Molecular cloning, chromosomal localization, tissue distribution, and functional expression of the human pancreatic sodium bicarbonate cotransporter.
AuthorsAbuladze N, Lee I, Newman D, Hwang J, Boorer K, Pushkin A, Kurtz I
JournalJ Biol Chem
PubMed ID9651366
We report the cloning, sequence analysis, tissue distribution, functional expression, and chromosomal localization of the human pancreatic sodium bicarbonate cotransport protein (pancreatic NBC (pNBC)). The transporter was identified by searching the human expressed sequence tag data base. An I.M.A.G.E. clone W39298 was identified, and a polymerase chain reaction probe was ... More
Kinetics of inactivation of the F1Fo ATPase of Propionigenium modestum by dicyclohexylcarbodiimide in relationship to H+ and Na+ concentration: probing the binding site for the coupling ions.
AuthorsKluge C, Dimroth P
JournalBiochemistry
PubMed ID8399181
Purified F1Fo ATPase of Propionigenium modestum was rapidly inactivated by dicyclohexylcarbodiimide (DCCD) with k2 = 1.2 x 10(5) M-1 min-1 at pH 5.6 and 0 degree C. Na+ ions provided specific protection from the modification by DCCD while protons stimulated the reaction. Plots of pseudo-first-order rate constants of inactivation (kobs) ... More
Identification of band 3-like proteins and Cl-/HCO3- exchange in isolated cardiomyocytes.
AuthorsPucéat M, Korichneva I, Cassoly R, Vassort G
JournalJ Biol Chem
PubMed ID7836397
'The identification of the protein that exerts the function of Cl-/HCO3- exchange is still unresolved in cardiac tissue. We have addressed this issue by using a multiple technical approach. Western blotting analysis with an antibody raised against human erythroid whole band 3 protein, the so-called protein that mediates the Cl-/HCO3- ... More
Amiloride analogues induce responses in isolated rat cardiovascular tissues by inhibition of Na+/Ca2+ exchange.
AuthorsBrown L, Cragoe EJ, Abel KC, Manley SW, Bourke JR
JournalNaunyn Schmiedebergs Arch Pharmacol
PubMed ID1834951
'The role of inhibition of Na+/Ca2+ exchange in the positive inotropic, negative chronotropic and vasorelaxant responses to amiloride and some of its analogues was investigated in isolated cardiovascular tissues from female Wistar rats. The compounds tested were amiloride, 5-(N-ethyl-N-isopropyl)amiloride (EIPA, a potent inhibitor of Na+/H+ exchange), phenamil and 2'',4''-dimethylbenzamil (DMB), ... More
Regulation of intracellular pH in the perfused heart by external HCO3- and Na(+)-H+ exchange.
AuthorsGrace AA, Kirschenlohr HL, Metcalfe JC, Smith GA, Weissberg PL, Cragoe EJ, Vandenberg JI
JournalAm J Physiol
PubMed ID8393626
'Both Na(+)-dependent HCO3- influx and the Na(+)-H+ antiport have been shown to contribute to recovery from intracellular acidosis in avian and mammalian cardiac tissue. We have investigated the participation of these mechanisms in the recovery of intracellular pH (pHi) after an acid load in the Langendorff-perfused ferret heart. pHi was ... More
Volume-dependent regulation of sodium and potassium fluxes in cultured vascular smooth muscle cells: dependence on medium osmolality and regulation by signalling systems.
'To identify ion transport systems involved in the maintenance of vascular smooth muscle cell volume the effects of incubation medium osmolality and ion transport inhibitors on the volume and 86Rb and 22Na transport in cultured smooth muscle cells from rat aorta (VSMC) have been studied. A decrease of medium osmolality ... More
Epidermal growth factor elevates intracellular pH in chicken granulosa cells.
AuthorsLi M, Morley P, Asem EK, Tsang BK
JournalEndocrinology
PubMed ID1649743
'Many bioregulators, such as epidermal growth factor (EGF), induce intracellular alkalinization by activating a membrane bound Na+/H+ antiporter. The present studies were designed to examine the influence of EGF on intracellular pH (pHi) in chicken granulosa cells. pHi in granulosa cells from the two largest preovulatory follicles of hens was ... More
'The effects of two amiloride analogues, ethylisopropylamiloride and methylisopropylamiloride, were tested on active Na+ transport and oxidative metabolism of a rabbit proximal renal tubule suspension. These two analogues have been recently reported to inhibit Na+-H+ antiport activity of various tissues with greater potency than amiloride. In proximal tubules, no effects ... More
Effects of angiotensin II on intracellular calcium and contracture in metabolically inhibited cardiomyocytes.
AuthorsBoston DR, Koyama T, Rodriguez-Larrain J, Zou A, Su Z, Barry WH
JournalJ Pharmacol Exp Ther
PubMed ID9580618
'Angiotensin II (A-II) is known to potentiate ischemic dysfunction during ischemia, but the mechanisms involved are not completely established. We examined the effects of A-II on intracellular calcium concentration ([Ca++]i) and cell contracture caused by metabolic inhibition in isolated adult rabbit ventricular myocytes. [Ca++]i was assessed by flow cytometry, using ... More
Analysis of ion transport perturbations caused by hu MDR 1 protein overexpression.
AuthorsHoffman MM, Roepe PD
JournalBiochemistry
PubMed ID9287158
'In previous work [Luz et al. (1994) Biochemistry 33, 7239-7249; Roepe et al. (1994) Biochemistry 33, 11008-11015] we measured changes in Cl- and HCO3--dependent pHi regulation for LR73 Chinese hamster ovary fibroblasts overexpressing mu MDR 1 protein. However, only one clonal cell line overexpressing the protein but not previously exposed ... More
Opposite effects of pressurized steady versus pulsatile perfusion on vascular endothelial cell cytosolic pH: role of tyrosine kinase and mitogen-activated protein kinase signaling.
AuthorsWittstein IS, Qiu W, Ziegelstein RC, Hu Q, Kass DA
JournalCirc Res
PubMed ID10864913
'Endothelial cytosolic pH (pH(i)) modulates ion channel function, vascular tone, and cell proliferation. Steady shear induces rapid acidification in bicarbonate buffer. However, in vivo shear is typically pulsatile, potentially altering this response. We tested effects and mechanisms of pH(i) modulation by flow pulsatility, comparing pressurized steady versus pulse-flow responses in ... More
An epithelial high-affinity amiloride-binding site, different from the Na+ channel.
AuthorsGoldstein O, Asher C, Barbry P, Cragoe E, Clauss W, Garty H
JournalJ Biol Chem
PubMed ID8385123
'Specific binding of the radioactive amiloride analogues [3H]phenamil and [3H]benzamil was studied in plasma membrane from chicken lower intestine. A single population of sites whose affinities and specificities towards pyrazinecarboxamides roughly resemble those of the epithelial Na+ channel, was identified. However, a matched comparison of pyrazinecarboxamide binding and Na+ transport ... More
Activation of the Na(+)-H+ exchanger modulates angiotensin II-stimulated Na(+)-dependent Mg2+ transport in vascular smooth muscle cells in genetic hypertension.
AuthorsTouyz RM, Schiffrin EL
JournalHypertension
PubMed ID10489391
'This study investigated the role of the Na(+)-H+ exchanger (NHE) on angiotensin II (Ang II)-induced activation of Na(+)-dependent Mg2+ transport in vascular smooth muscle cells (VSMCs) from Wistar-Kyoto rats (WKY; n=20) and spontaneously hypertensive rats (SHR; n=20). Intracellular free concentrations of Mg2+ ([Mg2+]i) and Na+ ([Na+]i) and intracellular pH (pHi) ... More
Characterisation of proton fluxes across the cytoplasmic membrane of the yeast Saccharomyces cerevisiae.
AuthorsHaworth RS, Lemire BD, Crandall D, Cragoe EJ, Fliegel L
JournalBiochim Biophys Acta
PubMed ID1661160
'We have tested the efficacy of fluorescent probes for the measurement of intracellular pH in Saccharomyces cerevisiae. Of the compounds tested (fluorescein, carboxyseminaphthorhodafluor-1 (C.SNARF-1) and 2'',7''bis(carboxyethyl)-5(6'')-carboxyfluorescein), C.SNARF-1 was found to be the most useful indicator of internal pH. Fluorescence microscopy showed that in Saccharomyces cerevisiae strain DAUL1, C.SNARF-1 and fluorescein ... More
Transporters involved in regulation of intracellular pH in primary cultured rat brain endothelial cells.
AuthorsTaylor CJ, Nicola PA, Wang S, Barrand MA, Hladky SB,
JournalJ Physiol
PubMed ID16916905
'Fluid secretion across the blood-brain barrier, critical for maintaining the correct fluid balance in the brain, entails net secretion of HCO(3)(-), which is brought about by the combined activities of ion transporters situated in brain microvessels. These same transporters will concomitantly influence intracellular pH (pH(i)). To analyse the transporters that ... More
Differential stimulation of the Na+/H+ exchanger determines chloroquine uptake in Plasmodium falciparum.
AuthorsWünsch S, Sanchez CP, Gekle M, Grosse-Wortmann L, Wiesner J, Lanzer M
JournalJ Cell Biol
PubMed ID9442109
'Here we describe the identification and characterization of a physiological marker that is associated with the chloroquine-resistant (CQR) phenotype in the human malarial parasite Plasmodium falciparum. Single cell in vivo pH measurements revealed that CQR parasites consistently have an elevated cytoplasmic pH compared to that of chloroquine-sensitive (CQS) parasites because ... More
Assessment of uncoupling by amiloride analogs.
AuthorsDavies K, Solioz M
JournalBiochemistry
PubMed ID1324725
'The amiloride analogs N5-methyl-N5-isobutylamiloride, N5-ethyl-N5-isopropylamiloride, and N5,N5-hexamethyleneamiloride are frequently used to investigate NaH exchange on the premise that they are highly specific inhibitors of the NaH-antiporters. We assessed the relative protonophoric activity of these compounds in reconstituted and native membrane vesicles, using acridine orange fluorescence to measure intravesicular pH. All ... More
Targeted disruption of the Nhe1 gene prevents muscarinic agonist-induced up-regulation of Na(+)/H(+) exchange in mouse parotid acinar cells.
AuthorsEvans RL, Bell SM, Schultheis PJ, Shull GE, Melvin JE
JournalJ Biol Chem
PubMed ID10506152
'The onset of salivary gland fluid secretion in response to muscarinic stimulation is accompanied by up-regulation of Na(+)/H(+) exchanger (NHE) activity. Although multiple NHE isoforms (NHE1, NHE2, and NHE3) have been identified in salivary glands, little is known about their specific function(s) in resting and secreting acinar cells. Mice with ... More
Glucose-induced increase in cytoplasmic pH in pancreatic beta-cells is mediated by Na+/H+ exchange, an effect not dependent on protein kinase C.
AuthorsJuntti-Berggren L, Arkhammar P, Nilsson T, Rorsman P, Berggren PO
JournalJ Biol Chem
PubMed ID1660875
'Glucose-induced changes in cytoplasmic pH (pHi) were investigated using pancreatic beta-cells isolated from obese hyperglycemic mice. Glucose, at concentrations above 3-5 mM, depolarized the beta-cell and increased pHi, cytoplasmic free Ca2+ ([Ca2+]i), and insulin release. This increase in pHi was dependent on the presence of extracellular Na+ and was inhibited ... More
G protein regulation of the Na+/H+ antiporter in Xenopus laevis oocytes. Involvement of protein kinases A and C.
AuthorsBusch S, Wieland T, Esche H, Jakobs KH, Siffert W
JournalJ Biol Chem
PubMed ID7629094
'We have characterized the regulation of the endogenous Na+/H+ exchanger in Xenopus laevis oocytes by G proteins and protein kinases by measuring the ethylisopropylamiloride-sensitive Li+ uptake. Injection of oocytes with the stable GTP analog GTP gamma S stimulated Li+ uptake up to almost 4-fold, an effect blocked by coinjection with ... More
Amiloride-sensitive Na+ conductance in native Xenopus oocytes.
AuthorsWeber WM, Liebold KM, Clauss W
JournalBiochim Biophys Acta
PubMed ID7488625
'Endogenous Na+ conductances in the plasma membrane of oocytes of the South African clawed toad Xenopus laevis were investigated by microelectrode techniques and influx measurements. Removal of Na+ from the bath solution under voltage clamp conditions led to a decrease in the clamp current indicating the existence of native Na+ ... More
A role for Na+/H+ exchange in contraction of guinea pig airways by endothelin-1 in vitro.
AuthorsBattistini B, Filep JG, Cragoe EJ, Fournier A, Sirois P
JournalBiochem Biophys Res Commun
PubMed ID1850247
'Endothelin-1-induced contractions of guinea pig tracheal and bronchial strips were dose-dependently attenuated by the amiloride analogues 5-(N-ethyl-N-isopropyl)amiloride (EIPA, 1-10 microM) and 5-(N,N-hexamethylene)amiloride (HMA, 1-10 microM). The calculated Ki values for EIPA and HMA were 0.11 +/- 0.02 microM and 0.06 +/- 0.02 microM in the trachea, and 0.28 +/- 0.11 ... More
Apoptosis in an interleukin-2-dependent cytotoxic T lymphocyte cell line is associated with intracellular acidification. Role of the Na(+)/H(+)-antiport.
AuthorsLi J, Eastman A
JournalJ Biol Chem
PubMed ID7852405
'Apoptosis is a form of cell death associated with DNA fragmentation and chromatin condensation. We recently established that intracellular acidification occurred during apoptosis following cytotoxic insult. The current studies were designed to determine whether intracellular acidification was more generally associated with apoptosis, specifically in a model of growth factor withdrawal. ... More
Cytoplasmic domain of the ubiquitous Na+/H+ exchanger NHE1 can confer Ca2+ responsiveness to the apical isoform NHE3.
'The Na+/H+ exchanger isoforms NHE1 and NHE3 are regulated differently by various stimuli. Calcium has been recognized as one of the major second messengers in such exchanger regulation. We previously proposed that Ca(2+)-induced activation of NHE1 occurs via displacement of its autoinhibitory domain from the H+ modifier site due to ... More
Sodium entry mechanisms in distal convoluted tubule cells.
AuthorsGesek FA, Friedman PA
JournalAm J Physiol
PubMed ID7840252
'Sodium transport across apical membranes of distal convoluted tubules is thought to be mediated by Na-Cl cotransport and conductive Na entry. Immortalized mouse distal convoluted tubule cells were used to characterize Na entry pathways. Chlorothiazide, an inhibitor of Na-Cl cotransport, and amiloride, which blocks epithelial Na channels, reduced ouabain-suppressible oxygen ... More
The lung amiloride-sensitive Na+ channel: biophysical properties, pharmacology, ontogenesis, and molecular cloning.
AuthorsVoilley N, Lingueglia E, Champigny G, Mattéi MG, Waldmann R, Lazdunski M, Barbry P
JournalProc Natl Acad Sci U S A
PubMed ID8278374
'Water balance in the lung is controlled via active Na+ and Cl- transport. Electrophysiological measurements on lung epithelial cells demonstrated the presence of a Na+ channel that is inhibited by amiloride (K0.5 = 90 nM) and some of its derivatives such as phenamil (K0.5 = 19 nM) and benzamil (K0.5 ... More
Inhibition of colonic Na+ transport by amiloride analogues.
AuthorsBridges RJ, Cragoe EJ, Frizzell RA, Benos DJ
JournalAm J Physiol
PubMed ID2912138
'The potency of several amiloride analogues to inhibit electrogenic Na+ transport in colon from dexamethasone-treated rats was compared. Short-circuit current (Isc) across the colonic mucosa and 22Na+ uptake into membrane vesicles derived from colonic enterocytes was determined in dexamethasone-treated rats. Kinetic analysis of inhibition of Isc and 22Na+ uptake revealed ... More
Angiotensin II stimulates NHE3 activity by exocytic insertion of the transporter: role of PI 3-kinase.
Authorsdu Cheyron D, Chalumeau C, Defontaine N, Klein C, Kellermann O, Paillard M, Poggioli J
JournalKidney Int
PubMed ID12911544
'BACKGROUND: Low-concentration angiotensin II (Ang II) stimulates Na+/H+ exchanger 3 (NHE3) activity in renal proximal tubule mainly via angiotensin II type 1 (AT1) receptors. The mechanisms that mediate the increase in NHE3 activity elicited by Ang II remain incompletely settled. METHODS: To assess a potential role of NHE3 trafficking in ... More
Biochemical evidence for the presence of an amiloride binding protein in adult alveolar type II pneumocytes.
AuthorsOh Y, Matalon S, Kleyman TR, Benos DJ
JournalJ Biol Chem
PubMed ID1326526
'An amiloride binding protein in adult rat and rabbit alveolar type II (ATII) cells was characterized using three different antibodies against epithelial Na+ channel proteins. We found that 1) polyclonal antibodies raised against epithelial Na+ channel proteins from bovine kidney cross-react with a 135-kDa protein in ATII membrane vesicles on ... More
Essential requirement of cytosolic phospholipase A(2) for activation of the H(+) channel in phagocyte-like cells.
AuthorsLowenthal A, Levy R
JournalJ Biol Chem
PubMed ID10419467
'The NADPH oxidase-producing superoxide is the major mechanism by which phagocytes kill invading pathogens. We previously established a model of cytosolic phospholipase A(2) (cPLA(2))-deficient differentiated PLB-985 cells (PLB-D cells) and demonstrated that cPLA(2)-generated arachidonic acid (AA) is essential for NADPH oxidase activation (Dana, R., Leto, T., Malech, H., and Levy, ... More
Effects of bradykinin on cell volume and intracellular pH in NIH 3T3 fibroblasts expressing the ras oncogene.
AuthorsRitter M, Wöll E, Häussinger D, Lang F
JournalFEBS Lett
PubMed ID1322838
'BCECF fluorescence has been applied to determine intracellular pH (pHi) in NIH 3T3 fibroblasts expressing the Ha-ras oncogene (+ras) and otherwise identical cells not expressing the oncogene (-ras). In +ras cells, pHi is significantly more alkaline (6.79 +/- 0.03 n = 12) than in -ras cells (6.64 +/- 0.02, n ... More
Effects of barium and 5-(N-ethyl-N-isopropyl)-amiloride on proximal tubule ammonia transport.
'Ionic NH+4 transport is an important mode of ammonia transport in the proximal convoluted tubule (PCT). NH+4 transport via the Na-H exchanger has been previously demonstrated. Potassium channels are present in the proximal tubule, but their role in ammonia transport has not been evaluated. We studied rat PCTs perfused in ... More
NHE1, NHE2, and NHE4 contribute to regulation of cell pH in T84 colon cancer cells.
'The isoforms of the Na+/H+ exchanger present in T84 human colon cells were identified by functional and molecular methods. Cell pH was measured by fluorescence microscopy using the probe BCECF. Based on the pH recovery after an ammonium pulse and determination of buffering capacity of these cells, the rate of ... More
Cytosolic pH regulation in chicken enterocytes: Na(+)-independent regulatory cell alkalinization.
AuthorsPeral MJ, Calonge ML, Ilundáin AA
JournalBiochim Biophys Acta
PubMed ID7530492
'The mechanisms involved in intracellular pH (pHi) recovery from an acid load have been investigated in enterocytes isolated from chicken. Following an intracellular acidification, by abrupt withdrawal of NH4Cl, pHi alkalinized in the nominally absence of Na+ and bicarbonate. This Na(+)- and bicarbonate-independent (NBI) regulatory cell alkalinization became negligible when ... More
Effect of vacuolar proton ATPase on pHi, Ca2+, and apoptosis in neonatal cardiomyocytes during metabolic inhibition/recovery.
AuthorsKarwatowska-Prokopczuk E, Nordberg JA, Li HL, Engler RL, Gottlieb RA
JournalCirc Res
PubMed ID9633914
'Recently, we found that vacuolar proton ATPase (VPATPase) operates in cardiomyocytes as a complementary proton-extruding mechanism. Its activity was increased by preconditioning with resultant attenuation of intracellular acidification during ischemia. In this study, we examined whether VPATPase-mediated proton efflux during metabolic inhibition/recovery may spare Na+ overload via Na+-H+ exchange, attenuate ... More
Amiloride and 5-(N-ethyl-N-isopropyl) amiloride inhibit medium acidification and glucose metabolism by the fission yeast Schizosaccharomyces pombe.
AuthorsHaworth RS, Cragoe EJ, Fliegel L
JournalBiochim Biophys Acta
PubMed ID8431459
'We have investigated the mechanism by which amiloride and 5-(N-ethyl-N-isopropyl)amiloride (EIPA) inhibit glucose-stimulated medium acidification in the fission yeast Schizosaccharomyces pombe. The addition of glucose to an unbuffered suspension of cells results in the extrusion of acid. This process was inhibited by diethylstilbestrol (DES), an inhibitor of the H(+)-ATPase (IC50 ... More
Delineation of transmembrane domains of the Na+/H+ exchanger that confer sensitivity to pharmacological antagonists.
AuthorsOrlowski J, Kandasamy RA
JournalJ Biol Chem
PubMed ID8702706
'Plasma membrane Na+/H+ exchanger (NHE) isoforms NHE1 and NHE3 exhibit very different sensitivities to amiloride and its 5-amino-substituted analogues, benzoyl guanidinium derivatives (e.g. (3-methylsulfonyl-4-piperidinobenzoyl)guanidine methanesulfonate (HOE694)), and cimetidine. To define structural domains that confer differential sensitivity to these antagonists, unique restriction endonuclease sites were engineered into cDNAs for each isoform ... More
Angiotensin II activates Na+-independent Cl--HCO3- exchange in ventricular myocardium.
AuthorsCamilión de Hurtado MC, Alvarez BV, Pérez NG, Ennis IL, Cingolani HE
JournalCirc Res
PubMed ID9506708
'The effect of angiotensin II (Ang II) on the activity of the cardiac Na+-independent Cl--HCO3- exchanger (anionic exchanger [AE]) was explored in cat papillary muscles. pHi was measured by epifluorescence with BCECF-AM. Ang II (500 nmol/L) induced a 5-(N-ethyl-N-isopropyl)amiloride-sensitive increase in pHi in the absence of external HCO3- (HEPES buffer), ... More
Heterogeneous patterns of pH regulation in glial cells in the dorsal and ventral medulla.
AuthorsErlichman JS, Cook A, Schwab MC, Budd TW, Leiter JC
JournalAm J Physiol Regul Integr Comp Physiol
PubMed ID14525723
'We examined pH regulation in two chemosensitive areas of the brain, the retrotrapezoid nucleus (RTN) and the nucleus tractus solitarius (NTS), to identify the proton transporters involved in regulation of intracellular pH (pHi) in medullary glia. Transverse brain slices from young rats [postnatal day 8 (P8) to P20] were loaded ... More
Potentiation by adrenaline of thrombin-induced elevation of pHi is not essential for synergistic activation of human platelets.
AuthorsSteen VM, Cook CA, Tysnes OB, Holmsen H
JournalFEBS Lett
PubMed ID2546796
'Gel-filtrated human platelets were stimulated with thrombin in the absence and presence of adrenaline. Adrenaline markedly enhanced the thrombin-induced increase in cytoplasmic pH (pHi) in BCECF-loaded platelets. This rise in pHi was strongly inhibited by the Na+/H+ exchange blocker EIPA. The potentiation by adrenaline of thrombin-induced PLC activation measured as ... More
Direct characterization of the Na+/H+ exchanger in human platelets.
AuthorsAstarie C, David-Dufilho M, Devynck MA
JournalFEBS Lett
PubMed ID2176618
'The kinetic properties of the Na+/H+ exchanger in human platelets were investigated by direct measurements of pHi as detected with the fluorescent dye, BCECF. In acid-loaded cells, the antiporter displayed a hyperbolic dependence regarding external Na+ with an apparent Km of 38 +/- 4 mM (pHo 7.2 at 25 degrees ... More
Mechanisms of pHi regulation studied in individual neurons cultured from mouse cerebral cortex.
AuthorsPedersen SF, Jørgensen NK, Damgaard I, Schousboe A, Hoffmann EK
JournalJ Neurosci Res
PubMed ID9514197
'Maintenance and regulation of intracellular pH (pHi) was studied in single cultured mouse neocortical neurons using the fluorescent probe 2'',7''-bis-(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF). Reversal of the Na+ gradient by reduction of the extracellular Na+ concentration ([Na+]o) resulted in rapid intracellular acidification, inhibited by 5''-(N-ethyl-N-isopropyl)amiloride (EIPA), an inhibitor of Na+/H+ exchange. In the ... More
Regulation of mu-opioid receptor in neural cells by extracellular sodium.
AuthorsYabaluri N, Medzihradsky F
JournalJ Neurochem
PubMed ID9048750
'SH-SY5Y neural cells expressing mu- and delta-opioid receptors were maintained viable in isotonic, sodium-free buffer in vitro. Intracellular sodium levels were manipulated by various methods, and ligand binding to intact cells was studied. In physiological buffer containing 118 mM sodium, [3H]Tyr-D-Ala-Gly-(Me)Phe-Gly-ol ([3H]-DAMGO) and [3H]naltrexone bound to mu receptor with KD ... More
Apparent absence of Na+/H+ antiport activity in the two-cell mouse embryo.
AuthorsBaltz JM, Biggers JD, Lechene C
JournalDev Biol
PubMed ID2156738
We have used the pH-sensitive dye BCECF to investigate the regulation of intracellular pH (pHi) by two-cell stage mouse embryos in bicarbonate-free medium. There is no indication of a Na+/H+ antiport active in regulating pHi, as recovery from acid-loading was insensitive to amiloride, ethylisopropylamiloride, or the absence of extracellular Na+. ... More
Structure-activity relationships of amiloride and certain of its analogues in relation to the blockade of the Na+/H+ exchange system.
AuthorsVigne P, Frelin C, Cragoe EJ, Lazdunski M
JournalMol Pharmacol
PubMed ID6323947
Amiloride and 38 amiloride analogues were tested for their inhibitory action on the Na+/H+ exchanger of chick skeletal muscle cells. The unsubstituted guanidino group of amiloride is essential for the activity of the molecule, since substitution of its results in almost inactive molecules. Selected modification of position 3 and 5 ... More
Influence of extracellular pH on intracellular pH in arterioles and skeletal muscle of spontaneously hypertensive and Wistar-Kyoto rats.
AuthorsWimberger P, Marin-Grez M
JournalKidney Int Suppl
PubMed ID9736283
The effect of changing extracellular pH (pHo) on intracellular pH (pHi) in mesenteric arterioles of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats was investigated using the fluorescent indicator seminaphthorhodafluor c-SNARF-1 to measure pHi. Although the pHi of arterioles from WKY varied directly with pHo, that of SHR arterioles varied inversely. ... More
Amiloride and its analogs as tools to inhibit Na+ transport via the Na+ channel, the Na+/H+ antiport and the Na+/Ca2+ exchanger.
AuthorsFrelin C, Barbry P, Vigne P, Chassande O, Cragoe EJ, Lazdunski M
JournalBiochimie
PubMed ID2852509
Amiloride analogs inhibit a number of transmembrane Na+ transport systems: 1) the epithelium Na+ channel, 2) the Na+/H+ exchange system and 3) the Na+/Ca2+ exchange system. Structure--activity relationships using amiloride derivatives with selected modification of each of the functional groups of the molecule indicate that the 3 Na+ transporting systems ... More
The relationship between Na(+)/H(+) exchanger expression and tyrosinase activity in human melanocytes.
The activity of melanosome-associated tyrosinase in human melanocytes differs based on racial skin type. In melanocytes from Black skin, tyrosinase activity is high while in White melanocytes the activity of the enzyme is low. Recent studies suggest that low tyrosinase activity in White melanocytes may be due to an acidic ... More
Tissue-specific regulation of sodium/proton exchanger isoform 3 activity in Na(+)/H(+) exchanger regulatory factor 1 (NHERF1) null mice. cAMP inhibition is differentially dependent on NHERF1 and exchange protein directly activated by cAMP in ileum versus proximal tubule.
AuthorsMurtazina R, Kovbasnjuk O, Zachos NC, Li X, Chen Y, Hubbard A, Hogema BM, Steplock D, Seidler U, Hoque KM, Tse CM, De Jonge HR, Weinman EJ, Donowitz M,
JournalJ Biol Chem
PubMed ID17580307
The multi-PDZ domain containing protein Na(+)/H(+) Exchanger Regulatory Factor 1 (NHERF1) binds to Na(+)/H(+) exchanger 3 (NHE3) and is associated with the brush border (BB) membrane of murine kidney and small intestine. Although studies in BB isolated from kidney cortex of wild type and NHERF1(-/-) mice have shown that NHERF1 ... More
Flow cytometric kinetic assay of the activity of Na+/H+ antiporter in mammalian cells.
AuthorsDolz M, O'Connor JE, Lequerica JL,
JournalCytometry A
PubMed ID15382148
BACKGROUND: The Na(+)/H(+) exchanger (NHE) of mammalian cells is an integral membrane protein that extrudes H(+) ion in exchange for extracellular Na(+) and plays a crucial role in the regulation of intracellular pH (pHi). Thus, when pHi is lowered, NHE extrudes protons at a rate depending of pHi that can ... More
HCO3(-) secretion by murine nasal submucosal gland serous acinar cells during Ca2+-stimulated fluid secretion.
AuthorsLee RJ, Harlow JM, Limberis MP, Wilson JM, Foskett JK,
JournalJ Gen Physiol
PubMed ID18591422
Airway submucosal glands contribute to airway surface liquid (ASL) composition and volume, both important for lung mucociliary clearance. Serous acini generate most of the fluid secreted by glands, but the molecular mechanisms remain poorly characterized. We previously described cholinergic-regulated fluid secretion driven by Ca(2+)-activated Cl(-) secretion in primary murine serous ... More
Competitive inhibition of tritium-labeled platelet-activating factor binding to rabbit platelet membranes by amiloride and amiloride analogs.
AuthorsHwang SB
JournalBiochem Biophys Res Commun
PubMed ID2549986
Amiloride and its structural analogs, ethylisopropyl amiloride, benzamil, and dichlorobenzamil, inhibit both the specific [3H]C18-PAF binding to rabbit platelet membranes and PAF-induced aggregation of gel-filtered rabbit platelets. Detailed analysis of binding inhibitions demonstrate that ethylisopropyl amiloride is a competitive inhibitor with an equilibrium dissociation constant (KB) of 23 microM. The ... More
Na+/H+ exchange in porcine cerebral capillary endothelial cells is inhibited by a benzoylguanidine derivative.
AuthorsSchmid A, Scholz W, Lang HJ, Popp R
JournalBiochem Biophys Res Commun
PubMed ID1314582
Na+/H+ exchange activity has been examined in endothelial cells isolated from porcine brain capillaries. Intracellular pH (pHi) changes were monitored using a confocal laser scanning microscope and the pH-sensitive fluorescence indicator 2',7'-bis-(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF). Acid load of the brain capillary endothelial cells was performed with a NH4Cl (20 mM) prepulse. In ... More
Activation of sodium-proton exchange is not a prerequisite for Ca2+ mobilization and aggregation in human platelets.
AuthorsHunyady L, Sarkadi B, Cragoe EJ, Spät A, Gárdos G
JournalFEBS Lett
PubMed ID2826247
Recently it has been suggested [(1987) Nature 325, 456-458; (1987) FEBS Lett. 212, 123-126] that the activation of Na+/H+ exchange is a prerequisite for platelet aggregation and the development of the Ca2+ signal. As direct evidence for the role of the Na+/H+-exchange pathway the inhibition of the Ca2+ signal by ... More
Cloning, tissue distribution, genomic organization, and functional characterization of NBC3, a new member of the sodium bicarbonate cotransporter family.
AuthorsPushkin A, Abuladze N, Lee I, Newman D, Hwang J, Kurtz I
JournalJ Biol Chem
PubMed ID10347222
Previous functional studies have demonstrated that muscle intracellular pH regulation is mediated by sodium-coupled bicarbonate transport, Na+/H+ exchange, and Cl-/bicarbonate exchange. We report the cloning, sequence analysis, tissue distribution, genomic organization, and functional analysis of a new member of the sodium bicarbonate cotransporter (NBC) family, NBC3, from human skeletal muscle. ... More
Single-cell analysis of the intracellular pH and its regulation during the monocytic differentiation of U937 human leukemic cells.
AuthorsLadoux A, Miglierina R, Krawice I, Cragoe EJ, Abita JP, Frelin C
JournalEur J Biochem
PubMed ID3165863
Monocytic differentiation of U937 cells induced by retinoic acid is accompanied by a 0.2-pH-unit cell alkalinisation. The effect of retinoic acid on intracellular pH (pHi) develops slowly and it precedes the differentiation of the cells by 24 h. Heterogeneity in cellular pHi values was assessed using flow cytometry. It was ... More
Amiloride analogs induce the phosphorylation of elongation factor-2 in vascular endothelial cells.
AuthorsDemolle D, Lecomte M, Boutherin-Falson O, Cragoe EJ, Nairn AC, Boeynaems JM
JournalMol Pharmacol
PubMed ID2359404
5-(N-Ethyl-N-isopropyl)amiloride (EIPA), a potent inhibitor of Na+/H+ antiport, reduced [35S]methionine incorporation in proteins and induced the phosphorylation of a Mr 95,000 protein in bovine aortic endothelial cells. This protein was previously shown to become phosphorylated in response to ATP, bradykinin, and A23187 (1) and was identified as elongation factor-2 (2). ... More
Mechanisms of stimulus-evoked intracellular acidification in frog nerve fibres.
AuthorsKhodorov B, Valkina O, Turovetsky V
JournalFEBS Lett
PubMed ID8137911
Measurements of cytoplasmic pH (pHi) in frog nerve fibers (sciatic nerve and its thin bundles) were performed by using fluorescein diacetate. Earlier it had been established that veratridine (VER) treatment of the nerve greatly enhances the stimulus-evoked intracellular acidification (SEIA) which becomes irreversible after blockade of the Na+/K+ pump with ... More
Skeletal muscle Na+/H+ exchange in rats: pH dependency and the effect of training.
AuthorsJuel C
JournalActa Physiol Scand
PubMed ID9805099
Skeletal muscle Na+/H+ exchange was studied using giant sarcolemmal vesicles obtained from rat hind limb muscle. Experiments with either the 22Na tracer technique or with the Na+ sensitive fluorescent probe SBFI were conducted to determine the activity of the Na+/H+ exchanger, which was quantified from the amiloride or amiloride derivative ... More
Elicitor-activated phospholipase A(2) generates lysophosphatidylcholines that mobilize the vacuolar H(+) pool for pH signaling via the activation of Na(+)-dependent proton fluxes.
AuthorsViehweger K, Dordschbal B, Roos W
JournalPlant Cell
PubMed ID12119371
The elicitation of phytoalexin biosynthesis in cultured cells of California poppy involves a shift of cytoplasmic pH via the transient efflux of vacuolar protons. Intracellular effectors of vacuolar proton transport were identified by a novel in situ approach based on the selective permeabilization of the plasma membrane for molecules of ... More
Na(+)-dependent pH regulation by the amitochondriate protozoan parasite Giardia intestinalis.
Giardia intestinalis is a pathogenic fermentative parasite, which inhabits the gastrointestinal tract of animals and humans. G. intestinalis trophozoites are exposed to acidic fluctuations in vivo and must also cope with acidic metabolic endproducts. In this study, a combination of independent techniques ((31)P NMR spectroscopy, distribution of the weak acid ... More
Cellular uptake of chloroquine is dependent on binding to ferriprotoporphyrin IX and is independent of NHE activity in Plasmodium falciparum.
AuthorsBray PG, Janneh O, Raynes KJ, Mungthin M, Ginsburg H, Ward SA
JournalJ Cell Biol
PubMed ID10209030
Here we provide definitive evidence that chloroquine (CQ) uptake in Plasmodium falciparum is determined by binding to ferriprotoporphyrin IX (FPIX). Specific proteinase inhibitors that block the degradation of hemoglobin and stop the generation of FPIX also inhibit CQ uptake. Food vacuole enzymes can generate cell-free binding, using human hemoglobin as ... More
Use of cultured tubular cells isolated from human urine for investigation of renal transporter.
AuthorsInoue CN, Kondo Y, Ohnuma S, Morimoto T, Nishio T, Iinuma K
JournalClin Nephrol
PubMed ID10711410
AIM: To facilitate the understanding of the transporter function of human renal tubular cells, we have developed a simple method using primary cultured proximal tubule (PT) cells isolated from voided urine. METHODS: PT cells grown to confluence on glass coverslips could be identified by parallel arrays of spindle cells and ... More
Intracellular pH and the stimulus-secretion coupling in insulin-producing RINm5F cells.
AuthorsJuntti-Berggren L, Rorsman P, Siffert W, Berggren PO
JournalBiochem J
PubMed ID1417791
The regulation of intracellular pH (pHi) and its role in the insulin-secretory process were evaluated, by using the clonal insulin-secreting cell line RINm5F. Glyceraldehyde, lactate and dihydroxyacetone decreased pHi, but only the first two released insulin. In the presence of extracellular Na+ the cells counteracted the acidification. Blocking the Na+/H+ ... More
The Na(+)-H+ exchanger of the placental brush-border membrane is pharmacologically distinct from that of the renal brush-border membrane.
AuthorsKulanthaivel P, Leibach FH, Mahesh VB, Cragoe EJ, Ganapathy V
JournalJ Biol Chem
PubMed ID2153122
We have compared the pharmacological properties of the human placental brush-border membrane Na(+)-H+ exchanger with those of the rabbit renal brush-border membrane Na(+)-H+ exchanger. The exchanger activity in both preparations was inhibited by cimetidine, clonidine, and harmaline. Cimetidine was found to be 4-5 times more potent than clonidine in inhibiting ... More
Inhibition of both Na/H and bicarbonate-dependent exchange is required to prevent recovery of intracellular pH in single cardiomyocytes exposed to metabolic stress.
AuthorsSerrano OK, Jovanovic A, Terzic A
JournalBiosci Rep
PubMed ID10888472
Although tight regulation of intracellular pH (pHi) is critical for the survival under stress, paradoxically a slowed recovery of pHi under hypoxic injury may be cardioprotective. In this study, we investigated the recovery of pHi after hypoxia-induced intracellular acidosis in cardiomyocytes loaded with the H+-sensitive dye SNARF-1. Exposure of single ... More
Aldosterone influences free intracellular calcium in human mononuclear leukocytes in vitro.
AuthorsWehling M, Käsmayr J, Theisen K
JournalCell Calcium
PubMed ID2285925
Mineralocorticoid receptors have been detected in human mononuclear leukocytes (HML) and a physiological effector mechanism was demonstrated subsequently by which aldosterone is able to prevent the loss of intracellular sodium, potassium and cell water during incubation in an aldosterone-free medium. In the present paper, free intracellular calcium, [Ca2+]i, was measured ... More
pH regulation in the intracellular malaria parasite, Plasmodium falciparum. H(+) extrusion via a v-type h(+)-atpase.
AuthorsSaliba KJ, Kirk K
JournalJ Biol Chem
PubMed ID10559194
The mechanism by which the intra-erythrocytic form of the human malaria parasite, Plasmodium falciparum, extrudes H(+) ions and thereby regulates its cytosolic pH (pH(i)), was investigated using saponin-permeabilized parasitized erythrocytes. The parasite was able both to maintain its resting pH(i) and to recover from an imposed intracellular acidification in the ... More
Acute inhibition of brain-specific Na(+)/H(+) exchanger isoform 5 by protein kinases A and C and cell shrinkage.
AuthorsAttaphitaya S, Nehrke K, Melvin JE
JournalAm J Physiol Cell Physiol
PubMed ID11546650
Little is known of the functional properties of the mammalian, brain-specific Na(+)/H(+) exchanger isoform 5 (NHE5). Rat NHE5 was stably expressed in NHE-deficient PS120 cells, and its activity was characterized using the fluorescent pH-sensitive dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. NHE5 was insensitive to ethylisopropyl amiloride. The transport kinetics displayed a simple Michaelis-Menten relationship ... More
Cloning and expression of a rabbit cDNA encoding a serum-activated ethylisopropylamiloride-resistant epithelial Na+/H+ exchanger isoform (NHE-2).
AuthorsTse CM, Levine SA, Yun CH, Montrose MH, Little PJ, Pouyssegur J, Donowitz M
JournalJ Biol Chem
PubMed ID7685025
A unique Na+/H+ exchanger isoform, NHE-2, was cloned and characterized. NHE-2 is a protein of 809 amino acids with a calculated size of 90,787. It exhibits overall amino acid identity of 50, 44, and 60% with other cloned mammalian Na+/H+ exchangers NHE-1, NHE-3, and NHE-4, respectively. Northern blot analysis of ... More
Adenovirus triggers macropinocytosis and endosomal leakage together with its clathrin-mediated uptake.
Adenovirus type 2 (Ad2) binds the coxsackie B virus Ad receptor and is endocytosed upon activation of the alphav integrin coreceptors. Here, we demonstrate that expression of dominant negative clathrin hub, eps15, or K44A-dynamin (dyn) inhibited Ad2 uptake into epithelial cells, indicating clathrin-dependent viral endocytosis. Surprisingly, Ad strongly stimulated the ... More
Renal epithelial protein (Apx) is an actin cytoskeleton-regulated Na+ channel.
AuthorsPrat AG, Holtzman EJ, Brown D, Cunningham CC, Reisin IL, Kleyman TR, McLaughlin M, Jackson GR, Lydon J, Cantiello HF
JournalJ Biol Chem
PubMed ID8663566
Apx, the amphibian protein associated with renal amiloride-sensitive Na+ channel activity and with properties consistent with the pore-forming 150-kDa subunit of an epithelial Na+ channel complex initially purified by Benos et al. (Benos, D. J., Saccomani, G., and Sariban-Sohraby, S.(1987) J. Biol. Chem. 262, 10613-10618), has previously failed to generate ... More
Kinetic and pharmacological properties of human brain Na(+)/H(+) exchanger isoform 5 stably expressed in Chinese hamster ovary cells.
AuthorsSzabó EZ, Numata M, Shull GE, Orlowski J
JournalJ Biol Chem
PubMed ID10692428
The recently cloned Na(+)/H(+) exchanger isoform 5 (NHE5) is expressed predominantly in brain, yet little is known about its functional properties. To facilitate its characterization, a full-length cDNA encoding human NHE5 was stably transfected into NHE-deficient Chinese hamster ovary AP-1 cells. Pharmacological analyses revealed that H(+)(i)-activated (22)Na(+) influx mediated by ... More
Na-H exchange acts downstream of RhoA to regulate integrin-induced cell adhesion and spreading.
AuthorsTominaga T, Barber DL
JournalMol Biol Cell
PubMed ID9693382
The ubiquitously expressed Na-H exchanger NHE1 functions in regulating intracellular pH and cell volume. NHE1 activity is stimulated by hormones, growth factors, and activation of integrin receptors. We recently determined that NHE1 activity is also stimulated by activation of the low molecular weight GTPase RhoA and that increases in NHE1 ... More
Utilization of amiloride analogs for characterization and labeling of the plasma membrane Na+/H+ antiporter from Dunaliella salina.
AuthorsKatz A, Kleyman TR, Pick U
JournalBiochemistry
PubMed ID8117698
The interactions of amiloride analogs with the Na+/H+ antiporter from plasma membrane of the halotolerant alga Dunaliella salina [Katz et al. (1989) Biochem. Biophys. Acta 983, 9-14] have been investigated. Analogs bearing hydrophobic substitutions at the guanidino moiety of amiloride, such as benzamil, are the most effective inhibitors of Na+ ... More
Sodium overload through voltage-dependent Na(+) channels induces necrosis and apoptosis of rat superior cervical ganglion cells in vitro.
AuthorsKoike T, Tanaka S, Oda1 T, Ninomiya T
JournalBrain Res Bull
PubMed ID10704786
Using the failure to exclude trypan blue as a criterion for cell death, we found that veratridine, the voltage-dependent Na(+) channel activator, exerted its toxicity to cultured sympathetic neurons in a dose-dependent manner (half-maximal toxicity occurred at 2 microM). The co-presence of tetrodotoxin completely reversed the toxicity only at concentrations ... More
Apical membrane Na+/H+ exchange in rat medullary thick ascending limb. pH-dependence and inhibition by hyperosmolality.
AuthorsWatts BA, Good DW
JournalJ Biol Chem
PubMed ID8051116
Apical membrane Na+/H+ exchange mediates virtually all of transepithelial HCO3- absorption in the rat medullary thick ascending limb (MTAL). Regulation of the apical exchanger by intracellular pH (pHi) and hyperosmolality was studied in the isolated, perfused MTAL by measurement of pHi using the fluorescent probe 2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein. Under isosmotic conditions (290 ... More
Characterization of Mg2+ transport in brush border membrane vesicles of rabbit ileum studied with mag-fura-2.
AuthorsJüttner R, Ebel H
JournalBiochim Biophys Acta
PubMed ID9518549
Mg2+ transport in rabbit ileal brush border membrane vesicles (BBMV) was characterized by means of a modified mag-fura-2 technique. In the presence of an i>o Na+ gradient, BBMV showed a saturable Mg2+ uptake with a Km of 1.64 mmol l-1. There was no evidence of an overshoot. K+, Li+, and ... More
Intracellular pH regulation in cecal epithelial cells from the chick.
AuthorsCalonge ML, Peral MJ, Ilundáin A
JournalBiochim Biophys Acta
PubMed ID8274490
Intracellular pH (pHi) regulation has been investigated in cells isolated from the proximal ceca of the chicken. pHi was measured with the pH-sensitive dye, 2',7'-bis(carboxyethyl)-5 (6)-carboxyfluorescein in nominally HCO(3-)-free solutions. Under resting conditions the pHi was 7.08. Removal of extracellular Na+ decreased pHi by approx. 0.24 pH units and the ... More
Sodium-dependent antiporters in choroid plexus epithelial cultures from rabbit.
AuthorsMayer SE, Sanders-Bush E
JournalJ Neurochem
PubMed ID8384246
The mechanism of recovery from an acid load in primary cultures of rabbit choroid plexus epithelium (CPE) was examined, with emphasis on Na(+)-dependent antiports. Cells were incubated in saline solutions buffered to pH 7.38 with either HEPES or HCO3- plus 95% O2/5% CO2. Intracellular pH (pHi) was determined from the ... More
Role of Na+/H+ exchange and HCO3- transport in pHi recovery from intracellular acid load in cultured epithelial cells of sheep rumen.
AuthorsMüller F, Aschenbach JR, Gäbel G
JournalJ Comp Physiol [B]
PubMed ID10935525
This study sought to investigate effects of short-chain fatty acids and CO2 on intracellular pH (pHi) and mechanisms that mediate pHi recovery from intracellular acidification in cultured ruminal epithelial cells of sheep. pHi was studied by spectrofluorometry using the pH-sensitive fluorescent indicator 2',7'-bis (carboxyethyl)-5(6')-carboxyfluorescein acetoxymethyl ester (BCECF/AM). The resting pHi ... More
Loss of GSH, oxidative stress, and decrease of intracellular pH as sequential steps in viral infection.
AuthorsCiriolo MR, Palamara AT, Incerpi S, Lafavia E, Buè MC, De Vito P, Garaci E, Rotilio G
JournalJ Biol Chem
PubMed ID9006907
Madin-Darby canine kidney cells infected with Sendai virus rapidly lose GSH without increase in the oxidized products. The reduced tripeptide was quantitatively recovered in the culture medium of the cells. Since the GSH loss in infected cells was not blocked by methionine, a known inhibitor of hepatocyte GSH transport, a ... More
Macula densa Na(+)/H(+) exchange activities mediated by apical NHE2 and basolateral NHE4 isoforms.
AuthorsPeti-Peterdi J, Chambrey R, Bebok Z, Biemesderfer D, St John PL, Abrahamson DR, Warnock DG, Bell PD
JournalAm J Physiol Renal Physiol
PubMed ID10710550
Functional and immunohistochemical studies were performed to localize and identify Na(+)/H(+) exchanger (NHE) isoforms in macula densa cells. By using the isolated perfused thick ascending limb with attached glomerulus preparation dissected from rabbit kidney, intracellular pH (pH(i)) was measured with fluorescence microscopy by using 2',7'-bis-(2-carboxyethyl)-5-(and -6) carboxyfluorescein. NHE activity was ... More
Extracellular ATP stimulates an amiloride-sensitive sodium influx in human lymphocytes.
AuthorsWiley JS, Jamieson GP, Mayger W, Cragoe EJ, Jopson M
JournalArch Biochem Biophys
PubMed ID2369117
Extracellular ATP has been shown to increase the Na+ permeability of human lymphocytes by 3 to 12-fold. The kinetics of this ATP-induced response were studied by measuring 22Na+ influx into chronic lymphocytic leukemic lymphocytes incubated in low-sodium media without divalent cations. ATP-stimulated uptake of 22Na-ions was linear over 4 min ... More
Amiloride and its analogs as tools in the study of ion transport.
AuthorsKleyman TR, Cragoe EJ
JournalJ Membr Biol
PubMed ID2852254
Amiloride inhibits most plasma membrane Na+ transport systems. We have reviewed the pharmacology of inhibition of these transporters by amiloride and its analogs. Thorough studies of the Na+ channel, the Na+/H+ exchanger, and the Na+/Ca2+ exchanger, clearly show that appropriate modification of the structure of amiloride will generate analogs with ... More
Heterogeneity of intracellular pH and of mechanisms that regulate intracellular pH in populations of cultured cells.
AuthorsLee AH, Tannock IF
JournalCancer Res
PubMed ID9581831
Cells within solid tumors are known to exist in a microenvironment that may be acidic and depend on membrane-based mechanisms (Na+/H+ antiport and Na+-dependent Cl-/HCO3- exchanger) that regulate intracellular pH (pHi). We have used the fluorescent pH indicator 2',7'-bis-(2-carboxyethyl) 5 (and 6)-carboxyfluorescein and flow cytometry to study the distribution of ... More
Functional coupling of Na+/H+ and Na+/Ca2+ exchangers in the alpha 1-adrenoreceptor-mediated activation of hepatic metabolism.
AuthorsUrcelay E, Butta N, Ciprés G, Martín-Requero A, Ayuso MS, Parrilla R
JournalJ Biol Chem
PubMed ID8288639
The purpose of this study was to characterize the role of ions other than Ca2+ in hepatic responses to alpha 1-adrenergic stimulation. We report that the alpha 1-adrenoreceptor activation of hepatic functions is accompanied by extracellular acidification and an increase in intracellular pH. These effects are dependent on extracellular Na+ ... More
Regulation of acidification and apoptosis by SHP-1 and Bcl-2.
Recruitment of the SH2 domain containing cytoplasmic protein-tyrosine phosphatase SHP-1 to the membrane by somatostatin (SST) is an early event in its antiproliferative signaling that induces intracellular acidification-dependent apoptosis in breast cancer cells. Fas ligation also induces acidification-dependent apoptosis in a manner requiring the presence of SHP-1 at the membrane. ... More
Characterization of potent Na+/H+ exchange inhibitors from the amiloride series in A431 cells.
AuthorsZhuang Y, Cragoe EJ, Shaikewitz T, Glaser L, Cassel D
JournalBiochemistry
PubMed ID6091747
Na+/H+ exchange is stimulated in a variety of cell types by addition of mitogenic polypeptides such as epidermal growth factor or platelet-derived growth factor. In order to assess the importance of Na+/H+ exchange in the mitogenic response, it is desirable to have available inhibitors of this process which exhibit high ... More
Atrial natriuretic peptide has different effects on contractility and intracellular pH in normal and hypertrophied myocytes from pressure-overloaded hearts.
AuthorsTajima M, Bartunek J, Weinberg EO, Ito N, Lorell BH
JournalCirculation
PubMed ID9851964
BACKGROUND: Atrial natriuretic peptide (ANP) depresses contractility in left ventricular myocytes. Its expression is upregulated in pressure-overloaded hypertrophied hearts; however, the effects of ANP on contractility in hypertrophied myocytes are not known. Our aims were (1) to examine the cellular mechanisms of this depression in contractility in normal myocytes and ... More
Gauging of the PhoE channel by a single freely diffusing proton.
AuthorsBransburg-Zabary S, Nachliel E, Gutman M
JournalBiophys J
PubMed ID12496072
In the present study we combined a continuum approximation with a detailed mapping of the electrostatic potential inside an ionic channel to define the most probable trajectory for proton propagation through the channel (propagation along a structure-supported trajectory (PSST)). The conversion of the three-dimensional diffusion space into propagation along a ... More
Intracellular pH regulation in cultured astrocytes from rat hippocampus. I. Role Of HCO3-.
AuthorsBevensee MO, Weed RA, Boron WF
JournalJ Gen Physiol
PubMed ID9379175
We studied the regulation of intracellular pH (pH) in single cultured astrocytes passaged once from the hippocampus of the rat, using the dye 2',7'-biscarboxyethyl-5,6-carboxyfluorescein (BCECF) to monitor pH. Intrinsic buffering power (beta) was 10.5 mM (pH unit) at pH 7.0, and decreased linearly with pH; the best-fit line to the ... More
Plasma membrane Na+/H+ exchanger isoforms (NHE-1, -2, and -3) are differentially responsive to second messenger agonists of the protein kinase A and C pathways.
Na+/H+ exchanger (NHE) activity is regulated by several types of receptors directly coupled to distinct classes (i.e. Gs, Gi, Gq, and G12) of heterotrimeric (alpha beta gamma) GTP-binding proteins (G proteins), which, upon activation, modulate production of various second messengers (e.g. cAMP, cGMP, diacylglycerol, inositol trisphosphate, and Ca2+). Recently, four ... More
The mechanism of protection from 5 (N-ethyl-N-isopropyl)amiloride differs from that of ischemic preconditioning in rabbit heart.
AuthorsSato H, Miki T, Vallabhapurapu RP, Wang P, Liu GS, Cohen MV, Downey JM
JournalBasic Res Cardiol
PubMed ID9486355
We investigated the effects of 5-(N-ethyl-N-isopropyl)amiloride (EIPA) on infarction in isolated rabbit hearts and cardiomyocytes. Thirty min of regional ischemia caused 29.6 +/- 2.8% of the risk zone to infarct in untreated Krebs buffer-perfused hearts. Treatment with EIPA (1 microM) for 20 min starting either 15 min before ischemia or ... More
Molecular cloning and functional expression of different molecular forms of rat amiloride-binding proteins.
AuthorsLingueglia E, Renard S, Voilley N, Waldmann R, Chassande O, Lazdunski M, Barbry P
JournalEur J Biochem
PubMed ID8375402
The colon and lung amiloride-binding proteins were cloned from rat tissues. Two sizes of transcripts were identified. The 2.7-kb transcript codes for an 85-kDa protein, whereas the 1.2-kb transcript codes for a 25-kDa polypeptide. The 2.7-kb transcript was detected in the proximal and distal colon and in duodenum, liver, placenta ... More
Muscarinic receptor-induced acidification in sublingual mucous acinar cells: loss of pH recovery in Na+-H+ exchanger-1 deficient mice.
AuthorsNguyen HV, Shull GE, Melvin JE
JournalJ Physiol
PubMed ID10673550
1. Intracellular pH (pHi) plays an important role in regulating fluid and electrolyte secretion by salivary gland acinar cells. The pH-sensitive, fluorescent dye 2', 7'-bis(carboxyethyl)-5(6)-carboxylfluorescein (BCECF) was used to characterize the mechanisms involved in regulating pHi during muscarinic stimulation in mouse sublingual mucous acinar cells. 2. In the presence of ... More
Vanadate stimulates system A amino acid transport activity in skeletal muscle. Evidence for the involvement of intracellular pH as a mediator of vanadate action.
AuthorsMuñoz P, Gumà A, Camps M, Furriols M, Testar X, Palacín M, Zorzano A
JournalJ Biol Chem
PubMed ID1375219
Sodium orthovanadate caused a 2-fold stimulation of system A transport activity in soleus muscle, as assessed by the uptake of the nonmetabolizable analog 2-(methylamino)isobutyric acid (MeAIB). The effect of vanadate on system A was rapid, concentration-dependent and was characterized by an increased Vmax without modification of Km for MeAIB. Under ... More
Role of protein kinase C and the Na+/H+ antiporter in suppression of apoptosis by granulocyte macrophage colony-stimulating factor and interleukin-3.
AuthorsRajotte D, Haddad P, Haman A, Cragoe EJ, Hoang T
JournalJ Biol Chem
PubMed ID1315776
Granulocyte macrophage colony-stimulating factor (GM-CSF) or interleukin-3 (IL-3) suppress apoptosis in hemopoietic cells, a process of active cell death characterized by the degradation of genomic DNA into oligonucleosomic fragments. The present study was therefore initiated with the view that the two growth factors may trigger the same early events in ... More
Mutations of Arg440 and Gly455/Gly456 oppositely change pH sensing of Na+/H+ exchanger 1.
AuthorsWakabayashi S, Hisamitsu T, Pang T, Shigekawa M
JournalJ Biol Chem
PubMed ID12562776
To identify important amino acid residues involved in intracellular pH (pH(i)) sensing of Na(+)/H(+) exchanger 1, we produced single-residue substitution mutants in the region of the exchanger encompassing the putative 11th transmembrane segment (TM11) and its adjacent intracellular (intracellular loop (IL) 5) and extracellular loops (extracellular loop 6). Substitution of ... More
Amiloride and analogues inhibit Na(+)-H+ exchange and cell proliferation in AR42J pancreatic cell line.
AuthorsDelvaux M, Bastié MJ, Chentoufi J, Cragoe EJ, Vaysse N, Ribet A
JournalAm J Physiol
PubMed ID2173418
To study the relation between activation of the Na(+)-H+ antiporter and gastrointestinal cell proliferation, we characterized this antiporter in a pancreatic cell line (AR42J) and studied the effects of mitogenic and nonmitogenic agents as well as those of Na(+)-H+ exchange blocking agents on DNA synthesis. Characteristics of amiloride-sensitive Na+ uptake ... More