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

---

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

Mast cells possess specialized granules that, upon stimulation of surface FcR with IgE, fuse with the plasma membrane, thereby releasing inflammatory mediators. A family of membrane fusion proteins called SNAREs, which are present on both the granule and the plasma membrane, plays a role in the fusion of these granules with the plasma membrane of mast cells. In addition to the SNAREs themselves, it is likely that the SNARE accessory protein, N-ethylmaleimide-sensitive factor (NSF), affects the composition and structure of the SNARE complex. NSF is a cytoplasmic ATPase that disassembles the SNARE complexes. To investigate the role of NSF in mast cell degranulation, we developed an assay to measure secretion from transiently transfected RBL (rat basophilic leukemia)-2H3 mast cells (a tumor analog of mucosal mast cells). RBL-2H3 cells were cotransfected with a plasmid encoding a human growth hormone secretion reporter along with either wild-type NSF or an NSF mutant that lacks ATPase activity. Human growth hormone was targeted to and released from secretory granules in RBL-2H3 cells, and coexpression with mutant NSF dramatically inhibited regulated exocytosis from the transfected cells. Biochemical analysis of SNARE complexes in these cells revealed that overexpression of the NSF mutant decreased disassembly and resulted in an accumulation of SNARE complexes. These data reveal a role for NSF in mast cell exocytosis and highlight the importance of SNARE disassembly, or priming, in regulated exocytosis from mast cells.
...
PMID:Mast cell degranulation requires N-ethylmaleimide-sensitive factor-mediated SNARE disassembly. 1460 37

Ghrelin, a novel growth hormone (GH)-releasing peptide, was isolated from the rat stomach as an endogenous ligand to the growth hormone secretagogues receptor. It is known that ghrelin stimulates the release of GH from the rat anterior pituitary gland, but the intracellular signal cascade in somatotrophs has not yet been clarified. In this study, using an isolated cell perifusion system, we examined whether ghrelin- and growth hormone-releasing hormone (GHRH)-induced GH secretion from rat pituitary cells depends on intra- and extracellular Ca(2+) and voltage-gated Ca(2+) channels. For this purpose, we first measured ghrelin- or GHRH-stimulated GH concentration following treatment with reduced extracellular Ca(2+) and/or thapsigargin, an endoplasmic reticulum Ca(2+) ATPase inhibitor. Reductions in the extracellular Ca(2+) concentration to 0.25 mM and to 0 mM resulted in decreases in ghrelin-stimulated GH secretion to 81% and 39% and decreases in GHRH-induced GH secretion to 83% and 13%, respectively, compared to the levels in the case of 2.5 mM Ca(2+) concentration, suggesting that extracellular Ca(2+) is essential for both ghrelin- and GHRH-induced GH secretion. Pretreatment with thapsigargin resulted in a reduction in ghrelin-induced GH secretion to approximately 60% of the control level, but GHRH treatment had not effect on the GH secretion. Moreover, preincubation with thapsigargin and 0 mM extracellular Ca(2+) concentration resulted in significant inhibition of GHRH- and ghrelin-induced GH secretion. Subsequently, to determine whether ghrelin-stimulated GH secretion was induced through voltage-gated Ca(2+) channels, we measured the ghrelin-stimulated GH concentration following treatment with nifedipine, an L-type Ca(2+) channel inhibitor, and found that the amount of GH secretion was reduced to 44% of the control level. Furthermore, by replacement of extracellular Na(2+) in the medium with N-methyl-D(-)-glucamine, an impermeable molecule, GH secretion was reduced to 47%. In this study, we demonstrated that the GH-stimulatory effect of ghrelin, unlike that of GHRH, is achieved through both intracellular and extracellular Ca(2+) sources and that ghrelin-induced extracellular Ca(2+) influx involves an L-type voltage-gated Ca(2+) channel and Na(+) influx.
...
PMID:Ghrelin-induced growth hormone release from isolated rat anterior pituitary cells depends on intracellullar and extracellular Ca2+ sources. 1550 May 42

In this study, we set out to examine the role of the somatotropic axis in the ion-regulation process in rainbow trout. Specifically, our objective was to examine whether plasma insulin-like growth factor-binding proteins (IGFBPs) are modulated by gradual salinity exposure. To this end, freshwater (FW)-adapted rainbow trout were subjected to gradual salinity increases, up to 66% seawater, over a period of 5 days. During this acclimation process, minimal elevations in plasma Ca2+ and Cl- were seen in the salinity-acclimated groups compared with FW controls. There were no changes in plasma Na+ levels, and only a minor transient change in plasma cortisol levels was seen with salinity exposure. The salinity challenged animals responded with elevations in plasma growth hormone (GH) and IGF-I levels and gill Na+-K+-ATPase activity. We identified IGFBPs of 21, 32, 42, and 50 kDa in size in the plasma of these animals, and they were consistently higher with salinity. Despite the overall increase in IGFBPs with salinity, transient changes in individual BPs over the 5-day period were noted in the FW and salinity-exposed fish. Specifically, the transient changes in plasma levels of the 21-, 42-, and 50-kDa IGFBPs were different between the FW and salinity groups, while the 32-kDa IGFBP showed a similar trend (increases with sampling time) in both groups. Considered together, the elevated plasma IGFBPs suggest a key role for these binding proteins in the regulation of IGF-I during salinity acclimation in salmonids.
...
PMID:Salinity acclimation affects the somatotropic axis in rainbow trout. 1560 5

Rainbow trout Oncorhynchus mykiss were injected intraperitoneally with slow-release implants of vegetable oil alone or containing ovine growth hormone (oGH) (2 and 5 microgg(-1) body weight), and sampled after 5 days to assess the simultaneous effects of GH on both osmoregulation and carbohydrate metabolism. An enhanced hypoosmoregulatory capacity of oGH-implanted fish is suggested by the increase observed in gill Na+,K+-ATPase activity, and the decrease observed in plasma ion concentration (Na+ and Cl-) and osmolality. GH treatment also elicited increased plasma glucose levels and metabolic changes in liver, gills, kidney, and brain. Major metabolic changes elicited by GH treatment included (1) decreased glycolytic potential and capacity for exporting glucose in liver, (2) enhanced glycogenolytic potential and capacity for use of exogenous glucose in gills and kidney, as well as increased glycolytic capacity in the later tissue, and (3) enhanced glycogenolytic and glycolytic capacities in brain. These metabolic changes elicited by GH treatment support a role for GH in the control of carbohydrate metabolism in salmonids that could be related either to the metabolic changes occurring during osmotic acclimation in nature (a process in which changes in GH levels and carbohydrate metabolism have both been reported) or to metabolic changes associated with growth.
...
PMID:Actions of growth hormone on carbohydrate metabolism and osmoregulation of rainbow trout (Oncorhynchus mykiss). 1580 8

The full length genes encoding the catalytic alpha and glycosylated beta subunits of the sodium pump (Na+-K+-ATPase) were cloned and characterized from silver sea bream gill. Using in vitro preparations of gill tissue it was found that growth hormone (10 and 100 ng/ml) caused an increase in subunit transcription, translation, and Na+-K+-ATPase enzyme activity. Similarly, insulin-like growth factor 1 (10 and 100 ng/ml) also caused an increase in Na+-K+-ATPase subunit amounts and enzyme activity. Cortisol (10 and 100 ng/ml) increased alpha subunit transcript and protein but did not modulate beta subunit expression or enzyme activity. Ovine prolactin did not cause any changes in Na+-K+-ATPase subunit transcription, translation or enzyme activity. This study is the first to describe how both Na+-K+-ATPase alpha and beta subunits are modulated at transcriptional and translational levels in fish osmoregulatory tissue upon exposure to hormones.
...
PMID:Cloning and characterization of sea bream Na+-K+-ATPase alpha and beta subunit genes: in vitro effects of hormones on transcriptional and translational expression. 1588 7

Ouabain, a cardiac glycoside and inhibitor of Na(+), K(+)-ATPase, is now believed to be a steroid hormone in mammals. We have recently identified ouabain immunoreactivity in the plasma of the tilapia, a euryhaline teleost. Changes in plasma concentrations of immunoreactive ouabain (20-40 pM) in response to salinity change were well correlated with the changes in plasma osmolality and cortisol. Our previous studies have shown that cortisol rapidly inhibits prolactin (PRL) release from the tilapia pituitary by suppressing intracellular Ca(2+) ([Ca(2+)]i) and cAMP. In the present study, low doses of ouabain (10-1000 pM) inhibited PRL release dose-dependently during 2-24 h of incubation. There was no effect on growth hormone (GH) release, except for a significant increase at 1000 pM during 8-24 h of incubation. Significant dose-related increases in PRL release were observed at higher doses of ouabain (100-1000 nM), whereas significant inhibition was seen in GH release at 1000 nM during 2-24h of incubation. Ouabain at 1-100 pM had no effect on Na(+), K(+)-ATPase activity of the pituitary homogenate. The enzyme activity was inhibited by higher concentrations of ouabain, 10% at 1 nM, 15% at 10 nM, 28% at 100 nM, and 45% at 1000 nM. Ouabain also attenuated stimulation of PRL release by the Ca(2+) ionophore, A23187, and by a combination of dibutyryl cAMP and a phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthin. Intracellular Ca(2+) concentrations were monitored in the dispersed PRL cells with the Ca(2+)-sensitive dye, fura-2. Ouabain at 1 nM reversibly reduced [Ca(2+)]i within seconds, whereas 1 microM ouabain increased [Ca(2+)]i. A rapid reduction in [Ca(2+)]i was also observed when PRL cells were exposed to 1 microM cortisol, whereas there was no consistent effect at 1 nM. These results suggest that ouabain at physiological concentrations rapidly inhibits PRL release from the tilapia pituitary by suppressing intracellular Ca(2+) and cAMP metabolism. The stimulation of PRL release by high concentrations of ouabain (100-1000 nM) may result from an increase in [Ca(2+)]i, and subsequent depolarization due to the inhibition of Na(+), K(+)-ATPase activity.
...
PMID:Physiological concentrations of ouabain rapidly inhibit prolactin release from the tilapia pituitary. 1592 43

The involvement of intracellular Ca(2+) stores and their regulatory mechanisms in mediating pituitary adenylate cyclase-activating polypeptide (PACAP) stimulation of growth hormone (GH) and maturational gonadotrophin (GTH-II) secretion from goldfish pituitary cells was investigated using a cell column perifusion system. Pretreatment with caffeine abolished the GH and GTH-II responses to PACAP. Dantrolene attenuated PACAP-elicited GTH-II release but did not affect the GH response, whereas ryanodine and 8-bromo-cADP ribose did not alter PACAP-induced GH and GTH-II release. Two endoplasmic/sarcoplasmic reticulum Ca(2+) ATPase (SERCA) inhibitors, thapsigargin and cyclopiazonic acid, augmented PACAP-induced GTH-II release; similarly, thapsigargin elevated GH responses to PACAP. Treatment with carbonyl cyanide m-chlorophenylhydrazone, a mitochondrial uncoupler, reduced PACAP-stimulated GH release; however, inhibition of the mitochondrial Ca(2+) uniport by Ru360 did not affect GH and GTH-II responses. The phosphatidyl inositol (PI)-specific phospholipase C (PLC) inhibitor ET-18-OCH(3) inhibited, whereas the phosphatidyl-choline (PC)-specific PLC inhibitor D609 enhanced, PACAP-stimulated GH and GTH-II responses. On the other hand, the IP(3) receptor blocker xestospongin D had no effect on PACAP-induced GTH-II response and potentiated the GH response. These results suggest that, despite some differences between GH and GTH-II cells, PACAP actions in both cell types generally rely on a caffeine-sensitive, but a largely ryanodine receptor-independent, mechanism. PC-PLC and some SERCA negatively modulate PACAP actions but mitochondrial Ca(2+) stores per se are not important. A novel PI-PLC mechanism, which does not involve the traditional IP(3)/Ca(2+) pathway, is also suggested.
...
PMID:Intracellular calcium involvement in pituitary adenylate cyclase-activating polypeptide stimulation of growth hormone and gonadotrophin secretion in goldfish pituitary cells. 1592 41

The serine-threonine kinase Akt/PKB mediates stimuli from different classes of cardiomyocyte receptors, including the growth hormone/insulin like growth factor and the beta-adrenergic receptors. Whereas the growth-promoting and antiapoptotic properties of Akt activation are well established, little is known about the effects of Akt on myocardial contractility, intracellular calcium (Ca(2+)) handling, oxygen consumption, and beta-adrenergic pathway. To this aim, Sprague-Dawley rats were subjected to a wild-type Akt in vivo adenoviral gene transfer using a catheter-based technique combined with aortopulmonary crossclamping. Left ventricular (LV) contractility and intracellular Ca(2+) handling were evaluated in an isolated isovolumic buffer-perfused, aequorin-loaded whole heart preparations 10 days after the surgery. The Ca(2+)-force relationship was obtained under steady-state conditions in tetanized muscles. No significant hypertrophy was detected in adenovirus with wild-type Akt (Ad.Akt) versus controls rats (LV-to-body weight ratio 2.6+/-0.2 versus 2.7+/-0.1 mg/g, controls versus Ad.Akt, P, NS). LV contractility, measured as developed pressure, increased by 41% in Ad.Akt. This was accounted for by both more systolic Ca(2+) available to the contractile machinery (+19% versus controls) and by enhanced myofilament Ca(2+) responsiveness, documented by an increased maximal Ca(2+)-activated pressure (+19% versus controls) and a shift to the left of the Ca(2+)-force relationship. Such increased contractility was paralleled by a slight increase of myocardial oxygen consumption (14%), while titrated dose of dobutamine providing similar inotropic effect augmented oxygen consumption by 39% (P<0.01). Phospholamban, calsequestrin, and ryanodine receptor LV mRNA and protein content were not different among the study groups, while sarcoplasmic reticulum Ca(2+) ATPase protein levels were significantly increased in Ad.Akt rats. beta-Adrenergic receptor density, affinity, kinase-1 levels, and adenylyl cyclase activity were similar in the three animal groups. In conclusion, our results support an important role for Akt/PKB in the regulation of myocardial contractility and mechanoenergetics.
...
PMID:Adenoviral gene transfer of Akt enhances myocardial contractility and intracellular calcium handling. 1609 11

The presence of growth hormone (GH) and GH receptors (GHRs) in the lung suggests it is an autocrine/paracrine target site for pulmonary GH action and/or an endocrine site of pituitary GH action. Roles for GH in lung growth or pulmonary function are, however, uncertain. The possibility that pituitary and/or pulmonary GH have physiological roles in lung development has therefore been investigated in GHR knockout (KO or -/-) mice, using a proteomics approach to determine if an absence of GH-signaling affects the proteome of the developing lung. More than 600 proteins were detected by 2-DE in the lungs of control [GHR (+/+)] and GHR (-/-) mice at the end of the alveolarization period (at day 14 postnatally). Of these, 39 differed significantly in protein content at the p>0.05 level [6 were of higher abundance in the GHR (-/-) group, 33 were of lower abundance] and 17 differed at the p>0.02 level [5 of higher abundance in the GHR (-/-) group, 12 of lower abundance] and 7 were definitively identified by MS. Vimentin, a protein involved in cellular proliferation, was reduced in content by approximately 75% in the lungs of the GHR (-/-) mice. Three proteins involved in oxidative protection [SH3 domain-binding glutamic acid-rich-like protein, peroxiredoxin 6 (Prdx6), and isocitrate dehydrogenase 1] were also of lower content in the GHR (-/-) lungs (by approximately 88%, 81% and 70%, respectively). Prdx6 is also involved in lipid and surfactant metabolism, as is apolipoprotein A-IV, the lung content of which was reduced by approximately 73% in these mice. Proteasome 26S ATPase subunit 4, a protein involved in the non-lysosomal degradation of intracellular proteins, and electron flavoprotein alpha subunit , involved in intracellular metabolism, were also reduced in content in the lungs of the GHR (-/-) mice (by approximately 70% and 49%, respectively). These results therefore suggest that these proteins are normally dependent upon GH signaling, and that GH is normally involved in early lung growth, oxidative protection, lipid and energy metabolism and in proteasomal activity. These roles may reflect endocrine actions of pituitary GH and/or local autocrine/paracrine actions of GH produced within the lung.
...
PMID:Growth hormone (GH) receptor knockout mice reveal actions of GH in lung development. 1628 72

Euryhaline teleosts possess the capacity to osmoregulate under various environmental conditions (freshwater to hypersaline water). This physiological capacity is generally monitored using enzyme activity assays (Na+/K+ -ATPase...), hormones quantification (prolactine, growth hormone) or their mRNAs expression. To date, few studies addressed the genetic correlates of adaptation to varying salinity at a molecular level in such fish. In the sea bass Dicentrarchus labrax, genetic differentiation was observed at specific allozyme loci between lagoon- and open-sea populations. In the present study, we investigated transcriptomic response of D. labrax to salt- and freshwater acclimation in two organs involved in osmoregulation, gill and intestine. By using suppression subtractive hybridisation, we characterised 586 partial cDNA sequences encoding proteins potentially involved in the metabolism of sea bass acclimated to salt- or freshwater under experimental conditions. Using these results, we first characterised complete genomic sequence of a carbonic anhydrase and then analysed mRNA expression of genes potentially involved in osmoregulation mechanisms (Na+/K+ -ATPase, carbonic anhydrase, angiotensin-converting enzyme and claudin-3), cell-cycle regulation (secretagogin) and immune system (nephrosin) in gill and intestine of wild fish from open sea and lagoons. Our analyses indicate a strong tissue- and environmental-dependant expression pattern for all the genes studied. A transcriptomic approach such as described in the present paper provides thus a first description of genes involved in metabolic or structural functions important for coping with environmental salinity variations in a euryhaline fish like the common sea bass D. labrax. It should be supplemented by proteomics to check the direct involvement of the gene products at the protein level, and by polymorphism analyses if one is to understand population or individual fluctuations in acclimation to salinity variation.
...
PMID:A transcriptomic approach of salinity response in the euryhaline teleost, Dicentrarchus labrax. 1673 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---