Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deoxycytidine kinase (dC kinase) is the rate-limiting enzyme in the anabolism of important anticancer and retroviral nucleoside derivatives. Its activity is often decreased in resistance to these drugs. To analyze the structure, function, and control of this clinically important enzyme we isolated 15 cDNA clones for human deoxycytidine kinase from lambda gt11 thymus and Molt 4 libraries. Four clones were sequenced. The largest clone is 2.9 kilobases and codes for a 626-amino acid open reading frame. The DNA and deduced amino acid sequence of the human dC kinase clones are homologous with a previously unidentified murine cDNA clone p3.4J (EMBL:MM34j) reported to be related to granulocyte-macrophage colony-stimulating factor. Deoxycytidine kinase also has cysteine-rich regions that are homologous with thioredoxin, the beta subunit of prolyl 4-hydroxylase, phosphoinositide-specific phospholipase C, thyroid hormone-binding protein, and protein disulfide isomerase. No differences were seen in the amount and size of deoxycytidine kinase protein and mRNA between CCRF/CEM and L1210 leukemic cell lines that express and do not express enzyme activity. Genomic restriction fragments were similar between the active and inactive CCRF/CEM cell lines. These data suggest that the cells deficient in dC kinase activity have a small defect in the structural gene.
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PMID:Human deoxycytidine kinase. Sequence of cDNA clones and analysis of expression in cell lines with and without enzyme activity. 200 68

The mRNA levels for four types of inositol phospholipid-specific phospholipase C (PLC) in various tissues and cell cultures have been studied by Northern analysis using cDNA probes for PLC isozyme I, II, and III [Sue, P.-G., Ryu, S.H., Moon, K.H., Sue, H.W., and Rhee, S.G. (1988) Proc. Natl. Acad. Sci. USA 85, 5419-5423 and Cell 54, 161-169], and the recently identified isozyme IV. All four types are ubiquitously expressed in rat tissues, but the levels of the mRNAs vary among tissues and cell lines. PLC-I mRNA levels are extremely high in brain and rat C6 glioma cells with lower levels in other tissues tested. PLC-II and -III have a more widespread distribution, with relatively high levels in brain, lung, spleen, thymus, and testis in the case of PLC-II, and in skeletal muscle, spleen, and testis for PLC-III. PLC-II and -III mRNAs were also detected in all cell lines examined except human promyelocytic HL60 cells. PLC-IV mRNA levels are extraordinarily high in spleen and HL60 cells. These results indicate that rat C6 glioma cells, together with most rat tissues, contain all four PLC isozymes. Other cultured cell types examined also contain two or three PLC isozymes except for HL60 cells, which contain only PLC-IV. The concomitant expression of PLC isozymes in cultured cells suggests a diverse function for PLC isozymes in single cells.
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PMID:Tissue- and cell type-specific expression of mRNAs for four types of inositol phospholipid-specific phospholipase C. 255 17

Thy-1 molecules have been shown to become anchored to the membrane of thymocytes and of T-cells via a phosphatidylinositol link. In the present study the intensity of immunofluorescent staining of mouse thymus cells by monoclonal xenoantibodies and alloantibodies specific for the Thy-1.2 determinant was significantly reduced following exposure of the cells to phosphatidylinositol-specific phospholipase C (PI-PLC). The majority of the PI-PLC-treated thymus cells retained, however, some reactivity with Thy-1.2 antibodies. In contrast, the immunofluorescent staining of thymus cells with monoclonal autoantibodies to Thy-1 determinants (20-10-5 and C16-31) was completely abolished by PI-PLC treatment. These results suggest that whereas monoclonal autoantibodies to Thy-1 react preferentially with PI-PLC-sensitive Thy-1 molecules, monoclonal antibodies to the Thy-1.2 specificity react with all cell surface Thy-1 molecules, regardless of their sensitivity to PI-PLC treatment.
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PMID:Treatment of mouse thymus cells with phosphatidylinositol-specific phospholipase C preferentially abrogates their reactivity with autoantibodies to the Thy-1 antigen. 256 57

The formation of rosettes with MRBC is not an exclusive property of chronic lymphocytic leukemia cells and of human B-lymphocytes. Human thymus cells and the HD-MAR T-cell line were also found to be capable of forming rosettes with MRBC. The binding of MRBC by thymocytes differed from that of sheep (SRBC), rabbit (RRBC) and human (HRBC) erythrocytes by a number of parameters: monoclonal antibodies against the E-receptor inhibited the attachment of SRBC, RRBC, and HRBC, but not of MRBC to thymus cells. The presence of EDTA had the opposite effect, abrogating only the attachment of MRBC to thymus cells but not of RBC from the other sources. Exposure of thymus cells to pronase eliminated their capacity to bind SRBC, RRBC, and HRBC, but only slightly inhibited the attachment of MRBC. Treatment with Vibrio cholerae neuraminidase enhanced the formation of rosettes with SRBC, RRBC, and HRBC, but had no effect on the formation of rosettes with MRBC. Exposure of thymus cells and of the HD-MAR cells to phospholipase C enhanced the proportion of rosettes formed with MRBC, but had no effect on the binding of other RBC. Treatment with either phospholipase A2 or phospholipase D had no such effect. The binding of MRBC by Raji cells was not increased by phospholipase C treatment. The present study indicates that the binding of MRBC by human thymus cells is mediated by receptors distinct from those involved in the binding of SRBC, RRBC, and HRBC and also from those mediating the binding of MRBC to human B-cells.
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PMID:Binding of mouse red blood cells (MRBC) by human thymocytes: augmentation of rosette formation by phospholipase C treatment. 290 Feb 27

Glucocorticoid-receptor complexes in rat thymus cytosol were characterized by gel-filtration chromatography on Agarose A-1.5 m and Sephacryl S-300. Two forms of non-transformed complex were identified at low ionic strength in the presence of molybdate, with Stokes radii of approx 8 nm and 6 nm. The 8 nm molybdate-stabilized form could be converted to the 6 nm form by chromatography on Sephacryl S-300 or Lipidex 1000 or by incubation with dextran-charcoal or phospholipase C, but not by chromatography on Sephadex G-25; none of the treatments promoted receptor transformation. It is suggested that the change in Stokes radius from 8 to 6 nm results from the removal of a lipid factor responsible for maintaining the complex in the 8 nm form.
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PMID:Identification of two forms of molybdate-stabilized, non-transformed glucocorticoid hormone-receptor complex by gel filtration chromatography. 358 62

[Arg8]vasopressin (AVP) stimulates adrenocorticotropic hormone release from the anterior pituitary by acting on the V1b AVP receptor. This receptor can be distinguished from the vascular/hepatic V1a and renal V2 AVP receptors by its differential binding affinities for structural analogous of AVP. Recent studies have shown that the cloned V1a and V2 receptors are structurally related. We have isolated a clone encoding the V1b receptor from a rat pituitary cDNA library using polymerase chain reaction (PCR)-based methodology. The rat V1b receptor is a protein of 421 amino acids that has 37-50% identity with the V1a and V2 receptors. Homology is particularly high in the seven putative membrane-spanning domains of these guanine nucleotide-binding protein-coupled receptors. Expression of the recombinant receptor in mammalian cells shows the same binding specificity for AVP agonists and antagonists as the rat pituitary V1b receptor. AVP-stimulated phosphotidylinositol hydrolysis and intracellular Ca2+ mobilization in Chinese hamster ovary or COS-7 cells expressing the cloned receptor suggest second messenger signaling through phospholipase C. RNA blot analysis, reverse transcription PCR, and in situ hybridization studies reveal that V1b receptor mRNA is expressed in the majority of pituitary corticotropes as well as in multiple brain regions and a number of peripheral tissues, including kidney, thymus, heart, lung, spleen, uterus, and breast. Thus, the V1b receptor must mediate some of the diverse biological effects of AVP in the pituitary as well as other organs.
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PMID:Extrapituitary expression of the rat V1b vasopressin receptor gene. 762 19

We have isolated bovine phospholipase C (PLC)-alpha cDNA from bovine thymus. Sequence analysis showed that PLC-alpha is highly conserved among rat, mouse, and calf and that it has two Trp-Cys-Gly-His-Cys-Lys motifs completely conserved in the mammals. Southern blot analysis revealed that bovine PLC-alpha is derived from a single gene. When PLC-alpha cDNA was stably transfected in NIH3T3 cells, there was no increase in PLC activity. PLC-alpha is supposed to be a member not of PLC superfamily but of Trp-Cys-Gly-His-Cys-Lys motif-containing proteins consisting of protein disulfide isomerase, P5, ERp72, and thioredoxin. PLC-alpha should be redesignated ERp57 (ER-resided p57).
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PMID:Molecular cloning and characterization of a cDNA for bovine phospholipase C-alpha: proposal of redesignation of phospholipase C-alpha. 794 84

Phospholipase Cbeta3 (PLCbeta3) is a member of the family of phospholipase C isoenzymes, a second messenger system that plays an important role in initiating receptor-mediated signal transduction in response to extracellular signals. Using RNA in situ hybridization we showed that in the embryonic rat nervous system, PLCbeta3 is expressed in dorsal root ganglia (DRGs) and the trigeminal ganglion. Characterization of the hybridization signal in the adult rat nervous system revealed that PLCbeta3 expression is confined mainly to small-sized DRG neurons. In non-neuronal tissues, PLCbeta3 is expressed by cells of epithelial origin, such as skin and the mucous lining airways and the gastrointestinal canal, and in lung and thymus.
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PMID:Expression of the phosphoinositide-specific phospholipase Cbeta3 gene in the rat. 874 58

We recently described an mAb (MTS23) reactive with a membrane Ag expressed on a subset of thymic medullary stromal cells. This Ag is also constitutively expressed at high levels on peripheral B cells, macrophages, and thymic and splenic dendritic cells of C57BL/6 mice. A number of stromal cell lines derived from thymus and bone marrow also stain with MTS23, but thymocytes and peripheral T cells only weakly express the Ag detected by MTS23. Here we show that the molecule detected by MTS23 is a member of the Ly-6 family of phosphatidylinositol-anchored membrane proteins. Treatment of stromal cells with phosphatidylinositol-phospholipase C before staining completely abolished expression. Using transient expression of 293T cells and a cDNA library of a stromal cell line cloned into the pEF-BOS vector, a cDNA encoding the MTS23-target Ag was isolated. Partial sequencing and restriction enzyme mapping revealed that it represents the Ly-6A/E protein. While the physiologic significance of the presence of Ly-6 molecules on stromal cells is not clear, it has been known for some time that, at least in lymphocytes, cellular activation events can be induced upon Ly-6 engagement. We now demonstrate that Ly-6 also functions as a signal transduction molecule on stromal cells, in that granulocyte-macrophage CSF can be produced by a variety of stromal cell lines upon mAb-mediated cross-linking of Ly-6. Together with the dramatic up-regulation of Ly-6 expression on stromal cells upon IFN-gamma treatment, this is the first indication of a biologic function of an Ly-6 gene product on nonhemopoietic cells. The results suggest that Ly-6 may play a role in the cross-talk between lymphocyte precursors and stromal cells.
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PMID:Identification and functional analysis of Ly-6A/E as a thymic and bone marrow stromal antigen. 878 96

The rat monoclonal antibody LR-1 was initially described to be reactive with an antigen present on murine splenic B lymphocytes. However, flow-cytometric analyses of cells obtained from thymus, bone marrow, spleen, and lymph nodes showed that LR-1 stained approximately 95, 95, 60-70 and 20% of cells present within these tissues in normal DBA/2 mice. The marker recognized by LR-1 was present on peripheral erythrocytes and splenic dendritic cells, and activation with lipopolysaccharide A further increased expression of this antigen by splenic B cells. This particular tissue and cellular distribution was similar to that delineated with monoclonal antibodies reactive with heat-stable antigen (HSA). Duallabelling studies were conducted to compare the reactivity patterns of LR-1 and the HSA-reactive monoclonal antibody J11d and indicated that both antibodies recognized splenocytes bearing B cell (IgM) or erythroid (TER-119, CD71) but not T cell (CD4, CD8) markers. Splenocytes exposed to phosphoinostol-specific phospholipase C showed marked reduction in LR-1 binding, indicating that this antibody recognized a glycosylphosphatidylinositol-anchored cell surface protein, consistent with the known structure of HSA. Mixing of LR-1 with the HSA-specific antibodies J11d or M1/69 provided flow-cytometric profiles indistinguishable from those obtained with either antibody alone. However, LR-1 inhibited M1/69 binding to splenocytes by 83%, while J11d reduced M1/69 binding to these cells by only 18%. This finding suggested that LR-1 and M1/69 recognize identical splenic HSA epitopes, while LR-1 and J11d bind distinct antigenic determinants of spleen HSA. Western blot analysis of splenocyte, thymocyte, bone marrow cell and erythrocyte detergent extracts revealed that LR-1 reacted with glycoforms of HSA of known molecular weights (30-55 kD). Thus, LR-1 recognizes HSA, the murine analogue of human CD24, and will be a useful reagent with which to investigate the role of HSA in the immune response and hematopoiesis.
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PMID:Monoclonal antibody LR-1 recognizes murine heat-stable antigen, a marker of antigen-presenting cells and developing hematopoietic cells. 891 16


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