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

The present studies have demonstrated the production of transforming growth factor-beta 1 (TGF-beta 1) by porcine thyroid follicular cells (TFCs) maintained in vitro as subconfluent monolayers, and have confirmed a stimulatory effect of iodide on thyroidal TGF-beta 1 mRNA and peptide release. RNA extracted from TFCs maintained in the absence of iodide contained a 2.5 kb transcript which hybridized specifically with a cDNA probe for human TGF-beta 1, and which showed an approximate doubling in intensity in cells exposed to 10 mumol NaI/1. In the presence of the anti-thyroid thionamide drug methimazole (MMI; 1 mmol/l), the action of iodide on TGF-beta 1 mRNA was attenuated, although MMI alone had no effect on the control level of TGF-beta 1 mRNA. The TGF-beta 1 peptide content of TFC-conditioned media (TFC-CM) was assessed using the fetal mink lung cell line Mv1Lu, in which activated TGF-beta 1 specifically suppresses trichloroacetic acid-precipitable [methyl-3H]thymidine incorporation. Newly conditioned TFC-CM stimulated [methyl-3H]thymidine incorporation into Mv1Lu cells, but after heat treatment to inactivate growth stimulators and activate the latent TGF-beta 1 component this medium inhibited [methyl-3H]thymidine incorporation. This inhibitory effect was prevented by immunoadsorption of TFC-CM with a TGF-beta 1-neutralizing antiserum, confirming the specificity of the inhibitory response. The inhibitory activity of TFC-CM was increased when the TFCs were preincubated with 10 mumol NaI/1, and lost when TFCs were exposed to MMI. In conclusion, TFCs produce TGF-beta 1 mRNA and TGF-beta 1 peptide, which are both increased by iodide treatment in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
J Mol Endocrinol 1992 Dec
PMID:Transforming growth factor-beta 1 production in porcine thyroid follicular cells: regulation by intrathyroidal organic iodine. 147 6

The Ca2+/Mg2+ ATPase, which is activated by millimolar concentrations of Ca2+ or Mg2+, was solubilized from rat heart plasma membrane by employing lysophosphatidylcholine, CHAPS, NaI, EDTA and Tris-HCl at pH 7.4. The enzyme was purified by sucrose density gradient, Affi-Gel Blue column and Sepharose 6B column chromatography. The purified enzyme was seen as a single peptide band in the sodium dodecyl sulfate polyacrylamide gel electrophoresis with a molecular weight of about 90,000. The apparent molecular weight of the holoenzyme as determined under non-dissociating conditions by gel filtration on Sepharose 6B column was about 180,000 indicating two subunits. The enzyme was insensitive to ouabain, verapamil, vanadate, oligomycin, N,N-dicyclohexylcarbodiimide and NaN3, but was markedly inhibited by 20 microM gramicidin S and 50 microM trifluoperazine. Analysis of the purified Ca2+/Mg2+ ATPase revealed the presence of 17 amino acids where leucine, glutamic acid and aspartic acid were the major components and histidine, cysteine and methionine were the minor components. The purified enzyme was associated with 19.7 mumol phospholipid/mg protein which was 60 times higher than the phospholipid content in plasma membrane. The cholesterol content in the purified enzyme preparation was 0.75 mumol/mg protein and this represented an 8-fold enrichment over plasma membrane. The glycoprotein nature of the enzyme was evident from the positive periodic acid-Schiff staining of the purified Ca2+/Mg2+ ATPase in the sodium dodecyl sulfate polyacrylamide gel. The polysaccharide content of the enzyme was enriched 8-fold over plasma membrane; neuraminidase treatment decreased the polysaccharide content. Concanavalin A prevented the ATP-dependent inactivation of the purified Ca2+/Mg2+ ATPase and was found to bind to the purified enzyme with a KD of 576 nM and Bmax of 4.52 nmol/mg protein. The results indicate that Ca2+/Mg2+ ATPase is a glycoprotein and contains a large amount of lipids.
Mol Cell Biochem 1991 Oct 16
PMID:Purification and composition of Ca2+/Mg2+ ATPase from rat heart plasma membrane. 183 89

The N-glycan-processing inhibitors swainsonine (Sw) and deoxymannojirimycin (dMM) were used to study the influence of N-glycans on iodide organification in cultured porcine thyroid cells. Incubations with [125I]NaI were followed by determination of labeled trichloroacetic acid-insoluble material in culture media, follicular contents and cells. In controls, most of this material was in the follicular contents. With Sw and dMM, total acid-insoluble material was less than 10% of control. Iodide uptake was slightly inhibited and hydrogen peroxide release was not affected by inhibitors. Cell-surface thyroid peroxidase (TPO) activity, assayed by its ability to iodinate bovine serum albumin, was strongly inhibited. Pronase glycopeptide analysis indicated that with drugs the content in complex-type N-glycans was strongly decreased while that in hybrid or oligomannosidic type was increased. In conclusion, inhibition of N-glycan processing prevents iodide organification in cultured porcine thyroid cells by decreasing the recovery of cell-surface TPO activity.
Mol Cell Endocrinol 1990 Oct 22
PMID:Inhibition of N-glycan processing affects iodide organification in porcine thyroid cells. 214 33

(-)-N6-(R-4-Hydroxyphenylisopropyl)adenosine (HPIA) was iodinated with NaI and trace 125I. Mono- and diiodinated reaction products and the starting material were separated by high pressure liquid chromatography and the structures of the reaction products were verified by NMR. (-)-N6-(R-Phenylisopropyl)adenosine (PIA), IHPIA, and I2HPIA decreased rat atrial contractility with ED50 values of 24, 28, and 33 nM, respectively. The contractile effects of these compounds were competitively blocked by theophylline (KI = 7.9 microM), but were not affected by adenosine deaminase. IHPIA also inhibited (-)isoproterenol-stimulated cyclic AMP accumulation in adipocytes with an ED50 (10 nM) and to an extent (83%) nearly identical to PIA. [125I]HPIA prepared using carrier-free 125I bound to adenosine receptors on membranes from rat cerebral cortex, adipocyte ghosts, and heart ventricles. Binding was inhibited stereospecifically by PIA and by other adenosine analogues and alkylxanthines. The KD of [125I]HPIA determined kinetically using brain membranes at 21 degrees was 0.94 nM (K1 = 2.55 X 10(7) M-1 min-1; K-1 = 0.024 min-1) in good agreement with the equilibrium determination of 1.94 nM. The density of adenosine receptors in brain membranes was found to be 871 fmol/mg of protein. When normalized to protein, the density of receptors in heart membranes and adipocyte ghosts, respectively, was found to be 39- and 2.3-fold less than in brain membranes. We conclude that [125I]HPIA can be rapidly synthesized and purified, binds to adenosine R-sites and is an agonist radioligand resistant to adenosine deaminase. Computer modeling of the equilibrium binding resulting from the use of mixed stereoisomers of a radioligand indicates that the combined use of (-)[125I]HPIA and (+)[125I]HPIA would result in the generation of nonlinear Scatchard plots.
Mol Pharmacol 1984 Nov
PMID:Purification and characterization of (-)[125I]hydroxyphenylisopropyladenosine, an adenosine R-site agonist radioligand and theoretical analysis of mixed stereoisomer radioligand binding. 609 94

Various monovalent salts have been shown to inhibit the binding of radioiodinated human follitropin [( 125I]hFSH) to receptors present in calf testis. We examined the effects of salts on the affinity constant (Ka) and number of binding sites (R0) in the FSH-calf testis receptor system. A constant amount of [125I]hFSH and increasing amounts of unlabeled hFSH were allowed to bind to a constant amount of receptor in the absence or presence (0.10 M) of halides, nitrates or acetates of the alkali ions at 20.0 degrees C. There was an appreciable variation of the affinity constant depending on the salt being used, but there was no change in receptor number (R0). Within an alkali cation series (e.g. NaCH3CO2, NaF, NaCl, NaBr, NaNO3, NaI or a similar potassium series) the affinity decreased with decreasing B coefficient of viscosity. Within a halide series (e.g. LiCl, NaCl, KCl, RbCl or the similar bromide series) the minimum value of the affinity constant occurred with the Na+ salt. The special inhibitory potency of Na+ may suggest that it has a unique interaction with calf testis FSH receptor or with follitropin. The studies indicate a correlation between the B coefficient of viscosity and the ability of salts to inhibit binding of [125I]hFSH to receptor.
Mol Cell Endocrinol 1984 Apr
PMID:Correlation of B coefficient of viscosity for monovalent salts with effects on binding of human follitropin to receptor. 632 78

Photosystem I catalyzes the light-driven oxidation of plastocyanin or cytochrome c6 and the reduction of ferredoxin or flavodoxin. PsaJ is a 4.4 kDa hydrophobic subunit of photosystem I from cyanobacteria and chloroplasts. To investigate the function of PsaJ, we generated a mutant strain of the cyanobacterium Synechocystis sp. PCC 6803 in which the psaJ gene is replaced by a gene for chloramphenicol resistance. Deletion of psaJ led to a reduction in the steady state RNA level from psaF which is located upstream from psaJ. Immunoquantification using an anti-PsaF antibody revealed a significant decrease in the amount of PsaF in membranes of the mutant strain. Trimeric photosystem I complexes isolated from the mutant strain using n-dodecyl beta-D-maltoside lacked PsaJ, contained ca. 80% less PsaF, but maintained wild-type levels of other photosystem I subunits. In contrast, the photosystem I purified using Triton X-100 contained less than 2% PsaF when compared to the wild type, showing the more extractable nature of PsaF in PsaJ-less photosystem I in the presence of Triton X-100. PsaE was more accessible to removal by NaI in a mutant strain lacking PsaF and PsaJ than in the wild type. The presence of PsaF in photosystem I from the PsaJ-less strain did not alter the increased susceptibility of PsaE to removal by NaI. These results indicate an interaction between PsaJ and PsaF in the organization of the complex.
Plant Mol Biol 1994 Oct
PMID:Targeted deletion of psaJ from the cyanobacterium Synechocystis sp. PCC 6803 indicates structural interactions between the PsaJ and PsaF subunits of photosystem I. 752 26

Crystallins are proteins that accumulate to very high concentrations in the fiber cells of the lens of the eye. Crystallins are responsible for the transparency and high refractive index that are essential for lens function. In the chicken embryo, delta-crystallin accounts for more than 70% of the newly synthesized lens proteins. We used density labeling and gene-specific polymerase chain reaction (PCR) to determine the mechanism regulating the expression of the two very similar delta-crystallin genes. Newly synthesized RNA was separated from preexisting RNA by incubating the lenses with 15N- and 13C-labeled ribonucleosides and then separating newly synthesized, density-labeled RNA from the bulk of light RNA by equilibrium density centrifugation in NaI-KI gradients. The relative abundances of the two crystallin mRNAs in the separated fractions were then determined by PCR. This method permitted the quantitation of newly synthesized processed and unprocessed delta-crystallin mRNAs. Additional studies used intron- and gene-specific PCR primers to determine the relative expression of the two delta-crystallin genes in processed RNA and unprocessed RNA extracted from different regions of the embryonic lens. Results of these tests indicated that the differential expression of the delta-crystallin genes was regulated primarily at the level of transcription. This outcome was not expected on the basis of the results of previous studies, which used in vitro transcription and transfection methods to evaluate the relative strengths of delta-crystallin promoter and enhancer sequences. Our data suggest that the cultured cells used in these earlier studies may not have provided an accurate view of delta-crystallin regulation in the intact lens.
Mol Cell Biol 1993 Jun
PMID:Transcriptional control of delta-crystallin gene expression in the chicken embryo lens: demonstration by a new method for measuring mRNA metabolism. 768 94

To develop androgen and progesterone receptor-based radioligands for SPECT imaging we synthesized several radioiodinated 17 alpha-iodovinyl testosterone and 19-nortestosterone analogs and evaluated their biological properties. The synthesis of these compounds proceeds via the (17 alpha,20E/Z)stannyl intermediates and involves addition of tri-n-butyltin hydride to the 17 alpha-ethynyl group of the steroid using either azobisiso butyronitrile or triethylborane as a catalyst. The stannyl derivatives are stereospecifically converted to the corresponding (17 alpha,20E/Z)iodovinyl derivatives using molecular iodine, or to the [125I]iodovinyl analogs using [125I]NaI and H2O2. Androgen and progesterone receptor (AR and PgR) binding affinities were measured via a competitive in vitro binding assay. In general 19-nortestosterone derivatives showed higher receptor affinities as compared to the testosterone derivatives. In the latter series the highest PgR binding affinities were observed with the (17 alpha,20Z)iodovinyl-19-nortestosterone (IVNT) (92 vs 100 for R5020) followed by the 7 alpha-methyl analog, whereas the highest AR binding affinity was observed with the 7 alpha-Me-(17 alpha,20Z)IVNT (54 vs 100 for 5 alpha-dihydrotestosterone). These derivatives were also labeled with 125I and evaluated for their in vivo target organ uptake (prostate and estrogen-primed uterus). The highest PgR-mediated target tissue uptake was observed with the (17 alpha,20Z)-[125I]IVNT and its 7 alpha-methyl derivatives whereas only one derivative, the 7 alpha-Me-(17 alpha,20Z)-[125I]IVNT, showed AR-mediated dorsal prostate retention. Although some of the IVNT derivatives have interesting binding properties, the lack of in vivo selectivity does suggest that the 123I-labeled analogs are unlikely to be suitable for imaging of AR and PgR-rich tissues.
J Steroid Biochem Mol Biol 1994 May
PMID:Synthesis of (17 alpha,20E/Z)iodovinyl testosterone and 19-nortestosterone derivatives as potential radioligands for androgen and progesterone receptors. 800 36

The effects of several biologically important inorganic salts, including NaCl, NaI, NaBr, KCl, MgCl2, MgSO4 and CaCl2 on the electronic absorption and fluorescence spectra of Merocyanine 540 (MC-540) have been investigated in aqueous media at 25 degrees C. Depending on both the MC-540 concentration and the nature of salt, a new absorption band appears at about 515 nm, above the critical salt concentration (CSC), corresponding to salt-induced MC-540 aggregation. Several types of MC-540 fluorescence quenching by the salts are observed, according to their cationic charge and the nature of anion: in the case of monovalent ions (Na+, K+), a non-linear Stern-Volmer behaviour is observed, indicating variable contributions of dynamic and static quenching mechanisms, whereas for divalent alkaline-earth (Mg2+, Ca2+) ions, linear Stern-Volmer relationships are obtained. Using these results, an analytical quenchofluorimetric approach is proposed for the determination of magnesium ions.
Spectrochim Acta A Mol Biomol Spectrosc 2002 Feb
PMID:A spectroscopic study of the fluorescence quenching interactions between biomedically important salts and the fluorescent probe merocyanine 540. 1190 40

The sodium/iodide symporter (NIS) has been recognized as an attractive target for radioiodine-mediated cancer gene therapy. In this study we investigated the role of human NIS for cellular uptake of the high LET alpha-emitter astatine-211 ((211)At) in comparison with radioiodine as a potential radionuclide for future applications. A mammalian NIS expression vector was constructed and used to generate six stable NIS-expressing cancer cell lines (three derived from thyroid carcinoma, two from colon carcinoma, one from glioblastoma). Compared with the respective control cell lines, steady state radionuclide uptake of NIS-expressing cell lines increased up to 350-fold for iodine-123 ((123)I), 340-fold for technetium-99m pertechnetate ((99m)TcO(4)(-)) and 60-fold for (211)At. Cellular (211)At accumulation was found to be dependent on extracellular Na(+) ions and displayed a similar sensitivity towards sodium perchlorate inhibition as radioiodide and (99m)TcO(4)(-) uptake. Heterologous competition with unlabelled NaI decreased NIS-mediated (211)At uptake to levels of NIS-negative control cells. Following uptake both radioiodide and (211)At were rapidly (apparent t(1/2) 3-15 min) released by the cells as determined by wash-out experiments. Data of scintigraphic tumour imaging in a xenograft nude mice model of transplanted NIS-modified thyroid cells indicated that radionuclide uptake in NIS-expressing tumours was up to 70 times ((123)I), 25 times ((99m)TcO(4)(-)) and 10 times ((211)At) higher than in control tumours or normal tissues except stomach (3-5 times) and thyroid gland (5-10 times). Thirty-four percent and 14% of the administered activity of (123)I and (211)At, respectively, was found in NIS tumours by region of interest analysis ( n=2). Compared with cell culture experiments, the effective half-life in vivo was greatly prolonged (6.5 h for (123)I, 5.2 h for (211)At) and preliminary dosimetric calculations indicate high tumour absorbed doses (3.5 Gy/MBq(tumour) for (131)I and 50.3 Gy/MBq(tumour) for (211)At). In conclusion, NIS-expressing tumour cell lines of different origin displayed specific radionuclide uptake in vitro and in vivo. We provide first direct evidence that the high-energy alpha-emitter (211)At is efficiently transported by NIS. Application of (211)At may direct higher radiation doses to experimental tumours than those calculated for (131)I. Thus, (211)At may represent a promising alternative radionuclide for future NIS-based tumour therapy.
Eur J Nucl Med Mol Imaging 2002 Jul
PMID:Establishment of radioactive astatine and iodine uptake in cancer cell lines expressing the human sodium/iodide symporter. 1211 Nov 24


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