Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We demonstrate that endogenous phosphatases are active in cytosolic and nuclear androgen receptor fractions from the rat ventral prostate. Under our androgen binding assay conditions, the effect of acid phosphatase inhibitors (sodium fluoride, tartaric acid, sodium orthovanadate) on the endogenous phosphatases could be correlated with an increase in dihydrotestosterone (DHT) binding to fractions of partially purified cytosolic androgen receptor. In contrast, tetramisole, an alkaline phosphatase inhibitor, did not alter the binding of DHT to the same receptor fraction. Immunoprecipitation of androgen receptor fractions with polyclonal anti-phosphotyrosine antibody resulted in the recovery of [3H]-DHT binding activity from nuclear receptor fractions and partially purified cytosolic receptor fractions prepared from 20- to 24-hr castrated rats. In control fractions depleted of androgen receptor, negligible levels of binding activity were recovered following immunoprecipitation with the antibody. Therefore, acid phosphatases may be acting on phosphotyrosyl residues of the androgen receptor, thus playing a role in the dephosphorylation and inactivation of the androgen receptor.
...
PMID:Phosphorylation status of nuclear and cytosolic androgen receptors in the rat ventral prostate. 246 75

Extraction of rat kidney cytosol with 10% charcoal at 4 C inactivated specific T3 binding. The decreased T3 binding in extracted cytosol could be restored by addition of boiled kidney cytosol. Three different factors (a, b, and c) which could increase T3 binding were identified by Sephadex G-50 column chromatography of boiled cytosol. Two factors (b and c) were eluted as relatively small molecules. Factor a was present in small amounts. Factor c was neutralized by incubation with EDTA, but factor b was not. Factor b was not destroyed by trypsin, protease, DNase, or RNase, but was destroyed by alkaline phosphatase. Factor b was destroyed by incubation with nicotinamide adenine dinucleotide phosphate (NADPH)-dependent glutathione reductase in the presence of oxidized glutathione. Although T3 binding to charcoal-extracted cytosol protein was not influenced by reduced glutathione or dithiothreitol, it was markedly increased by NADPH. Maximal activation induced by 50 microM NADPH was not further increased by further addition of endogenous factor b. The elution position of NADPH in gel chromatography corresponded to the elution position of factor b. Factor b or NADPH increased maximal binding capacity without changes in affinity constant. These observations suggest that T3-binding protein in cytosol is present in inactive and active forms and that the active form is generated by NADPH, which is present as one of the activators in cytosol. The effect of these cytosolic T3-binding proteins on nuclear T3 binding in vitro was also studied. In the absence of cytosolic T3-binding protein, [125I]T3 binding to nuclear receptor was decreased by unlabeled T3 in a concentration-dependent manner. In the presence of inactive form of cytosolic T3-binding protein, nuclear [125I]T3 binding was slightly diminished. In the presence of NADPH and cytosolic T3-binding protein, however, the amount of [125I]T3 bound to nuclei markedly decreased, which was associated with an increase of cytosolic [125I]T3 binding. NADPH alone did not influence nuclear T3 binding. These results suggest that T3 binding to nuclear receptor is regulated by an active form of cytosolic T3-binding protein in vitro.
...
PMID:Active and inactive forms of 3,5,3'-triiodo-L-thyronine (T3)-binding protein in rat kidney cytosol: possible role of nicotinamide adenine dinucleotide phosphate in activation of T3 binding. 301 55

To investigate the increased alkaline phosphatase activity of bone origin in patients with hyperthyroidism, we studied the thyroid hormone effects on alkaline phosphatase activity in a clonal rat osteoblastic cell line (ROS 17/2.8). T4 and T3 increased alkaline phosphatase activity in ROS 17/2.8 cells in a dose-dependent manner. The minimal effective T4 and T3 concentrations in medium containing 10% thyroid hormone-depleted fetal calf serum were 10(-8) M (free T4, 8 X 10(-11) M) and 10(-9) M (free T3, 4 X 10(-11) M), respectively. ROS 17/2.8 cells possessed high affinity, low capacity nuclear receptors specific for T3 [dissociation constant (Kd) approximately 150 pM; maximal binding capacity, approximately 2000 T3 binding sites per nucleus]. The relative affinity of T3, T4, rT3, MIT, and DIT were in good agreement with their biological activity. These findings suggest that rat osteoblast-like cells contain T3 nuclear receptors and that alkaline phosphatase activity is stimulated by thyroid hormone via a nuclear receptor-mediated process at free thyroid hormone concentrations attainable in patients with Graves' disease.
...
PMID:Thyroid hormone stimulates alkaline phosphatase activity in cultured rat osteoblastic cells (ROS 17/2.8) through 3,5,3'-triiodo-L-thyronine nuclear receptors. 356 18

5'-Deoxypyridoxal, a vitamin B-6 analogue, increased the rate of dissociation of [3H]dexamethasone from HeLa S3 cytoplasmic glucocorticoid receptor complexes in vitro. This effect was achieved at millimolar concentrations of 5'-deoxypyridoxal, suggesting a low-affinity interaction of 5'-deoxypyridoxal with receptor. Loss of [3H]dexamethasone-receptor binding in the presence of 5'-deoxypyridoxal was pH dependent, and a plot of Kdiss vs. pH fit a simple sigmoidal titration curve with an inflection point at pH 7.8, suggesting that deprotonation of a single functional group on 5'-deoxypyridoxal increases Kdiss. Loss of [3H]dexamethasone binding in the presence or absence of unlabeled steroid also increased with pH, but no inflection point occurred over the range of pH tested. A titration of 5'-deoxypyridoxal indicated a pK of 7.94 for the pyridinium proton, suggesting deprotonation of the pyridinium nitrogen may account for the pH dependence of Kdiss of dexamethasone from receptor. 5'-Deoxypyridoxal also caused a decrease in nuclear [3H]-dexamethasone-receptor binding when incubated with whole HeLa S3 cells at 37 degrees C. Furthermore, 5'-deoxypyridoxal was effective in reducing nuclear binding of dexamethasone when added either simultaneously with [3H]dexamethasone or after achievement of equilibrium of steroid with receptor. The reduction in nuclear [3H]dexamethasone binding is highly specific for 5'-deoxypyridoxal. Several analogues of this compound, including 5'-deoxypyridoxamine, were ineffective. In addition, this effect was reversible following removal of extracellular 5'-deoxypyridoxal. Under these conditions, 5'-deoxypyridoxal was competitive with dexamethasone for binding to nuclear receptor, with KI = 8.1 X 10(-6) M. Scatchard plot analysis of dexamethasone-receptor binding in the presence or absence of 5'-deoxypyridoxal was consistent with an apparent reduced affinity of [3H]dexamethasone for receptor, which again suggests competitive interaction or allosteric interaction mediated dissociation. Glucocorticoids are known to stimulate alkaline phosphatase activity within HeLa S3 cells. In whole cell incubations, 5'-deoxypyridoxal was effective in reducing the dexamethasone-induced increase in alkaline phosphatase activity by 60% under conditions in which cell viability and cell growth were not affected.
...
PMID:5'-deoxypyridoxal interaction with dexamethasone receptor: a new probe for structure and function of steroid receptors. 717 76

To understand the molecular basis of the phosphorylation-enhanced transcriptional activity of human thyroid hormone nuclear receptor subtype beta 1 (hTR beta 1), we studied the effect of phosphorylation on the interaction of hTR beta 1 with the retinoid X receptor beta (RXR beta), we studied the effect of phosphorylation on the interaction of hTR beta 1 with the retinoid X receptor beta (RXR beta). In vitro, the extent of hTR beta 1.RXR beta heterodimer bound to various thyroid hormone response elements (TREs) was compared before and after phosphorylation of hTR beta 1. Without phosphorylation, hTR beta 1.RXR beta heterodimer was barely detectable under the experimental conditions. After phosphorylation of hTR beta 1, heterodimer bound to (i) the chicken lysozyme gene TRE, (ii) a TRE consisting of direct repeats of half-site binding motifs separated by four gaps, and (iii) a palindromic TRE was enhanced by approximately 10-, 7-, and 6-fold, respectively. The effect of phosphorylation on hTR beta 1.RXR beta heterodimerization was reversible. Dephosphorylation of the phosphorylated hTR beta 1 by alkaline phosphatase led to loss of the ability of hTR beta 1 to form a heterodimer with RXR beta in either the absence or the presence of DNA. These results indicate that the heterodimerization is enhanced by phosphorylation. To evaluate the effect of phosphorylation on the interaction of hTR beta 1 with RXR beta in vivo, we cotransfected hTR beta 1, RXR beta and TRE-chloramphenicol acetyltransferase (CAT) expression plasmids into CV-1 cells. CAT activity was assessed in the presence or absence of okadaic acid. Okadaic acid is a potent inhibitor of phosphatases 1 and 2A and increases the in vivo phosphorylation of hTR beta 1 by approximately 10-fold. Using the CAT reporter gene under control of the TRE from the malic enzyme gene, we found that RXR beta increased the okadaic acid-enhanced hTR beta 1-mediated CAT activity by 2- to 3-fold in the presence of 3,3',5-triiodo-L-thyronine. However, 9-cis-retinoic acid did not enhance the effect of okadaic acid. Our results indicate that phosphorylation is essential for the interaction of hTR beta 1 with RXR beta. Thus, phosphorylation plays a pivotal role in the gene-regulating activity of hTR beta 1.
...
PMID:Phosphorylation enhances the target gene sequence-dependent dimerization of thyroid hormone receptor with retinoid X receptor. 805 36

Hepatocyte growth factor (HGF) secreted from human promyelocytic leukemia cell line, HL-60, is indistinguishable from HGF in human plasma and its release is significantly stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA), a differentiation-inducer of HL-60 cells into monocytes/macrophages (Nishino T et al: Biochem Biophys Res Commun 181:323, 1991). TPA stimulated HGF release from the cells through an activation of C-kinase, but not through a formation of reactive oxygen species. Furthermore, dibutyryl cAMP (dbcAMP), an activator of A-kinase and granulocyte-inducer, also stimulated HGF release. 1,25-Dihydroxyvitamin D3, another monocyte/macrophage-inducer, abated either TPA- or dbcAMP-stimulated synthesis and release of HGF in a dose-dependent manner probably via its nuclear receptor as reflected by vitamin D analog study. The effects of these three reagents on the steady-state levels of HGF mRNA of 6.0 kb corresponded with their effects on its protein levels. Furthermore, a close correlation between intracellular and extracellular HGF levels strongly suggested that these reagents affected HGF release mainly on its synthesis step. Recombinant human HGF significantly stimulated the proliferation and alkaline phosphatase activity of mouse osteoblastic cell line, MC3T3-E1. In summary, HL-60 cells secrete HGF, whose synthesis is specifically regulated by various reagents independent of their differentiation-inducing effects. Because HGF shows a direct effect on osteoblast-like cells, it might be involved in the interaction of bone marrow cells with bone cells.
...
PMID:Regulation of release of hepatocyte growth factor from human promyelocytic leukemia cells, HL-60, by 1,25-dihydroxyvitamin D3, 12-O-tetradecanoylphorbol 13-acetate, and dibutyryl cyclic adenosine monophosphate. 839 78

A ubiquitously expressed nuclear receptor-associating protein of approximately 46 kDa (RAP46) was identified recently. Interaction experiments with in vitro-translated proteins and proteins contained in cell extracts revealed that a great variety of cellular regulators associate with RAP46. However, in direct interaction tests by the far-Western technique, only 70 kDa proteins showed up and were identified as members of the 70 kDa heat shock protein (hsp70) family. Interaction is specific since not all members of the hsp70 family bind to RAP46; interaction occurs through their ATP-binding domain. RAP46 forms complexes with hsp70 in mammalian cells and interacts with hsp70 in the yeast two-hybrid system. Consistent with the fact that hsp70 can bind a multitude of proteins, we identified heteromeric complexes of RAP46-hsp70 with some selected proteins, most notably c-Jun. Complex formation is increased significantly by pre-treatment with alkaline phosphatase, thus suggesting modulation of interactions by protein phosphorylation. We observed that RAP46 interferes with efficient refolding of thermally denatured luciferase. Moreover, ATP-dependent binding of misfolded proteins to hsp70 was greatly inhibited by RAP46. These data suggest that RAP46 functions as a regulator of hsp70 in higher eukaryotes.
...
PMID:Mammalian protein RAP46: an interaction partner and modulator of 70 kDa heat shock proteins. 931 7

A population of estrogen receptor-alpha (ER alpha) proteins, located at the plasma membrane, is postulated to mediate the rapid, nongenomic responses of GH3/B6/F10 pituitary cells to estrogen. To demonstrate the presence of ER alpha at the plasma membrane and to distinguish this receptor population from that in the nucleus, GH3/B6/F10 cells were first prepared in 2% paraformaldehyde/0.1% glutaraldehyde in PBS (P/G) without detergent, then exposed to one of several antibodies (Abs) raised against nuclear ER alpha. Ab binding was visualized as a fluorescent/chromagenic reaction product catalyzed by avidin-biotin-complexed alkaline phosphatase. With P/G fixation, Abs could only access antigens at the cell surface, as evidenced by the inability of 70K mol wt dextrans to permeate cells and the absence of intracellular staining by Abs to cytoplasmic or nuclear antigens. ER alpha Abs generated membrane, but not nuclear, staining in P/G-fixed cells; nuclear receptor labeling could only be detected in detergent-treated cells. Specificity of staining for ER alpha was confirmed by three approaches: first, treatment with an antisense oligodeoxynucleotide to nuclear ER alpha mRNA reduced immunolabeling of both membrane and nuclear ER alpha; second, labeling by two Abs raised against different ER alpha oligopeptides was neutralized by competing peptide; third, six Abs (ER21, H226, R4, H222, MC20, and C542) that recognize unique epitopes on rodent ER alpha produced immunolabeling, but neither primate-specific ER alpha Ab nor Ab to ER beta caused staining. In addition to demonstrating the plasma membrane ER alpha in GH3/B6/F10 cells, this method should be applicable to other cell types that exhibit nongenomic responses to estrogen or other steroid hormones.
...
PMID:Estrogen receptor-alpha detected on the plasma membrane of aldehyde-fixed GH3/B6/F10 rat pituitary tumor cells by enzyme-linked immunocytochemistry. 1043 42

Several lines of evidence suggest that vitamin K has nutritional and pharmacological effects against bone loss. To clarify effects of vitamin K on bone marrow cells, which contains progenitors of both osteoblasts and osteoclasts, we examined mouse bone marrow cell cultures in the presence of vitamin K(1) (K1) and menatetrenone (MK4), a vitamin K(2) with four isoprene units. Treatment with MK4 but not K1 inhibited the formation of adipocytes and stimulated alkaline phosphatase activity, an early differentiation marker of osteoblast. Although nuclear receptor PPARgamma2 plays a pivotal role in adipogenesis, MK4 had no effects on the expression of PPARgamma2 mRNA and PPARgamma2-dependent transcriptional activity. MK4 inhibited the expression of osteoclast differentiation factor (ODF)/RANK ligand and the formation of osteoclast-like cells induced by 1,25-dihydroxyvitamin D(3). These results suggest that MK4 specifically influences differentiation and functions of bone marrow cells to inhibit adipogenesis and osteoclastogenesis. At the expense of adipogenesis, MK4 might stimulate osteoblastogenesis in bone marrow cells. Therefore, MK4 may favor bone metabolism to spare bone mass as a compound that modulates cellular differentiation and functions in bone marrow in addition to as a nutrient factor.
...
PMID:Vitamin K(2) inhibits adipogenesis, osteoclastogenesis, and ODF/RANK ligand expression in murine bone marrow cell cultures. 1111 87

1alpha,25-(OH)(2)D(3) mediates its effects on growth zone chondrocytes via rapid membrane-associated events as well as through traditional nuclear receptor mechanisms. The membrane-associated signaling pathways include rapid production of diacylglycerol and activation of protein kinase C (PKC), as well as activation of phospholipase A(2) (PLA(2)), increased production of arachidonic acid, and increased production of prostaglandins. This study examined the roles of PLA(2) and cyclooxygenase (Cox) in the mechanism of action of 1alpha,25-(OH)(2)D(3) in these cells to determine whether one or both enzymes catalyze the rate limiting step and whether constitutive or inducible Cox is involved. Cultures were incubated with 1alpha,25-(OH)(2)D(3) for 9 min to measure PKC or for 24 h to measure physiological responses ([(3)H]-thymidine incorporation, alkaline phosphatase specific activity, [(35)S]-sulfate incorporation). Based on RT-PCR and Northern blot analysis, growth zone chondrocytes expressed mRNAs for both Cox-1 and Cox-2 and neither Cox was modulated by 1alpha,25-(OH)(2)D(3). To examine the role of Cox, the cultures were also treated with resveratrol (a specific inhibitor of Cox-1), NS-398 (a specific inhibitor of Cox-2), or indomethacin (a general Cox inhibitor). The results showed that Cox-1 inhibition reduced the 1alpha,25-(OH)(2)D(3)-dependent effects on proliferation, differentiation, and matrix production, whereas inhibition of Cox-2 only had an effect on proliferation. The effects of Cox inhibition were not rate limiting, based on experiments in which PLA(2) was activated with melittin or inhibited with quinacrine. However, at least part of the action of 1alpha,25-(OH)(2)D(3) was regulated by metabolism of arachidonic acid to prostaglandins. This supports the hypothesis that 1alpha,25-(OH)(2)D(3) exerts its effects via more than one signaling pathway and that these pathways are interrelated via the modulation of PLA(2) as a rate-limiting step. PKC regulation may occur at multiple stages in the signal transduction cascade. J. Cell. Biochem. Suppl. 36: 32-45, 2001.
...
PMID:Effects of 1alpha,25-(OH)(2)D(3) on rat growth zone chondrocytes are mediated via cyclooxygenase-1 and phospholipase A(2). 1145 68


1 2 3 4 Next >>

---