Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a search for an invertebrate muscle from which the muscle regulatory proteins could be obtained in a great quantity and at high homogeneity, the regulatory proteins, tropomyosin (Tm) and three subunits of troponin (Tn), have been isolated from the lobster tail muscle, purified and partially characterized. The calcium-sensitive ATPase of lobster myofibril was restored when purified lobster Tm and lobster Tn were added to actin. Quantitative SDS-polyacrylamide gel electrophoresis showed that the lobster muscle contains actin, Tm, Tn with a molar ratio 7:1:1 and that lobster Tn consists of three subunits, one of each I, C and T. Each subunit was identified according to its effect on the acto-S1 ATPase rate. The isomer composition in each fraction of purified Tn subunit and in Tm are different from the rabbit skeletal muscle proteins; Tm consists of a single species of polypeptide of M(r) 38,000; the TnT fraction appears to be homogeneous with M(r) 43,000; the TnI fraction contains five isomers, all showing similar isoelectric pH, differing in M(r) in the range from 28,000 to 31,000; two TnC fractions contain three isomers in total with a range of M(r) from 18,500 to 19,000. Further study of the lobster Tm elucidated that digestion by carboxypeptidase A gave rise to a homogeneous preparation of truncated and non-polymerizable Tm which is devoid of 11 residues at the C-terminus of the molecule. The C-terminal amino acid sequence of 11 residues is homologous to the thoracic isomer generated from Drosophila melanogaster Tm-I gene. The present study indicated that, despite heterogeneities owing to the occurrence of isomers, the lobster regulatory proteins serve as an invertebrate source of the proteins for structural and biophysical studies, alternative to vertebrate counterparts.
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PMID:Isolation, purification and partial characterization of tropomyosin and troponin subunits from the lobster tail muscle. 149 Oct 69

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

The effect of chronic hyperglycemia and polyol pathway activation on the Schwann cell has not been resolved although injury to this cell has long been suspected in diabetic neuropathy. Hyperglycemia, resulting from galactose intoxication of four months duration, induces dose-dependent accumulations of endoneurial fluid sodium and chloride that are linked to polyol pathway activity and associated with dose-dependent increases in sciatic nerve water content, endoneurial fluid pressure and (Na+, K+)-ATPase activity. In order to understand the impact of these changes on the nerve microenvironment, cellular elements of the endoneurium were quantitatively and qualitatively assessed in rats receiving 0%, 10%, 20% or 40% galactose diets. After four months of galactose intoxication, dose-dependent changes in the size distribution of myelinated nerve fibers were apparent. A shift in size-frequency histograms of galactose-intoxicated animals towards smaller fibers was accompanied by a decrease in axon diameter and the volume fraction ratio of axon to myelinated nerve fibers. In the sciatic nerve of all 40% galactose-fed rats examined by electron microscopy, Schwann cells of myelinated fibers showed both reactive and degenerative changes. Demyelination was preceded by splitting at the intraperiod line. Remyelination was identified by axons with disproportionately thin myelin sheaths. Axonal dystrophy and degeneration were infrequently seen, but there was axonal regeneration. Dose-dependent increases in mast cell number were observed with degranulation apparent in rats receiving 20% and 40% galactose. Endothelial cell number and basal lamina thickness were increased in the endoneurial vessels of galactose-intoxicated rats. Increased cytoplasmic area and degenerative changes in pericytes were also noted. These observations indicate that significant morphologic changes accompany the hyperosmotic imbalance resulting from galactose intoxication of four months duration. Schwann cell injury and demyelination are present in a disorder linked to polyol metabolism since aldose reductase, the anabolic enzyme of the polyol pathway, is localized to this myelin-forming cell.
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PMID:Cellular pathology of the nerve microenvironment in galactose intoxication. 202 66

Incubation of oat root plasma membrane vesicles in the presence of ATP with trypsin or chymotrypsin increased the rate of ATP hydrolysis and ATP-dependent proton pumping by the plasma membrane H(+)-ATPase. Proton pumping was stimulated more than 200%, whereas ATP hydrolytic activity was stimulated about 30%. The Km (ATP) for both proton pumping and ATP hydrolysis was lowered from about 0.3 mM to below 0.1 mM. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of trypsin-treated plasma membranes revealed a decrease in a 100-kDa band and the appearance of a 93-kDa band. Western blot analysis using antibodies against the H(+)-ATPase showed that both of these bands represented the H(+)-ATPase and suggested that a 7-kDa segment was released. Extensive treatment with carboxypeptidase A also activated the H(+)-ATPase indicating that the 7-kDa segment originated from the C terminus.
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PMID:Proteolytic activation of the plant plasma membrane H(+)-ATPase by removal of a terminal segment. 214 84

Histochemical and ultrastructural analyses were performed postflight on hind limb skeletal muscles of rats orbited for 12.5 days aboard the unmanned Cosmos 1887 biosatellite and returned to Earth 2 days before sacrifice. The antigravity adductor longus (AL), soleus, and plantaris muscles atrophied more than the non-weight-bearing extensor digitorum longus, and slow muscle fibers were more atrophic than fast fibers. Muscle fiber segmental necrosis occurred selectively in the AL and soleus muscles; primarily, macrophages and neutrophils infiltrated and phagocytosed cellular debris. Granule-rich mast cells were diminished in flight AL muscles compared with controls, indicating the mast cell secretion contributed to interstitial tissue edema. Increased ubiquitination of disrupted myofibrils implicated ubiquitin in myofilament degradation. Mitochondrial content and succinic dehydrogenase activity were normal, except for subsarcolemmal decreases. Myofibrillar ATPase activity of flight AL muscle fibers shifted toward the fast type. Absence of capillaries and extravasation of red blood cells indicated failed microcirculation. Muscle fiber regeneration from activated satellite cells was detected. About 17% of the flight AL end plates exhibited total or partial denervation. Thus, skeletal muscle weakness associated with spaceflight can result from muscle fiber atrophy and segmental necrosis, partial motor denervation, and disruption of the microcirculation.
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PMID:Skeletal muscle fiber, nerve, and blood vessel breakdown in space-flown rats. 215 85

Recent studies have shown that inhaled frusemide exerts a protective effect against various bronchoconstrictor stimuli in asthma including exercise, fog and allergen. Since mast cell activation seems to be a component of bronchoconstriction by these stimuli it is possible that inhibition of mediator release accounts for some or all of the inhibitory effects of frusemide in asthma. Since inhaled adenosine 5'-monophosphate (AMP) is another stimulus that produces bronchoconstriction by augmenting mast cell mediator release, we have investigated the ability of this drug to antagonise the airway effects of inhaled AMP and methacholine in a randomized, placebo-controlled, double-blind study of 12 asthmatic subjects. Inhaled frusemide (approximately 28 mg) administered 5 min prior to challenge increased the provocation concentration of inhaled AMP and methacholine required to reduce forced expiratory volume in one second (FEV) by 20% from baseline from 30 to 96 mg.ml-1 (p less than 0.01) and from 1.1 to 1.8 mg.ml-1 (p less than 0.01), respectively. The protection that frusemide afforded against AMP was significantly greater than that against methacholine (p less than 0.05). These data suggest that inhaled frusemide may serve as a functional antagonist against a smooth muscle spasmogen, such as methacholine, possibly by augmenting prostanoid generation. Its more potent activity against AMP and other bronchoconstrictor stimuli, that are considered to involve mast cell mediators, suggests an additional action on mast cell functions possibly at the level of the Ca++/Mg(++)-ATPase.
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PMID:Inhibition of adenosine 5'-monophosphate- and methacholine-induced bronchoconstriction in asthma by inhaled frusemide. 215 Oct 34

We have previously reported the presence of an ATPase, stimulated by calcium and magnesium, on the outer surface of the rat peritoneal mast cell. Experiments in which the enzyme activity was enhanced or inhibited showed a relationship to histamine secretion. Enhanced enzyme activity with increasing concentrations of the substrate (ATP) was associated with a potentiation of histamine release, and a pronounced inhibition of the enzyme caused an inhibition of the release. In the present work we have studied the influx and efflux of calcium in mast cells in relation to the activity of the Ca2+-Mg2+ ATPase on the mast cell membrane. The enzyme activity is shown to be related to calcium influx and has no effect on calcium efflux. Stimulation of the enzyme with ATP is associated with increased calcium influx into the mast cell, and inhibition of the enzyme with AMP causes inhibition of the calcium uptake. In both cases calcium efflux is unaffected. The function of the enzyme is thus different from the calcium efflux enzyme on the cytoplasmic surface, described in other cells. In addition, the Ca2+-Mg2+ ATPase on the mast cell surface is neither stimulated by calmodulin nor inhibited by the calmodulin antagonists, trifluoperazine and W-7. In mast cells the low cytosolic calcium concentration seems to be maintained by Na+-Ca2+ countertransport. Phosphorylation of the Ca2+-Mg2+ ATPase on the mast cell is likely to be associated with Ca2+ release at the cytoplasmic surface of the plasma membrane. It is thus possible that ATP hydrolysis in the membrane stimulates the contraction of microfilaments in the membrane and the cytoskeleton, and promotes the migration of the granules to the plasma membrane.
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PMID:Role of a Ca2+-Mg2+ ATPase on the mast cell surface in calcium transport and histamine secretion. 244 Feb 67

In order to study the characteristics of the intracellular Ca store of mast cells, organelles of rat peritoneal mast cells were fractionated. The binding of 45Ca was at its peak in the fractions where the highest activity of glucose-6-phosphatase, the marker enzyme for the endoplasmic reticulum (ER), was measured. The ER-rich fraction exhibited an ATP-dependent uptake of 45Ca and this uptake was inhibited by pretreatment with ATPase inhibitors such as LaCl3 or Na3VO4. When inositol 1,4,5-trisphosphate (IP3) was added to a medium containing the 45Ca-loaded ER fraction, it caused a dose-dependent release of 45Ca at concentrations higher than 0.5 microM, while inositol 1-monophosphate and inositol 1,4-bisphosphate were not effective even at higher concentrations. The results of a binding assay using 3H-labeled IP3 indicated that there exist two kinds of IP3 binding site in the ER: one is of high affinity but low capacity while the other is of low affinity and high capacity. IP3-induced 45Ca release was dose-dependently inhibited by pretreatment with c-AMP. The present study supports the assumption that the intracellular Ca store associated with histamine release from the mast cell is the ER.
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PMID:Ca uptake and Ca releasing properties of the endoplasmic reticulum in rat peritoneal mast cells. 246 54

In the present study some properties of an inhibitory extract of synaptosomal membrane Na+, K+-ATPase were investigated. This extract (peak II) was prepared by gel filtration in Sephadex G-50 of a soluble fraction of the rat cerebral cortex. Ultrafiltration of peak II through Amicon membranes indicated that the inhibitor has a low MW (less than 1000). The inhibitory activity was not modified by heating in neutral pH at 95 degrees C for 20 min but it was destroyed by charring in acid pH at 200 degrees C for 120 min. The inhibitory activity decreased by incubation of peak II with carboxypeptidase A. These findings suggest that the factor responsible for the inhibition of Na+, K+-ATPase activity is probably a polypeptide. On the other hand, the inhibition was reverted by the chelators EDTA and EGTA, indicating the participation of an ionic compound as well. The increase of Mg2+ concentration during the enzyme assay did not increase the inhibition, indicating that the ion involved might not be vanadate. It is suggested that both a polypeptide and an ionic compound coparticipate in the inhibitory effect of peak II on Na+, K+-ATPase activity.
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PMID:The inhibitory activity of a brain extract on synaptosomal Na+, K+-ATPase is sensitive to carboxypeptidase A and to chelating agents. 283 64

Bone marrow-derived leukocytes of murine epidermis can express two phenotypes: typical Langerhans cells, which are Ia+ and Thy-1-, and a recently discovered second population that is Thy-1+ and Ia-. To verify that these phenotypes are expressed by two different cell types, and to help understand their lineage and function, we have studied morphology and reactivity with a large panel of antibodies. Dual antibody immunofluorescence combined with electron microscopy showed that Thy-1+ and Ia+ cells were each distributed in a regular fashion and formed adjacent dendritic systems in or close to the basal layer. Double-labeling studies with anti-Ia and a second monoclonal antibody revealed that all Langerhans cells expressed F4/80 (macrophage), Mac-1 (C3bi receptor), and 2.4G2 (Fc receptor), as well as the thymus leukemia (TL) and heat-stable (M1.69/16) antigens. A large fraction expressed S100 and all exhibited membrane ATPase and nonspecific esterase. In contrast, Thy-1+ cells lacked all these features of Langerhans cells, except that a minority were strongly reactive with 2.4G2. Thy-1+ cells also lacked differentiation antigens of most other types of leukocytes, except they were rich in asialo GM1. By electron microscopy, Thy-1+ cells had cytoplasmic granules that were similar in structure and in their aryl sulfatase content to those previously described in natural killer cells. The granules were enlarged in beige mice, suggesting a lysosomal origin, and were present in mast cell-deficient W/Wv mice, indicating no relation to mast cells. We conclude that Thy-1+ epidermal cells are thoroughly distinct from Langerhans cells. On the basis of morphology and phenotype, they may represent a type of tissue natural killer cell. Thy-1+ natural killer cells are now being identified in several nonlymphoid sites, such as gut epithelium and the livers of mice given adjuvants. If Thy-1+ epidermal cells prove to be natural killer cells, it is noteworthy that they represent a resident population regularly distributed in the basal layer of all mouse strains. The notion that Thy-1+ epidermal cells are immature natural killer cells is intriguing in light of recent evidence that Ia+ Langerhans cells are also immature with respect to accessory cell function. The epidermis may not have the functional capacities of a lymphoid organ, but it could contribute immature cells important for both natural and acquired resistance.
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PMID:The Thy-1-bearing cell of murine epidermis. A distinctive leukocyte perhaps related to natural killer cells. 286 Dec 45


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