Fluorescent labelling of Na+, K(+)-ATPase in intact cells by use of a fluorescent derivative of ouabain: salinity and teleost chloride cells.
AuthorsMcCormick SD
JournalCell Tissue Res
PubMed ID2164884
'Anthroylouabain, a fluorescent derivative of ouabain, was used to localize Na+, K(+)-ATPase in transport epithelia of two species of teleosts. Exposure of the opercular membrane of seawater-adapted tilapia (Oreochromis mossambicus) and the jaw skin of the long-jawed mudsucker (Gillichthys mirabilis) to a 2 microM anthroylouabain solution resulted in the appearance ... More
Basolateral membrane lipid dynamics alter Na-K ATPase activity in rabbit small intestine.
AuthorsMadsen KL, Meddings JB, Fedorak RN
JournalCan J Physiol Pharmacol
PubMed ID1338373
'The role of basolateral membrane fluidity in regulating Na-K ATPase activity along the crypt-villus axis in rabbit distal small intestine was assessed. Basolateral membranes were prepared from isolated villus and crypt enterocytes at 24- to 28-fold enhancement. Villus basolateral membranes were significantly (p < 0.001) more fluid than crypt basolateral ... More
Human hypertensive placenta contains an increased amount of Na,K-ATPase with higher affinity for cardiac glycosides.
AuthorsAmler E, Cester N, Salvolini E, Staffolani R, Burkhard M, Mazzanti L, Kotyk A, Romanini C
JournalCell Biol Int
PubMed ID7920379
'Placentas of women suffering from pregnancy-induced hypertension (PIH) were found to contain a greater amount of Na,K-ATPase molecules, estimated from anthroyl ouabain binding, than normotensive individuals. Both the microsomal fraction of placental cells and purified Na,K-ATPase showed an increased affinity for the specific inhibitor ouabain which, in the case of ... More
The prostate plasma membrane as an androgen receptor.
AuthorsFarnsworth WE
JournalMembr Biochem
PubMed ID1716343
'The pivotal role of the cell nucleus in androgenic control of target organs, such as the prostate, has become increasingly suspect. Equally qualified receptor activities have been found in the cytosol, endoplasmic reticulum, and plasma membrane. It is presently difficult to explain how a sex steroid can manage proliferation, metabolism, ... More
Localisation of potassium pumps in Drosophila ovarian follicles.
AuthorsBohrmann J, Heinrich UR
JournalZygote
PubMed ID8785677
'It has been shown previously that, in Drosophila oogenesis, potassium ions are important for bioelectric phenomena as well as for other physiological and developmental processes. In the present study we determined the spatial distribution and activity of the Na+,K+)-pump and of ouabain-insensitive K+ pumps in plasma membranes of vitellogenic ovarian ... More
The active site structure of Na+- and K+-stimulated ATPase. Location of a specific fluorescein isothiocyanate reactive site.
'Fluorescein 5''-isothiocyanate (FITC) has been shown to specifically inactivate the Na+- and K+-stimulated adenosine triphosphatase ((Na,K)-ATPase) at low concentrations (Karlish, S. J. D. (1979) Na+,K+ATPase Structure and Kinetics 115-128). The site of modification of purified dog kidney (Na,K)-ATPase by FITC has been investigated by enzymatic cleavage and fluorescence resonance energy ... More
Alphabeta protomers of Na+,K+-ATPase from microsomes of duck salt gland are mostly monomeric: formation of higher oligomers does not modify molecular activity.
AuthorsMartin DW, Marecek J, Scarlata S, Sachs JR
JournalProc Natl Acad Sci U S A
PubMed ID10706623
'The distance that separates alphabeta protomers of the Na(+), K(+)-ATPase in microsomes and in purified membranes prepared from duck nasal salt glands was estimated by measuring fluorescence resonance energy transfer between anthroylouabain bound to a population of alphabeta protomers and either N-[7-nitrobenz-2-oxa-1, 3-diazol-4-yl]-6-aminohexyl ouabain or 5-(and-6)-carboxyfluorescein-6-aminohexyl ouabain bound to the ... More
Distribution of ionocytes in the saccular epithelium of the inner ear of two teleosts (Oncorhynchus mykiss and Scophthalmus maximus).
AuthorsMayer-Gostan N, Kossmann H, Watrin A, Payan P, Boeuf G
JournalCell Tissue Res
PubMed ID9182600
'The saccular membranes of trout (Oncorhynchus mykiss) and turbot (Scophthalmus maximus) were examined to characterize specialized epithelial cells that might be responsible for ion exchange. The approach for localizing cell types was new for this tissue, as observations were made with a stereomicroscope and a light microscope in order to ... More
Modifications induced by insulin-dependent diabetes mellitus on human placental Na+/K+-adenosine triphosphatase.
AuthorsZolese G, Rabini RA, Fumelli P, Staffolani R, Curatola A, Kvasnicka P, Kotyk A, Cester N, Mazzanti L
JournalJ Lab Clin Med
PubMed ID9358075
'The causes of the reduced activity of Na+/K+-adenosine triphosphatase (ATPase) in human diabetes are still the object of controversy. The aim of this work was to investigate the mechanisms of inhibition by means of the study of the Na+/K+-ATPase purified from human placenta. We purified Na+/K+-ATPase from term placentas of ... More
A fluorometric method for the determination of functional (Na,K)-ATPase and cardiac glycoside receptors.
AuthorsFortes PA
JournalAnal Biochem
PubMed ID3028209
'A method to measure high-affinity binding sites for fluorescent ligands is described. The method is applied to the determination of (Na,K)-ATPase using the fluorescent ouabain derivative anthroylouabain (P. A. G. Fortes (1977) Biochemistry 16, 531-540). The method consists of measurements of the fluorescence intensities of a saturating concentration of anthroylouabain ... More
Na,K-ATPase from placenta of women with pregnancy-induced hypertension exhibits an increased affinity for cardiac glycosides.
AuthorsAmler E, Cester N, Magnanelli R, Mazzanti L, Kotyk A, Romanini C
JournalPhysiol Res
PubMed ID8054335
'Microsomes were prepared from placentas of normotensive women and of patients suffering from pregnancy-induced hypertension (PIH). Activity of Na,K-ATPase (estimated as ATP hydrolysis) from the hypertensive tissue was lower than from tissue of normotensive women, even if the number of Na,K-ATPase molecules (monitored by anthroyl ouabain binding) was actually greater ... More
Can insulin-dependent diabetes mellitus be understood at the molecular level through Na+/K+-adenosine triphosphatase?
AuthorsAmler E
JournalJ Lab Clin Med
PubMed ID9358071
Determination of ox brain Na,K-ATPase isoforms and their phosphorylated intermediates by analysis of anthroylouabain binding and its inhibition by oligomycin.
AuthorsFortes PA, Plesner L, Plesner IW
JournalProg Clin Biol Res
PubMed ID2843871
Kinetics of cardiac glycoside binding to a sodium, potassium adenosine triphosphatase studied with a fluorescent derivative of ouabain.
AuthorsMoczydlowski EG, Fortes PA
JournalBiochemistry
PubMed ID6243961
Fluorescence studies of the sodium and potassium transport adenosine triphosphatase labeled with fluorescein mercuric acetate and anthroylouabain.
AuthorsJesaitis AJ, Fortes PA
JournalJ Biol Chem
PubMed ID6243279
Presence of Na-K-ATPase in mitochondria-rich cells in the yolk-sac epithelium of larvae of the teleost Oreochromis mossambicus.
AuthorsHwang PP, Lee TH, Weng CF, Fang MJ, Cho GY
JournalPhysiol Biochem Zool
PubMed ID10068616
The purpose of this study is to provide biochemical evidence for the functions of the mitochondria-rich cell (MR cell) in the yolk-sac epithelium of the developing larvae of tilapia Oreochromis mossambicus. Western blotting with the antibody (6F) raised against avian Na-K-ATPase alpha1 subunit demonstrated the presence of Na-K-ATPase in yolk-sac ... More
The actin filament-severing domain of plasma gelsolin.
AuthorsChaponnier C, Janmey PA, Yin HL
JournalJ Cell Biol
PubMed ID3021782
Gelsolin, a multifunctional actin-modulating protein, has two actin-binding sites which may interact cooperatively. Native gelsolin requires micromolar Ca2+ for optimal binding of actin to both sites, and for expression of its actin filament-severing function. Recent work has shown that an NH2-terminal chymotryptic 17-kD fragment of human plasma gelsolin contains one ... More
Transient kinetics and thermodynamics of anthroylouabain binding to Na/K-ATPase.
AuthorsHellen EH, Yacono B, Pratap PR
JournalBiophys Chem
PubMed ID9648210
The Na/K-ATPase is an integral membrane protein enzyme which uses energy derived from hydrolysis of ATP to pump Na+ out of and K+ into the cell. Ouabain belongs to a class of drugs known as cardiac glycosides, which are useful for treating congestive heart failure. Therapeutic value is achieved when ... More
Effects of prolactin on chloride cells in opercular membrane of seawater-adapted tilapia.
AuthorsHerndon TM, McCormick SD, Bern HA
JournalGen Comp Endocrinol
PubMed ID1655557
Effects of prolactin on morphology and numbers of chloride cells in the opercular membrane of seawater-adapted tilapia (Oreochromis mossambicus) have been examined. Following five daily injections of ovine prolactin at a dose of 10 micrograms.g body wt-1, blood samples were taken and opercular membranes were removed and stained with a ... More
Structural dynamics and oligomeric interactions of Na+,K(+)-ATPase as monitored using fluorescence energy transfer.
AuthorsAmler E, Abbott A, Ball WJ
JournalBiophys J
PubMed ID1312368
The oligomeric nature of the purified lamb kidney Na+,K(+)-ATPase was investigated by measuring the fluorescence energy transfer between catalytic (alpha) subunits following sequential labeling with fluorescein 5'-isothiocyanate (FITC) and erythrosin 5'-isothiocyanate (ErITC). Although these two probes had different spectral responses upon reaction with the enzyme, our studies suggest that a ... More
Molecular distance measurements reveal an (alpha beta)2 dimeric structure of Na+/K+-ATPase. High affinity ATP binding site and K+-activated phosphatase reside on different alpha-subunits.
AuthorsLinnertz H, Urbanova P, Obsil T, Herman P, Amler E, Schoner W
JournalJ Biol Chem
PubMed ID9786881
ATP hydrolysis by Na+/K+-ATPase proceeds via the interaction of simultaneously existing and cooperating high (E1ATP) and low (E2ATP) substrate binding sites. It is unclear whether both ATP sites reside on the same or on different catalytic alpha-subunits. To answer this question, we looked for a fluorescent label for the E2ATP ... More
Regulation of Na+,K+-ATPase by persistent sodium accumulation in adult rat thalamic neurones.
AuthorsSenatorov VV, Stys PK, Hu B
JournalJ Physiol
PubMed ID10835038
The present study investigated the regulatory mechanism of the Na+, K+-ATPase and the level of internal Na+ and Ca2+ in response to persistent Na+ influx in acutely dissociated rat thalamic neurones. Whole-cell patch-clamp recordings and Na+ imaging revealed a stable [Na+]i and low background pump activity. Exposure to veratridine (50 ... More
Modifications induced by plasma from insulin-dependent diabetic patients and by lysophosphatidylcholine on human Na+,K(+)-adenosine triphosphatase.
AuthorsRabini RA, Fumelli P, Zolese G, Amler E, Salvolini E, Staffolani R, Cester N, Mazzanti L
JournalJ Clin Endocrinol Metab
PubMed ID9661619
To investigate the molecular mechanisms of the inhibition of Na+,K(+)-adenosine triphosphatase (Na+,K(+)-ATPase) in diabetes mellitus, we incubated Na+,K(+)-ATPase purified from human placenta of six healthy nondiabetic women with plasma from six insulin-dependent diabetic (IDDM) men and six healthy controls and with different concentrations of lysophosphatidylcholine (LPC). We determined the enzyme ... More
Mechanisms of inhibition of (Na,K)-ATPase by hydrostatic pressure studied with fluorescent probes.
AuthorsChong PL, Fortes PA, Jameson DM
JournalJ Biol Chem
PubMed ID2997210
To investigate the mechanisms by which hydrostatic pressure inhibits (Na,K)-ATPase, we measured enzyme activity, as a function of pressure and temperature, of purified (Na,K)-ATPase from dog kidney and eel electroplax, and we monitored protein conformation, possible subunit interactions, and the fluidity of the membrane with fluorescent probes. The (Na,K)-ATPase and ... More
Identification of a model cardiac glycoside receptor: comparisons with Na+,K+-ATPase.
The availability of high-affinity anti-digoxin monoclonal antibodies (mAbs) offers the potential for their use as models for the characterization of the relationship between receptor structure and cardiac glycoside binding. We have characterized the binding of anthroylouabain (AO), a fluorescent derivative of the cardiac glycoside ouabain, to mAbs 26-10, 45-20, and ... More
Spatial relationship and conformational changes between the cardiac glycoside site and beta-subunit oligosaccharides in sodium plus potassium activated adenosinetriphosphatase.
AuthorsLee JA, Fortes PA
JournalBiochemistry
PubMed ID3028471
(Na,K)-ATPase, the enzyme responsible for active transport of Na and K across the plasma membranes of animal cells, consists of a catalytic subunit (alpha) and a glycoprotein subunit (beta) with unknown function. We have determined the distance between fluorescent probes directed to specific sites on the alpha- and beta-subunits and ... More
Cortisol directly stimulates differentiation of chloride cells in tilapia opercular membrane.
AuthorsMcCormick SD
JournalAm J Physiol
PubMed ID1699439
Opercular membranes from freshwater tilapia (Oreochromis mossambicus) were maintained in vitro for 4 days and exposed to several concentrations of cortisol (0, 0.01, 0.1, 1, and 10 micrograms/ml). Chloride cell size, number, and Na(+)-K(+)-ATPase content were examined using a fluorescent mitochondrial dye (dimethylaminostyrylethylpyridiniumiodine), a fluorescent analogue of ouabain (anthroylouabain) that ... More
Anthroylouabain: a specific fluorescent probe for the cardiac glycoside receptor of the Na-K ATPase.
AuthorsFortes PA
JournalBiochemistry
PubMed ID138437
Anthroylouabain (AO) was synthesized by reaction of anthracene-9-carboxylic chloride with ouabain. Nuclear magnetic resonance spectroscopy of AO suggests that the anthracene is esterfied to the rhamnose in the glycoside. AO inhibits Na-K ATPase from human red cells, eel electroplax and rabbit and dog kidney with a KI less than 1muM. ... More
Steady-state levels of phosphorylated intermediates of (Na,K)-ATPase monitored with oligomycin and anthroylouabain.
AuthorsFortes PA, Lee JA
JournalJ Biol Chem
PubMed ID6088533
We present experiments designed to test whether or not the ADP-sensitive (E1P) and the K-sensitive (E2P) phosphoenzyme forms of (Na,K)-ATPase are intermediates of ATP hydrolysis in the presence of Na and K. We have used the apparent rate constant of anthroylouabain binding, k' on, and its inhibition by oligomycin to ... More
Interactions between cardiac glycosides and sodium/potassium-ATPase: three-dimensional structure-activity relationship models for ligand binding to the E2-Pi form of the enzyme versus activity inhibition.
AuthorsPaula S, Tabet MR, Ball WJ
JournalBiochemistry
PubMed ID15641774
Sodium/potassium-ATPase (Na/K-ATPase) is a transmembrane enzyme that utilizes energy gained from ATP hydrolysis to transport sodium and potassium ions across cell membranes in opposite directions against their chemical and electrical gradients. Its transport activity is effectively inhibited by cardiac glycosides, which bind to the extracellular side of the enzyme and ... More