Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the identification and characterization of specific vasopressin-binding sites on intact cells and membranes of the established vascular smooth muscle cell line A-10, the fate of vasopressin associated with the cells, the role of guanine nucleotides in the regulation of the affinity of the vasopressin-binding sites, and the determination of the vasopressin receptor subtype. We have found specific vasopressin-binding sites on intact cells in monolayer (110,000 sites per cell during log growth and 60,000 sites per cell in stationary culture) with a KD of 6 nM at 37 degrees. After incubation of [3H]-8-arginine vasopressin ([3H]AVP) and cells for less than 20 min, cell-associated AVP was intact; with longer incubation times, AVP was progressively degraded. The major metabolites included phenylalanine and a fraction that eluted from a C18 reverse phase high performance liquid chromatography column between AVP and 8-arginine, 9-desglycinamide vasopressin. Extensive degradation also occurred when AVP was allowed to dissociate from the cells. With increased time of incubation, the amount of specifically bound AVP that could dissociate decreased, suggesting receptor-mediated endocytosis. In saturation equilibrium binding experiments with plasma membranes, two affinity states with KD of 0.7 nM and 379 nM were observed. The number of high affinity binding sites was similar to the number of receptors found on intact cells. Guanosine 5'-(beta,gamma-imido)triphosphate decreased vasopressin binding to the high affinity sites and did not significantly affect the low affinity sites. Competition binding experiments indicated that the vasopressin-binding sites of A-10 cells belong to the vascular V1 receptor subtype. We conclude that the established vascular smooth muscle cell line A-10 expressed vasopressin receptors of the vascular V1 subtype. Vasopressin bound to the receptors reversibly, but could also be degraded by the cells presumably after receptor-mediated endocytosis. The receptors might exist in different affinity states; guanosine 5'-(beta,gamma-imido)triphosphate decreased the affinity of the high affinity binding state.
Mol Pharmacol 1987 Mar
PMID:Identification and characterization of vascular (V1) vasopressin receptors of an established smooth muscle cell line. 295 84

A cell line (T17) was derived from C3H 10T1/2 C18 cells after 17 treatments with increasing concentrations of 5-aza-2'-deoxycytidine. The T17 cell line was very resistant to the cytotoxic effects of 5-aza-2'-deoxycytidine, and the 50% lethal dose for 5-aza-2'-deoxycytidine was ca. 3 microM, which was 30-fold greater than that of the parental C3H 10T1/2 C18 cells. Increased drug resistance was not due to a failure of the T17 cell line to incorporate 5-aza-2'-deoxycytidine into DNA. The cells were also slightly cross-resistant to 5-azacytidine. The percentage of cytosines modified to 5-methylcytosine in T17 cells was 0.7%, a 78% decrease from the level of 3.22% in C3H 10T1/2 C18 cells. The DNA cytosine methylation levels in several clones isolated from the treated lines were on the order of 0.7%, and clones with methylation levels lower than 0.45% were not obtained even after further drug treatments. These highly decreased methylation levels appeared to be unstable, and DNA modification increased as the cells divided in the absence of further drug treatment. The results suggest that it may not be possible to derive mouse cells with vanishingly low levels of 5-methylcytosine and that considerable de novo methylation can occur in cultured lines.
Mol Cell Biol 1984 Oct
PMID:DNA methylation in 5-aza-2'-deoxycytidine-resistant variants of C3H 10T1/2 C18 cells. 620 56

Four trypanosomatid flagellates of the genera Phytomonas and Herpetomonas have been found to carry out the de novo biosynthesis of a variety of iso-branched, C18, C20 and C22, polyunsaturated fatty acids, with 2-5 methylene-interrupted double bonds, which have not been described heretofore from natural materials; iso-C18 delta 6,9, iso-C18 delta 9,12, iso-C20 delta 8,11,14, iso-C 20 delta 5,8,11,14, iso-C22 delta 4,7,10,13,16. Identifications were based upon combinations of chromatographic, chemical degradative, mass spectrometric and proton nuclear magnetic resonance spectrometric techniques. Under appropriate culture conditions, 85% of the total fatty acids of the organisms were branched. The subject trypanosomatids are recommended as model organisms with which to investigate influences of the physical properties of phospholipid fatty acyl groups on eukaryotic cell membrane functions.
Mol Biochem Parasitol 1982 Jan
PMID:Some Phytomonas and Herpetomonas species form unique iso-branched polyunsaturated fatty acids. 706 37

DNA isolated from cell nuclei by intensive deproteinization with chloroform/isoamyl alcohol and phenol extractons contains a low molecular weight peptidic fraction in a quantity of about 20 micrograms/mg DNA. These peptides were characterized by chromatography on CM-Sephadex, Sephadex G-25, high performance liquid chromatography on microBondapak C18 and amino acid composition. The peptides control transcription in a reconstituted cell-free system with prokaryotic and eukaryotic RNA polymerase and stabilize the structure of double stranded DNA, while increasing its melting point. Their level is markedly decreased (by about 40%) in DNA prepared from tumor cells as compared to normal cell DNA. Transcriptional studies showed only a slightly increased template activity of DNA extracted at pH 9.5 versus DNA extracted at pH 6.0 for DNA preparations from tumor cells. However, there was a marked increase in template activity for DNA preparations treated at pH 9.5 from normal cells--232%, 124%, 97% and 78% for rat liver, mouse liver, mouse thymus and fibroblast L-929 cells, respectively. Also there was no difference in the melting point between these two preparations of DNA from tumor cells; normal cell DNA preparations showed increased melting point of preparations treated at pH 6.5. The data obtained indicate that the loss of low molecular weight peptides from tumor DNA during carcinogenesis is responsible for uncontrolled gene expression observed in cancer.
Mol Biol Rep 1980 Jul 31
PMID:Low molecular weight peptidic fraction in the chromatin from normal and cancer cells: control of transcription. 741 71

We have found that the introduction of a single 2'-hydroxyl group on the sugar-phosphate backbone of the B-DNA decamer d(CCGGCGCCGG) transforms it to A-DNA. Thus, for the first time the X-ray structures of the same sequence have been observed in both the A and B-DNA conformations, permitting a comparison. Crystals of the DNA-RNA chimeric decamer d(CCGGC)r(G)d(CCGG) belong to the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions a = 25.63 A, b = 45.24 A and c = 47.99 A, and one decamer duplex in the asymmetric unit. The structure was solved by a rigid body search using the coordinates of the isomorphous structure d(CCCGGCCGGG) and refined to an R value of 0.136 using 2753 unique reflections at 1.9 A resolution. The final model contains 406 nucleotide atoms and 61 water molecules. The chimeric duplex exhibits typical A-DNA geometry, with all the sugars in the C(3')-endo puckering and the base-pairs inclined and displaced from the helix axis. The 2'-hydroxyl groups on rG6 and rG16 protrude into the minor groove surface and form different types of hydrogen bonds; that on strand 1 forms an intermolecular hydrogen bond with the furanose ring O(4') of a symmetry-related C1 residue, while that on strand 2 is involved in two water bridges. Crystal packing forces the G4-G17 base-pair in the top half of the duplex to slide significantly into the minor groove compared to the corresponding G7-G14 base-pair in the bottom half, resulting in these base-pairs exhibiting different base stacking and intermolecular interactions. The base G4 of the G4-G17 base-pair forms an unorthodox base "triple", G4*(G10-C11), hydrogen-bonding through its minor groove sites N(2) and N(3) to the minor groove atoms N(2) and O(2) of both bases of the G10-C11 base-pair of a symmetry-related molecule. The base G10 of this triple in turn forms a second similar unorthodox base triple, G10*(G3*C18), with the adjacent base-pair G3-C18 of the duplex, thus G10 is involved in a double triple. On the other hand, in the bottom half of the duplex, the C7-G14 base-pair is involved only in a single similar unorthodox base triple with G20, (C7-G14)*G20, while the adjacent base-pair rG6-C15 is involved in a novel quadruple with C1-G20, (rG6-C15) *(C1-G20), where the latter base-pairs are hydrogen-bonded to each other via the minor groove sites G(N(2))...C(O(2)).(ABSTRACT TRUNCATED AT 400 WORDS)
J Mol Biol 1994 Feb 11
PMID:A single 2'-hydroxyl group converts B-DNA to A-DNA. Crystal structure of the DNA-RNA chimeric decamer duplex d(CCGGC)r(G)d(CCGG) with a novel intermolecular G-C base-paired quadruplet. 750 84

In order to study the influence of cell shape as modulated by the extracellular matrix on the cellular activity, hepatocytes isolated from liver were maintained on collagen I coated plastic substrata and collagen I gel substrata and certain hepatocyte specific functions were investigated. The incorporation of 3[H]-leucine into total proteins and albumin secreted by cells maintained on collagen gel was found to be significantly higher compared to those maintained on a collagen coated plastic substrata, indicating that hepatocytes on collagen gel have an enhanced albumin synthesizing capacity. Increased incorporation of 35[S]-sulphate into total proteoglycans (PG) and a relatively higher fraction of the 35[S]-PG in the extracellular space showed an increased rate of synthesis and secretion of sulphated PGs by cells on collagen gels. But in contrast to the above results, the incorporation of 3[H]-leucine into cytokeratins C8, C18 and actin were significantly low in cells maintained on collagen gel. The tyrosine amino transferase activity exhibited by hepatocytes preincubated with dexamethasone on collagen gel was also significantly low. The different forms of collagen substrata appeared to have no effect on the amino acid transport by hepatocytes, further suggesting that the various hepatocyte specific functions are not uniformly altered when hepatocytes are maintained on three-dimensional collagen gel substrata. These results indicate that the shape of the cell as determined by the nature of the matrix substratum influences the synthetic activity of secretory proteins and those remaining intracellularly, differently.
Mol Cell Biochem 1994 Aug 31
PMID:Influence of collagen gel substrata on certain biochemical activities of hepatocytes in primary culture. 753 Dec 79

The enzyme 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) catalyzes the 17 beta-oxidation/reduction of C18- and C19-steroids in a variety of tissues. Three human genes encoding isozymes of 17 beta-HSD, designated 17 beta-HSD types 1, 2 and 3 have been cloned. 17 beta-HSD type 1 (also referred to as estradiol 17 beta-dehydrogenase) catalyzes the conversion of estrone to estradiol, primarily in the ovary and placenta. The 17 beta-HSD type 2 is expressed to high levels in the liver, secretory endometrium and placenta. The type 2 isozyme catalyzes the oxidation of androgens and estrogens equally efficiently. Also, the enzyme possesses 20 alpha-HSD activity demonstrated by its ability to convert 20 alpha-dihydroprogesterone to progesterone. Testicular 17 beta-HSD type 3 catalyzes the conversion of androstenedione to testosterone, dehydroepiandrosterone to 5-androstenediol and estrone to estradiol. The 17 beta-HSD3 gene is mutated in male pseudohermaphrodites with the genetic disease 17 beta-HSD deficiency.
J Steroid Biochem Mol Biol 1995 Jun
PMID:The molecular biology of androgenic 17 beta-hydroxysteroid dehydrogenases. 762 83

The effect of hypersaline stress on the lipid composition of the salt-tolerant yeast Candida membranefaciens was studied. Fatty acid analyses of the plasma membrane showed a growth phase- and dose-dependent increase in the level of linolenic acid (C18:3) in 1.35 M NaCl-stressed cells. Palmitoleic acid (C16:1) was completely undetectable at all phases of the life cycle. Changes in the levels of other fatty acids were insignificant. The degree of unsaturation of fatty acids in the plasma membranes was higher in presence of 1.35 M NaCl. The fluorescence polarisation value of DPH (1,6-diphenyl- 1,3,5-hexatriene) in the spheroplasts of the stressed cells was lower as compared to the control cells, indicating the fact that a higher membrane fluidity favours osmotic adaptation against NaCl stress. Among different phospholipids, levels of Phosphatidylinositol and Phosphatidylethanolamine were elevated in the salt-adapted cells as compared to their controls. The levels of Phosphatidylcholine and cardiolipin did not change significantly in response to hypersaline stress. The study points out that hypersalinity signals affect the lipid composition which in turn affects the membrane fluidity of C. membranefaciens.
Biochem Mol Biol Int 1995 Apr
PMID:High membrane fluidity is related to NaCl stress in Candida membranefaciens. 762 36

We characterized the phospholipid inhibition of estradiol and progesterone binding to guinea-pig and human myometrial receptors. Of twelve compounds studied, phosphatidylinositol (PI), lysophosphatidic acid and lysophosphatidylcholine (lyso-PC) were the most active inhibitors (50% inhibition at 10(-5) M). Lyso-PC with fatty acid chain length C14:0 inhibited ligand binding both to estrogen receptor (ER) and progesterone receptor (PR), C16:0 only to PR and C18:0 neither to ER nor to PR. The lyso-derivates were more inhibitory than the parent compounds. The ionic detergent (sodium taurocholate) inhibited both ER and PR binding, but the non-ionic detergent (Triton X-100) only PR. Triton X-100 enhanced the PI-induced inhibition of ER binding by a factor of 10. PR was more sensitive to inhibition than ER in all cases. The type of inhibition was non-competitive. At term pregnancy, ligand binding to myometrial ER or PR was low or absent in humans, but moderate in the guinea-pig. Phospholipid extracts of human decidua and fetal membranes contained PI and phosphatidylserine rather than lyso-PC. The extract was a potent inhibitor of ligand binding to PR (50% inhibition at 10(-6) M phospholipid phosphorus), but not to ER. The physicochemical environment, modulated by phospholipids acting as detergents, may regulate sex steroid function also in vivo. This might have special significance for pregnancy maintenance.
J Steroid Biochem Mol Biol 1995 Mar
PMID:Myometrial estrogen and progesterone receptor binding in pregnancy: inhibition by the detergent action of phospholipids. 769 51

The fatty acid compositions of phospholipids and triacylglycerols from selected orthognath spider tissues, scorpion body segments, whole millipedes, and whole labidognath spiders were determined. The major components were C16 and C18 saturated and unsaturated fatty acids as well as C20 polyunsaturated fatty acids. The eicosanoid precursor polyunsaturated fatty acids 20:4n-6 and 20:5n-3 were present in substantial proportions of phospholipids in all tissues examined. The fatty acid profiles of these terrestrial arthropods differ markedly from corresponding profiles of terrestrial insects in that substantially greater proportions of C20 polyunsaturated fatty acids are present in the organisms in this study. This finding supports the idea that maintaining low proportions of C20 polyunsaturated fatty acids is a special condition of terrestrial insects.
Comp Biochem Physiol Biochem Mol Biol 1994 Mar
PMID:Fatty acid compositions of phospholipids and triacylglycerols from selected terrestrial arthropods. 774 9


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