [Ca2+]. In this paper, we investigate the action of EGF on inositol phosphate metabolism, and we compare it with the previously described effects of bradykinin on the same cell system [Tilly, van Paridon, Verlaan, Wirtz, de Laat & Moolenaar (1987) Biochem. J. 244, 129-135]. In cells prelabelled with [3H]inositol, EGF slowly but persistently (for at least 30 min) stimulates the formation of [3H]inositol phosphates, whereas bradykinin causes an immediate but transient release of inositol phosphates, which lasts for only a few minutes. The EGF effect is additive to bradykinin stimulation and does not require extracellular Ca2+. In contrast, inositol phosphate formation induced by Ca2+-ionophore A23187 has an absolute requirement for external Ca2+. Treatment of the cells with 12-O-tetradecanoylphorbol 13-acetate completely abolishes the response to EGF and to sub-optimal doses of bradykinin, suggesting a negative-feedback function of protein kinase C. Pretreatment of the cells with pertussis toxin has no effect on inositol phosphate formation induced by either EGF or bradykinin. Unlike bradykinin, EGF stimulates very little accumulation of inositol 1,4,5-trisphosphate, with only a small and rather variable release of Ca2+ from intracellular stores. EGF rapidly but transiently increases inositol 1,3,4-trisphosphate and 1,3,4,5-tetrakisphosphate, but the effects are much smaller than those of bradykinin. In addition, EGF increases both inositol mono- and bis-phosphate. At 10 min after EGF addition, inositol monophosphate, unlike the other inositol phosphates, is still increasing. It is concluded that the EGF-dependent pattern of stimulation is different from that observed in bradykinin-stimulated A431 cells, suggesting that there are separate mechanisms of inositol-lipid hydrolysis involved.
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Affiliation(s)
- B C Tilly
- Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Utrecht
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18
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Wahl M, Carpenter G. Regulation of epidermal growth factor-stimulated formation of inositol phosphates in A-431 cells by calcium and protein kinase C. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68539-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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19
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Frelin C, Vigne P, Ladoux A, Lazdunski M. The regulation of the intracellular pH in cells from vertebrates. EUROPEAN JOURNAL OF BIOCHEMISTRY 1988; 174:3-14. [PMID: 2836200 DOI: 10.1111/j.1432-1033.1988.tb14055.x] [Citation(s) in RCA: 257] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Eukaryotic cells control their intracellular pH using ion-transporting systems that are situated in the plasma membrane. This paper describes the different mechanisms that are involved and how their activity is regulated.
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Affiliation(s)
- C Frelin
- Centre de Biochimie, Centre National de la Recherche Scientifique, Nice, France
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Nygren P, Gylfe E, Larsson R, Johansson H, Juhlin C, Klareskoq L, Akerström G, Rastad J. Modulation of the Ca2+-sensing function of parathyroid cells in vitro and in hyperparathyroidism. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 968:253-60. [PMID: 3342264 DOI: 10.1016/0167-4889(88)90014-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
When raising the extracellular Ca2+ concentration stepwise from 0.5 to 3.0 mM, bovine parathyroid cells reacted with initial transient and sustained elevations of the cytoplasmic Ca2+ concentration (Ca2+i), as well as more than 50% inhibition of parathyroid hormone (PTH) release. Human parathyroid adenoma cells and bovine cells cultured for 1 day or exposed to a low concentration of a monoclonal antiparathyroid antibody exhibited right-shifted dependencies of PTH release and Ca2+i on extracellular Ca2+ and reduced Ca2+i transients. The protein kinase C activator 12-O-tetradecanoylphorbol-13-acetate (TPA) further right-shifted the dose response relationship for Ca2+ regulated Ca2+i of the adenoma cells, whereas the protein kinase C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) tended to normalize it, without affecting Ca2+i of normal bovine cells. In cells from an oxyphil adenoma and a parathyroid carcinoma as well as in bovine cells cultured 4 days or exposed to a high concentration of the antiparathyroid antibody, there were no Ca2+i transients, very small increases in steady-state Ca2+i and nonsuppressible PTH release. The results suggest that reduced availability of a putative Ca2+-receptor and increased protein kinase C activity may be important factors in the decreased Ca2+ sensitivity of abnormal parathyroid cells.
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Affiliation(s)
- P Nygren
- Department of Medical Cell Biology, University of Uppsala, Sweden
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Abstract
Several ion fluxes are stimulated when mitogenic polypeptides are added to cells. The precise mechanism by which this activation takes place is not understood, but compelling evidence exists in the case of the activation of sodium-hydrogen exchange that it requires the tyrosine kinase activity associated with the mitogen receptor. The activation of sodium-hydrogen exchange by mitogens is associated with changes in intracellular pH that appear to be permissive but not causal in allowing cells to proceed through the cell cycle. When added to cells, mitogens also activate protein kinase C, which acts as part of a feedback loop to control the activity of the mitogen receptor. Possible mechanisms for this control are discussed.
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Affiliation(s)
- L Glaser
- Department of Biological Chemistry, Washington University School of Medicine, St. Louis, Missouri
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Modification of the internal pH sensitivity of the Na+/H+ antiporter by parathyroid hormone in a cultured renal cell line. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)48055-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Young S, Parker PJ, Ullrich A, Stabel S. Down-regulation of protein kinase C is due to an increased rate of degradation. Biochem J 1987; 244:775-9. [PMID: 3446191 PMCID: PMC1148063 DOI: 10.1042/bj2440775] [Citation(s) in RCA: 361] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The phorbol-ester-induced loss of protein kinase C that has been documented in many cell types appears to be a critical event in the generation of a cellular refractory state. We have investigated here the synthesis and degradation of the protein kinase C polypeptide in order to determine why its steady-state amounts are depleted in response to phorbol esters. These results indicate that depletion is due to an increased rate of degradation, with no change either in mRNA amounts or in rates of polypeptide synthesis.
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Affiliation(s)
- S Young
- Imperial Cancer Research Fund, Lincoln's Inn Fields, London, U.K
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Kariya K, Fukumoto Y, Tsuda T, Kawahara Y, Fukuzaki H, Yamamoto T, Takai Y. Inhibition of DNA synthesis by phorbol esters through protein kinase C in cultured rabbit aortic smooth muscle cells. FEBS Lett 1987; 217:69-73. [PMID: 3496241 DOI: 10.1016/0014-5793(87)81245-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In cultured rabbit aortic smooth muscle cells (SMC), 12-O-tetradecanoylphorbol-13-acetate (TPA) induced DNA synthesis in the presence of plasma-derived serum to a small extent, but inhibited markedly the rabbit whole blood serum (WBS)-, platelet-derived growth factor (PDGF)- and epidermal growth factor-induced DNA synthesis. Phorbol-12,13-dibutyrate (PDBu) mimicked this antiproliferative action of TPA, but 4 alpha-phorbol-12,13-didecanoate was inactive in this capacity. Prolonged treatment of the cells with PDBu caused the partial down-regulation of protein kinase C. In these protein kinase C-reduced cells, WBS still induced DNA synthesis, but TPA did not inhibit the WBS-induced DNA synthesis. We have previously shown that protein kinase C is involved at least partially in the PDGF-induced DNA synthesis in rabbit aortic SMC. The present results together with this earlier observation suggest that protein kinase C has not only a proliferative but also an antiproliferative action in rabbit aortic SMC.
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26
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Angiotensin II-stimulated Na+/H+ exchange in cultured vascular smooth muscle cells. Evidence for protein kinase C-dependent and -independent pathways. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)61153-6] [Citation(s) in RCA: 169] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
Catecholamines were found to activate Na/H exchange in a concentration-dependent manner in primary cultures of vascular smooth muscle cells (VSMC). The potency order was found to be epinephrine greater than norepinephrine greater than isoproterenol. The major pathway for catecholamine effects appeared to be via interaction with an alpha 1 adrenergic receptor. In addition, it was found that alpha 1 receptor-mediated Na/H exchange in VSMC was increased by angiotensin II and inhibited by 12-O-tetradecanoyl phorbol-13-acetate (TPA). Adrenergic receptors have been shown to be coupled to both adenylate cyclase and to inositol phosphate release (Leeb-Lundberg, L. M. F., S. Cotecchia, J. W. Lomasney, J. F. DeBernadis, R. J. Lefkowitz, and M. G. Caron, 1985, Proc. Natl. Acad. Sci. USA, 82:5651-5655.). It was found that catecholamines increased AMP levels in the potency order isoproterenol greater than norepinephrine greater than epinephrine and the receptor involved was a beta adrenergic receptor. Since these findings did not parallel the results obtained for catecholamine stimulation of Na/H exchange, an increase in AMP levels was probably not the mechanism by which major pathway for catecholamine-stimulated Na/H exchange in VSMC (via the alpha 1 receptor) was activated. When the effects of catecholamines were measured on inositol phosphate release, the potency order for catecholamine stimulation was epinephrine greater than norepinephrine greater than isoproterenol, and the receptor involved was an alpha 1 adrenergic receptor. In addition, angiotensin II increased and TPA inhibited catecholamine-stimulated inositol phosphate release. Since these findings paralleled the results obtained for catecholamine stimulation of Na/H exchange, inositol phosphate release may be the mechanism by which the major pathway for catecholamine-stimulated Na/H exchange in VSMC (via the alpha 1 receptor) was activated.
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30
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Jean T, Frelin C, Vigne P, Lazdunski M. The Na+/H+ exchange system in glial cell lines. Properties and activation by an hyperosmotic shock. EUROPEAN JOURNAL OF BIOCHEMISTRY 1986; 160:211-9. [PMID: 3021452 DOI: 10.1111/j.1432-1033.1986.tb09959.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The properties of the Na+/H+ exchange system in the glial cell lines C6 and NN were studied from 22Na+ uptake experiments and measurements of the internal pH (pHi) using intracellularly trapped biscarboxyethyl-carboxyfluorescein. In both cell types, the Na+/H+ exchanger is the major mechanism by which cells recover their pHi after an intracellular acidification. The exchanger is inhibited by amiloride and its derivatives. The pharmacological profile (ethylisopropylamiloride greater than amiloride greater than benzamil) is identical for the two cell lines. Both Na+ and Li+ can be exchanged for H+. Increasing the external pH increases the activity of the exchanger in the two cell lines. In NN cells the external pH dependence of the exchanger is independent of the pHi. In contrast, in C6 cells, changing the pHi value from 7.0 to 6.5 produces a pH shift of 0.6 pH units in the external pH dependence of the exchanger in the acidic range. Decreasing pHi activates the Na+/H+ exchanger in both cell lines. Increasing the osmolarity of the external medium with mannitol produces an activation of the exchanger in C6 cells, which leads to a cell alkalinization. Mannitol action on 22Na+ uptake and the pHi were not observed in the presence of amiloride derivatives. Mannitol produces a modification of the properties of interaction of the antiport with both internal and external H+. It shifts the pHi dependence of the system to the alkaline range and the external pH (pHo) dependence to the acidic range. It also suppresses the interdependence of pHi and pHo controls of the exchanger's activity. NN cells that possess an Na+/H+ exchange system with different properties do not respond to mannitol by an increased activity of the Na+/H+ exchanger. The action of mannitol on C6 cells is unlikely to be mediated by an activation of protein kinase C.
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31
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Whiteley B, Glaser L. Epidermal growth factor (EGF) promotes phosphorylation at threonine-654 of the EGF receptor: possible role of protein kinase C in homologous regulation of the EGF receptor. J Cell Biol 1986; 103:1355-62. [PMID: 3021781 PMCID: PMC2114331 DOI: 10.1083/jcb.103.4.1355] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Treatment of cells with tumor-promoting phorbol diesters, which causes activation of protein kinase C, leads to phosphorylation of the epidermal growth factor (EGF) receptor at threonine-654. Addition of phorbol diesters to intact cells causes inhibition of the EGF-induced tyrosine-protein kinase activity of the EGF receptor and it has been suggested that this effect of phorbol diesters is mediated by the phosphorylation of the receptor by protein kinase C. We measured the activity of protein kinase C in A431 cells by determining the incorporation of [32P]phosphate into peptides containing threonine-654 obtained by trypsin digestion of EGF receptors. After 3 h of exposure to serum-free medium, A431 cells had no detectable protein kinase C activity. Addition of EGF to these cells resulted in [32P] incorporation into threonine-654 as well as into tyrosine residues. This indicates that EGF promotes the activation of protein kinase C in A431 cells. The phosphorylation of threonine-654 induced by EGF was maximal after only 5 min of EGF addition and the [32P] incorporation into threonine-654 reached 50% of the [32P] in a tyrosine-containing peptide. This indicates that a significant percentage of the total EGF receptors are phosphorylated by protein kinase C. A variety of external stimuli activate Na+/H+ exchange, including EGF, phorbol diesters, and hypertonicity. To ascertain whether activation of protein kinase C is an intracellular common effector of all of these systems, we measured the activity of protein kinase C after exposure of A431 cells to hyperosmotic conditions and observed no effect on phosphorylation of threonine-654, therefore, activation of Na+/H+ exchange by hypertonic medium is independent of protein kinase C activity. Since stimulation of protein kinase C by phorbol diesters results in a decrease in EGF receptor activity, the stimulation of protein kinase C activity by addition of EGF to A431 cells contributes to a feedback mechanism which results in the attenuation of EGF receptor function.
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Connolly TM, Lawing WJ, Majerus PW. Protein kinase C phosphorylates human platelet inositol trisphosphate 5'-phosphomonoesterase, increasing the phosphatase activity. Cell 1986; 46:951-8. [PMID: 3019558 DOI: 10.1016/0092-8674(86)90077-2] [Citation(s) in RCA: 317] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Phosphoinositide breakdown in response to thrombin stimulation of human platelets results in the formation of the calcium-mobilizing messenger molecules inositol 1,4,5-trisphosphate and inositol 1,2-cyclic-4,5-trisphosphate and of diglyceride, which activates protein kinase C. We find that protein kinase C phosphorylates and thereby increases the activity of inositol 1,4,5-trisphosphate 5'-phosphomonoesterase, a phosphatase that hydrolyzes these molecules to inert compounds. The 5'-phosphomonoesterase phosphorylated using [gamma-32P]ATP comigrates on SDS-polyacrylamide gels with a protein (40 kd) phosphorylated rapidly in response to thrombin stimulation of 32PO4-labeled platelets. Peptide maps of proteolytic digests of these two phosphorylated proteins indicate that they are the same. We propose that platelet Ca2+ mobilization is regulated by protein kinase C phosphorylation of the inositol 1,4,5-trisphosphate 5'-phosphomonoesterase. These results explain the observation that phorbol ester treatment of intact human platelets results in decreased levels of inositol trisphosphate and decreased Ca2+ mobilization upon subsequent thrombin addition.
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Activation of 45Ca2+ influx and 22Na+/H+ exchange by epidermal growth factor and vanadate in A431 cells is independent of phosphatidylinositol turnover and is inhibited by phorbol ester and diacylglycerol. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67657-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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34
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Vicentini LM, Villereal ML. Inositol phosphates turnover, cytosolic Ca++ and pH: putative signals for the control of cell growth. Life Sci 1986; 38:2269-76. [PMID: 3014243 DOI: 10.1016/0024-3205(86)90632-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The signals that induce a cell to divide are usually external and in the form of a binding of growth factors. We focussed our attention in defining the sequence of events which occurs after the binding of the mitogens to their surface receptors. One of the early membrane events stimulated by growth factors is a Na+ flux coupled to a H+ efflux that is typically inhibited by amiloride. The importance of this event and of the consequent cytoplasmic alkalinization for the cell proliferation is discussed. Recent data indicate that mitogens increase intracellular Ca++ levels and activate protein kinase C by inducing the hydrolysis of membrane phosphoinositides. A role for Ca++ and protein kinase C in activating Na+/H+ A role for Ca++ and protein kinase C in activating Na+/H+ exchange system is discussed. Finally a model is presented that illustrates the first membrane events stimulated by the growth factors. The model reveals an intimate interconnections between phosphoinositide metabolism, cytosolic Ca++ rise, protein kinase C and cytoplasmic alkalinization.
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Schimmel RJ, Dzierzanowski D, Elliott ME, Honeyman TW. Stimulation of phosphoinositide metabolism in hamster brown adipocytes exposed to alpha 1-adrenergic agents and its inhibition with phorbol esters. Biochem J 1986; 236:757-64. [PMID: 3024623 PMCID: PMC1146908 DOI: 10.1042/bj2360757] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The present experiments were undertaken to investigate the role of the phosphoinositides phosphatidylinositol 4-phosphate (PtdIns-4-P) and phosphatidylinositol 4,5-biphosphate (PtdIns-4,5-P2) in the alpha 1-adrenergic stimulation of respiration in isolated hamster brown adipocytes. Exposure of isolated brown adipocytes to the alpha-adrenergic-receptor agonist phenylephrine provoked a breakdown of 30-50% of the PtdIns-4-P and PtdIns-4,5-P2 after prelabelling of the cells with [32P]Pi. Coincident with the breakdown of phosphoinositides was an accumulation of labelled phosphatidic acid, which continued for the duration of the cell incubation. The time course of phosphoinositide breakdown was defined more precisely by pulse-chase experiments. Under these conditions, phenylephrine caused radioactivity in phosphatidylinositol, PtdIns-4-P and PtdIns-4,5-P2 to fall by more than 50% within 30 s and to remain at the depressed value for the duration of the incubation (10 min). This phospholipid response to alpha-adrenergic stimulation was blocked by exposure of the cells to phorbol 12-myristate 13-acetate (PMA); likewise phenylephrine stimulation of respiration was prevented by PMA. beta-Adrenergic stimulation of respiration and inhibition of respiration by 2-chloroadenosine and insulin were, however, unaffected by treatment with PMA. On the assumption that PMA is acting in these cells as an activator of protein kinase C, these results suggest the selective interruption of alpha-adrenergic actions in brown adipocytes by activated protein kinase C. These findings suggest that breakdown of phosphoinositides is an early event in alpha-adrenergic stimulation of brown adipocytes which may be important for the subsequent stimulation of respiration. The results from the pulse-chase studies also suggest, however, that phenylephrine-stimulated breakdown of inositol phospholipids is a short-lived event which does not appear to persist for the entire period of exposure to the alpha 1-adrenergic ligand.
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36
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Protein phosphorylation during activation of Na+/H+ exchange by phorbol esters and by osmotic shrinking. Possible relation to cell pH and volume regulation. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)57504-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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37
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Shen SS, Burgart LJ. 1,2-Diacylglycerols mimic phorbol 12-myristate 13-acetate activation of the sea urchin egg. J Cell Physiol 1986; 127:330-40. [PMID: 3009501 DOI: 10.1002/jcp.1041270222] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Phorbol diesters have been reported to stimulate the Na+/H+ antiport of a variety of cells including sea urchin eggs. Since stimulation of the Na+/H+ antiport is necessary for metabolic derepression during fertilization and protein kinase C is a target of phorbol diesters, enhanced Na+/H+ exchange during fertilization may be a result of protein kinase C activity. Protein kinase C is probably physiologically activated by diacylglycerols, which are derived from hydrolysis of phosphatidylinositol. Treatment of sea urchin eggs with 1,2-diacylglycerols was found to stimulate the Na+/H+ antiport. The 1,3-isomers were without effect. Further, the effects of 1,2-diacylglycerol and phorbol diester are not additive with respect to Na+/H+ exchange. While a direct participation of protein kinase C activity during fertilization remains to be demonstrated, these data support the hypothesis that protein kinase C activity plays a role in fertilization. However, the cytotoxic effect of protein kinase C activators suggests effects associated with their pleiotropic nature.
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38
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Paris S, Pouysségur J. Growth factors activate the bumetanide-sensitive Na+/K+/Cl-cotransport in hamster fibroblasts. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(19)84545-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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39
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Na+/H+ exchange in Ehrlich ascites tumor cells. Regulation by extracellular ATP and 12-O-tetradecanoylphorbol 13-acetate. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(17)38533-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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40
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Olsnes S, Carvajal E, Sandvig K. Interactions between diphtheria toxin entry and anion transport in vero cells. III. Effect on toxin binding and anion transport of tumor-promoting phorbol esters, vanadate, fluoride, and salicylate. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(17)35976-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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42
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Cassel D, Rothenberg P, Whiteley B, Mancuso D, Schlessinger P, Reuss L, Cragoe E, Glaser L. Chapter 9 Control of Mitogenic Activation of Na+-H+ Exchange. CURRENT TOPICS IN MEMBRANES AND TRANSPORT 1986. [DOI: 10.1016/s0070-2161(08)60731-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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43
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Grinstein S, Furuya W, Biggar WD. Cytoplasmic pH regulation in normal and abnormal neutrophils. Role of superoxide generation and Na+/H+ exchange. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(17)36120-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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44
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Moolenaar WH, Aerts RJ, Tertoolen LG, de Laat SW. The epidermal growth factor-induced calcium signal in A431 cells. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(17)42466-5] [Citation(s) in RCA: 174] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Chapter 11 B Lymphocyte Differentiation: Role of Phosphoinositides, C Kinase, and Na+-H+ Exchange. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/s0070-2161(08)60733-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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46
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Chapter 5 Early Stimulation of Na+-H+Antiport, Na+-K+Pump Activity, and Ca2+Fluxes in Fibroblast Mitogenesis. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/s0070-2161(08)60356-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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47
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Chapter 1 Mitogens and Ion Fluxes. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/s0070-2161(08)60352-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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48
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Vicentini LM, Villereal ML. Activation of Na+/H+ exchange in cultured fibroblasts: synergism and antagonism between phorbol ester, Ca2+ ionophore, and growth factors. Proc Natl Acad Sci U S A 1985; 82:8053-6. [PMID: 2999790 PMCID: PMC391440 DOI: 10.1073/pnas.82.23.8053] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The effects of phorbol 12-myristate 13-acetate (PMA), a potent activator of protein kinase C, on Na+ influx were investigated in cultured human foreskin fibroblasts (HSWP cells). We report here that in serum-deprived HSWP cells the addition of PMA alone has no significant effect on Na+ influx. However, the addition of PMA to cells whose Na+/H+ exchanger is partially activated with a submaximal dose of the Ca2+ ionophore A23187 leads to a larger stimulation than seen with A23187 alone. These data suggest that although stimulation of protein kinase C is not a sufficient signal to activate the Na+/H+ exchanger in HSWP cells or in another human foreskin line (Jackson fibroblasts) studied, there are some cooperative effects of protein kinase C activation with a rise in Ca2+ to stimulate Na+/H+ exchange. In addition, we found that PMA actually inhibits the mitogen-induced stimulation of Na+ influx in HSWP and Jackson fibroblasts. This observation strengthens the argument that in these cells activation of protein kinase C is not sufficient to activate Na+/H+ exchange and suggests that there is a negative feedback control via protein kinase C that inhibits some signal that is necessary for activating Na+/H+ exchange. However, in contrast to observations in HSWP cells, we were able to activate the Na+/H+ exchanger in mouse 3T3 and human WI-38 cells with PMA alone, suggesting that there is some diversity in the mechanism for activation of Na+/H+ exchange in different types of fibroblasts.
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Ahn J, Chang EB, Field M. Phorbol ester inhibition of Na-H exchange in rabbit proximal colon. THE AMERICAN JOURNAL OF PHYSIOLOGY 1985; 249:C527-30. [PMID: 3864381 DOI: 10.1152/ajpcell.1985.249.5.c527] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
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.
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Stimulation of the T3-T cell receptor-associated Ca2+ influx enhances the activity of the Na+/H+ exchanger in a leukemic human T cell line. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)38683-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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