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)

MCF-7 (estrogen receptor positive--ER+) and MDA-MB-231 (estrogen receptor negative--ER-) are human breast cancer cell lines which express functional thyroid hormone receptors (c-erb A alpha1 and c-erb beta1) as indicated by stimulation of mitochondrial alpha-glycerophosphate dehydrogenase. In MCF-7, mimicking E2, T3 stimulated growth in a dose-dependent (10(10) M - 10(-8) M) manner, induced the expression of progesterone receptor and growth factor TGFalpha mRNAs and inhibited that of TGFbeta mRNA; T3 also increased progesterone binding and LDH5 isozyme activities. None of these effects were observed in (ER-) MDA-MB-231 cells. 10(-6) M tamoxifen (TAM) reverted growth stimulation, suppressed progesterone receptor and TGFalpha mRNA induction and restored TGFbeta mRNA to control levels in T3-treated MCF-7 cells. That T3 is acting in MCF-7 cells via its binding to ER is suggested by the immunoprecipitation of pre-bound 125I-T3 from MCF-7 nuclear extracts by an ER-specific monoclonal antibody and by the displacement of 3H-estradiol binding to ER by radioinert T3.
J Steroid Biochem Mol Biol 1996 Nov
PMID:Triiodothyronine mimics the effects of estrogen in breast cancer cell lines. 901 Mar 19

Molecular mechanisms of lipid synthesis and their controls in hepatic stellate cells are not known. We have previously proposed that, in contrast to other fat storing cells, hepatic stellate cells are not involved in energy storage, but they represent a particular cell population specialized in storage of lipid-soluble substances, the major one being probably retinol. In agreement with this hypothesis, induction of the lipocyte phenotype in stellate cells is not under the control of insulin, but responds to retinoids and other molecules that modify the gene expression program in these cells. In the present study we have monitored the activity of the two major enzymes involved in lipid synthesis during the induction of the lipocyte phenotype in hepatic stellate cells: glycerol-3-phosphate dehydrogenase (GPDH) that mediates the de novo lipid synthesis, and lipoprotein lipase that mediates incorporation of plasma lipids. In early stages of lipocyte induction, both pathways of lipid synthesis are activated. When lipocytes have already constituted the lipid droplets, lipoprotein lipase pathway is downregulated, while GPDH activity remains high. Adult liver has been reported to lack lipoprotein lipase, but under stress, lipase activity was detected around and at the surface of the intrahepatic vasculature. We have now shown that the lipase activity can be induced in the hepatic stellate cells, located in the Disse's space. The high lipoprotein lipase activity under acute induction of lipocyte phenotype, followed by the low activity under conditions of metabolic equilibrium, are in compass with the increased activity of this enzyme under stress, and its low activity in adult liver parenchyma under normal conditions.
Mol Cell Biochem 1997 Mar
PMID:Lipid metabolism during in vitro induction of the lipocyte phenotype in hepatic stellate cells. 906 91

Ascofuranone, a prenylphenol antibiotic isolated from a phytopathogenic fungus, Ascochyta visiae, strongly inhibited both glucose-dependent cellular respiration and glycerol-3-phosphate-dependent mitochondrial O2 consumption of long slender bloodstream forms of Trypanosoma brucei brucei. This inhibition was suggested to be due to inhibition of the mitochondrial electron-transport system, composed of glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) and plant-like alternative oxidase. Ascofuranone noncompetitively inhibited the reduced coenzyme Q1-dependent O2 uptake of the mitochondria with respect to ubiquinol (Ki = 2.38 nM). Therefore, the susceptible site is deduced to be the ubiquinone redox machinery which links the two enzyme activities. Further, ascofuranone in combination with glycerol completely blocked energy production, and potently inhibited the in vitro growth of the parasite. Our findings suggest that ascofuranone might be a promising candidate for the chemotherapeutic agents of African trypanosomiasis.
Mol Biochem Parasitol 1997 Feb
PMID:An antibiotic, ascofuranone, specifically inhibits respiration and in vitro growth of long slender bloodstream forms of Trypanosoma brucei brucei. 889 29

The alpha-glycerophosphate (alpha-GP) shuttle has been shown to play a role in reducing equivalent transfer in neonatal cardiac mitochondria. In adult heart mitochondria, alpha-GP shuttle activity is not detectable. The goals of the current study were to define the time course of the age-dependent decline in alpha-GP shuttle capacity and to identify the enzymatic step(s) of the alpha-GP shuttle which are regulated during development. Intact mitochondria were isolated from porcine hearts of various ages and assayed for alpha-GP shuttle capacity. By 5 weeks of age, alpha-GP shuttle capacity had decreased by nearly 39%. The cytosolic step of the shuttle, catalysed by cytosolic alpha-glycerophosphate dehydrogenase (c alpha-GPDH), demonstrated a significant increase between 0-2-day-old animals and adults. Partial cDNA clones of porcine c alpha-GPDH and mitochondrial alpha-glycerophosphate dehydrogenase (m alpha-GPDH) were prepared and used to quantitate expression of these genes. Using mRNA isolated from neonatal and adult porcine myocardium, expression of the c alpha-GPDH was unchanged, while expression of the m alpha-GPDH gene was present in neonatal but absent in adult myocardium. These results demonstrate a rapid postnatal decline in myocardial alpha-GP shuttle capacity which appears to be regulated by a decline in m alpha-GPDH gene expression.
J Mol Cell Cardiol 1997 Jun
PMID:Developmental regulation of the alpha-glycerophosphate shuttle in porcine myocardium. 922 Mar 46

Control rats and diabetic animals injected with streptozotocin during the neonatal period were either maintained on a standard diet or given access to food supplemented with dehydroepiandrosterone (DHEA, 0.2%) for 11 days before sacrifice. In both control and diabetic rats, DHEA feeding augmented the activity of the mitochondrial FAD-linked glycerophosphate dehydrogenase and cytosolic NADP-linked malate dehydrogenase in liver, but not so in either the parotid gland or pancreatic islets. DHEA lowered, in both control and diabetic rats, the ratio between D-glucose oxidation and utilization and the rate of insulin release in pancreatic islets exposed to a high concentration of D-glucose, as well as the insulin concentration and insulin/glucose ratio in plasma. These findings support the view that, in diabetes, DHEA, by increasing sensitivity to insulin, may allow islet B-cells to avoid the otherwise unfavorable consequences of chronic hyperactivity.
Biochem Mol Med 1997 Jun
PMID:Effects of dehydroepiandrosterone in rats injected with streptozotocin during the neonatal period. 923

Successful zygote formation during yeast mating requires cell fusion of the two haploid mating partners. To ensure that cells do not lyse as they remodel their cell wall, the fusion event is both temporally and spatially regulated: the cell wall is degraded only after cell-cell contact and only in the region of cell-cell contact. To understand how cell fusion is regulated, we identified mutants defective in cell fusion based upon their defect in mating to a fus1 fus2 strain (Chenevert, J., N. Valtz, and I. Herskowitz. 1994. Genetics 136:1287-1297). Two of these cell fusion mutants are defective in the FPS1 gene, which codes for a glycerol facilitator (Luyten, K., J. Albertyn, W.F. Skibbe, B.A. Prior, J. Ramos, J.M. Thevelein, and S. Hohmann. 1995. EMBO [Eur. Mol. Biol. Organ.] J. 14:1360-1371). To determine whether inability to maintain osmotic balance accounts for the defect in cell fusion in these mutants, we analyzed the behavior of an fps1Delta mutant with reduced intracellular glycerol levels because of a defect in the glycerol-3-phosphate dehydrogenase (GPD1) gene (Albertyn, J., S. Hohmann, J.M. Thevelein, and B.A. Prior. 1994. Mol. Cell. Biol. 14:4135-4144): deletion of GPD1 partially suppressed the cell fusion defect of fps1 mutants. In contrast, overexpression of GPD1 exacerbated the defect. The fusion defect could also be partially suppressed by 1 M sorbitol. These observations indicate that the fusion defect of fps1 mutants results from inability to regulate osmotic balance and provide evidence that the osmotic state of the cell can regulate fusion. We have also observed that mutants expressing hyperactive protein kinase C exhibit a cell fusion defect similar to that of fps1 mutants. We propose that Pkc1p regulates cell fusion in response to osmotic disequilibrium. Unlike fps1 mutants, fus1 and fus2 mutants are not influenced by expression of GPD1 or by 1 M sorbitol. Their fusion defect is thus unlikely to result from altered osmotic balance.
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PMID:Osmotic balance regulates cell fusion during mating in Saccharomyces cerevisiae. 928 76

Structural relationships between the myofibrillar contractile apparatus and the enzymes that generate ATP for muscle contraction are not well understood. We explored whether glycolytic enzymes are localized in Drosophila flight muscle and whether localization is required for function. We find that glycerol-3-phosphate dehydrogenase (GPDH) is localized at Z-discs and M-lines. The glycolytic enzymes aldolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) are also localized along the sarcomere with a periodic pattern that is indistinguishable from that of GPDH localization. Furthermore, localization of aldolase and GAPDH requires simultaneous localization of GPDH, because aldolase and GAPDH are not localized along the sarcomere in muscles of strains that carry Gpdh null alleles. In an attempt to understand the process of glycolytic enzyme colocalization, we have explored in more detail the mechanism of GPDH localization. In flight muscle, there is only one GPDH isoform, GPDH-1, which is distinguished from isoforms found in other tissues by having three C-terminal amino acids: glutamine, asparagine, and leucine. Transgenic flies that can produce only GPDH-1 display enzyme colocalization similar to wild-type flies. However, transgenic flies that synthesize only GPDH-3, lacking the C-terminal tripeptide, do not show the periodic banding pattern of localization at Z-discs and M-lines for GPDH. In addition, neither GAPDH nor aldolase colocalize at Z-discs and M-lines in the sarcomeres of muscles from GPDH-3 transgenic flies. Failure of the glycolytic enzymes to colocalize in the sarcomere results in the inability to fly, even though the full complement of active glycolytic enzymes is present in flight muscles. Therefore, the presence of active enzymes in the cell is not sufficient for muscle function; colocalization of the enzymes is required. These results indicate that the mechanisms by which ATP is supplied to the myosin ATPase, for muscle contraction, requires a highly organized cellular system.
Mol Biol Cell 1997 Sep
PMID:Flight muscle function in Drosophila requires colocalization of glycolytic enzymes. 930 64

SecB maintains the structures of a subset of precursor proteins competent for translocation across the Escherichia coli cytoplasmic membrane. SecG, a membrane component of the translocation machinery, stimulates protein translocation by undergoing the cycle of membrane topology inversion. Null mutants of secB and secG are unable to form isolated colonies on rich medium and at low temperature respectively. A 3.2 kb DNA fragment carrying the secB-gpsA region on a multicopy plasmid was found to suppress the null mutation of either gene. However, subcloning of the DNA fragment revealed that secB is not involved in the suppression of either mutation. Instead, gpsA located downstream from the secB gene was found to be responsible for the suppression of both mutations. The activity of the gpsA-encoded sn-glycerol-3-phosphate dehydrogenase, which is involved in phospholipid synthesis, was significantly lower in the secB null mutant than in the wild type, presumably because of a polar effect. Suppression of the secB null mutation required the wild-type level of GpsA activity. In contrast, overexpression of the enzyme was essential for suppression of the secG null mutation. Moreover, the gpsA-dependent suppression of the secG null mutation occurred only on rich medium, i.e. not on minimal medium. These results indicate that the SecB function is dispensable even in rich medium, and further demonstrate that overexpression of enzymes involved in phospholipid synthesis partly compensates for the SecG function.
Mol Microbiol 1997 Dec
PMID:Expression of gpsA encoding biosynthetic sn-glycerol 3-phosphate dehydrogenase suppresses both the LB- phenotype of a secB null mutant and the cold-sensitive phenotype of a secG null mutant. 942 38

The mitochondrial enzyme FAD-linked glycerophosphate dehydrogenase (mGDH) plays a key role in the recognition of glucose as a stimulus for insulin release from the pancreatic islet B-cell. In the present study, an ELISA procedure was used for the measurement of mGDH antibodies in both insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetic patients. Positive readings, exceeding the upper limit of the normal range, were recorded in 7 out of 12 IDDM patients, as distinct (P < 0.01) from 2 out of 12 nondiabetic subjects of comparable age. The study conducted in 41 NIDDM patients and 15 control subjects of similar age indicated that the incidence of mGDH-positive cases was not significantly different in the diabetic (4/41) and control (1/15) groups, the measurement of optical density in the positive cases barely exceeding the upper limit of the normal range. These findings indicate that the mitochondrial enzyme mGDH often acts as an antigenic determinant in IDDM, but not in NIDDM, patients.
Biochem Mol Med 1997 Dec
PMID:Enzyme-linked immunosorbent assay of autoantibodies against mitochondrial glycerophosphate dehydrogenase in insulin-dependent and non-insulin-dependent diabetic subjects. 944 69

11Beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD-1) catalyses the reversible metabolism of physiological glucocorticoids (cortisol, corticosterone) to inactive metabolites (cortisone, 11-dehydrocorticosterone), thus regulating glucocorticoid access to receptors. 11Beta-HSD-1 expression is regulated during development and by hormones in a tissue specific manner. The enzyme is highly expressed in liver, where it may influence glucocorticoid action on fuel metabolism, processes also important in adipose tissue. Here we show that 11beta-HSD-1 is expressed in white adipose tissue, in both the adipocyte and stromal/vascular compartments, and in the adipocyte cell lines 3T3-F442A and 3T3-L1. In these cells, 11beta-HSD-1 expression is induced upon differentiation into adipocytes and is characteristic of a 'late differentiation' gene, with maximal expression 6-8 days after confluence is reached. In intact 3T3-F442A adipocytes the enzyme direction is predominantly 11beta-reduction, activating inert glucocorticoids. The expression of 11beta-HSD-1 mRNA is altered in fully differentiated 3T3-F442A adipocytes treated with insulin, dexamethasone or a combination of the hormones, in an identical manner to glycerol-3-phosphate dehydrogenase (GPDH) mRNA (encoding a key enzyme in triglyceride synthesis and a well-characterised marker of adipocyte differentiation). The demonstration of 11beta-HSD-1 expression in adipocytes and its predominant reductase activity in intact 3T3-F442A adipocytes suggests that 11beta-HSD-1 may play an important role in potentiating glucocorticoid action in these cells. 3T3-F442A and 3T3-L1 represent useful model systems in which to examine the factors which regulate 11beta-HSD-1 gene expression and the role of 11beta-HSD-1 in modulating glucocorticoid action in adipose tissue.
J Steroid Biochem Mol Biol 1998 Mar
PMID:11Beta-hydroxysteroid dehydrogenase 1 in adipocytes: expression is differentiation-dependent and hormonally regulated. 961 26


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