Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

T cell activation is triggered by antigen stimulation and is characterized by the production of a wide range of cytokines and other immunomodulators crucial for the growth and development of other haemopoietic cells. Activation also induces the T cells to express, on their cell surface, receptors that enable the T cell to respond to the various cytokines generated during an immune response. One well characterized event that occurs when mature T cells are activated is the production of the cytokine IL2 and the acquisition by the T cell of IL2 receptors. Interaction between IL2 and its cellular receptor then directs T cell growth. Expression of the IL2 gene in T cells is regulated by signalling pathways that originate from the T cell antigen receptor complex (TCR). This review discusses the role of p21ras in these events. The TCR regulates the activity of p21ras, and a range of experiments have shown that p21ras couples the TCR to an intracellular kinase cascade involving the serine/threonine kinase Raf-1 and the MAP kinase ERK2. Analysis of more distal receptor signals shows that p21ras controls a signalling pathway that cooperates with a calcium/calcineurin controlled signalling system to stimulate the transcriptional factor NFAT and hence the IL2 gene. These studies identify p21ras as a critical signalling molecule in immune cells.
Cancer Surv 1995
PMID:Regulation and function of p21ras in T lymphocytes. 772 60

Treatment of HL-60 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) (1-5 nM) induced inhibition of cell growth and the appearance of an adherent monocyte-like cell type in a dose- and time-dependent manner. The extent of TPA-induced monocytic differentiation was found to be markedly reduced by okadaic acid (OA) (35 nM). OA had to be present for the early 12 h during treatment with TPA to reduce the induction of monocytic differentiation. The majority of cells (80%) were non-adherent but morphologically resembled mature myelocytes or granulocytes after treatment with TPA (5 nM) in the presence of OA (35 nM). Vanadate (VD), on the other hand, enhanced the extent of monocytic differentiation induced by low-dose of TPA (1 nM). These results indicated that dephosphorylation by tyrosine protein phosphatase and serine-threonine protein phosphatase may play an important role in the induction of monocytic and granulocytic differentiation.
Cancer Lett 1995 Apr 14
PMID:Effects of okadaic acid and vanadate on TPA-induced monocytic differentiation in human promyelocytic leukemia cell line HL-60. 773 56

The p80cdc25 protein is a protein phosphatase directly involved in p34cdc2 protein kinase activation by dephosphorylation. The cdc25B gene is one of three human cdc25 homologs which can complement the temperature-sensitive cdc25 mutation of Schizosaccharomyces pombe, and is expressed a high levels in human cell lines, particularly in some cancer cells. A fusion protein of glutathione-S-transferase (GST) and the catalytic domain of cdc25B protein was constructed and found to retain phosphatase activity in the manner of a p80cdc25 phosphatase by using a chromogenic substrate, p-nitrophenylphosphate. Two benzoquinoid antitumor compounds, dnacin A1 and dnacin B1, inhibited phosphatase activity in a non-competitive manner.
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PMID:Dnacin A1 and dnacin B1 are antitumor antibiotics that inhibit cdc25B phosphatase activity. 780 5

The expression of the three catalytic subunits of protein phosphatase (PP) type 1 and 2A, PP1 alpha, PP1 gamma 1, and PP2AC, was examined in 8 cases of lipoma as a benign tumor and 4 cases of liposarcoma as a malignant tumor using immunohistochemical analysis. Both types of of tumor cells stained positively with antisera against PP1 catalytic subunit isoforms PP1 alpha and PP1 gamma 1 were significantly higher in liposarcoma than in lipoma. Furthermore, liposarcoma showed a markedly high S-phase fraction in the cell cycle of tumor cells, as compared with lipoma. These results suggest that PP1 is involved in the accelerated growth of malignant cells in liposarcoma.
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PMID:Enhanced expression of catalytic subunits of protein phosphatase type 1 and high S-phase fraction in liposarcoma. 782 12

To elucidate the roles of protein phosphatases type 1 (PP1) and type 2A (PP2A) in 1,25-dihydroxy-cholecalciferol [1,25(OH)2D3]-induced differentiation of HL-60 cells into monocytes, we examined the enzyme activity and the protein and gene expressions of PP1 and PP2A in these cells. Calyculin-A augmented the 1,25(OH)2D3-induced differentiation of the cells. Treatment of the cells with 1,25(OH)2D3 led to a decrease in PP1-like activity in the cytosol fraction, with a concomitant increase in the membrane and nuclear PP1-like activity, as determined when protein phosphatase activity was assayed using myosin light chain as substrate in the presence of 5 nM okadaic acid. Western blot analysis with antibodies specific for PP1 catalytic subunit isozymes (PP1 alpha, PP1 gamma, and PP1 delta) showed that all three PP1 isozymes were expressed but were differentially distributed in each cellular fraction. Subcellular redistribution of PP1-like activity during 1,25(OH)2D3-induced differentiation was mainly attributed to PP1 gamma and PP1 alpha proteins. In contrast, the localizations of PP1 delta and PP2A catalytic and regulatory subunits were not significantly affected by 1,25(OH)2D3 treatment. The gene expressions of PP1 alpha and PP1 gamma appeared to be constant during processes of monocytic differentiation. The correlation between phenotypic and functional changes of HL-60 cells on the one hand and subcellular redistribution of PP1-like activity on the other suggest that the translocations of PP1 alpha and PP1 gamma isozymes may contribute to the 1,25(OH)2D3-induced monocytic differentiation of HL-60 cells.
Cancer Res 1995 Feb 15
PMID:Translocation of protein phosphatase 1 catalytic subunits during 1,25-dihydroxyvitamin D3-induced monocytic differentiation of HL-60 cells. 785 Jul 88

The expressions of the three catalytic subunits of protein phosphatase (PP) type 1 and 2A, PP1 alpha, PP1 gamma 1, and PP2AC, were examined in 14 cases of three types of osteogenic tumor using immunohistochemical analysis. The percentage of tumor cells stained positively with antiserum against PP1 catalytic subunit-isoform PP1 gamma 1 was significantly higher in malignant osteogenic tumors than in benign osteogenic tumors. Furthermore, malignant osteogenic tumor showed markedly high S-phase fraction in the cell cycle of tumor cells, as compared to benign osteogenic tumors. These results suggest that PP1 gamma 1 is involved in the accelerated growth of malignant cells in osteogenic tumors.
Cancer Lett 1995 Feb 10
PMID:Enhanced expression of catalytic subunit isoform PP1 gamma 1 of protein phosphatase type 1 associated with malignancy of osteogenic tumor. 788 91

Okadaic acid (OA), a specific protein phosphatase inhibitor, has various biological functions. To elucidate the mechanism of OA resistance, we have established a small-cell lung-cancer subline (H69/OA100) resistant to the growth-inhibitory effect of OA; this was done by using the parental cell line (H69) and increasing the concentration of OA. H69/OA100 was about 8 times more resistant to OA than H69. Intracellular retention of the fluorescent OA derivative in H69/OA100 was the same as that in H69. The catalytic activity of protein phosphatase from H69/OA100 was significantly reduced compared with that from H69. The protein phosphatase from H69/OA100 was 3.6 times more resistant to OA than that from H69. We examined the effect of OA on the activity of the immunoprecipitated protein phosphatase type I (PPI) and type 2A (PP2A) from the 2 cell lines. The PPI and PP2A from H69/OA100 showed more resistance to OA than those from H69. We next examined the effect of OA on the cell cycle of H69 and H69/OA100. In H69, G2/M block was observed at an OA concentration of 30 ng/ml whereas in H69/OA100, no G2/M block was observed at concentrations up to 100 ng/ml OA. We finally evaluated the amount of p34cdc2 kinase expression and the phosphorylation status of p34cdc2. There was no difference in p34cdc2 expression between H69 and H69/OA100 at several concentrations of OA. However, dephosphorylation of p34cdc2 was observed at 30 ng/ml OA in H69, but not in H69/OA100 up to 100 ng/ml OA. These data suggest that the resistance to OA and the resistance of the cell-cycle block to OA in H69/OA100 might be due to alteration of protein phosphatase activity.
Int J Cancer 1994 Sep 15
PMID:Establishment of a human small-cell lung-cancer subline resistant to okadaic acid. 792 83

In most eukaryotic cells, entry into mitosis is tightly controlled and requires completely replicated and undamaged DNA. We show that the antitumor drug, fostricin, interferes with this control; it induces cycling cells to enter mitosis prematurely, and it can overcome the mitotic entry checkpoint, forcing into mitosis cells that were arrested in the division cycle by treatment with the DNA replication inhibitor aphidicolin or with the DNA-damaging agents camptothecin and teniposide. This effect was observed in all rodent, simian, and human cell lines tested. Fostriecin also hampers progression through the later stages of mitosis as determined by the absence of normal half-spindles, anaphase figures, and telophase figures. The only previously known target for fostriecin is topoisomerase II, which is inhibited in vitro with a 50% inhibitory concentration of 40 microM (T. J. Boritzki, T. S. Wolfard, J. A. Besserer, R. C. Jackson, and D. W. Fry. Inhibition of type II topoisomerase by fostriecin. Biochem. Pharmacol., 37: 4063-4068, 1988). We show that fostriecin is a more potent inhibitor of protein phosphatase 1, with a 50% inhibitory concentration of 4 microM and protein phosphatase 2A, with a 50% inhibitory concentration of 40 nM. Inhibition of the mitotic entry checkpoint and inhibition of protein phosphatases are novel properties for antitumor drugs with potential or proven therapeutic value.
Cancer Res 1994 Dec 01
PMID:Antitumor drug fostriecin inhibits the mitotic entry checkpoint and protein phosphatases 1 and 2A. 795 57

Gene expression of protein phosphatases 1 alpha, 1 gamma 1, 2A alpha, and 2C alpha in 14 rat ascites hepatoma cell lines was studied by Northern blot hybridization. The expression of PP1 alpha and PP2C alpha was increased and decreased, respectively, in all of the ascites hepatoma (AH) cells compared to rat liver, whereas the expression of PP1 gamma 1 and PP2A alpha was increased in about 50% of them. Relative gene expression was affected by several factors, such as harvest time, transplantation rate, percentage of free cells, and sex; the first factor was more important than the others. Relative gene expression of PP1 alpha had a negative correlation with harvest time, whereas gene expression of PP1 gamma 1 and PP2A alpha had a nonlinear (hyperbolic) correlation with harvest time. We suggest that there is a relationship between growth rate and expression of protein phosphatase genes. Our data also suggest that PP1 gamma 1 mRNA is positively controlled by PP2A alpha mRNA.
Cancer Detect Prev 1994
PMID:Gene expression of protein phosphatases in rat ascites hepatoma cell lines. 802 93

The majority of signal transduction studies have focused on events induced by mitogen stimulation. However, little is known about the negative control signals that cause or maintain growth arrest and must be overcome for mitogenesis to occur. We investigated the possible role of protein phosphatases in this negative regulatory process. Treatment of quiescent hamster and human fibroblasts with low doses of the phosphatase inhibitors sodium o-vanadate or okadaic acid allowed 30-40% of cells to progress from G0-G1 arrest to S phase. This was accompanied by phosphorylation of the retinoblastoma and MAP-kinase proteins, as well as induction of the cdc2 protein. Furthermore, we observed that protein phosphatase inhibitor treatment could override the block to DNA synthesis in senescent cells, which are normally nonresponsive to mitogens. These data suggest that protein phosphatases may play a role in the negative regulation of cell growth and maintenance of growth arrest.
Cancer Res 1994 May 01
PMID:Disruption of G0-G1 arrest in quiescent and senescent cells treated with phosphatase inhibitors. 816 73


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