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)

Highly purified glycoprotein from the intimal region of porcine aorta was isolated with minor modifications of the procedure described previously. The molecular weight of the glycoprotein as determined by sedimentation equilibrium method either in presence of 0.1 M NaCl or 6 M guanidine-HCl containing beta-mercaptoethanol was 72 000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the native glycoprotein and its S-carboxyamidomethyl derivative at different acrylamide concentrations showed no difference in the molecular weight indicating the absence of subunits. Attempts to determine the identity of the amino-terminal acid by a dansylation technique indicated that the amino group is not free. The carboxy-terminal amino acid was found to be serine after treatment of the glycoprotein with carboxypeptidase A. The glycoprotein did not contain an alkali-labile (O-glycosidic) carbohydrate-protein linkage as tested by the beta-elimination reaction. The release of monosaccharides from the glycoprotein as a function of time was studied employing mild acid hydrolysis (0.5 M HCl, 80 degrees C) and also by the use of neuraminidase, alpha-D-and beta-D-glucosidases and beta-D-N-acetylglucosaminidase. From the observations of the release of monosaccharides and analogy with standard features determined by other investigators on soluble aortic glycoproteins, a prediction has been made as to the general features of the carbohydrate moiety of the glycoprotein.
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PMID:Further studies on a highly purified glycoprotein from the intimal region of procine aorta. 95 56

Incubation of either C3a, C3ades Arg, or synthetic analogues of the C-terminal sequence of C3a with purified rat peritoneal mast cells resulted in a rapid and dose-dependent histamine release. The natural factors C3a and C3ades Arg were the most active of the factors tested exhibiting EC50 values of 3.3 and 2.2 microM, respectively. The corresponding 21- and 22-residue C-terminal analogues of C3a (Y21R and Y21) were less potent than intact factor exhibiting EC50 values of 10.9 and 25.1 microM, respectively. Histamine was released in a nonlytic manner and the mast cell stimulation by both natural and synthetic factors was sensitive to pertussis toxin, neuraminidase, benzalkonium chloride, and to an excess of calcium. C3a stimulated the generation of inositol polyphosphates that was inhibited by either pertussis toxin or benzalkonium chloride. The C3a anaphylatoxin also directly stimulates purified G proteins (i.e., GTPase activity) in a dose-dependent manner. The evident correlation between efficiency of C3a and C3a analogues to stimulate purified G proteins and their capacity to induce cellular histamine release led us to conclude that C3a fails to activate mast cells via a mechanism involving specific receptors on the cell. Instead, we propose that C3a either causes direct activation of G proteins of the Gi subtype, with a subsequent activation of phospholipase C, or interacts with a binding site of the cell surface specific for cationic molecules that is coupled to the G protein cascade.
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PMID:A mechanism of action for anaphylatoxin C3a stimulation of mast cells. 137 70

We have investigated certain aspects of the mechanism whereby substance P triggers secretion of 5-hydroxytryptamine (5-HT) from rat peritoneal mast cells in vitro. Substance P-induced release of 5-HT was inhibited following pretreatment of rat peritoneal cells with 0.01-1.0 units/ml neuraminidase; secretion induced by anti-IgE antibody was inhibited by pretreatment with 1.0 units/ml but not by lower concentrations of enzyme. Addition of the sialic acid-rich substances N-acetyl-neuraminlactose (up to 1.0 mM) and mucin (up to 1.0 mg/ml) to substance P in free solution failed to block the activity of the neuropeptide. Limulin, a sialic acid-specific lectin, failed to block substance P-induced secretion of 5-HT, but was found to possess intrinsic non-lytic secretory activity (at 5-20 micrograms/ml). Release of 5-HT induced by limulin was independent of that induced by substance P. A range of octapeptides incorporating the C-terminal sequence Gly-Ser-Phe-Phe, but differing in degree of cationicity and positioning of cationic residues in the four N-terminal positions, were tested for their capacity to antagonise the mast cell-triggering activity of substance P. A peptide incorporating two lysine residues at the N-terminus was found to have partial substance P antagonist activity; no effects on IgE-mediated secretion were observed.
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PMID:The mast cell response to substance P: effects of neuraminidase, limulin, and some novel synthetic peptide antagonists. 242 85

Non-immunologic and immunologic stimulation of mast cells have been compared. Non-immunologic stimulation relys heavily on cellular Ca, is unaffected by neuraminidase treatment, shows a rapid inactivation, and elicits no increase in the incorporation of 3H-methyl groups into the lipid fraction. In contrast, stimulation by immunologic agents relys primarily on extracellular Ca, is inhibited by neuraminidase treatment, shows a comparatively slow rate of inactivation, and causes a significant increase in the incorporation of 3H-methyl groups into the lipid fraction. We found no evidence of cross-inactivation or desensitization between immunologic and non-immunologic agents. However, pretreatment of mast cells with neurotensin desensitized them to subsequent stimulation by compound 48/80. Our results support the hypothesis that immunologic and non-immunologic agents activate exocytotic mast cell secretion via separate mechanisms.
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PMID:Mast cell secretion: differences between immunologic and non-immunologic stimulation. 243 14

Incubation of rat peritoneal mast cells with substance P resulted in the transient stimulation of phosphoinositol breakdown and histamine secretion through an exocytotic process. These effects were inhibited markedly by a prior 2-hr exposure of the cells to pertussis toxin. Pertussis toxin also inhibited exocytosis induced by substance P, mastoparan and compound 48/80, but did not modify the secretory effect of the ionophore A23187. The transfer of rat peritoneal mast cells from balanced salt solution to calcium-free buffer led to a similar time-dependent decrease in their response to substance P and mastoparan. The concomitant absence of potassium from the calcium-free buffer enabled the mast cells to retain their secretory response. These data demonstrate identical dependency for calcium and monovalent ions of the secretory process elicited by substance P, mastoparan and compound 48/80. Pretreatment of mast cells with neuraminidase decreased the secretagogic effect of substance P, mastoparan and compound 48/80 without modifying the efficiency of the ionophore A23187. Thus, sialic acid residues might be involved in the initial binding of peptides and compound 48/80 to mast cells, which activate a pertussis toxin-sensitive G-protein and allows the increase in phospholipase C activity to induce exocytosis. This sequence of events might characterize the physiological pathway of mast cell activation by peptides, without necessarily requiring selective membrane receptors.
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PMID:Activation of rat peritoneal mast cells by substance P and mastoparan. 247 89

The neuronal membrane protein which binds the K+-channel ligands dendrotoxin, mast cell degranulating peptide, and beta-bungarotoxin was purified from rat brain membranes. When analysed on 10% SDS gel electrophoresis, the purified protein contained two peptides: the toxin-binding subunit of apparent Mr 90,000 and another peptide of Mr 38,000. Neuraminidase treatment reduced the Mr of the toxin-binding subunit to 70,000. Glycopeptidase F gave a further reduction to Mr 65,000. In contrast, the peptide of Mr 38,000 showed no change in Mr upon treatment with neuraminidase and/or glycopeptidase F. It is concluded that the toxin-binding subunit of the dendrotoxin-binding protein, a presumptive K+ channel, is a sialated membrane protein with a peptide core of, at most, Mr 65,000.
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PMID:Enzymatic deglycosylation of the dendrotoxin-binding protein. 270 49

Apolipoproteins C are involved in many ways in the metabolism of plasma lipoproteins. Apolipoproteins C from the delipidated VLDL of 35 controls and 165 normo- and hyperlipoproteinemic patients were analyzed by isoelectric focusing on an immobilized pH gradient, pH 4.0-5.0, with 7 M urea, which raised the apparent pH range to 4.8-5.7. This method is an improvement over conventional isoelectric focusing with carrier ampholytes with regard to both resolution and reproducibility. Due to the high resolution (0.1 pH units per cm) additional apolipoprotein C-III bands: C-III0 A1, C-III0 A2, C-III1 C and C-III2 C (the designations A, anodic, and C, cathodic, refer to direction of migration on IEF in relation to the main band) are described for the first time. The possible artifactual nature of these protein bands could be excluded. Cleavage with neuraminidase and peptidases, immunological detection and/or two-dimensional electrophoresis were used to obtain more information. The additional bands seem, in part, to be hydrolysis products of carboxypeptidase A (C-III1 C, C-III2 C). The appearance of C-III1 C and C-III2C was dependent upon the serum triglyceride concentration. The percent distribution of C apolipoproteins in very low density lipoproteins (VLDL) from control serum agreed with previously published data. Apolipoproteins C can also be focused in immobilized pH gradients from VLDL and serum without delipidation.
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PMID:Analysis of human apolipoproteins C by isoelectric focusing in immobilized pH gradients. 324 52

Chrysotile asbestos interacts with mucin-secreting cells of tracheal organ cultures, causing an increase in secretion of mucin into the culture medium. This response occurs in the absence of obvious morphologic damage to tracheal epithelial cells. We speculated that asbestos-induced hypersecretion was regulated by the interaction of fibers with specific carbohydrate residues on the cell surface. To test this hypothesis, lectins, i.e., proteins with a high affinity for mono- and oligosaccharides on the plasma membrane, were added to tissues 30 min before addition of chrysotile. Secretion of mucin into the medium was then determined over a 2-hr period by using incorporation of 3H-glucosamine. Blocking of alpha-D-mannose and alpha-D-glucose residues inhibited chrysotile-induced hypersecretion (p less than 0.05), whereas lectins blocking residues of alpha-D-N-acetylgalactosamine, beta-D-N-acetylglucosamine, alpha-L-fucose and sialic acids were ineffective. Preincubation of cultures with carboxypeptidase A or phospholipase A2, but not with neuraminidase, diminished mucin secretion caused by chrysotile. To determine if the positive surface charge of chrysotile was important in interaction with mucin cells, we examined comparatively the effects of various polycations (cationic ferritin, polylysine, DEAE-dextran) and chrysotile after leaching of fibers to remove Mg2+. Although use of polycations enhanced secretion of mucin, effects were not as striking as those observed with chrysotile. In contrast, leached chrysotile failed to elicit a hypersecretory response. These results suggest the interaction of a positively charged component (presumably Mg2+) of chrysotile with glycolipids and glycoproteins containing terminal residues of alpha-D-mannose or alpha-D-glucose.
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PMID:Studies using lectins to determine mineral interactions with cellular membranes. 631 63

The amino-terminal and the carboxy-terminal amino acids of the hemagglutinin-neuraminidase glycoprotein of the Ulster strain of Newcastle disease virus have been analyzed before and after proteolytic activation of the precursor HNo (Mr approximately 82K). The amino termini of HNo and of the large cleavage fragment HN (approximately 74K) obtained by in vivo and in vitro proteolysis could not be sequenced by Edman degradation. This indicates that in both instances the amino termini are blocked. The carboxy termini of HNo and HN are different as demonstrated by end-point digestion with carboxypeptidase A. Furthermore, a small cleavage fragment (approximately 9K) of HNo that was removed from the virion after trypsin treatment could be purified by HPLC. In contrast to HN, this fragment displays a free amino terminus susceptible to Edman degradation. These data indicate that conversion of HNo involves removal of a 9K glycopeptide from the carboxy-terminal end. Thus, it has to be concluded that, unlike most other viral glycoproteins, the hemagglutinin-neuraminidase is inserted in the envelope with its carboxy terminus exposed at the surface of the virus particle.
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PMID:The carboxyterminus of the hemagglutinin-neuraminidase of Newcastle disease virus is exposed at the surface of the viral envelope. 653 31

Two types of inhibition of basic peptide-induced rat mast cell secretion are reported. Pretreatment of rat peritoneal mast cells with Vibrio comma neuraminidase, an enzyme which cleaves sialic acid from oligosaccharides, led to inhibition of 5-hydroxytryptamine release induced by the basic peptides polylysine, corticotropin 1-24 and a decapeptide sequence of human IgE. Inhibition was similarly observed when mast cells were challenged in the presence of the cationic cell membrane-active substance benzalkonium chloride. It is postulated that both of these experimental procedures inhibit basic peptide-induced secretion by depletion of cell surface negative charge. Sialic acid itself does not act as a specific receptor for basic peptides, since a molar excess of sialic acid in free solution failed to inhibit secretion by binding to basic peptides in the fluid phase.
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PMID:Neuraminidase- and benzalkonium chloride-dependent inhibition of basic peptide-induced rat mast cell secretion. 717 80


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