Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A rapid and continuous proteolysis of tryptophan hydroxylase was demonstrated with two mast cell lines derived from rat basophilic leukemia cells (RBL2H3) and mouse mastocytoma (FMA3). Under conditions in which protein biosynthesis was arrested by administration of cycloheximide, the decay profile of tryptophan hydroxylase protein was traced by Western blot analysis. Incorporation of [35S]methionine and the chase experiment performed without interfering with the metabolic stage also showed that tryptophan hydroxylase had been cleaved rapidly. The half life of the enzyme was 11-15 min in RBL2H3 cells and 40-60 min in FMA3 cells, and the process was demonstrated to be dependent on intracellular ATP.
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PMID:Rapid turnover of tryptophan hydroxylase in serotonin producing cells: demonstration of ATP-dependent proteolytic degradation. 761 72

The mi locus of mice encodes a transcription factor of the basic-helix-loop-helix-leucine zipper protein family (MITF). The MITF encoded by the mutant mi allele (mi-MITF) deletes 1 of 4 consecutive arginines in the basic domain. The mice of mi/mi genotype express mi-MITF, whereas the mice of tg/tg genotype have a transgene at the 5' flanking region of the mi gene and do not express any MITF. To investigate the function of mi-MITF in cultured mast cells (CMCs), we took two approaches. First, mRNA obtained from mi/mi CMCs or tg/tg CMCs was subtracted from complementary (c) DNA library of normal (+/+) CMCs, and the (+/+-mi/mi) and (+/+-tg/tg) subtraction libraries were obtained. When the number of clones that hybridized more efficiently with +/+ CMC cDNA probe than with mi/mi or tg/tg CMC cDNA probe was compared using Southern analysis, the number was larger in the (+/+-mi/mi) library than in the (+/+-tg/tg) library. Second, we compared mRNA expression of six genes between mi/mi and tg/tg CMCs by Northern analysis. The transcription of three genes encoding mouse mast cell proteases was impaired in both mi/mi and tg/tg CMCs. On the other hand, the transcription of three genes encoding c-kit receptor, tryptophan hydroxylase, and granzyme B was markedly reduced in mi/mi CMCs, but the reduction was significantly smaller in tg/tg CMCs. These results indicated the inhibitory effect of mi-MITF on the transactivation of particular genes in CMCs.
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PMID:Inhibitory effect of the transcription factor encoded by the mi mutant allele in cultured mast cells of mice. 994 61

Tryptophan hydroxylase requires Fe2+ for in vitro enzyme activity. In this study, the intracellular activity of tryptophan hydroxylase was assessed by applying 3-hydroxybenzylhydrazine (NSD-1015), an inhibitor of aromatic l-amino acid decarboxylase, to monolayer cultures of RBL2H3 cells, a serotonin producing mast cell line. The effect of manipulating intracellular 'free' iron levels on enzyme activity was analyzed by administration of iron chelators. Desferrioxamine (DFO) suppressed the intracellular enzyme activity. Salicylaldehyde isonicotinoyl hydrazone (SIH) also suppressed enzyme activity, but stimulated it when administered in the Fe-bound form. Hemin also stimulated enzyme activity, which progressively increased over several hours to more than sixfold the initial level. DFO and SIH inhibited the hemin stimulatory effect when administered simultaneously with hemin. Both suppression and stimulation with these chelators took place without a significant decrease or increase in the amount of enzyme. These results indicate that there was an inadequate supply of Fe2+ in the cells to support full activity of tryptophan hydroxylase.
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PMID:Iron dependence of tryptophan hydroxylase activity in RBL2H3 cells and its manipulation by chelators. 1021 90

The mi locus encodes a member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors (hereafter called MITF). Mutant alleles of mi, Mior, and Miwh are deletion or point mutation of the basic domain by which MITF binds DNA. The basic domain also has nuclear localization potential. In the present study, we compared the mast cell abnormalities of Mior/Mior and Miwh/Miwh mice with those of mi/mi mice, of which many have been described by us. The number of mast cells in the skin of Mior/Mior suckling mice was remarkably decreased from that observed in mi/mi suckling mice, but the number was normal in the skin of Miwh/Miwh suckling mice. The decrease in skin mast cells was more severe in the mi/mi embryos than in mi/mi suckling mice, but the magnitude of the decrease was comparable between Mior/Mior embryos and Mior/Mior suckling mice. The poor mRNA expression of granzyme B and tryptophan hydroxylase genes was observed in all cultured mast cells (CMCs) derived from the spleens of Miwh/Miwh, Mior/Mior, and mi/mi mice. However, the poor expression of mouse mast cell protease-4 (MMCP-4), MMCP-5, and MMCP-6 was observed only in Mior/Mior and mi/mi CMCs. MITF encoded by Miwh mutant allele (Miwh-MITF) showed deficient but demonstratable DNA binding, but mi-MITF and Mior-MITF did not show any DNA binding ability. Although Miwh-MITF and Mior-MITF showed normal nuclear localization potential, the potential was significantly impaired in mi-MITF. The rank order of mast cell abnormality (mi/mi > Mior/Mior > Miwh/Miwh) appears to be related to the functional abnormality of MITF encoded by each mutant gene.
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PMID:Different effect of various mutant MITF encoded by mi, Mior, or Miwh allele on phenotype of murine mast cells. 1036 Nov 15

MITF is a basic helix-loop-helix leucine zipper-type transcription factor and is important for development of mast cells. MITF encoded by Mi(wh) allele (Mi(wh)-MITF) was mutated at a single amino acid of basic domain, and possessed a deficient but apparent DNA-binding ability. Here, we characterized the unique effects of Mi(wh)-MITF on the expression of mast cell-related genes. The expression level of mouse mast cell protease (mMCP)-4, -5, and -6 genes in Mi(wh)/Mi(wh) cultured mast cells (CMCs) was intermediate between levels of normal (+/+) CMCs and tg/tg CMCs, which did not express any MITFs. Mi(wh)-MITF appeared to show the positive transactivation effect through the remaining DNA-binding ability. On the other hand, the expression level of tryptophan hydroxylase gene was lower in Mi(wh)/Mi(wh) CMCs than in tg/tg CMCs, suggesting the inhibitory effect of Mi(wh)-MITF on the transactivation. Mi(wh)-MITF possessed dual abnormal effects on transactivation of mast cell-related genes.
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PMID:Dual abnormal effects of mutant MITF encoded by Mi(wh) allele on mouse mast cells: decreased but recognizable transactivation and inhibition of transactivation. 1222 May 16

We previously demonstrated in mast cell lines RBL2H3 and FMA3 that tryptophan hydroxylase (TPH) undergoes very fast turnover driven by 26S-proteasomes [Kojima, M., Oguro, K., Sawabe, K., Iida, Y., Ikeda, R., Yamashita, A., Nakanishi, N. & Hasegawa, H. (2000) J. Biochem (Tokyo) 2000, 127, 121-127]. In the present study, we have examined an involvement of TPH phosphorylation in the rapid turnover, using non-neural TPH. The proteasome-driven degradation of TPH in living cells was accelerated by okadaic acid, a protein phosphatase inhibitor. Incorporation of 32P into a 53-kDa protein, which was judged to be TPH based on autoradiography and Western blot analysis using anti-TPH serum and purified TPH as the size marker, was observed in FMA3 cells only in the presence of both okadaic acid and MG132, inhibitors of protein phosphatase and proteasome, respectively. In a cell-free proteasome system constituted mainly of RBL2H3 cell extracts, degradation of exogenous TPH isolated from mastocytoma P-815 cells was inhibited by protein kinase inhibitors KN-62 and K252a but not by H89. Consistent with the inhibitor specificity, the same TPH was phosphorylated by exogenous Ca2+/calmodulin-dependent protein kinase II in the presence of Ca2+ and calmodulin but not by protein kinase A (catalytic subunit). TPH protein thus phosphorylated by Ca2+/calmodulin-dependent protein kinase II was digested more rapidly in the cell-free proteasome system than was the nonphosphorylated enzyme. These results indicated that the phosphorylation of TPH was a prerequisite for proteasome-driven TPH degradation.
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PMID:Proteasome-driven turnover of tryptophan hydroxylase is triggered by phosphorylation in RBL2H3 cells, a serotonin producing mast cell line. 1235 9

Using 1-ethyl-3(3-dimethyl-aminopropyl)-carbodiimide (EDAC) fixation and immunocytochemical confocal microscopic study, bright serotonin and histamine fluorescence appeared in the nucleus of rat peritoneal mast cells. In case of paraformaldehyde fixation, this was not observed. The phenomenon can be explained by the cross-linking effect of EDAC, which did not allow the efflux of biogenic amines from the nucleus. This means that biogenic amines are present in the nucleus of mast cells, and this is supported by the flow cytometric measurement data of the whole cell. Other hormones studied (triiodothyronine, insulin, and endorphin) were not present in the nucleus. Four pharmaca with biogenic amine-influencing character in the central nervous system were used for studying the relation between the external (surrounding and cytoplasmic) and nuclear biogenic amine content of mast cells. Fluoxetine, a serotonin reuptake inhibitor depleted nuclear as well as cytoplasmic serotonin content. Clorgyline, a MAO-A inhibitor, decreased cytoplasmic serotonin content and weakened nuclear serotonin fluorescence. The tryptophan hydroxylase inhibitor, para-chlorophenylalanine (PCPA), and the mast cell degranulator, Compound 48/80, reduced cytoplasmic serotonin content without influencing nuclear content. Histamine fluorescence was influenced solely by fluoxetine. The results show that nuclear 5-HT content is dependent firstly of serotonin uptake and reuptake. To our knowledge, this is the first exact report on the presence of non-steroid-type-receptor-transported hormones inside the nucleus of a cell.
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PMID:Hormones in the nucleus. Immunologically demonstrable biogenic amines (serotonin, histamine) in the nucleus of rat peritoneal mast cells. 1633 78

Antizymes and antizyme inhibitors are key regulatory proteins of polyamine levels by affecting ornithine decarboxylase and polyamine uptake. Our previous studies indicated a metabolic interplay among polyamines, histamine and serotonin in mast cells, and demonstrated that polyamines are present in mast cell secretory granules, being important for histamine storage and serotonin levels. Recently, the novel antizyme inhibitor-2 (AZIN2) was proposed as a local regulator of polyamine biosynthesis in association with mast cell serotonin-containing granules. To gain insight into the role of AZIN2 in the biosynthesis and storage of serotonin and histamine, we have generated bone marrow derived mast cells (BMMCs) from both wild-type and transgenic Azin2 hypomorphic mice, and have analyzed polyamines, serotonin and histamine contents, and some elements of their metabolisms. Azin2 hypomorphic BMMCs did not show major mast cell phenotypic alterations as judged by morphology and specific mast cell proteases. However, compared to wild-type controls, these cells showed reduced spermidine and spermine levels, and diminished growth rate. Serotonin levels were also reduced, whereas histamine levels tended to increase. Accordingly, tryptophan hydroxylase-1 (TPH1; the key enzyme for serotonin biosynthesis) mRNA expression and protein levels were reduced, whereas histidine decarboxylase (the enzyme responsible for histamine biosynthesis) enzymatic activity was increased. Furthermore, microphtalmia-associated transcription factor, an element involved in the regulation of Tph1 expression, was reduced. Taken together, our results show, for the first time, an element of polyamine metabolism -AZIN2-, so far described as exclusively devoted to the control of polyamine concentrations, involved in regulating the biosynthesis and content of other amines like serotonin and histamine.
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PMID:A novel role for antizyme inhibitor 2 as a regulator of serotonin and histamine biosynthesis and content in mouse mast cells. 2708 13