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
Transforming growth factor beta 1 increases the number of apoptotic bodies and decreases intracellular pH in isolated periportal and perivenular rat hepatocytes.
AuthorsBenedetti A, Di Sario A, Svegliati Baroni G, Jezequel AM
JournalHepatology
PubMed ID7590668
Transforming growth factor beta 1 (TGF beta 1) is involved in promoting cell death by apoptosis in the liver, whereas the activation of Na+/H+ exchanger has been related to cell proliferation. The aim of this study was to gain information on the effects of TGF beta 1 on intracellular pH ... More
Measurement of intracellular pH.
AuthorsBoyer MJ, Hedley DW
JournalMethods Cell Biol
PubMed ID7532259
Calcein: a novel marker for lymphocytes which enter lymph nodes.
AuthorsWeston SA, Parish CR
JournalCytometry
PubMed ID1451604
Previous studies have identified unique cell surface antigens which are associated with the specific binding of lymphocytes to high endothelial venules (HEV). Evidence is presented in this paper which demonstrates that uptake of the fluorescent dye calcein by lymphocytes represents an additional marker for the lymph node homing subpopulation of ... More
Effect of low extracellular Ca2+ on growth, spreading area, cytoplasmic Ca2+ concentration, and intracellular pH in normal and transformed human fibroblasts.
AuthorsYoshida T, Takahashi Y, Takashima S
JournalJ Cell Physiol
PubMed ID8425911
The transformation of certain cells reduces the requirement of extracellular Ca2+ for growth. The SV-40 transformed human lung fibroblasts, WI-38 VA13, require less Ca2+ than normal WI-38 cells. Spreading area of the normal cells decreases when cultured in 10 microM Ca2+ medium. Intracellular calcium concentration ([Ca2+]i) of the normal and ... More
Measurement of intracellular pH.
AuthorsMusgrove EA, Hedley DW
JournalMethods Cell Biol
PubMed ID2084486
Fall in intracellular pH mediated by GABAA receptors in cultured rat astrocytes.
AuthorsKaila K, Panula P, Karhunen T, Heinonen E
JournalNeurosci Lett
PubMed ID1650936
The influence of muscimol (a specific gamma-aminobutyric acid-A (GABAA) receptor agonist) on intracellular pH (pHi) was studied in cultured rat astrocytes by means of fluorescence spectrophotometry with BCECF as the H+ indicator. In an HCO3(-)-free medium, muscimol had little effect on pHi. In a solution containing 22 mM HCO3-, muscimol ... More
Effects of the peptide toxin from Microcystis aeruginosa on intracellular calcium, pH and membrane integrity in mammalian cells.
AuthorsFalconer IR, Runnegar MT
JournalChem Biol Interact
PubMed ID3119237
Extracts of water blooms of the toxic cyanobacterium Microcystis aeruginosa showed a range of toxicities not related to their ability to lyse mammalian red cells. The HPLC-purified heptapeptide toxin (mol. wt. 1035) from Microcystis did not lyse red cells at up to 500-fold higher concentrations than that required to kill ... More
Differentiation of human promyelocytic HL 60 cells by retinoic acid is accompanied by an increase in the intracellular pH. The role of the Na+/H+ exchange system.
AuthorsLadoux A, Cragoe EJ, Geny B, Abita JP, Frelin C
JournalJ Biol Chem
PubMed ID3027070
Retinoic acid, which induces the differentiation of HL 60 cells to granulocytes, produces a cell alkalinization from pHi = 7.03 to pHi = 7.37. The half-maximum effect of retinoic acid is observed at 10 nM. The effect of retinoic acid on the pHi develops slowly, and it precedes the differentiation ... More
Effect of potassium depletion of Hep 2 cells on intracellular pH and on chloride uptake by anion antiport.
AuthorsMadshus IH, Tønnessen TI, Olsnes S, Sandvig K
JournalJ Cell Physiol
PubMed ID3571337
The effect of K+ depletion of Hep 2 cells on ion fluxes, internal pH, cell volume, and membrane potential was studied. The cells were depleted of K+ by incubation in K+-free buffer with or without a preceding exposure to hypotonic medium. Efflux of K+ in cells not exposed to hypotonic ... More
Mechanism of collagen activation in human platelets.
AuthorsRoberts DE, McNicol A, Bose R
JournalJ Biol Chem
PubMed ID14981087
The mechanism of collagen-induced human platelet activation was examined using Ca2+, Na+, and the pH-sensitive fluorescent dyes calcium green/fura red, sodium-binding benzofuran isophthalate, and 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. Administration of a moderate dose of collagen (10 microg/ml) to human platelets resulted in an increase in [Ca2+](i) and platelet aggregation. The majority of this ... More
Basolateral anion transport mechanisms underlying fluid secretion by mouse, rat and guinea-pig pancreatic ducts.
AuthorsFernández-Salazar MP, Pascua P, Calvo JJ, López MA, Case RM, Steward MC, San Román JI
JournalJ Physiol
PubMed ID14978209
Fluid secretion by interlobular pancreatic ducts was determined by using video microscopy to measure the rate of swelling of isolated duct segments that had sealed following overnight culture. The aim was to compare the HCO(3)(-) requirement for secretin-evoked secretion in mouse, rat and guinea-pig pancreas. In mouse and rat ducts, ... More
Nongenomic stimulation of vacuolar H+-ATPases in intercalated renal tubule cells by aldosterone.
AuthorsWinter C, Schulz N, Giebisch G, Geibel JP, Wagner CA
JournalProc Natl Acad Sci U S A
PubMed ID14983061
Renal collecting ducts play a critical role in acid-base homeostasis by establishing steep transepithelial pH gradients necessary for the almost complete reabsorption of bicarbonate and the effective secretion of ammonium into the urine. The mechanisms of urine acidification in collecting ducts involve active, electrogenic hydrogen (H+) secretion and, less importantly, ... More
Distance measurements within a concatamer of the plasma membrane Cl?/HCO3? exchanger, AE1.
AuthorsBasu A, Mazor S, Casey JR,
JournalBiochemistry
PubMed ID20828148
'AE1, which exists in the erythrocyte plasma membrane as a noncovalent dimer, facilitates transmembrane Cl?/HCO3? exchange. Here a concatamer of AE1 (two AE1 monomers fused via a two-residue linker to form an intramolecular dimer) was designed to facilitate fluorescence resonance energy transfer (FRET) studies. The concatameric protein (AE1·AE1) was expressed ... More
Rapid assessment of physiological status in Escherichia coli using fluorescent probes.
AuthorsPorter J, Edwards C, Pickup RW
JournalJ Appl Bacteriol
PubMed ID7592133
'Rapid and direct viability assessment of Escherichia coli in filtered, sterile lake water was possible using multiparameter flow cytometry. Fluorescent dyes were used as probes for different cellular functions (membrane potential, membrane integrity and intracellular enzyme activity), which were correlated with the ability of the cells to respond to nutrient ... More
Overexpression of Na(+)/K (+)-ATPase parallels the increase in sodium transport and potassium recycling in an in vitro model of proximal tubule cellular ageing.
AuthorsSilva E, Gomes P, Soares-da-Silva P,
JournalJ Membr Biol
PubMed ID17334838
'Na(+)/K(+)-ATPase plays a key role in the transport of Na(+) throughout the nephron, but ageing appears to be accompanied by changes in the regulation and localization of the pump. In the present study, we examined the effect of in vitro cell ageing on the transport of Na(+) and K(+) ions ... More
DeltaF508 mutation results in impaired gastric acid secretion.
AuthorsSidani SM, Kirchhoff P, Socrates T, Stelter L, Ferreira E, Caputo C, Roberts KE, Bell RL, Egan ME, Geibel JP
JournalJ Biol Chem
PubMed ID17178714
'The cystic fibrosis transmembrane conductance regulator (CFTR) is recognized as a multifunctional protein that is involved in Cl(-) secretion, as well as acting as a regulatory protein. In order for acid secretion to take place a complex interaction of transport proteins and channels must occur at the apical pole of ... More
Inhibition of tumor necrosis factor alpha-mediated NFkappaB activation and leukocyte adhesion, with enhanced endothelial apoptosis, by G protein-linked receptor (TP) ligands.
AuthorsAshton AW, Ware GM, Kaul DK, Ware JA
JournalJ Biol Chem
PubMed ID12517920
'Tumor necrosis factor (TNF) alpha is a critical mediator of inflammation; however, TNFalpha is rarely released alone and the "cross-talk" between different classes of inflammatory mediators is largely unexplored. Thromboxane A(2) (TXA(2)) is released during I/R injury and exerts its effects via a G protein-linked receptor (TP). In this study, ... More
Mechanistic studies of lantibiotic-induced permeabilization of phospholipid vesicles.
AuthorsDriessen AJ, van den Hooven HW, Kuiper W, van de Kamp M, Sahl HG, Konings RN, Konings WN
JournalBiochemistry
PubMed ID7849020
'Nisin is a cationic polycyclic bacteriocin secreted by some lactic acid bacteria. Nisin has previously been shown to permeabilize liposomes. The interaction of nisin was analyzed with liposomes prepared of the zwitterionic phosphatidylcholine (PC) and the anionic phosphatidylglycerol (PG). Nisin induces the release of 6-carboxyfluorescein and other small anionic fluorescent ... More
Nramp2 expression is associated with pH-dependent iron uptake across the apical membrane of human intestinal Caco-2 cells.
AuthorsTandy S, Williams M, Leggett A, Lopez-Jimenez M, Dedes M, Ramesh B, Srai SK, Sharp P
JournalJ Biol Chem
PubMed ID10625641
'The absorption of dietary non-heme iron by intestinal enterocytes is crucial to the maintenance of body iron homeostasis. This process must be tightly regulated since there are no distinct mechanisms for the excretion of excess iron from the body. An insight into the cellular mechanisms has recently been provided by ... More
The alpha subunit cytoplasmic domain regulates the assembly and adhesiveness of integrin lymphocyte function-associated antigen-1.
AuthorsLu CF, Springer TA
JournalJ Immunol
PubMed ID9200463
'The integrin LFA-1 mediates activation-dependent leukocyte adhesion. The beta subunit cytoplasmic domain has been demonstrated previously to modulate the adhesiveness of LFA-1. To investigate whether the alpha subunit cytoplasmic domain is also involved in the regulation of LFA-1-adhesive function, we stably expressed cytoplasmic domain truncated forms of the alpha subunit ... More
Heat shock- and ethanol-induced ionic changes in C6 rat glioma cells determined by NMR and fluorescence spectroscopy.
AuthorsSkrandies S, Bremer B, Pilatus U, Mayer A, Neuhaus-Steinmetz U, Rensing L
JournalBrain Res
PubMed ID9037501
'The effects of two different stressors, heat shock (HS; 44 degrees C, 20 min) and ethanol (1.2 M, 60 min), on ion content and membrane potential were investigated in C6 rat glioma cells. Both treatments were previously shown to induce the HS response [26]. Intracellular pH (pH(i)), sodium ion concentration ... More
Role of alpha L beta 2 integrin avidity in transendothelial chemotaxis of mononuclear cells.
AuthorsWeber C, Lu CF, Casasnovas JM, Springer TA
JournalJ Immunol
PubMed ID9378985
'The leukocyte integrin alpha L beta 2 (LFA-1) is important in transendothelial migration. Since it is not fully understood how LFA-1 mediates transmigration, we studied the effects of alpha L and beta 2 cytoplasmic domain mutants that alter LFA-1 adhesiveness for intercellular adhesion molecule-1. Monocyte chemotactic protein-1 (MCP-1) induced LFA-1-dependent ... More
G alpha 13 stimulates Na+-H+ exchange through distinct Cdc42-dependent and RhoA-dependent pathways.
Authors Hooley R; Yu C Y; Symons M; Barber D L;
JournalJ Biol Chem
PubMed ID8626403
'Activity of the ubiquitously expressed Na+-H+ exchanger subtype NHE1 is stimulated upon activation of receptor tyrosine kinases and G protein-coupled receptors. The intracellular signaling pathways mediating receptor regulation of the exchanger, however, are poorly understood. Using transient expression of dominant interfering and constitutively active alleles in CCL39 fibroblasts, we determined ... More
Effects of hypoxia on isometric force, intracellular Ca(2+), pH, and energetics in porcine coronary artery.
AuthorsShimizu S, Bowman PS, Thorne G, Paul RJ
JournalCirc Res
PubMed ID10785508
'When exposed to hypoxic conditions, coronary arteries dilate, which is an important protective response. Although vessel sensitivity to oxygen is well documented, the mechanisms are not known with certainty. To further characterize the mechanisms of oxygen sensing in the coronary artery, we tested the major classes of hypotheses by measuring ... More
Regulation of cytosolic free calcium concentration by intrasynaptic mitochondria.
AuthorsMartínez-Serrano A, Satrústegui J
JournalMol Biol Cell
PubMed ID1550964
'By the use of digitonin permeabilized presynaptic nerve terminals (synaptosomes), we have found that intrasynaptic mitochondria, when studied "in situ," i.e., surrounded by their cytosolic environment, are able to buffer calcium in a range of calcium concentrations close to those usually present in the cytosol of resting synaptosomes. Adenine nucleotides ... More
Activation of the Na(+)-K(+)-2Cl- cotransporter in rat parotid acinar cells by aluminum fluoride and phosphatase inhibitors.
AuthorsPaulais M, Turner RJ
JournalJ Biol Chem
PubMed ID1383225
'The bumetanide-sensitive component of pHi recovery from an NH4Cl-induced acute alkaline load was used as a measure of Na(+)-K(+)-2Cl- cotransport activity in rat parotid acini. Acinar treatment with NaF/AlCl3 (15 mM NaF plus 10 microM AlCl3) induced a 5-fold stimulation in the initial rate of bumetanide-sensitive pHi recovery. This effect ... More
Ca2+ storage in Trypanosoma brucei: the influence of cytoplasmic pH and importance of vacuolar acidity.
AuthorsScott DA, Moreno SN, Docampo R
JournalBiochem J
PubMed ID7575411
'The hypothesis that changes in cytosolic pH effect the release from intracellular compartments of stored calcium in Trypanosoma brucei was addressed by the use of procyclic and bloodstream trypomastigotes of T. brucei loaded with the fluorescent reagents 2'',7''-bis-(2-carboxyethyl)-5(and 6)-carboxyfluorescein (BCECF) to measure intracellular pH (pHi), or fura 2 to measure ... More
Presynaptic calcium signals and transmitter release are modulated by calcium-activated potassium channels.
AuthorsRobitaille R, Charlton MP
JournalJ Neurosci
PubMed ID1370323
'The regulation of synaptic transmission by Ca(2+)-activated potassium (gKca) channels was investigated at the frog neuromuscular junction (nmj). Charybdotoxin (CTX), a blocker of certain types of gKca channels, induced a twofold increase of transmitter release. Similar results were obtained with purified natural toxin, synthetic toxin, and recombinant toxin. Apamin, a ... More
Transcription regulation of TNF-alpha-early response genes by poly(ADP-ribose) polymerase-1 in murine heart endothelial cells.
AuthorsCarrillo A, Monreal Y, Ramírez P, Marin L, Parrilla P, Oliver FJ, Yélamos J
JournalNucleic Acids Res
PubMed ID14762203
'Poly(ADP-ribose) polymerase-1 (PARP-1) has been involved in endothelial cell dysfunction associated with various pathophysiological conditions. The intrinsic mechanism of PARP-1-mediated endothelial cell dysfunction could be related to PARP-1 overactivation, NAD(+) consumption and ATP depletion. An alternative way could involve transcription regulation. By using high-density microarrays, we examined early tumor necrosis ... More
Magnesium homeostasis in cardiac cells.
AuthorsFreudenrich CC, Murphy E, Liu S, Lieberman M
JournalMol Cell Biochem
PubMed ID1461262
'Several aspects of Mg2+ homeostasis were investigated in cultured chicken heart cells using the fluorescent Mg2+ indicator, FURAPTRA. The concentration of cytosolic Mg2+ ([Mg2+]i) is 0.48 +/- 0.03 mM (n = 31). To test whether a putative Na/Mg exchange mechanism controls [Mg2+]i below electrochemical equilibrium, we manipulated the Na+ gradient ... More
Regulation of intracellular pH gradients by identified Na/H exchanger isoforms and a short-chain fatty acid.
AuthorsGonda T, Maouyo D, Rees SE, Montrose MH
JournalAm J Physiol
PubMed ID9887003
'Colonic luminal short-chain fatty acids (SCFA) stimulate electroneutral sodium absorption via activation of apical Na/H exchange. HT29-C1 cells were used previously to demonstrate that transepithelial SCFA gradients selectively activate polarized Na/H exchangers. Fluorometry and confocal microscopy (with BCECF and carboxy SNARF-1, respectively) are used to measure intracellular pH (pHi) in ... More
Na+, K+, and H+/HCO3- transport in submandibular salivary ducts. Membrane localization of transporters.
AuthorsZhao H, Xu X, Diaz J, Muallem S
JournalJ Biol Chem
PubMed ID7642647
'The mechanisms mediating transepithelial ion transport in salivary ducts were characterized and localized by studying the regulation of [Na+]i, [K+]i, and pHi in isolated intralobular ducts and perfused main ducts of the submandibular salivary gland. A new procedure was developed for the rapid preparation of intralobular ducts. Measurements of pHi ... More
Glucocorticoids enhance the expression of the basolateral Na+:HCO3- cotransporter in renal proximal tubules.
AuthorsAli R, Amlal H, Burnham CE, Soleimani M
JournalKidney Int
PubMed ID10720958
'BACKGROUND: Studies have shown that glucocorticoids enhance HCO3- reabsorption in proximal tubules. Functional and molecular studies indicate that HCO3- reabsorption in proximal tubules is mediated via luminal H(+)-ATPase and Na+/H+ exchanger (NHE-3), and basolateral Na+:HCO3- cotransporter (NBC) acting in series. The purpose of these experiments was to examine the effect ... More
Regulation of Cl/HCO3 exchange in gastric parietal cells.
AuthorsThomas HA, Machen TE
JournalCell Regul
PubMed ID1742343
'Microspectrofluorimetry of the fluorescent indicators 2',7'-bis-(2-carboxyethyl)-5(and-6)carboxyfluorescein and 6-methoxy-N-(3-sulfopropyl)-quinolinium was used to measure intracellular pH (pHi), intracellular Cl (Cli), and transmembrane fluxes of HCO3 and Cl in single parietal cells (PC) in isolated rabbit gastric glands incubated in HCO3/CO2-buffered solutions. Steady-state pHi was 7.2 in both resting (50 microM cimetidine) and ... More
Dynamic regulation of mucus gel thickness in rat duodenum.
AuthorsAkiba Y, Guth PH, Engel E, Nastaskin I, Kaunitz JD
JournalAm J Physiol Gastrointest Liver Physiol
PubMed ID10915654
'We examined the dynamic regulation of mucus gel thickness (MGT) in vivo in rat duodenum in response to luminal acid, cyclooxygenase (COX) inhibition, and exogenous PGE(2). An in vivo microscopic technique was used to measure MGT with fluorescent microspheres in urethan-anesthetized rats. Duodenal mucosa was topically superfused with pH 7.0 ... More
Dominant-negative effect of the lymphocyte function-associated antigen-1 beta (CD18) cytoplasmic domain on leukocyte adhesion to ICAM-1 and fibronectin.
AuthorsRey-Ladino JA, Pyszniak AM, Takei F
JournalJ Immunol
PubMed ID9531311
'The cytoplasmic domains of LFA-1 (CD11a/CD18) are thought to play an important role in the regulation of LFA-1 function. To further elucidate the role of the LFA-1 cytoplasmic domains, we transfected chimeric proteins consisting of the extracellular domain of CD4 fused with the transmembrane and cytoplasmic domains of LFA-1 into ... More
Effect of intracellular pH on cytosolic free [Ca2+] in human epidermoid A-431 cells.
AuthorsKiang JG
JournalEur J Pharmacol
PubMed ID1664334
'This study characterizes the correlation between intracellular pH (pHi) and the cytosolic free Ca2+ concentration ([Ca2+]i) in suspended and adherent human epidermoid A-431 cells. Using the fluorescent dyes 2,7-bis(carboxyethyl)carboxyfluorescein acetoxymethyl ester (BCECF) and fura-2, the resting pHi and [Ca2+]i in suspended cells were 7.23 +/- 0.03 and 209 +/- 30 ... More
Regulation of intracellular pH in single rat zona glomerulosa cells.
AuthorsShepherd RM, Williams GH, Quinn SJ
JournalAm J Physiol
PubMed ID1310209
'The cytosolic pH (pHi) regulation of rat adrenal zona glomerulosa (ZG) cells was studied using single-cell spectrofluorimetry. Basal pHi was similar for cells incubated in the absence or presence of the HCO3(-)-CO2 buffering system. In the absence of HCO3-, inhibition of the Na(+)-H+ exchanger by dimethylamiloride (DMA) or removal of ... 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
Effects of prostaglandin E2 and F2 alpha on cytoplasmic pH in a clonal osteoblast-like cell line, MOB 3-4.
AuthorsKawase T, Orikasa M, Suzuki A
JournalJ Cell Physiol
PubMed ID1846635
'Prostaglandin E2 (PGE2, 5 ng/ml to 5 micrograms/ml) induced a dose-dependent increase in cAMP accumulation, inositol phosphates (IPs) accumulation, and cytoplasmic free Ca2+ ([Ca2+]i) in a clonal osteoblast-like cell line, MOB 3-4. In contrast, prostaglandin F2 alpha (PGF2 alpha, 5 ng/ml to 5 micrograms/ml) stimulated increases in IPs accumulation and ... More
Rapid effects of aldosterone on sodium-hydrogen exchange in isolated colonic crypts.
'Aldosterone plays a central role in the homeostatic regulation of extracellular fluid volume by stimulating transepithelial electrolyte transport. These effects involve binding to an intracellular receptor, modification of genomic events and protein synthesis. Rapid cellular responses to steroid hormones have been observed in a variety of nonepithelial tissues. The term ... More
Cadmium induces both pyruvate kinase and Na+/H+ exchanger activity through protein kinase C mediated signal transduction, in isolated digestive gland cells of Mytilus galloprovincialis (L.).
AuthorsDailianis S, Kaloyianni M
JournalJ Exp Biol
PubMed ID15073199
'The present study investigates the transduction pathway mediated by cadmium in isolated digestive gland cells of mussel Mytilus galloprovincialis. The effects of cadmium treatment on a key glycolytic enzyme, pyruvate kinase (PK), and on Na(+)/H(+) exchanger activity were examined. Cadmium (50 micro mol l(-1)) caused a significant elevation of intracellular ... More
A new action of parathyroid hormone. receptor-mediated stimulation of extracellular acidification in human osteoblast-like SaOS-2 cells.
AuthorsBarrett MG, Belinsky GS, Tashjian AH
JournalJ Biol Chem
PubMed ID9334207
'The major physiological function of parathyroid hormone (PTH) is the maintenance of Ca2+/Pi homeostasis via the parathyroid hormone/parathyroid hormone-related protein receptor (PTHR) in kidney and bone. An important consequence of PTHR activation in bone is enhanced local acidification of the extracellular space. Agonist activation of some seven transmembrane-domain receptors increases ... More
Residues throughout the cytoplasmic domain affect the internalization efficiency of P-selectin.
Authors Setiadi H; Disdier M; Green S A; Canfield W M; McEver R P;
JournalJ Biol Chem
PubMed ID7592923
'The cytoplasmic domains of many membrane proteins have short sequences, usually including a tyrosine or a di-leucine, that function as sorting signals. P-selectin is an adhesion receptor for leukocytes that is expressed on activated platelets and endothelial cells. Its 35-residue cytoplasmic domain contains signals for sorting into regulated secretory granules, ... More
Effects of osmotic stresses on isolated rat hepatocytes. II. Modulation of intracellular pH.
AuthorsGleeson D, Corasanti JG, Boyer JL
JournalAm J Physiol
PubMed ID2305896
'To assess the roles of acid-base transport systems in cell volume regulation in rat hepatocytes, intracellular pH (pHi) was measured in subconfluent monolayers loaded with 2''-7''-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF) after exposure to hypotonic and relative hypertonic media, interventions that stimulate regulatory volume decrease (RVD) and increase (RVI), respectively. During RVD, pHi decreased ... More
Oxidative stress decreases pHi and Na(+)/H(+) exchange and increases excitability of solitary complex neurons from rat brain slices.
AuthorsMulkey DK, Henderson RA, Ritucci NA, Putnam RW, Dean JB
JournalAm J Physiol Cell Physiol
PubMed ID14668260
'Putative chemoreceptors in the solitary complex (SC) are sensitive to hypercapnia and oxidative stress. We tested the hypothesis that oxidative stress stimulates SC neurons by a mechanism independent of intracellular pH (pH(i)). pH(i) was measured by using ratiometric fluorescence imaging microscopy, utilizing either the pH-sensitive fluorescent dye BCECF or, during ... More
Actin assembly in electropermeabilized neutrophils: role of intracellular calcium.
AuthorsDowney GP, Chan CK, Trudel S, Grinstein S
JournalJ Cell Biol
PubMed ID2112547
'Assembly of microfilaments involves the conversion of actin from the monomeric (G) to the filamentous (F) form. The exact sequence of events responsible for this conversion is yet to be defined and, in particular, the role of calcium remains unclear. Intact and electropermeabilized human neutrophils were used to assess more ... More
The role of anions in pH regulation of Leishmania major promastigotes.
AuthorsVieira L, Lavan A, Dagger F, Cabantchik ZI
JournalJ Biol Chem
PubMed ID8206930
'The pH regulation of Leishmania major promastigotes was studied as a function of the ionic composition of the medium and in response to acid and alkali load. Intracellular pH (pHi) was monitored by on-line ratio fluorescence using the fluorescence-dependent pH indicator 2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein (BCECF). In Cl(-)-based medium (pH 7.4, 30 degrees ... More
Further characterization of the mechanisms mediating the rise in cytosolic free Na+ in thrombin-stimulated platelets. Evidence for inhibition of the Na+,K(+)-ATPase and for Na+ entry via a Ca2+ influx pathway.
AuthorsBorin M, Siffert W
JournalJ Biol Chem
PubMed ID1649180
'Human platelets were loaded with the fluorescent Na(+)-sensitive dye sodium-binding benzofuran isophtalate (SBFI), and changes in the fluorescence excited at 345 and 385 nm were analyzed after manipulations that evoked predictable changes in the cytosolic Na+ concentration ([Na+]i). Raising [Na+]i by either gramicidin D or monensin specifically increased the fluorescence ... More
Chemoattractant-induced cytoplasmic pH changes and cytoskeletal reorganization in human neutrophils. Relationship to the stimulated calcium transients and oxidative burst.
AuthorsNaccache PH, Therrien S, Caon AC, Liao N, Gilbert C, McColl SR
JournalJ Immunol
PubMed ID2538509
'The relationships between the chemotactic factor-stimulated mobilization of calcium, activation of the NADPH-oxidase, changes in cytosolic pH, and in the level of polymerized actin in human neutrophils have been examined. The approach taken was to use intracellular calcium chelators, and pharmacologic modulators (both positive and negative) of the NADPH-oxidase to ... More
Muscarinic cholinergic stimulation elevates intracellular pH in chicken granulosa cells by a Ca(2+)-dependent, Na(+)-independent mechanism.
AuthorsLi M, Morley P, Schwartz JL, Whitfield JF, Tsang BK
JournalEndocrinology
PubMed ID1612000
'Various hormones and growth factors act at least in part by raising the cytosolic pH of the target cell. In the present studies we examined the influence of the muscarinic cholinergic agonist carbachol on intracellular pH (pHi) in chicken granulosa cells. The pHi in granulosa cells from the two largest ... More
Amiloride kills malignant glioma cells independent of its inhibition of the sodium-hydrogen exchanger.
AuthorsHegde M, Roscoe J, Cala P, Gorin F
JournalJ Pharmacol Exp Ther
PubMed ID15010500
'Previously, we demonstrated that malignant glioma cell lines have increased intracellular pH (pHi) as a result of increased activities of the type I sodium/hydrogen exchanger (NHE1). This alkalotic pHi of 7.2 to 7.4 is favorable for augmented glycolysis, DNA synthesis, and cell cycle progression. Conversely, reductions in pHi have been ... More
Suppression of Ca2+ oscillations in cultured rat hepatocytes by chemical hypoxia.
AuthorsKawanishi T, Nieminen AL, Herman B, Lemasters JJ
JournalJ Biol Chem
PubMed ID1939069
'The model of "chemical hypoxia" with KCN plus iodoacetic acid mimics the ATP depletion and reductive stress of hypoxia. Here, we examined the effects of chemical hypoxia on cytosolic free Na+ and Ca2+ in single cultured rat hepatocytes by multiparameter digitized video microscopy and ratio imaging of sodium-binding furan indicator ... 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
Modulation of the mitochondrial cyclosporin A-sensitive permeability transition pore by the proton electrochemical gradient. Evidence that the pore can be opened by membrane depolarization.
AuthorsBernardi P
JournalJ Biol Chem
PubMed ID1374381
'This paper reports an investigation on the relationship between the proton electrochemical gradient (delta mu H+) and the cyclosporin A-sensitive permeability transition pore (PTP) in rat liver mitochondria. Using the SH group cross-linker phenylarsine oxide as the inducer, we show that both matrix pH and the membrane potential can modulate ... More
Ammonium ions mobilize calcium from an internal pool which is insensitive to TRH and ionomycin in bovine anterior pituitary cells.
'The effects of NH4Cl on cytoplasmic free calcium concentration ([Ca2+]i) and pH (pHi) in single bovine anterior pituitary cells were determined using fluorescence imaging microscopy. Addition of NH4Cl (10-40 mM) in the presence of 1 mM extracellular calcium ([Ca2+]e) increased [Ca2+]i to a peak which then fell to a sustained ... More
Defective parathyroid hormone regulation of NHE3 activity and phosphate adaptation in cultured NHERF-1-/- renal proximal tubule cells.
AuthorsCunningham R, Steplock D, Wang F, Huang H, E X, Shenolikar S, Weinman EJ
JournalJ Biol Chem
PubMed ID15218020
'The present experiments using primary cultures of renal proximal tubule cells derived from wild-type and NHERF-1 knockout animals examines the regulation of NHE3 by phenylthiohydantoin (PTH) and the regulation of phosphate transport in response to alterations in the media content of phosphate. Forskolin (34.8 +/- 6.2%) and PTH (29.7 +/- ... More
Intracellular pH in adipocytes: effects of free fatty acid diffusion across the plasma membrane, lipolytic agonists, and insulin.
AuthorsCivelek VN, Hamilton JA, Tornheim K, Kelly KL, Corkey BE
JournalProc Natl Acad Sci U S A
PubMed ID8816765
'The main function of white adipose tissue is to store nutrient energy in the form of triglycerides. The mechanism by which free fatty acids (FFA) move into and out of the adipocyte has not been resolved. We show here that changes in intracellular pH (pH1) in adipocytes correlate with the ... More
Anion exchanger isoform 2 operates in parallel with Na(+)/H(+) exchanger isoform 1 during regulatory volume decrease of human cervical cancer cells.
AuthorsShen MR, Wilkins RJ, Chou CY, Ellory JC
JournalFEBS Lett
PubMed ID11852051
'Intracellular pH (pH(i)) homeostasis was investigated in human cervical cancer SiHa cells undergoing regulatory volume decrease (RVD) to determine which transport systems were involved. Using isoform-specific primers, mRNA transcripts of Na(+)/H(+) exchanger isoform 1 (NHE1) and isoform 3 were identified by reverse transcriptase polymerase chain reaction (RT-PCR) and the results ... More
Accumulation of intracellular HCO3- by Na(+)-HCO3- cotransport in interlobular ducts from guinea-pig pancreas.
AuthorsIshiguro H, Steward MC, Lindsay AR, Case RM
JournalJ Physiol
PubMed ID8866360
'1. Short segments of interlobular duct were microdissected from guinea-pig pancreas following enzymatic digestion. After overnight culture, intracellular pH (pH1) and Na+ concentration ([Na+]i) were measured by microfluorometry in duct cells loaded with either the pH-sensitive fluoroprobe 2''7''-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) or the sodium-binding benzofuran isophthalate (SBFI). 2. The transporters responsible for ... More
Endosomal accumulation of pH indicator dyes delivered as acetoxymethyl esters.
AuthorsSlayman CL, Moussatos VV, Webb WW
JournalJ Exp Biol
PubMed ID7823037
'Intracellular distributions of the putative cytosolic pH indicator dyes BCECF [2',7'-bis-(2-carboxyethyl)-5(and 6)-carboxyfluorescein], C.SNARF [5(and 6)-carboxy-seminaphthorhodafluor-1], and C.SNARF-calcein have been examined in Neurospora crassa and in murine fibroblasts (NIH-3T3 cells) under conditions in which both kinds of cells produce visible microscopic vacuoles. All three dyes were administered in electroneutral forms, with ... More
Selective modulation by cGMP of the K+ channel activated by speract.
AuthorsCook SP, Babcock DF
JournalJ Biol Chem
PubMed ID7693667
'The egg peptide speract stimulates sperm guanylyl cyclase and presumably enhances fertilization, but the roles of cGMP in sperm responses are yet undetermined. Here we show that speract-induced accumulation of cGMP or cAMP is selectively enhanced by the phosphodiesterase inhibitors, 3-isobutyl-1-methylxanthine (IBMX) or papaverine, respectively. These inhibitors provided the unusual ... More
Yeast orotidine-5'-phosphate decarboxylase: steady-state and pre-steady-state analysis of the kinetic mechanism of substrate decarboxylation.
AuthorsPorter DJ, Short SA
JournalBiochemistry
PubMed ID10995247
'The catalytically active form of monofunctional yeast orotidine-5'-phosphate decarboxylase was a dimer (E(2)). The dimer equilibrium dissociation constant was 0.25 microM in 0.01 M MOPS Na(+) at pH 7.2. The bimolecular rate constant for dimer formation was 1.56 microM(-1) s(-1). The dimeric form of the enzyme was stabilized by NaCl ... More
Estimation of matrix pH in isolated heart mitochondria using a fluorescent probe.
AuthorsJung DW, Davis MH, Brierley GP
JournalAnal Biochem
PubMed ID2751096
'Isolated heart mitochondria hydrolyze the acetoxymethyl esters of the Ca2+-sensitive fluorescent probe fura-2 and the pH-sensitive 2'',7''-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF). The resulting charged forms of the probes are retained in the mitochondrial matrix and appear well-suited for the estimation of pCa and pH in this compartment. The mitochondria esterase activity is stimulated ... More
Differential use of very late antigen-4 and -5 integrins by hematopoietic precursors and myeloma cells to adhere to transforming growth factor-beta1-treated bone marrow stroma.
AuthorsRobledo MM, Sanz-Rodriguez F, Hidalgo A, Teixidó J
JournalJ Biol Chem
PubMed ID9575147
'The very late antigen (VLA)-4 and VLA-5 integrins mediate hematopoietic progenitor cell attachment to bone marrow (BM) stroma. Transforming growth factor-beta1 (TGF-beta1) is a cytokine present in the BM microenvironment that has been shown to regulate the synthesis of adhesion elements in several cell types. We have investigated whether TGF-beta1 ... More
Rapid diffusion of green fluorescent protein in the mitochondrial matrix.
AuthorsPartikian A, Olveczky B, Swaminathan R, Li Y, Verkman AS
JournalJ Cell Biol
PubMed ID9472034
'It is thought that the high protein density in the mitochondrial matrix results in severely restricted solute diffusion and metabolite channeling from one enzyme to another without free aqueous-phase diffusion. To test this hypothesis, we measured the diffusion of green fluorescent protein (GFP) expressed in the mitochondrial matrix of fibroblast, ... More
Comparison of spectrum-shifting intracellular pH probes 5'(and 6')-carboxy-10-dimethylamino-3-hydroxyspiro[7H-benzo[c]xanthene-7, 1'(3'H)-isobenzofuran]-3'-one and 2',7'-biscarboxyethyl-5(and 6)-carboxyfluorescein.
AuthorsOwen CS
JournalAnal Biochem
PubMed ID1514696
'The dyes carboxy-SNARF-1 and BCECF are fluorescent probes of intracellular pH that exhibit changes in spectral shape upon proton binding which allow one to use measurements of fluorescence at two or more wavelengths in order to measure pH without artifacts associated with variability in dye loading, etc. In evaluating these ... More
Hypoxia induces adhesion molecules on cancer cells: A missing link between Warburg effect and induction of selectin-ligand carbohydrates.
AuthorsKoike T, Kimura N, Miyazaki K, Yabuta T, Kumamoto K, Takenoshita S, Chen J, Kobayashi M, Hosokawa M, Taniguchi A, Kojima T, Ishida N, Kawakita M, Yamamoto H, Takematsu H, Suzuki A, Kozutsumi Y, Kannagi R, Kanangi R
JournalProc Natl Acad Sci U S A
PubMed ID15141079
'Cancer cells undergo distinct metabolic changes to cope with their hypoxic environment. These changes are achieved at least partly by the action of transcriptional factors called hypoxia-inducible factors (HIFs). We investigated gene expression in cultured human colon cancer cells induced by hypoxic conditions with special reference to cell-adhesion molecules and ... More
Calcium binding to the cytosol and calcium extrusion mechanisms in intact synaptosomes and their alterations with aging.
AuthorsMartinez-Serrano A, Blanco P, Satrústegui J
JournalJ Biol Chem
PubMed ID1531657
'A simple method to measure cytosolic calcium binding in intact presynaptic nerve terminals (synaptosomes) from rat brain, which is based on the simultaneous determination of [Ca2+]i and total [45Ca2+] in quin2-loaded synaptosomes undergoing a switch from high- to low-calcium containing medium, is presented. Binding to the cytosolic compartment alone was ... More
Gialpha3 protein-coupled dopamine D3 receptor-mediated inhibition of renal NHE3 activity in SHR proximal tubular cells is a PLC-PKC-mediated event.
AuthorsPedrosa R, Gomes P, Hopfer U, Jose PA, Soares-da-Silva P
JournalAm J Physiol Renal Physiol
PubMed ID15265766
'This study evaluated the transduction pathway associated with type 3 Na(+)/H(+) exchanger (NHE3) activity-induced inhibition during dopamine D(3) receptor activation in immortalized renal proximal tubular epithelial cells from the spontaneously hypertensive rat. The dopamine D(3) receptor agonist 7-OH-DPAT decreased NHE3 activity, which was prevented by the D(2)-like receptor antagonist S-sulpiride, ... More
Assessment of swelling-activated Cl- channels using the halide-sensitive fluorescent indicator 6-methoxy-N-(3-sulfopropyl)quinolinium.
AuthorsSrinivas SP, Bonanno JA, Hughes BA
JournalBiophys J
PubMed ID9649372
'This study describes a quantitative analysis of the enhancement in anion permeability through swelling-activated Cl- channels, using the halide-sensitive fluorescent dye 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). Cultured bovine corneal endothelial monolayers perfused with NO3- Ringer''s were exposed to I- pulses under isosmotic and, subsequently, hyposmotic conditions. Changes in SPQ fluorescence due to I- ... More
Identification of residues lining the translocation pore of human AE1, plasma membrane anion exchange protein.
AuthorsTang XB, Kovacs M, Sterling D, Casey JR
JournalJ Biol Chem
PubMed ID9920902
'AE1 is the chloride/bicarbonate anion exchanger of the erythrocyte plasma membrane. We have used scanning cysteine mutagenesis and sulfhydryl-specific chemistry to identify pore-lining residues in the Ser643-Ser690 region of the protein. The Ser643-Ser690 region spans transmembrane segment 8 of AE1 and surrounds Glu681, which may reside at the transmembrane permeability ... More
Phototropism and geotropism in maize coleoptiles are spatially correlated with increases in cytosolic free calcium.
AuthorsGehring CA, Williams DA, Cody SH, Parish RW
JournalNature
PubMed ID11540625
'Phototropism and gravitropism in the shoots and roots of higher plants are the result of asymmetric growth. This is explained by the redistribution of growth regulators following exposure to gravity or unilateral light (the Cholodny-Went hypothesis). The positive phototropism and the negative geotropism of grass seedling coleoptiles are believed to ... More
'Mechanically poking or damaging a single cell within a confluent astrocyte culture produces the so-called intercellular calcium (Ca(2+)) waves, that is, cell-to-cell propagating changes of intracellular free Ca(2+). We were interested whether intercellular Ca(2+) waves are also associated with changes in other intra- or extracellular ions. To that purpose, we ... More
Transforming growth factor-beta enhances the extent of intercellular communication between normal rat kidney cells.
Authorsvan Zoelen EJ, Tertoolen LG
JournalJ Biol Chem
PubMed ID2050701
'Normal rat kidney (NRK) cells cultured in the presence of epidermal growth factor are contact-inhibited at confluent densities. In the additional presence of transforming growth factor (TGF)-beta, however, cells undergo phenotypic transformation which is accompanied by a loss of contact inhibition. In this study, we show by means of the ... More
Fluorescence imaging in human identity testing.
AuthorsWorley J, Lee S, Ma MS, Eisenberg A, Chen HY, Mansfield E
JournalBiotechniques
PubMed ID9232247
'We have investigated the use of fluorescence detection and the FluorImager S1 System (Molecular Dynamics) for analyzing a comprehensive set of human DNA typing tests. We used an alkaline phosphatase-conjugated YNH24 oligonucleotide probe to the repeat-containing D2S44 locus to detect both alleles in 50 ng of human genomic DNA (0.025 ... More
'Activity of the ubiquitous Na-H exchanger (NHE1) is regulated by a number of receptors with tyrosine kinase activity as well as by several classes of receptors coupled to heterotrimeric GTP-binding proteins. We previously demonstrated that the beta 2-adrenergic receptor and other receptors that stimulate adenylyl cyclase by activating Gs stimulate ... More
An alkaline pH-activated Cl(-)-anion exchanger regulates pH homeostasis in fibroblasts.
AuthorsLin PY, Ahluwalia M, Gruenstein E
JournalAm J Physiol
PubMed ID1689112
'Alkalinization of the cytoplasm in human fibroblasts activates Cl- efflux. The pathway of Cl- efflux is inhibited by 4,4''-diisothiocyanostilbene-2,2''-disulfonic acid (DIDS) or by removal of Cl- from the extracellular medium, but it is insensitive to the Cl(-)-cation cotransport inhibitor bumetanide. These data indicate that the alkali-stimulated Cl- pathway is a ... More
The role of Na+/H+ exchange and the Na+/K+ pump in the regulation of [Na+]i during metabolic inhibition in guinea pig myocytes.
AuthorsKatoh H, Satoh H, Nakamura T, Terada H, Hayashi H
JournalBiochem Biophys Res Commun
PubMed ID8074732
'To investigate the mechanisms of Na+ loading during metabolic inhibition (MI), [Na+]i and pHi were measured in quiescent guinea pig myocytes using fluorescent probes, sodium-binding benzofuran isophthalate and 2,7,bis(carboxyethyl)-5,6-carboxyfluorescein. When myocytes were exposed to MI (3.3 mM amobarbital and 5 microM carbonyl cyanide m-chlorophenylhydrazone, without glucose) for 20 min, [Na+]i ... More
Ratiometric measurement of intracellular pH of cultured cells with BCECF in a fluorescence multi-well plate reader.
AuthorsGrant RL, Acosta D
JournalIn Vitro Cell Dev Biol Anim
PubMed ID9156340
'A number of methods have been developed to measure intracellular pH (pHi) because of its importance in intracellular events. A major advance in accurate pHi measurement was the development of the ratiometric fluorescent indicator dye, 2'',7''-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF). We have used a fluorescence multi-well plate reader and a ratiometric method for ... More
Changes in intracellular calcium during the development of epithelial polarity and junctions.
AuthorsNigam SK, Rodriguez-Boulan E, Silver RB
JournalProc Natl Acad Sci U S A
PubMed ID1631104
'The "Ca2+ switch" model with cultured Madin-Darby canine kidney (MDCK) cells is useful in studying the biogenesis of epithelial polarity and junction formation and provides insight into early steps in the morphogenesis of polarized epithelial tissues. When extracellular Ca2+ in the medium is changed from less than 5 microM to ... More
Effects of thrombin on intracellular calcium and pH in human and murine platelets.
AuthorsSalazar D, Valencia L, Sierra G, Paniagua R, Melendez E, Reyes JL
JournalPlatelets
PubMed ID10938903
'The aim of this study was to compare the effect of thrombin (Thr) on cytosolic calcium [Ca2]+i and intracellular pH [pH]i in human and murine platelets. Rich-platelet suspensions from both species were loaded with Fura-2 (2 microM) or BCECF (0.75 microM) by incubation with their respective acetoxymethyl esters to measure ... More
Cytoplasmic pH in isolated rat enterocytes. Role of Na+/H+ exchanger.
AuthorsHoinard C, Goré J
JournalBiochim Biophys Acta
PubMed ID2838077
'The cytoplasmic pH (pHi) was determined in isolated rat intestinal cells with four methods. The pHi of cells in physiological saline buffered with Hepes (pH 7.3) at 37 degrees C was close to 7.0. The most reliable method, using the fluorescent pH indicator 2'',7''-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF), furnished a mean value of ... More
Effects of auxin and abscisic acid on cytosolic calcium and pH in plant cells.
AuthorsGehring CA, Irving HR, Parish RW
JournalProc Natl Acad Sci U S A
PubMed ID11607135
'Dark-grown corn coleoptiles and parsley hypocotyls and their roots were loaded with acetoxymethyl esterified forms of the Ca2+ indicator fluo-3, and the pH indicator 2'',7''-bis (2-carboxyethyl)-5(and-6)-carboxyfluorescein. These tissues were treated with the plant growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D), an auxin analogue, or abscisic acid (ABA), and the cytosolic pH (pHcyt) ... More
Glutamate induces the production of reactive oxygen species in cultured forebrain neurons following NMDA receptor activation.
AuthorsReynolds IJ, Hastings TG
JournalJ Neurosci
PubMed ID7751912
'Using the fluorescent dye 2'',7''-dichlorodihydrofluorescein (DCF-H2) we investigated the role of glutamate in the production of reactive oxygen species (ROS) in cultured neurons from fetal rat forebrain. The addition of an excitotoxic concentration of glutamate (100 microM) produced a generalized decrease in cellular DCF fluorescence accompanied by local areas of ... More
Inhibition of endosome function in CHO cells bearing a temperature-sensitive defect in the coatomer (COPI) component epsilon-COP.
AuthorsDaro E, Sheff D, Gomez M, Kreis T, Mellman I
JournalJ Cell Biol
PubMed ID9412469
'Recent evidence has suggested that subunits of the coatomer protein (COPI) complexes are functionally associated with endosomes in mammalian cells. We now provide genetic evidence that COPI plays a role in endocytosis in intact cells. The ldlF mutant CHO cell line bears a temperature-sensitive defect in the COPI subunit epsilon-COP. ... More
Real-time multi-wavelength fluorescence imaging of living cells.
AuthorsMorris SJ
JournalBiotechniques
PubMed ID2331370
'We describe a new real-time fluorescence video microscope design for capturing intensified images of cells containing dual wavelength "ratio" dyes or multiple dyes. The microscope will perform real-time capture of two separate fluorescence emission images simultaneously, improving the time resolution of spatial distribution of fluorescence to video frame rates (30 ... More
The effects of metabolic inhibition on intracellular calcium and pH in isolated rat ventricular cells.
AuthorsEisner DA, Nichols CG, O'Neill SC, Smith GL, Valdeolmillos M
JournalJ Physiol
PubMed ID2614727
'1. Intracellular calcium concentration [( Ca2+]i) and pH (pHi) were measured in single, isolated rat ventricular myocytes using, respectively, the fluorescent indicators Fura-2 and BCECF (2',7'-bis(carboxyethyl-5(6)-carboxyfluorescein). Contraction was measured simultaneously. The intracellular calibration of BCECF is demonstrated. In a HEPES-buffered bathing solution of pH 7.4, pHi had a mean value ... More
An apical K(+)-dependent HCO(3)- transport pathway opposes transepithelial HCO(3)- absorption in rat medullary thick ascending limb.
AuthorsWatts BA, Good DW
JournalAm J Physiol Renal Physiol
PubMed ID15026301
'Absorption of HCO(3)(-) in the medullary thick ascending limb (MTAL) is mediated by apical membrane Na(+)/H(+) exchange. The identity and function of other apical acid-base transporters in this segment have not been defined. The present study was designed to examine apical membrane HCO(3)(-)/OH(-)/H(+) transport pathways in the rat MTAL and ... More
Calcium mobilization and Na+/H+ antiport activation by endothelin in human skin fibroblasts.
AuthorsGardner JP, Maher E, Aviv A
JournalFEBS Lett
PubMed ID2553480
'Endothelin (ET-1) has been shown to exert vasoconstrictor activity in vivo and mobilize Ca2+ in vascular smooth muscle cells in culture. In this paper we show that the human skin fibroblast exhibits specific receptors to ET-1 and that activation of these receptors results in increased intracellular Ca2+ (Ca2+i) and accelerated ... More
Defining extracellular integrin alpha-chain sites that affect cell adhesion and adhesion strengthening without altering soluble ligand binding.
AuthorsPujades C, Alon R, Yauch RL, Masumoto A, Burkly LC, Chen C, Springer TA, Lobb RR, Hemler ME
JournalMol Biol Cell
PubMed ID9398682
'It was previously shown that mutations of integrin alpha4 chain sites, within putative EF-hand-type divalent cation-binding domains, each caused a marked reduction in alpha4beta1-dependent cell adhesion. Some reports have suggested that alpha-chain "EF-hand" sites may interact directly with ligands. However, we show here that mutations of three different alpha4 "EF-hand" ... More
The induction of ornithine decarboxylase by L-asparagine and intracellular alkalinization.
AuthorsFong WF, Law CL
JournalBiochem Int
PubMed ID2835049
'The uptake of transport systems A and N amino acids, most noticeably L-asparagine, is essential for the induction of ornithine decarboxylase (L-ornithine carboxylase, EC 4.1.1.17) in cultured cells and we have proposed that the uptake-associated pH and ionic changes might constitute part of the cell activation signal (1). In the ... More
Mutations in the P. falciparum digestive vacuole transmembrane protein PfCRT and evidence for their role in chloroquine resistance.
AuthorsFidock DA, Nomura T, Talley AK, Cooper RA, Dzekunov SM, Ferdig MT, Ursos LM, Sidhu AB, Naudé B, Deitsch KW, Su XZ, Wootton JC, Roepe PD, Wellems TE
JournalMol Cell
PubMed ID11090624
'The determinant of verapamil-reversible chloroquine resistance (CQR) in a Plasmodium falciparum genetic cross maps to a 36 kb segment of chromosome 7. This segment harbors a 13-exon gene, pfcrt, having point mutations that associate completely with CQR in parasite lines from Asia, Africa, and South America. These data, transfection results, ... More
NHERF associations with sodium-hydrogen exchanger isoform 3 (NHE3) and ezrin are essential for cAMP-mediated phosphorylation and inhibition of NHE3.
AuthorsWeinman EJ, Steplock D, Donowitz M, Shenolikar S
JournalBiochemistry
PubMed ID10821685
'The sodium-hydrogen exchanger regulatory factor (NHERF) is an essential cofactor for cAMP-mediated inhibition of the Na(+)/H(+) exchanger isoform, NHE3, in renal brush border membranes. NHERF is also an ezrin-binding protein. To define the functional importance of ezrin binding for NHERF''s function as a NHE3 regulator, we transfected stable PS120 cells ... More
Localization of a substrate specificity domain in the multidrug resistance protein.
AuthorsStride BD, Cole SP, Deeley RG
JournalJ Biol Chem
PubMed ID10428874
'Multidrug resistance protein (MRP) confers resistance to a number of natural product chemotherapeutic agents. It is also a high affinity transporter of some physiological conjugated organic anions such as cysteinyl leukotriene C(4) and the cholestatic estrogen, 17beta-estradiol 17(beta-D-glucuronide) (E(2)17betaG). We have shown that the murine orthologue of MRP (mrp), unlike ... More
Activation of the Na+/H+ antiporter during cell volume regulation. Evidence for a phosphorylation-independent mechanism.
AuthorsGrinstein S, Woodside M, Sardet C, Pouyssegur J, Rotin D
JournalJ Biol Chem
PubMed ID1331102
'A variety of cell types regulate their volume in anisotonic media by stimulating Na+/H+ exchange. Like growth factors, osmotic challenge activates the Na+/H+ antiport by increasing its sensitivity to intracellular [H+]. To investigate the molecular mechanism underlying this shift in pH sensitivity, the antiporter of 32P-labeled human bladder carcinoma cells ... More