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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epithelial cells (80-90% "granular" type) were isolated from urinary bladders of Bufo marinus and Rana catesbiana. The inhibitory effect of alpha-methyl-D-mannoside on fluorescein-labeled concanavalin A (Con A) binding to these cells indicates that they possess specific binding sites for Con A. The lectin also mediates adsorption of erythrocytes to these cells. Both Con A binding and Con A-mediated hemadsorption to epithelial cells are depressed at 4 degrees C, as compared with cells maintained at 22 degrees C. Elevation of temperature to 37 degrees C, however, enhances hemadsorption independently of alterations in lectin binding. Treatment of cells with antidiuretic hormone (ADH) at 22 degrees C followed by 15 min of incubation at 22 degrees or 37 degrees C before exposure of cells to Con A promotes increments in Con A-mediated hemadsorption, but not in lectin binding, at 22 degrees or 37 degrees C. These hormonal effects are not significant when hemadsorption is assayed at 4 degrees C. Treatment of cells with another octapeptide, angiotensin, elicits a small, but significant, increment in hemadsorption to epithelial cells which is likewise uninfluenced by quantitative changes in lectin binding. Collectively, these data and other independent observations suggest that treatment with octapeptide hormones acts to enhance the redistribution and aggregation of lectin-binding proteins in the membranes of granular epithelial cells from amphibian urinary bladder. Such changes, in turn, may contribute to the alterations in membrane transport properties which characterize the hormonal response.
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PMID:Surface modifications evoked by antidiuretic hormone in isolated epithelial cells: evidence from lectin probes. 81 65

1. A vasopressin (AVP) binding protein was purified from rat liver membranes by an improved method using [125I][d(CH2)5'Sarcosine7]AVP, a selective V1 AVP radioligand and a combination of CHAPS solubilization, gel filtration, lectin affinity and FPLC ion exchange chromatography. 2. The purified protein exhibited a maximum binding activity of 2480 pmol/mg protein with a KD of 4.5 nmol/L, which corresponds to a purification of approximately 26,700-fold. The molecular weight of this protein was 70,000 Da. 3. The binding of [125I][d(CH2)5'Sarcosine7]AVP to the solubilized membranes was dependent on the protein concentration, and was inhibited by the unlabelled peptides [d(CH2)5'Sarcosine7]AVP, AVP, and to a lesser degree by peptides with high V2 receptor affinity, such as 1-desamino-D-AVP and [d(CH2)5'D-Ileu2-Ileu4]AVP. 4. In addition, an AVP anti-idiotypic monoclonal antibody bound to both the partially purified and purified lectin affinity AVP binding protein in a concentration-dependent manner. These results indicate that the purified protein displays similar characteristics to the liver membrane-bound AVP V1 receptor.
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PMID:Isolation and characterization of the rat liver AVP receptor using [125I][d(CH2)5'sarcosine7]AVP. 151 73

The role of N-glycosylation in the function and biosynthesis of the vasopressin V2-receptor in LLC-PK1 renal epithelial cells was examined using various lectins and inhibitors operating at different steps of the glycosidic pathway. Tunicamycin, which blocks all N-glycosylation, and castanospermine, which inhibits glycosidase I and hence blocks formation of high-mannose-type N-glycosylated intermediates, resembled one another in affecting V2-receptor biosynthesis and internalization in a concentration-dependent manner. In contrast, swainsonine, an inhibitor of mannosidase II and hence of complex-type oligosaccharide formation, had no effect. Interestingly, the alpha-D-mannose/alpha-D-glucose-specific lectin concanavalin A, (Con A), in contrast to the beta-D-galactose-specific lectin ricin, had a marked effect on the V2-receptor in LLC-PK1 cells, increasing both receptor numbers up to twofold in vivo and specific [3H]AVP binding up to 50% in vitro in a concentration-dependent manner. The concentrations inducing half-maximal response were about 0.2 and 20 micrograms/ml for the in vivo and in vitro responses, respectively, implying distinct effects on V2-expression and ligand binding. That the in vitro effect on binding was due to a direct effect on the V2-receptor could be shown by the lack of a Con A effect on [3H]AVP binding in membranes prepared from LLC-PK1 cells down-regulated for the V2-receptor or from cells of the LLC-PK1 V2-receptor deficient mutant M18. All results were consistent with a functional role for N-glycosylation of the V2-receptor in LLC-PK1 cells.
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PMID:N-glycosylation plays a role in biosynthesis and internalization of the adenylate cyclase stimulating vasopressin V2-receptor of LLC-PK1 renal epithelial cells: an effect of concanavalin A on binding and expression. 153 96

Labeling of the Golgi complex with the lectin conjugate wheat germ agglutinin-horseradish peroxidase (WGA-HRP), which binds to cell surface membrane and enters cells by adsorptive endocytosis, was analyzed in secretory cells of the anterior, intermediate, and posterior lobes of mouse pituitary gland in vivo. WGA-HRP was administered intravenously or by ventriculo-cisternal perfusion to control and salt-stressed mice; post-injection survival times were 30 min-24 hr. Peroxidase reaction product was identified within the extracellular clefts of anterior and posterior pituitary lobes through 24 hr but was absent in intermediate lobe. Endocytic vesicles, spherical endosomes, tubules, dense and multivesicular bodies, the trans-most saccule of the Golgi complex, and dense-core secretory granules attached or unattached to the trans Golgi saccule were peroxidase-positive in the different types of anterior pituitary cells and in perikarya of supraoptico-neurohypophyseal neurons; endoplasmic reticulum and the cis and intermediate Golgi saccules in the same cell types were consistently devoid of peroxidase reaction product. Dense-core secretory granules derived from cis and intermediate Golgi saccules in salt-stressed supraoptic perikarya likewise failed to exhibit peroxidase reaction product. The results suggest that in secretory cells of anterior and posterior pituitary lobes, WGA-HRP, initially internalized with cell surface membrane, is eventually conveyed to the trans-most Golgi saccule, in which the lectin conjugate and associated membrane are packaged in dense-core secretory granules for export and potential exocytosis of the tracer. Endoplasmic reticulum and the cis and intermediate Golgi saccules appear not to be involved in the endocytic/exocytic pathways of pituitary cells exposed to WGA-HRP.
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PMID:Lectin-labeled membrane is transferred to the Golgi complex in mouse pituitary cells in vivo. 243 60

The functional and structural changes induced by apical wheat germ agglutinin (WGA) 100 micrograms/ml exposure on frog urinary bladder have been investigated and the possible correlations between these effects discussed. Bladders, apically exposed to WGA for 30 min to 3 hr exhibit a marked reduction of their response to antidiuretic hormone (ADH) challenge and of their hydrosmotic reactivity. Structural changes triggered by WGA treatment are: 1. apical invaginations of the plasma membrane, interpreted as endocytotic in nature, taking into account the results of carbohydrate cytochemical detection and horseradish peroxidase (HRP) exposure: 2. cytoskeleton disorganization and microvilli collapse. These phenomena do not interfere with cortical granule traffic and are independent of ADH challenge: they occur in ADH-stimulated bladders as well as in bladders at rest. These findings could be interpreted as follows: binding of the divalent lectin WGA to its coat specific receptors would induce changes in the apical membrane structure which in turn could provoke disorganization and disruption of apical cytoskeletal elements associated with plasma membrane. Reduction of bladder response to ADH challenge could result from a reduced recycling of aggrephores, as they are associated with cytoskeletal elements in the subapical cytoplasm. Collapse of microvilli and endocytotic events also could result from apical cytoskeleton disruption, as microvilli are sustained by bundles of actin filaments interconnected with apical cytoskeletal filaments and as plasma membrane is associated with apical cytoskeleton. However, these two last events evidently occur in ADH-challenged or non-challenged bladders.
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PMID:Wheat germ agglutinin (WGA) reduces ADH-induced water flow and induces cell surface changes in epithelial cells of frog urinary bladder. 263 78

Two types of mitochondria-rich (MR) cells have been identified in the rabbit collecting tubule based on differences in immuno- and lectin cytochemistry. We have produced a monoclonal antibody, immunoglobulin (Ig) G1 (mr-mct), that reacts specifically with the MR cells (identified by positive histochemical staining for succinate dehydrogenase) found predominantly in the outer medulla (OM) and cells of the proximal tubule. IgG1 (mr-mct) reacted with 18 +/- 2% of the cells of the outer medullary collecting tubule (OMCT) and did not colocalize with peanut lectin-binding MR cells in the cortex. To isolate MR-OMCT cells, collecting tubule cells from collagenase dispersions of the OM were first adsorbed onto plates treated with a monoclonal antibody reactive against all of the OMCT cells. Of the isolated OMCT cells, 17% reacted with IgG1 (mr-mct). Cells were then detached from the plate and transferred to plates coated with IgG1. Greater than 70% of the adsorbed cells were MR as determined by positive staining with IgG1 (mr-mct). This enrichment of MR-OMCT cells was associated with a severalfold increase in adenosine 3',5' cyclic monophosphate (cAMP) production in response to isoproterenol and an attenuated increase in cAMP production to vasopressin. In summary, we report the isolation of highly enriched populations of MR cells from the OM using two-stage solid-phase immunoadsorption. This approach should provide a useful and convenient method for further investigations of the physiological role of these poorly understood tubular cells.
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PMID:Immunodissection of mitochondria-rich cells from rabbit outer medullary collecting tubule. 283 10

The GTPase activity of plasma membranes isolated from rat livers was stimulated 20% over basal by vasopressin. A concentration dependency curve showed that maximal stimulation was obtained with 10(-8) M vasopressin. The vasopressin-stimulated GTPase activity was not inhibited in plasma membranes that had been ADP-ribosylated with either cholera toxin or pertussis toxin. Identical results were obtained from plasma membranes that had been solubilized with 1% digitonin. When membranes that had been solubilized after preincubation with [3H]vasopressin were subjected to sucrose gradient centrifugation, the majority of protein-bound [3H]vasopressin migrated as a single band with a sedimentation constant of 16.8 S. Moreover, there was a GTPase activity that migrated with the bound [3H]vasopressin. This peak of bound [3H]vasopressin was decreased by 90% when the sucrose gradient centrifugation was run in the presence of 10 microM guanosine 5'-O-(thiotriphosphate). When the 16.8 S peak of bound [3H]vasopressin was further purified over a wheat germ lectin-Sepharose column, a GTPase activity co-eluted from the column with the protein-bound [3H]vasopressin. Direct evidence that a GTP-binding protein was present in the 16.8 S peak was obtained by the immunodetection of a 35-kDa beta subunit of a GTP-binding protein. These results support the conclusion that liver plasma membranes contain a GTP-binding protein that can complex with the vasopressin receptor.
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PMID:Solubilization of the vasopressin receptor from rat liver plasma membranes. Evidence for a receptor X GTP-binding protein complex. 294 91

The V1 vasopressin receptor has been solubilized from rat liver membranes with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammoniol]-1-propanesulfonate (CHAPS) and reconstituted into phospholipid vesicles. There is essentially complete solubilization of the receptor by 3% CHAPS at a protein concentration of 15 mg/ml. Reconstitution into soybean phospholipid vesicles is readily achieved either by gel filtration chromatography or by membrane dialysis. The binding of [3H]vasopressin to proteoliposomes is specific, saturable, reversible, and magnesium-dependent. In contrast, the detergent-soluble vasopressin receptor does not display specific binding. The apparent affinity of the reconstituted receptor for [3H]vasopressin is approximately 4-fold lower than that of the receptor in native membranes. In addition, the binding of [3H]vasopressin to reconstituted vesicles is not sensitive to 100 microM guanosine 5'-O-thiotriphosphate (GTP gamma S) as it is in native membranes. However, the apparent affinity of the reconstituted receptor for ligand approximates that of native membranes when membranes are prebound with vasopressin prior to solubilization and reconstitution into vesicles. Furthermore, vesicles reconstituted from membranes prebound with vasopressin show GTP gamma S sensitivity of [3H] vasopressin binding. This finding strongly suggests that vasopressin stabilizes a receptor-G-protein complex during solubilization. The rat liver vasopressin receptor is a glycoprotein, as shown by its specific binding to the lectin "wheat germ agglutinin." The vasopressin receptor can be reconstituted from the N-acetylglucosamine-eluted peak of a wheat germ agglutinin-Sepharose column, and [3H] vasopressin binding activity is purified 5-6-fold from membranes by this chromatographic procedure. The functionality of the partially purified receptor is indicated by its ability to bind ligand with high affinity and by its ability to functionally interact with a G-protein when vasopressin is bound prior to solubilization.
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PMID:Reconstitution of the rat liver vasopressin receptor coupled to guanine nucleotide-binding proteins. 295 55

Utilizing a proteoliposome reconstitution system, we have purified the rat liver V1 vasopressin receptor to near homogeneity. The receptor was purified approximately 21,000-fold from rat liver membranes, using differential detergent solubilization, size exclusion gel filtration, lectin affinity, and ion-exchange chromatography. The purified receptor exhibits a Kd of 6 nM, when, prior to solubilization, the membranes were exposed to 1 microM vasopressin. This resulted in the association of a pertussis toxin-insensitive guanine nucleotide-binding protein with the receptor during most of the purification procedure. In the absence of this association, the receptor had a Kd of approximately 30 nM. Association of the receptor with a G-protein was confirmed by the ability of vasopressin to stimulate the hydrolysis of [gamma-32P]GTP. The specific activity of the vasopressin-stimulated hydrolysis was 25 nmol/min/mg, approximately 8,000-fold higher than values obtained with crude reconstituted receptor preparations. Cross-linking of 125I-vasopressin to a partially purified preparation of receptor demonstrated that the receptor had a molecular weight of approximately 68,000 under reducing conditions, and 58,000 under nonreducing conditions. The purification procedure may prove useful in purifying a number of small peptide hormone receptors (e.g. bradykinin, angiotensin II) and perhaps their associated G-proteins as well.
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PMID:Purification and characterization of the rat liver vasopressin (V1) receptor. 295 56

Glycoconjugates were localized by light microscopy with lectin-peroxidase conjugates and by electron microscopy with the periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) sequence in immunocytochemically or morphologically identified cell types in rat pituitary. Lectin histochemistry demonstrated sialic acid and glycoconjugates with N-glycosidically linked oligosaccharides in gonadotrophs, thyrotrophs, and corticotrophs. Galactose penultimate to sialic acid was observed mostly in gonadotrophs. The terminal galactose-N-acetylgalactosamine disaccharide was detected in a few gonadotrophs and in a moderate number of mammotrophs. Fucose was localized in only corticotrophs with two fucose-binding lectins and in thyrotrophs with another. Several different monosaccharides were seen in glycoconjugates in melanotrophs and in Herring bodies. Melanotrophs displayed heterogeneous staining with fucose-binding lectins. A small number of nonsecretory cells were also visualized in the pars distalis by virtue of their glycogen content. PA-TCH-SP staining revealed complex carbohydrates in secretory granules and some Golgi cisternae in all types of hormone-producing cells in the pars distalis except for the somatotrophs. Melanotrophs of pars intermedia exhibited stained secretory granules and irregular dense bodies containing a stained meshwork. Corticotrophs of the pars distalis lacked the latter bodies, although they form the same glycoprotein precursor hormone as melanotrophs. Lectin conjugates and the PA-TCH-SP sequence stained some groups of secretion granules in Herring bodies, possibly representing vasopressin-containing granules as well as other cell types in the pars nervosa.
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PMID:Glycoconjugate localization with lectin and PA-TCH-SP cytochemistry in rat hypophysis. 299 73


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