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)

To study sphingolipid function(s) in Saccharomyces cerevisiae, we have investigated the effects of environmental stress on mutant (SLC) strains (R. C. Dickson, G. B. Wells, A. Schmidt, and R. L. Lester, Mol. Cell. Biol. 10:2176-2181, 1990) that either contain or lack sphingolipids, depending on whether they are cultured with a sphingolipid long-chain base. Strains lacking sphingolipid were unable to grow at low pH, at 37 degrees C, or with high salt concentrations in the medium; these environmental stresses are known to inhibit the growth of some S. cerevisiae strains with a defective plasma membrane H(+)-ATPase. We found that sphingolipids were essential for proton extrusion at low pH and furthermore found that cells lacking sphingolipid no longer exhibited net proton extrusion at normal pH after a 1-min exposure to pH 3. Cells lacking sphingolipid appeared to rapidly become almost completely permeable to protons at low pH. The deleterious effects of low pH could be partially prevented by 1 M sorbitol in the suspension of cells lacking sphingolipid. Proton extrusion at normal pH (pH 6) was significantly inhibited at 39 degrees C only in cells lacking sphingolipid. Thus, the product of an SLC suppressor gene permits life without sphingolipids only in a limited range of environments. Outside this range, sphingolipids appear to be essential for maintaining proton permeability barriers and/or for proton extrusion.
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PMID:Phenotypes of sphingolipid-dependent strains of Saccharomyces cerevisiae. 142 41

Aldose reductase was visualized by light and electron microscopy using a goat anti-rat antibody with immunoperoxidase and immunogold, respectively. Ouabain-sensitive, K(+)-dependent, p-nitro-phenylphosphatase, a component of (Na+, K+)-ATPase, was localized at the electron microscopic level by enzyme histochemistry using p-nitro-phenylphosphate as substrate. In peripheral nerve, spinal ganglia and roots, the Schwann cell of myelinated fibers was the principal site of aldose reductase localization. Immunostaining was intense in the paranodal region and the Schmidt-Lanterman clefts as well as in cytoplasm of the terminal expansions of paranodal myelin lamellae and the nodal microvilli. Schwann cell cytoplasm of unmyelinated fibers were faintly labelled. Endoneurial vessel endothelia, pericytes and perineurium failed to bind appreciable amounts of aldose reductase antibody. However, mast cell granules bound antibody strongly. In contrast, p-nitro-phenylphosphatase reaction product was detected in the nodal axolemma, terminal loops of Schwann cell cytoplasm and the innermost layer of perineurial cells. In endothelial cells, reaction product was localized on either the luminal or abluminal, or on both luminal and abluminal plasmalemma. Endothelial vesicular profiles were often loaded with reaction product. Occasional staining of myelin and axonal organelles was noted. Mast cells lacked reaction product.
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PMID:Fine-structural localization of aldose reductase and ouabain-sensitive, K(+)-dependent p-nitro-phenylphosphatase in rat peripheral nerve. 165 Jan 13

There is no published description of the distribution of free Ca2+, nor of the distribution of Ca(2+)-ATPase activity associated with the maintenance of low axoplasmic Ca2+ concentrations, in normal central myelinated nerve fibres. We have used the oxalate-pyroantimonate technique to localise free Ca2+, together with the lead-citrate technique to localise Ca(2+)-ATPase activity within myelinated fibres from the adult guinea-pig optic nerve. Pyroantimonate precipitate occurred within the axoplasm at nodes of Ranvier and the internode, at areas of myelin disruption, within Schmidt-Lanterman incisures (SLI) and glial paranodal loops. But precipitate was absent from the axoplasm beneath SLI and at the paranode. Ca(2+)-ATPase activity was localised in axonal smooth endoplasmic reticulum (SER), the outer membrane of mitochondria, the nodal axolemma, the glial membranes of the paranodal loops, the SLI and the external aspect of the myelin sheath. We have demonstrated large domains within the axons of CNS fibres where calcium is present or absent. Moreover, we have shown that, where calcium is absent, there is localisation of Ca(2+)-ATPase activity, which would serve to remove calcium from the adjacent axoplasm. Our results are compared with information obtained from PNS fibres and some differences of distribution discussed.
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PMID:Localisation of calcium ions and calcium-ATPase activity within myelinated nerve fibres of the adult guinea-pig optic nerve. 183 65

ATPase activity was studied in the structures of axon-myelin-Schwann cell complex of sciatic nerves of rabbits of pre-and postnatal development. Positive reaction was observed on the plasma membrane, mitochondria and endoplasmic reticulum of Schwann cells, on the intraperiod lines of the compact myelin, in the split myelin lamellae in the paranodal regions and Schmidt-Lanterman clefts, in segment of outermost lamellae split off from the interparanodal myelin, in the mesaxons, in the loose myelin lamellae in the earlier stages of myelinization, on the axolemma (periaxonal space) and axoplasm. The ATPase activity on the Schwannian plasmalemma, axolemma and myelin sheath surface was found to be heterogeneously distributed. An accumulated of reaction deposits at the origin of the outer mesaxon, at the axoglial contacts as well as at the terminal part of the myelin sheath was respectively observed. Alterations of the enzyme activity distribution in axon-myelin-Schwann cell complex during rabbit's development were found to be associated with the growing myelin sheath and its node-paranode. Using controls with ouabain an attempt was made the possibilities of Wachstein and Meisel's method to be shown and the place of alpha+ form of Na+, K+-ATPase in the axon-myelin-Schwann cell Complex to be establish.
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PMID:Cytochemical localization of ATPase in axon-myelin-Schwann cell complex type. 252 80

We used electron microscopic immunocytochemistry to study the distribution of calmodulin in rat sciatic nerve. Calmodulin immunoreactivity was found throughout the axoplasmic matrix, but particularly along microtubules. Schwann cell cytoplasm and nuclei demonstrated immunoreactivity, while compact myelin did not. There was particularly intense immuno-gold deposition within Schmidt Lanterman clefts. At the nodes of Ranvier, calmodulin appeared preferentially in the paranodal region, along the apposition of the axolemma to the paranodal loops of myelin and extending into the paranodal loops. The presence of calmodulin immunoreactivity along microtubules supports biochemical and pharmacological evidence of calmodulin involvement in regulating the assembly and phosphorylation of microtubules, and in fast axonal transport along microtubules. The co-localization of paranodal calmodulin immunoreactivity with Ca-ATPase activity demonstrated cytochemically (Mata et al., Brain Research, in press) supports the notion that the paranodal Ca-ATPase activity may be regulated by calmodulin, and agrees with the in vitro biochemical evidence for Ca-ATPase of other cells.
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PMID:Calmodulin distribution in peripheral nerve: an EM immunocytochemical study. 321 37

In addition to the previously described deoxyribonucleic acid (DNA) polymerase, DNA ligase, DNA exonuclease, and DNA endonuclease activities, purified virions of Schmidt-Ruppin strain of Rous sarcoma virus (SRV) have nucleotides and nucleotide kinase, phosphatase, hexokinase, and lactate dehydrogenase activities. The SRV virions have no glucose-6-phosphate dehydrogenase activity. All enzyme activities, but glucose-6-phosphate dehydrogenase and adenosine triphosphatase, were increased by disruption of the virions. The DNA polymerase, DNA ligase, and hexokinase activities had a higher specific activity in purified virion cores. It is suggested that during assembly virions of SRV may pick up cytoplasmic components which bind to virion proteins. The role of these components in viral replication is not known at present.
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PMID:Enzymes and nucleotides in virions of Rous sarcoma virus. 433 49

Rates of uptake and intracellular concentrations of monovalent cations were measured in virus-transformed and nontransformed chick embryo (CE) cells. Uptake of 22Na+ into cells transformed by the BH strain of Rous sarcoma virus (RSV-BH) (CE-BH) was about double the rate of uptake into CE cells, or cells transformed by the Schmidt-Ruppin strain (RSV-SR): CE-SR. Likewise, the rate of efflux of 22Na+ was greater in CE-BH cells than in CE or CE-SR cells. The greater permeability of CE-BH cells to Na+ was apparent in higher intracellular Na+ concentrations. Experiments with cells exhibiting temperature-dependent transformation showed that new RNA and protein synthesis was a requirement for the acquisition of increased Na+ permeability, suggesting that the change is an indirect effect of the virus-coded transformation-inducing protein. Rates of 86Rb+ uptake, used as a measure of K+ influx, were indistinguishable in CE, CE-BH, and CE-SR cells. Also, equilibrium intracellular levels of 86Rb+ were similar in transformed and nontransformed cells, as were observed concentrations of K+. Also, no differences in ATPase activity, as indicated by ouabain binding or temperature sensitivity, were observed. We conclude that monovalent cations play no direct role in RSV-induced transformation, although the higher levels of Na+ in CE-BH cells may be responsible for other distinguishing biochemical features of these cells.
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PMID:Sodium and rubidium uptake in cells transformed by Rous sarcoma virus. 626 Aug 19

The transformation-specific protein pp60(src) coded for by avian sarcoma viruses and its associated protein kinase activity is present in virus particles of Rous sarcoma virus, Schmidt-Ruppin strain, subgroup D. Quantitative comparison of the immunoglobulin G-phosphorylating activity in Schmidt-Ruppin D virus and Schmidt-Ruppin D virus-transformed fibroblasts indicated that there was two- to fourfold less activity in the virus particles. Disruption of virus particles with nonionic detergent demonstrated that the protein kinase activity fractionated together with the viral membrane protein gp85. Therefore, viral membranes were isolated by floating detergent-disrupted virus through a discontinuous sucrose density gradient. At a characteristic density corresponding to 26% sucrose, viral membranes were identified by the radioactively labeled viral glycoprotein and furthermore by the membrane marker enzyme Na(+)-K(+)-stimulated, Mg(2+)-activated ATPase and were visualized by electron microscopy. Contamination by cell membranes could be ruled out, since (i) the virus preparation was free of cell membrane contaminants as judged from electron microscopy, (ii) floating of intact virus did not release membraneous material, and (iii) virus-free tissue culture fluid from Schmidt-Ruppin D virus-transformed nonproducer cells (which potentially contain cell membranes) did not contribute any immunoglobulin G-phosphorylating activity after mixing with nontransforming virus and pelleting it. Both pp60(src) and the protein kinase activity were found to be associated with the viral membrane. Solubilization of virus by detergent released two phosphoproteins, with molecular weights of 42,000 and 45,000 which reacted with sera specific for pp60(src) and revealed protein kinase activity but which were not membrane bound and may have represented degradation products of pp60(src). Surface iodination of intact virus particles (harvested at 3-h intervals) did not result in radioactive labeling of pp60(src), whereas collection at 24-h intervals allowed iodination of pp60(src). In contrast to the viral glycoprotein gp85, the iodinated virion-associated pp60(src) was insensitive to mild proteolytic treatment. Binding to tumorbearing-rabbit serum, immunoglobulin G phosphorylation, and endogenous phosphorylation of 60,000-, 45,000-and 42,000-dalton proteins required lysed virus and were not possible with intact virus. These results indicated that pp60(src) was embedded within the viral membrane. Membrane proteins phosphorylated in vitro were analyzed for their phosphoamino acid composition. Eight polypeptides exhibited phosphorylation in tyrosine and were absent in nontransforming viral controls.
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PMID:Association of the transformation-specific protein pp60src with the membrane of an avian sarcoma virus. 626 49

Use of the Flagyl selection procedure [Schmidt et al. (1977) Proc. Natl Acad. Sci. USA, 74, 610-614] led to the isolation of a nuclear mutant of Chlamydomonas reinhardtii designated thm-24. This mutant displays normal electron transport rates in vitro, possesses high latent ATPase activity bound to the thylakoid membrane, but is incapable of photophosphorylation. Decay of the transmembrane potential, as indicated by the kinetics of the 520-nm absorption change after illumination, is unusually slow and markedly biphasic. Sodium dodecylsulfate/polyacrylamide gel electrophoresis of purified thylakoid membranes shows mutant thm-24 to be lacking a number of polypeptides including those previously designated 4.1, 4.2 and 8.1. Treatment of purified thylakoid membranes of wild-type and mutant algae, using the chloroform-release procedure of Beechey et al. [(1975) Biochem. J. 148, 533-537] resulted in the removal of ATPase activity from each strain. In wild-type cells, the ATPase activity was of heterogeneous enzymatic origin; fractionation of the chloroform-release extracts by non-denaturing polyacrylamide gel electrophoresis yielded three distinct bands displaying ATPase activity, designated ATPases I, II and III. In contrast, extracts from membranes of mutant thm-24 yielded only one ATPase-containing fraction, co-migrating with ATPase I from wild-type. Use of electrophoretic, immunological and enzymatic methods established a correspondence of the polypeptide subunits of ATPases II and III and those of spinach coupling factor, CF1. ATPase I from either algal strain was shown to be structurally distinct from high plant CF1 and to C. reinhardtii ATPases II and III.
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PMID:A nuclear mutant of Chlamydomonas reinhardtii defective in photosynthetic photophosphorylation. Characterization of the algal coupling factor ATPase. 645 94

Ouabain-sensitive, K(+)-dependent, p-nitrophenylphosphatase (K-NPPase) is the second dephosphorylative property of the Na-K ATPase complex. Localization of its activity in the horizontal portion of the facial nerve in 11 normal cats was studied ultracytochemically using a cerium-based method. The fine granular reaction product of the K-NPPase activity was observed on the cytoplasmic side of the axolemma of the axon cylinder. Enzyme activity was also detected on the cytoplasmic side of the plasma membrane of Schmidt-Lanterman incisures and nodes of Ranvier. No reaction product was detected on the periaxonal and outermost plasma membrane of Schwann cells and in the myelin sheath. In control tissue samples, enzyme activity was almost completely inhibited by 10 mM ouabain, and no reaction was noted in medium without K+. The present findings indicate that localization of Na-K ATPase in the cat facial nerve simulates that of other peripheral and cranial nerves.
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PMID:Ultracytochemical demonstration of ouabain-sensitive, K(+)-dependent, p-nitrophenylphosphatase (Na-K ATPase) activity in cat facial nerve. 791 58


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