Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

While Western blot analysis clearly revealed the presence of the alpha- and beta-subunits of Na(+)-K(+)-ATPase in a variety of rat tissues, beta was not readily detectable in liver. This observation was consistent with a previous report indicating that Na(+)-K(+)-ATPase immunoprecipitated from rat liver gives no clear evidence for the presence of a beta-subunit (Hubert et al. Biochemistry 25: 4156-4163, 1986). However, Western blot analysis of density gradient-purified lamb and rat liver microsomes showed the presence of a protein with an approximate molecular mass of 42 kDa that was immunoreactive with beta-specific polyclonal antibodies as well as beta-directed monoclonal antibodies. Deglycosylation of this protein by N-glycosidase F generated a core protein (beta c, M(r) approximately 32,000) that had the identical electrophoretic mobility as the beta c protein of the purified kidney enzyme. Isoform-specific monoclonal and synthetic peptide-directed polyclonal antibodies were used to demonstrate the presence of only the alpha 1- and beta 1-proteins in the liver and the presence of beta 2 in rat brain. Functional studies then showed that although both rat and lamb liver enzymes had sensitivities to cardiac glycoside inhibition similar to that of their corresponding kidney enzyme, the lamb liver enzyme had higher affinities for Na+, K+, and ATP than the kidney enzyme.
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PMID:Determination of Na(+)-K(+)-ATPase alpha- and beta-isoforms and kinetic properties in mammalian liver. 131 75

Murine autoimmune gastritis, induced by neonatal thymectomy, bears a striking similarity in pathology to the human autoimmune disease, pernicious anemia. Autoantibodies to parietal cells are found in both murine and human diseases. Monoclonal immunoglobulin G autoantibodies, obtained from neonatally thymectomized mice, have previously been shown to recognize two groups of gastric parietal cell antigens. In the present study, it is shown that two of these monoclonal autoantibodies, designated 1H9 and 2B6, are directed against the alpha subunit and beta subunit, respectively, of the gastric hydrogen-potassium-stimulated adenosine triphosphatase (H+,K(+)-ATPase; proton pump). Monoclonal antibody 1H9 showed reactivity by immunoblotting with a 95-kilodalton component of dog gastric tubulovesicular membranes and with a fusion protein containing the hydrophilic domain of the alpha subunit of the H+,K(+)-ATPase. Monoclonal antibody 2B6 reacted by immunoblotting with the 60-90-kilodalton glycoprotein (beta subunit) of the tomato lectin-purified dog H+,K(+)-ATPase and with the 60-90-kilodalton autoantigen purified with human parietal cell autoantibodies. Monoclonal antibody 2B6 also reacted with the deglycosylated 35-kilodalton core protein of the tomato lectin-purified 60-90-kilodalton beta subunit and of the purified 60-90-kilodalton autoantigen. Parietal cell autoantibody-positive sera from 20 mice with experimentally induced gastritis showed reactivity predominantly with the alpha and/or beta subunit of the gastric H+,K(+)-ATPase. Therefore, it is concluded that the major molecules targeted by parietal cell autoantibodies from mice with neonatal thymectomy-induced murine autoimmune gastritis and from humans with pernicious anemia are identical.
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PMID:The parietal cell autoantigens recognized in neonatal thymectomy-induced murine gastritis are the alpha and beta subunits of the gastric proton pump [corrected]. 164 25

Disruption of the gene for subunit 6 of the yeast cytochrome bc1 complex (QCR6) causes a temperature-sensitive petite phenotype in contrast to deletion of the coding region of QCR6, which shows no growth defect. Mitochondria from the petite strain carrying the disruption allele were devoid of ubiquinol-cytochrome c oxidoreductase activity but retained cytochrome c oxidase and oligomycin-sensitive ATPase activities. Optical spectra of cytochromes in mitochondrial membranes from the petite strain lacked a cytochrome b absorption band and had a reduced amount of cytochrome c1. Analysis of mitochondrial translation products showed normal synthesis of cytochrome b. Western analysis of mitochondrial membranes from this disruption strain indicates core protein 1 of the cytochrome bc1 complex is present in normal amounts, while cytochrome c1, the Rieske iron-sulfur protein, subunit 6, and subunit 7 were absent or present in very low amounts. Taken together, these findings indicate a loss of assembly of the cytochrome bc1 complex. High copy suppressors of the disruption strain were selected. Two separate families of suppressors were found. The first contained QCR6. The second family consisted of overlapping clones of a second gene distinct from QCR6. These plasmids contained QCR9, the gene which codes for subunit 9 of the yeast cytochrome bc1 complex. Suppression of the QCR6 disruption strain by overexpression of QCR9 indicates a critical interaction between these two proteins in the assembly of the cytochrome bc1 complex.
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PMID:The petite phenotype resulting from a truncated copy of subunit 6 results from loss of assembly of the cytochrome bc1 complex and can be suppressed by overexpression of subunit 9. 165 16

The gastric H+/K(+)-transporting adenosine triphosphatase (H+/K+ ATPase) (proton pump) consists of a catalytic alpha-subunit and a recently proposed 60-90-kDa glycoprotein beta-subunit. Using dog gastric membranes as the antigen, we have produced two murine monoclonal antibodies, 4F11 (IgG1) and 3A6 (IgA), which are specific for the 60-90-kDa glycoprotein. The monoclonal antibodies (1) specifically stained the cytoplasm of unfixed and formalin-fixed dog gastric parietal cells; (2) specifically reacted by ELISA with gastric tubulovesicular membranes; (3) recognised epitopes located on the luminal face of parietal cell tubulovesicular membranes, the site of the proton pump, by immunogold electron microscopy; (4) immunoblotted a 60-90-kDa molecule from tubulovesicular membranes and a 35-kDa component from peptide N-glycosidase-F-treated membrane extracts; (5) immunoblotted the 60-90-kDa parietal cell autoantigen associated with autoimmune gastritis and pernicious anemia, purified by chromatography on parietal cell autoantibody- or tomato-lectin-Sepharose 4B affinity columns, and the 35-kDa protein core of this autoantigen; this autoantigen has amino acid sequence similarity to the beta-subunit of the related Na+/K(+)-transporting adenosine triphosphatase (Na+/K+ ATPase) [Toh et al. (1990) Proc. Natl Acad. Sci. 87, 6418-6422]; (6) co-precipitated a molecule of 95 kDa with the 60-90-kDa molecule from 125I-labelled detergent extracts of dog tubulovesicular membranes; and (7) co-purified the catalytic alpha-subunit of the H+/K+ ATPase with the 60-90-kDa molecule by immunoaffinity chromatography of tubulovesicular membrane extracts on a monoclonal antibody 3A6-Sepharose 4B column, indicating a physical association between the two molecules. These results provide further evidence that the 60-90-kDa glycoprotein is the beta-subunit of the gastric H+/K+ ATPase. We conclude that the monoclonal antibodies specifically recognise luminal epitopes on the 35-kDa core protein of the 60-90-kDa beta-subunit of the gastric proton pump, a major target molecule in autoimmune gastritis and pernicious anaemia. These monoclonal antibodies will be valuable probes to study the structure and function of this associated beta-subunit, as well as the ontogeny of the gastric proton pump.
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PMID:Monoclonal antibodies specific for the core protein of the beta-subunit of the gastric proton pump (H+/K+ ATPase). An autoantigen targetted in pernicious anaemia. 170 13

We have used a cloned fusion protein as antigen to generate an antiserum specific for the rat Na,K-ATPase beta 2 subunit. Utilizing this antiserum, we analyzed some of the structural features and tissue distribution of the beta 2 subunit. Treatment of a rat brain microsomal membrane fraction with N-glycanase F revealed that the beta 2 subunit is composed of an approximately 32 kDa core protein and at least two N-linked carbohydrate chains. The beta 2 subunit also was found to copurify with ouabain-inhibitable Na,K-ATPase activity from rat brain. Western blot analysis of rat tissue microsomes showed that beta 2 subunits were expressed in brain, pineal gland, and thymus. However, no beta 2 subunits were detected in kidney, heart, spleen, liver, mammary gland, or lung. These results suggest that the beta 2 subunit is a functional component of the rat brain Na,K-ATPase. The restricted tissue distribution of beta 2 subunits may reflect important differences in the functions of individual beta subunit isoforms.
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PMID:The Na,K-ATPase beta 2 subunit is expressed in rat brain and copurifies with Na,K-ATPase activity. 215 63

The effects of thyroid hormone on nuclear-encoded mitochondrial inner membrane proteins were investigated by in vitro translation of the endogenous mRNA present in a postmitochondrial fraction from the livers of rats treated in vivo with hormone. The levels of the mRNAs were estimated by quantitative immunoabsorption of the translation mixture. Total protein synthesis was increased 2.6-fold after 4 days of in vivo hormone treatment, but only 10-15% of the polypeptides were dramatically altered (greater than 5-fold). Among the most highly elevated were cytochrome c1 (greater than 10-fold increase) and the Rieske iron-sulfur protein of the cytochrome bc1 complex. Other inner membrane proteins (core protein 1, beta subunit of F1 ATPase, subunit IV of cytochrome oxidase, 3-hydroxybutyrate dehydrogenase) and non-mitochondrial proteins (rat serum albumin, beta 2-microglobulin) were not altered significantly by hormone treatment. Cytochrome c1 and the Rieske protein increased after 12 h of hormone treatment, a relatively early response in mammalian mitochondrial biogenesis. The possible significance of this response for the regulation of mitochondrial synthesis and assembly is discussed.
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PMID:Thyroid hormone regulation of nuclear-encoded mitochondrial inner membrane polypeptides of the liver. 277 68

Several inner membrane proteins from rat liver mitochondria have been translated for the first time in rabbit reticulocyte lysates. These include the Rieske iron-sulfur protein, cytochrome c1 and core protein I of the cytochrome bc1 complex, the alpha and beta subunits of F1 ATPase, and subunit IV of cytochrome oxidase. All were translated from free polysomes as larger-molecular-mass precursors, and were processed to their mature forms by isolated liver mitochondria or by the isolated mitochondrial matrix fraction. In vitro processing, catalyzed by the isolated matrix fraction, is inhibited by rhodamine 6G. The latter is a fluorescent probe, which accumulates specifically in mitochondria of whole cells and which is used extensively to visualize mitochondrial morphology. The concentration of rhodamine 6G required for inhibition in vitro is similar to that of o-phenanthroline. Rhodamine 6G inhibits matrix-catalyzed processing of all precursors tested, indicating that the mechanism of inhibition is common for a variety of functionally unrelated precursors. The novel action of rhodamine 6G reported here can form the basis for its inhibition of precursor processing in intact hepatoma cells [Kolarov, J. & Nelson, B.D. (1984) Eur. J. Biochem. 144, 387-392].
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PMID:Rhodamine 6G inhibits the matrix-catalyzed processing of precursors of rat-liver mitochondrial proteins. 286 95

The chicken gizzard smooth muscle extracellular ATPase (ecto-ATPase) is a low abundance, high specific activity, divalent cation-dependent, nonspecific nucleotide triphosphatase (NTPase). The ATPase is a 66-kDa glycoprotein with a protein core of 53 kDa (Stout, J.G. and Kirley, T.L. (1994) J. Biochem. Biophys. Methods 29, 61-75). In this study we evaluated the characteristics of a bank of monoclonal antibodies raised against a partially purified chicken gizzard ecto-ATPase. 18 monoclonal antibodies identified by an ATPase capture assay were tested for effects on ATPase activity as well as for their Western blot and immunoprecipitation potential. The five most promising monoclonal antibodies were used to immunopurify the ecto-ATPase. The one-step immunoaffinity purification of solubilized chicken gizzard membranes with all five of these monoclonal antibodies isolated a 66-kDa protein whose identity was confirmed by N-terminal sequence analysis to be the ecto-ATPase. Several of these monoclonal antibodies stimulated ecto-ATPase activity similar to that observed previously with lectins. Western blot analysis revealed that three of the five monoclonal antibodies recognized a major immunoreactive band at 66 kDa (53-kDa core protein), consistent with previous purification results. The other two antibodies recognized proteins of approximately 90 and 160 kDa on Western blots. The 90-kDa co-immunopurifying (and presumably associated or related) protein was identified by N-terminal analysis as LEP100, a glycoprotein that shuttles between the plasma and lysosomal membranes. The approximately 160-kDa co-immunopurifying protein was identified by N-terminal analysis as integrin, a protein involved in extracellular contacts with adhesion molecules. Extended N-terminal sequence analysis of the immunopurified 66-kDa ecto-ATPase revealed some sequence homology with mouse lysosomal associated membrane protein. Tissue distribution of the ecto-ATPase showed that the highest levels of protein were expressed in muscle tissues (cardiac, skeletal, and smooth) and brain.
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PMID:Properties of and proteins associated with the extracellular ATPase of chicken gizzard smooth muscle. A monoclonal antibody study. 774 34

The ecto-Mg-ATPase isolated from chicken gizzard smooth muscle was solubilized, purified and characterized. The purification did not require the use of expensive or specialized apparatus. The chromatographic and electrophoretic characteristics of the ecto-Mg-ATPase from chicken are similar to those reported earlier for the ecto-Mg-ATPase isolated from rabbit skeletal muscle transverse tubule membranes [1992, J. Biol. Chem. 267, 11777-11782]. One obvious difference found was that the solubilized chicken ecto-Mg-ATPase can be stimulated approximately 1900% by the lectin Concanavalin A (Con A) under the same conditions that the rabbit enzyme is inhibited by approximately 50%. This stimulatory effect of Con A is useful for following the purification, and also increases the specific activity of the chicken enzyme to a very high level similar to that observed for the rabbit enzyme. After purification of the solubilized chicken ecto-Mg-ATPase by three steps of anion exchange chromatography, as well as Con A and erythroagglutinating Phaseolus vulgaris (PHA-E) lectin affinity chromatographies, a single diffuse glycoprotein band at approximately 66 kDa is observed after SDS-PAGE. This protein could be deglycosylated to a core protein of 53 kDa. Thus, the chicken gizzard protein is very similar in molecular size to the rabbit skeletal muscle ecto-Mg-ATPase both before and after deglycosylation [1992, J. Biol. Chem. 267, 11777-11782]. The N-terminal sequence of the 66 kDa chicken gizzard protein was found to be: Ala-Arg-Arg-Ala-Ala-Ala-Val-Leu-Leu-Leu-Leu-Ala. This is a unique sequence which, while very different from the rabbit ecto-Mg-ATPase N-terminus, exhibits some of the same characteristics, since it contains basic residues as the second and third amino acids, with the remainder of the N-terminus being very hydrophobic in nature. Furthermore, the chicken gizzard ecto-Mg-ATPase can be separated from the adhesion molecule, truncated cadherin (T-cadherin) by anion exchange chromatography, and is therefore not identical to that protein, as had been recently proposed [1993, Arch. Biochem. Biophys. 303, 32-43].
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PMID:Purification and characterization of the ecto-Mg-ATPase of chicken gizzard smooth muscle. 798 47

A mouse monoclonal antibody has been used to localize Na+/K(+)-ATPase in the bovine corneal endothelium. The specificity of the antibody was demonstrated by reaction with a single protein of molecular mass 100 kDa on Western blots and immunoprecipitation of a complex consisting of 100 kDa and 50 kDa subunits. Treatment of the immunoprecipitated antigen with Peptide N-Glycanase F produced no change in the molecular mass of the 100 kDa protein, but resulted in a progressive decrease in the molecular mass of the 50 kDa subunit, to yield a core protein of molecular mass about 33 kDa. The pattern of deglycosylation suggested the presence of three N-linked glycans attached to the 33 kDa protein core. These results were consistent with the antibody being specific for the alpha subunit of the Na+/K(+)-ATPase. Immunocytochemical studies at the light and electron microscopic level demonstrated antibody binding to both the basal and lateral membranes of bovine corneal endothelial cells. This suggested a baso-lateral distribution of Na+/K(+)-ATPase in these cells, rather than the previously proposed lateral membrane-only distribution.
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PMID:Localization of Na+/K(+)-ATPase in the bovine corneal endothelium. 829 16


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