Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The localization of the protein tyrosine kinase pp60c-src to the plasma membrane and to the membrane of secretory vesicles in neurally derived bovine chromaffin cells has suggested that tyrosine phosphorylations may be associated with the process of secretion. In the present study we have identified two cytosolic proteins of approximately 42 and 45 kD that become phosphorylated on tyrosine in response to secretagogue treatment. Phosphorylation of these proteins reached a maximum (3 min after stimulation) before maximum catecholamine release was observed (5-10 min after stimulation). Both secretion and tyrosine phosphorylation of p42 and p45 required extracellular Ca2+. Tyrosine-phosphorylated proteins of similar Mr have previously been identified in 3T3-L1 adipocytes stimulated with insulin (MAP kinase; Ray, L. B., and T. W. Sturgill. 1987. Proc. Natl. Acad. Sci. USA. 84:1502-1506) and in avian and rodent fibroblasts stimulated with a variety of mitogenic agents (Cooper, J. A., D. F. Bowen-Pope, E. Raines, R. Ross, and T. Hunter. 1982. Cell. 31:263-273; Nakamura, K. D., R. Martinez, and M. J. Weber. 1983. Mol. Cell. Biol. 3:380-390). Comparisons of the secretion-associated 42-kD protein of chromaffin cells with the 42-kD protein of Swiss 3T3 fibroblasts and 3T3-L1 adipocytes provide evidence that these three proteins are highly related. This evidence includes comigration during one-dimensional SDS-PAGE, cochromatography using ion exchange and hydrophobic matrices, similar isoelectric points, identical cyanogen-bromide peptide maps, and cochromatography of MAP kinase activity with the tyrosine-phosphorylated form of pp42. This protein(s), which appears to be activated in a variety of cell types, may serve a common function, perhaps in signal transduction involving a cascade of kinases.
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PMID:A 42-kD tyrosine kinase substrate linked to chromaffin cell secretion exhibits an associated MAP kinase activity and is highly related to a 42-kD mitogen-stimulated protein in fibroblasts. 168 32

We have characterized the insulin-like growth factor-binding proteins (IGF-BPs) released by isolated sheep thyroid epithelial cells. Thyroid follicles were isolated with collagenase and cultured in Coon's modified F-12 M (0H medium) supplemented with insulin, cortisol, transferrin, glycyl-histidyl-lysine and somatostatin (5H medium) and TSH (6H medium). Conditioned 0H medium specifically bound both 125I-labelled IGF-I and -II, although binding capacity was reduced following acid-gel filtration to separate endogenous IGF-BP complexes, suggesting some destruction of BPs. The binding of 125I-labelled IGF-I or -II to conditioned (0H) medium was progressively displaced by increasing amounts of unlabelled homologous peptides, while fractionation on concanavalin A-Sepharose showed that the IGF-BPs consisted of both glycoprotein and non-glycoprotein components. The molecular sizes of the IGF-BPs were resolved by separation of 0H medium on SDS-PAGE and ligand blot analysis with 125I-labelled IGF-I or -II. Conditioned medium contained four specific binding species for IGF-II of 19, 30, 38 and 46 kDa; all but the smallest also binding radiolabelled IGF-I. Prior fractionation on concanavalin A-Sepharose showed that the 46 kDa binding species was a glycoprotein. Competition studies with increasing concentrations of unlabelled IGF-I or -II during ligand blotting suggested that the 46 and 30 kDa binding species had a greater affinity for IGF-II than IGF-I, while the 38 kDa had a greater relative affinity for IGF-I. Incubation of cells in 5H medium reduced the abundance of the 46 kDa binding protein, while incubation in 6H medium decreased the release of all binding protein species. Results show that isolated thyroid follicles released several forms of IGF-BP with differing relative affinities for IGF-I and -II. Gross changes seen in the presence of BPs between 0H, 5H and 6H media suggest acute hormonal control of release.
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PMID:Characterization of insulin-like growth factor-binding proteins secreted by isolated sheep thyroid epithelial cells. 169 63

Both insulin and glucocorticosteroid (GS) deficiency causes a reduction of amylase synthesis and changes in the dose-response curve of cholecystokinin (CCK) stimulated enzyme secretion in rats. Since we found a reduction of plasma insulin in adrenalectomized rats, we now tested the hypothesis that the regulation of amylase synthesis by insulin may be mediated by GS. Three groups of male rats were investigated: controls, streptozotocin induced diabetics, and diabetics treated with GS. Animals were sacrificed 10-14 days after injection of streptozotocin and isolated pancreatic acini prepared by collagenase digestion. Protein synthesis was measured on the translational level by incubation of acini with 35S-methionine followed by lysis of cells and separation of proteins by SDS-PAGE. In addition, protein synthesis was measured on the transcriptional level by isolation of mRNA from pancreatic acini and translation of proteins using the rabbit reticulocyte lysate system. The loss of insulin in diabetic rats was associated with a 70-90% decrease in amylase synthesis and increases of synthesis of various proteases. This was due to a specific decrease in mRNA coding for amylase and increase in mRNA coding for proteases. Furthermore, the known rightward shift of the dose response curves of CCK stimulated amylase secretion was seen in diabetic animals. Treatment of diabetic rats with GS did deteriorate the catabolic status seen in diabetes with increases in mortality as compared to diabetes alone. However, neither the overall pattern of enzyme synthesis seen in diabetic rats nor the alterations in CCK stimulated enzyme secretion were changed by treatment with GS. We conclude that the regulation of amylase synthesis and enzyme secretion by insulin is not mediated via GS.
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PMID:Pancreatic enzyme synthesis and secretion are independently regulated by insulin and glucocorticosteroids. 170 71

Insulin-like growth factor-binding protein-1 (IGFBP-1) has been purified from amniotic fluid by anion exchange, hydrophobic interaction and gel filtration chromatography. The overall recovery of the purification process was 12.2%. The purified IGFBP-1 yielded a single band on SDS-PAGE gel but showed two bands (34 kDa and 68 kDa) on Western blot under non-reducing conditions. Polyclonal antisera were raised by immunization of sheep using the purified IGFBP-1. The best antiserum bound 50% of 125I-labelled IGFBP-1 at a final dilution of 1:500,000. A radioimmunoassay for IGFBP-1 was developed. This assay had a minimum detection limit of 5 micrograms/l, and was used to determine serum levels in non-pregnant and pregnant women. There was no cross-reaction with a wide variety of materials tested. Serum IGFBP-1 levels in non-pregnant individuals (33 +/- 16 (S.D.) micrograms/l) were found to be significantly lower than those in the second (96 +/- 64 micrograms/l) and third trimesters (95 +/- 60 micrograms/l) of pregnant women. During pregnancy, circulating IGFBP-1 levels increased rapidly in the first trimester and reached a peak at 12-13 weeks of gestation (107 +/- 75 micrograms/l). The level then remained at 80 +/- 53 to 103 +/- 70 micrograms/l until term.
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PMID:Purification and assay of insulin-like growth factor-binding protein-1: measurement of circulating levels throughout pregnancy. 170 72

Cyclic AMP phosphodiesterase in rat adipocytes is stimulated by insulin and also by agents that increase cyclic AMP levels. When the enzyme is immunoprecipitated from a solubilised microsomal preparation from adipocytes prelabelled with radioactive phosphate and separated on SDS polyacrylamide gels, label is found in a protein band at the expected Mr for adipose tissue phosphodiesterase. Treatment of the adipocytes with isoproterenol or methyl isobutylxanthine increased the labelling of this band. Insulin alone had no effect on its labelling but did decrease the incorporation of label caused by isoproterenol.
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PMID:Phosphorylation of hormone sensitive phosphodiesterase in isolated adipocytes. 170 64

The 3T3-L1 preadipocytes treated with insulin, dexamethasone and 3-methyl-1-isobutylxanthine (IBMX) two days before reaching monolayer undergo differentiation into adipocytes. Cell lysates were prepared from these cells under various conditions and analyzed by SDS-PAGE and transblot. Peroxidase-conjugated avidin used to detect endogenous proteins interacted strongly with a protein with an estimated molecular weight of 120 kDa, corresponding to pyruvate carboxylase, in the differentiated 3T3-L1 cells. On the other hand, this protein was not detected in undifferentiated 3T3-L1 cells.
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PMID:Identification of pyruvate carboxylase in 3T3-L1 cells by transblot and its correlation with differentiation into adipocytes. 172 95

A metallothiol protease called insulin-degrading enzyme (IDE) seems to be implicated in insulin metabolism to terminate the response of cells to hormone, as well as in other biological functions, including muscle differentiation, regulation of growth factor levels, and antigen processing. In order to obtain highly pure and biologically active IDE, we have developed an immunoaffinity method using a monoclonal antibody to this enzyme (9B12). When the cytosolic fraction of rat liver was first applied to a 9B12-coupled Affi-Gel 10 column, more than 97% of the insulin-degrading activity was absorbed. Among various kinds of buffers successfully eluting the enzyme, only the buffer with a high pH (pH 11) could retain the full biological activity of this enzyme. IDE was further purified via two steps of chromatography using Mono Q anion exchange and Superose 12 molecular sieve columns. The final preparation showed a single band at 110 kDa on reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In the eluate from the immunoaffinity column, the inhibitory activity associated with the enzyme was also observed. To better recover this endogenous inhibitor, heat-treated cytosolic fraction was fractionated by ammonium sulfate precipitation and applied to the immunoaffinity column on which IDE had been adsorbed. Then, IDE and its inhibitor could be co-eluted with pH 11 as a complex form. After heat treatment of this fraction, the inhibitor was further purified using the same series of chromatography as IDE to more than 20,000-fold; it showed a 14 kDa band on SDS-PAGE. It inhibited both the insulin degradation by IDE in a competitive manner and the cross-linking of 125I-insulin to IDE. Highly purified IDE and the endogenous inhibitor will be useful tools for better understanding the various biological functions of this enzyme.
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PMID:Affinity purification of insulin-degrading enzyme and its endogenous inhibitor from rat liver. 173 Jun 51

Scatchard plot analysis of the binding of 125I-labeled heparin binding cell growth-associated factor (125I-HBGAF) to NIH 3T3 cells revealed a single class of high affinity receptors (-5000/cell) with kd of -0.6 nM. 125I-HBGAF was covalently cross-linked to the cell surface receptor on NIH 3T3 cells with disuccinimidyl suberate (DSS). Two 125I-HBGAF-cross-linked complexes of 170 kDa and 142 kDa were observed on SDS-polyacrylamide gel electrophoresis under reducing and nonreducing conditions. The 125I-HBGAF-cross-linked complex formation was completely abolished in the presence of greater than or equal to 100-fold excess of unlabeled HBGAF but not PDGF, EGF, aFGF, bFGF, or insulin. 125I-HBGAF appeared to undergo rapid internalization and relatively slow degradation following binding to the HBGAF receptor on NIH 3T3 cells. These results suggest that NIH 3T3 cells express a high affinity HBGAF receptor which shows two different estimated molecular masses of -155 kDa and -127 kDa. This high affinity HBGAF receptor was also found to express in other cell types.
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PMID:Characterization of heparin-binding growth-associated factor receptor on NIH 3T3 cells. 173 78

Transfected mouse myeloma cells are of increasing interest for the production of a wide variety of solubilised recombinant fusion proteins. A stably transfected J558L mouse myeloma subclone (J558L-CD4) secreting human CD4-immunoglobulin type G1 receptor (CD4-H gamma 1) was employed as a model system for cell suspension culture and expression of chimaeric molecules. Cells were grown up to 3-5 x 10(6) cells/ml in serum-free and protein-reduced DHI medium consisting of a mixture of DMEM, HamF12 and IMDM media supplemented with transferrin, insulin, Primatone RL and Pluronic F68. Primatone RL was the essential growth-promoting factor in protein-free medium. The soluble CD4-H gamma 1 receptor, the production of which was not growth-associated, accumulated in the medium to concentrations of 40 micrograms/ml with a specific formation rate of 0.18 micrograms/10(6) cells/h in conventional cultures. The cell density was further increased by growing the cells in dialysis tubing or by using a perfusion system with cell retention. Because of the continuous exchange of nutrients and metabolic end-products average concentrations of 35 x 10(6) cells/ml were achieved. CD4-H gamma 1 accumulated in the dialysis tubing up to 1.3 mg/ml. After an initial rapid growth period, a ten-fold reduction in specific nutrient consumption rates and metabolic end-product formation was observed. Chimaeric proteins purified by protein G chromatography from conventional and perfusion cultures were indistinguishable when compared by SDS-PAGE, limited proteolysis and isoelectric focusing analysis (isoelectric point: 8.5-8.6).
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PMID:Propagation of a mouse myeloma cell line J558L producing human CD4 immunoglobulin G1. 173 75

The growth promoting effect of several hormones and growth factors on two human colon tumor cell lines (Caco-2 and SW 48) was studied using six different chemically defined serum-free media (SFM). Caco-2 grew in a simple SFM [GF3: Chee's Essential Medium (CEM) plus insulin, transferrin and selenium], whereas, SW 48 cells did not grow in GF3 medium. This suggested that Caco-2 cells probably secrete proteins in SFM which influence attachment and growth of Caco-2 and other tumor cells. Lyophilized Caco-2 conditioned medium and substratum, when added to plain CEM, supported growth of SW 48 and SW 948 cells. The substratum material was more effective than conditioned medium in promoting growth of the cell lines. The substratum material helps attachment and spreading of the cells and, thus, improves growth of the cells over conditioned medium. Caco-2 conditioned medium and substratum were analyzed for their components using SDS-PAGE system and gel filtration chromatography. The substratum was analyzed for the presence of fibronectin and laminin by the ELISA technique. The conditioned medium does not contain TGF alpha and TGF beta. The growth stimulating activity of the conditioned medium is due to a protein component, approximately 58Kd in size.
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PMID:Proteins secreted by Caco-2 cells support growth of other tumor cells in Chee's Essential Medium without supplements. 176 10


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