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)

Ultrafiltered fur seal muscle hydrolysate was divided into eleven fractions by gel filtration on Sephadex G-15. One of the fractions (Fraction G9) accelerated the ATPase activity of carp myosin B to a rate about two-fold faster than that of the control. Fraction G9 showed a single ninhydrin spot in its silica gel thin layer chromatograph, and gave a positive test for tryptophan by the p-dimethylaminobenzaldehyde method, while tests for tyrosine, and for arginine were negative. The ion exchange amino acid analysis of its acid hydrolysate showed a predominant content of lysine, nearly equivalent to the amount of tryptophan determined from its UV absorbancy and the p-dimethylaminobenzaldehyde method. The N-terminal amino acid analysis gave di-DNP-Lys as the sole DNP-amino acid. The structure of the ATPase accelerating peptide fraction, Fraction G9, was deduced to be Lys-Trp.
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PMID:Nature of adenosine triphosphatase accelerating peptide from hydrolysate of fur seal muscle. 16 Sep 12

Influence of protein deficiency on the neurobehavioral toxicity of styrene during gestation and early infancy was studied in rats. Eye opening and fur growth were delayed in rat pups born to dams receiving a low protein diet. These pups also showed a delay in the development of surface and air righting reflexes and cliff avoidance response and a marginal increase in the levels of dopamine and serotonin receptors in comparison to those born to dams receiving a normal protein diet. Alterations in these parameters were more marked in pups born to dams exposed to styrene and receiving a low protein diet. In addition, these pups also showed a significant decrease in the activity of monoamine oxidase, Na+, K(+)-ATPase and succinic dehydrogenase as well as significant increases in motor activity and receptor sensitivity when compared to rat pups born to dams receiving a low protein diet. No significant alterations in behavioral and biochemical parameters were observed in the pups born to dams exposed to styrene and receiving a normal protein diet at this dose level. These results suggest that protein deficiency during early life renders the animals more susceptible to styrene.
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PMID:Increased neurobehavioral toxicity of styrene in protein-malnourished rats. 164 82

The C57Bl/Ler-vit.vit mouse grows a black pelage after birth. During successive hair molts, the fur loses its pigmentation. By 6 months of age, most of the fur of the animal is white. The epidermis of the ears and tail also loses its pigmentation. Histologic studies confirm that in the epidermis and hair follicles there is an absence of pigment cells identifiable by various histochemical or electron microscopic techniques. This mouse may be an excellent model in which to study the role of Langerhans' cells and the immune response in the pathogenesis of vitiligo, a study not easily done in humans. From results of prior studies, we postulated that if Langerhans' cells were involved in the destruction of melanocytes, they would be abnormal (either more or less numerous) in number during the active phase of depigmentation and normal in number after depigmentation was complete. To determine whether the Langerhans cell (Ia+/adenosine triphosphatase dendritic epidermal cell) might be involved in destruction of pigment cells, we quantified the number of Ia+ and adenosine triphosphatase dendritic cells in the hair follicles in skin from the ear, abdomen, back, and tail from male C57Bl/Ler-vit.vit mice while the fur and skin were depigmenting and after depigmentation was almost completed. We found that Langerhans' cells were normal in number during depigmentation and were most numerous after depigmentation. Previous studies indicate that Langerhans' cells in these mice are functionally defective and respond poorly to some contact allergens. From these morphologic and functional data, we conclude that Langerhans' cells probably are uninvolved in causing depigmentation in these mice. We also observed that the epithelium of hair follicles has a significantly higher (up to 1600/mm2) population density of Langerhans' cells than interfollicular skin.
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PMID:Langerhans' cells in hair follicles of the depigmenting C57Bl/Ler-vit.vit mouse. A model for human vitiligo. 244 80

Activities of Na+,K(+)-ATPase were measured in brain regions of experimental animals with either congenital or acquired hyperammonemia. In the sparse-fur (spf) mutant mouse, with a genetic X-linked deficiency of ornithine transcarbamylase, an animal model of congenital hyperammonemia, Na+,K(+)-ATPase was increased in frontal cortex (by 57%, P < 0.001), cerebellum (by 61%, P < 0.001), brainstem (by 71%, P < 0.001) and striatum (by 48%, P < 0.01). Four weeks following portacaval anastomosis in the rat, Na+,K(+)-ATPase activities were increased in cerebellum and striatum (by 19%, P < 0.01) and in brainstem (by 28%, P < 0.01). Stimulation of Na+,K(+)-ATPase and the subsequent alteration of neuronal excitability could contribute to the CNS dysfunction characteristic of chronic hyperammonemic syndromes.
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PMID:Na+,K(+)-ATPase activities are increased in brain in both congenital and acquired hyperammonemic syndromes. 855 87

Salmonella typhimurium encounters a variety of acid stress situations during pathogenesis and in the natural environment. These include the extreme low pH encountered in the stomach and a less acidic intestinal environment containing large amounts of organic weak acids (volatile fatty acids). The acid tolerance response (ATR) is a complex defence system that can minimize the lethal effects of extreme low pH (pH3). The data presented illustrate that the ATR can also defend against weak acids such as butyric, acetic or propionic acids. Although an acid shock of pH 4.4 induced the ATR, growth in subinhibitory concentrations of weak acids did not. Various mutations shown to affect tolerance to extreme acid conditions (pH 3) were tested for their effects on tolerance to weak acids. An rpoS mutant lacking the alternative sigma factor sigma s failed to protect cells against weak acids as well as extreme acid pH. The fur (ferric uptake regulator) and atp (Mg(2+)-dependent ATPase) mutants defective in extreme acid tolerance showed no defects in their tolerance to weak acids. Curiously, the atbR mutant that exhibits increased tolerance to extreme acid pH proved sensitive to weak acids. Several insertions that rendered cells sensitive to organic acids were isolated, all of which proved to be linked to the rpoS locus.
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PMID:The acid tolerance response of Salmonella typhimurium provides protection against organic acids. 896 16

A small fraction of the molecules internalized by endocytosis reaches the Golgi complex through a retrograde pathway that is poorly understood. In the present work, we used bacterial toxins to study the retrograde pathway in Vero cells. The recombinant B subunit of verotoxin 1B (VT1B) was labeled with fluorescein to monitor its progress within the cell by confocal microscopy. This toxin, which binds specifically to the glycolipid globotriaosyl ceramide, entered endosomes by both clathrin-dependent and -independent pathways, reaching the Golgi complex. Once internalized, the toxin-receptor complex did not recycle back to the plasma membrane. The kinetics of internalization and the subcellular distribution of VT1B were virtually identical to those of another glycolipid-binding toxin, the B subunit of cholera toxin (CTB). Retrograde transport of VT1B and CTB was unaffected by addition of weak bases in combination with concanamycin, a vacuolar-type ATPase inhibitor. Ratio imaging confirmed that these agents neutralized the luminal pH of the compartments where the toxin was located. Therefore, the retrograde transport of glycolipids differs from that of proteins like furin and TGN38, which require an acidic luminal pH. Additional experiments indicated that the glycolipid receptors of VT1B and CTB are internalized independently and not as part of lipid "rafts" and that internalization is cytochalasin insensitive. We conclude that glycolipids utilize a unique, pH-independent retrograde pathway to reach compartments of the secretory system and that assembly of F-actin is not required for this process.
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PMID:pH-independent retrograde targeting of glycolipids to the Golgi complex. 948 20

The proprotein-processing endoprotease furin is localized in the gastric epithelial cells of the pit region in the rat gastric gland. The gastric pit is composed of several cell types, including gastric surface mucosal (GSM) cells and parietal cells. Furin converts many growth- or differentiation-related proproteins to their active forms. We examined identification of furin-positive cells by immunostaining of rat gastric mucosa and regulators of the furin expression by measuring the furin promoter activity by luciferase assay. Furin-positive cells were stained for H(+)-K(+)-ATPase, indicating that they are parietal cells. Furin-positive parietal cells were not stained for transforming growth factor-alpha (TGF-alpha) but were surrounded by TGF-alpha-positive GSM cells. In contrast, parietal cells below the proliferative zone were positive for TGF-alpha but not for furin. Furin-positive parietal cells expressed a high level of epidermal growth factor receptor (EGFR). TGF-alpha stimulated the furin promoter activity highly in a mouse GSM cell line GSM06. Thus we suggest that the parietal cells of the pit region have furin-mediated functions that can be stimulated by EGFR signaling.
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PMID:Kex2 family endoprotease furin is expressed specifically in pit-region parietal cells of the rat gastric mucosa. 1040 66

Lymphoma proprotein convertase (LPC) is a subtilisin-like serine protease of the mammalian proprotein convertase family. It is synthesized as an inactive precursor protein, and propeptide cleavage occurs via intramolecular cleavage in the endoplasmic reticulum. In contrast to other convertases like furin and proprotein convertase-1, propeptide cleavage occurs slowly. Also, both a glycosylated and an unglycosylated precursor are detected. Here we demonstrate that the unglycosylated precursor form of LPC is localized in the cytosol due to the absence of a signal peptide. Using a reducible cross-linker, we found that glycosylated pro-LPC is associated with the molecular chaperone BiP. In addition, we show that pro-LPC is prone to aggregation and forms large complexes linked via interchain disulfide bonds. BiP is associated mainly with non-aggregated pro-LPC and pro-LPC dimers and trimers, suggesting that BiP prevents aggregation. Overexpression of wild-type BiP or a dominant-negative BiP ATPase mutant resulted in reduced processing of pro-LPC. Taken together, these results suggest that binding of BiP to pro-LPC prevents aggregation, but results in slower maturation.
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PMID:Binding of BiP to the processing enzyme lymphoma proprotein convertase prevents aggregation, but slows down maturation. 1096 28

The virulence of pathogenic bacteria is dependent on their adaptation to and survival in the stressful conditions encountered in their hosts. Helicobacter pylori exclusively colonizes the acid stomach of primates, making it an ideal study model. Little is known about how H. pylori responds to the moderately acidic conditions encountered at its colonization site, the gastric mucus layer. Thus, we compared gene expression profiles of H. pylori 26695 grown at neutral and acidic pH, and validated the data for a selection of genes by real-time polymerase chain reaction, dot-blots or enzymatic assays. During growth in acidic conditions, 56 genes were upregulated and 45 genes downregulated. We found that acidity is a signal modulating the expression of several virulence factors. Regulation of genes related to metal ion homeostasis suggests protective mechanisms involving diminished transport and enhanced storage. Genes encoding subunits of the F0F1 ATPase and of a newly identified Na+/H+ antiporter (NhaC-HP0946) were downregulated, revealing that this bacterium uses original mechanisms to control proton entry. Five of the upregulated genes encoded proteins controlling intracellular ammonia synthesis, including urease, amidase and formamidase, underlining the major role of this buffering compound in the protection against acidity in H. pylori. Regulatory networks and transcriptome analysis as well as enzymatic assays implicated two metal-responsive transcriptional regulators (NikR and Fur) and an essential two-component response regulator (HP0166, OmpR-like) as effectors of the H. pylori acid response. Finally, a nikR-fur mutant is attenuated in the mouse model, emphasizing the link between response to acidity, metal metabolism and virulence in this gastric pathogen.
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PMID:Responsiveness to acidity via metal ion regulators mediates virulence in the gastric pathogen Helicobacter pylori. 1522 39

Proteolytic cleavage of the Hendra virus fusion (F) protein results in the formation of disulfide-linked F1 and F2 subunits, with cleavage occurring after residue K109 in the sequence GDVK/L. This unusual cleavage site and efficient propagation of Hendra virus in a furin-deficient cell line indicate that the Hendra F protein is not cleaved by furin, the protease responsible for proteolytic activation of many viral fusion proteins. To identify the subcellular site of Hendra F processing, Vero cells transfected with pCAGGS-Hendra F or pCAGGS-SV5 F were metabolically labeled and chased in the absence and presence of inhibitors of exocytosis. The addition of carbonyl-cyanide-3-chlorophenylhydrazone, monensin, brefeldin A, or NaF-AlCl3 or incubation of cells at 20 degrees C all inhibited processing of the Hendra F protein, suggesting that cleavage of Hendra F occurs either in secretory vesicles budding from the trans-Golgi network or at the cell surface. In contrast to proteolytic cleavage of the simian virus 5 (SV5) F protein by the Ca(2+)-dependent protease furin, proteolytic cleavage of the Hendra F protein was not significantly inhibited by decreases in Ca2+ levels following incubation with EGTA or A23187. However, in the presence of weak amines and H+ V-ATPase inhibitors, known to raise intracellular pH, cleavage of Hendra F protein was inhibited while processing of the SV5 F protein was not significantly affected. The subcellular location, sensitivity to pH changes, and decreased Ca2+ requirement suggest that the protease responsible for cleavage of Hendra F protein differs from proteases previously shown to be involved in the processing of other viral glycoproteins.
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PMID:Subcellular localization and calcium and pH requirements for proteolytic processing of the Hendra virus fusion protein. 1530 11


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