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:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The addition of either okadaic acid or calyculin A desensitizes human platelets to thrombin. One objective of this study was to determine which step(s) leading to secretion reactions may be affected by these protein phosphatase inhibitors. In a dose-dependent manner, okadaic acid or calyculin A inhibits phosphatidylinositol metabolism and Ca(2+)-transients. In all cases, calyculin A was approximately 10-fold more potent than okadaic acid, and it had maximal effects at a concentration of 1 microM. Although thrombin-induced rises in [Ca2+]i were diminished, an increase in the phosphorylation state of myosin light chains (MLC) was still observed. Changes in this phosphorylation were diminished, however, following the addition of thrombin to calyculin A-treated platelets that were loaded with dimethyl-BAPTA. These data demonstrate that calyculin A and okadaic acid lower agonist-induced Ca(2+)-transients, which in turn prevents responses such as secretion reactions. Calyculin A/okadaic acid-induced phosphorylation events were not diminished in BAPTA-loaded platelets, suggesting that these phosphorylations are Ca(2+)-insensitive. Thus, a second objective of this study was to identify the protein kinase(s) that was(were) responsible for the calyculin A-induced phosphorylations. In a platelet lysate system, calyculin A caused an increase in the incorporation of [32P]phosphate into p50. This phosphorylation event was identical to that observed in the intact platelet and was not mimicked by cAMP, cGMP, Ca2+, or a Ca2+/phospholipid/diacylglycerol mixture. Kinase activity was removed after the lysate was incubated with p13suc1-Sepharose. This suggests that a p13suc1-sensitive protein kinase, e.g., a cell cycle-dependent protein kinase, is responsible for the calyculin A-sensitive phosphorylation events.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Inhibitors of protein phosphatase type 1 and 2A attenuate phosphatidylinositol metabolism and Ca(2+)-transients in human platelets. Role of a cdc2-related protein kinase. 132 63

The Rel-associated protein pp40 is functionally related to I kappa B, an inhibitor of the transcription factor NF-kappa B. Purified pp40 inhibits the DNA binding activity of the NF-kappa B protein complex (p50:p65 heterodimers), p50:c-Rel heteromers, and c-Rel homodimers. The sequence of the complementary DNA encoding pp40 revealed similarity to the gene encoding MAD-3, a protein with mammalian I kappa B-like activity. Protein sequencing of I kappa B purified from rabbit lung confirmed that MAD-3 encodes a protein similar to I kappa B. The sequence similarity between MAD-3 and pp40 includes a casein kinase II and consensus tyrosine phosphorylation site, as well as five repeats of a sequence found in the human erythrocyte protein ankyrin. These results suggest that rel-related transcription factors, which are capable of cytosolic to nuclear translocation, may be held in the cytosol by interaction with related cytoplasmic anchor molecules.
...
PMID:Rel-associated pp40: an inhibitor of the rel family of transcription factors. 189 14

Mononuclear phagocyte activation is characterized by alterations in cellular metabolism and plasma membrane composition. In rodent and human systems, antibodies (conventional heteroantibodies or monoclonal reagents) that identify plasma membrane antigens selectively expressed by activated macrophages and monocytes have been generated. Among these activation-associated determinants is Mo3e (p50,80), a protease-sensitive antigen that is expressed by human monocytes activated in culture by exposure to bacterial lipopolysaccharide, muramyl dipeptide, or phorbol myristate acetate (PMA) (as well as other biologically active phorbol compounds). Mo3e is also expressed by the monoblastic cell line U-937 after culture in medium containing PMA and other pharmacological activators of protein kinase C (4 beta-phorbol-12,13-dibutyrate, 4 beta-phorbol-12,13-didecanoate, mezerein, and cell-permeable 1,2-diacylglycerol). The human promyelocytic cell line HL-60 becomes Mo3e positive after exposure in vitro to certain inducers of monocytic differentiation (PMA, dibutyryl cyclic AMP, and cholera toxin plus 3-isobutyl-1-methylxanthine). The surface expression of Mo3e is blocked by inhibitors of protein synthesis, N-linked glycosylation, and protein kinase activation, as well as by ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid and calcium antagonists. These data suggest the involvement of glycoprotein synthesis, protein kinase activation, and calcium ions in the stimulated expression of Mo3e by activated human mononuclear phagocytes. Anti-Mo3e antibody blocks the human monocyte response to migration inhibitory factor (MIF), which indicates an association between the expression of Mo3e antigen and responsiveness to MIF.
...
PMID:Mononuclear phagocyte activation: activation-associated antigens. 242 78

The human B lymphocyte and carcinoma-associated Ag, CDw40, (p50, Bp50) is a receptor candidate for normal growth regulation. Interaction of mAb with this pan-B Ag, together with preactivating agents such as 12-O-tetradecanoylphorbol-13-acetate or anti-mu, deliver strong growth-promoting signals to the cells. We here demonstrate that signaling through this Ag is dependent on its aggregation on the cell surface. Thus, monovalent antibody fragments were relatively inefficient in this respect but effectively blocked stimulation by intact antibody. By using affinity purified CDw40 protein we have also demonstrated that it is antigenically distinct from other B cell-associated Ag, including the six differentiation clusters CD19 to CD24. The mAb S2C6 and G28.5, prepared by immunizing mice with human bladder carcinoma cells or tonsillar B-cells, respectively, were the only antibodies giving detectable binding. Either of these antibodies could also completely block the binding of the other, suggesting an identity or structural proximity of the epitopes recognized. The CDw40 Ag was shown to be a phosphoprotein lacking intrinsic protein kinase activity. The results provide further evidence for CDw40 being an important B cell growth factor receptor which may also have growth regulatory functions in the development of certain human carcinomas.
...
PMID:The human B lymphocyte and carcinoma antigen, CDw40, is a phosphoprotein involved in growth signal transduction. 246 10

We examined the effect of insulin on nuclear factor kappa B (NF-kappa B) activity in Chinese ovary (CHO) cells overexpressing wild-type (CHO-R cells) or -defective insulin receptors mutated at Tyr1162 and Tyr1163 autophosphorylation sites (CHO-Y2 cells). In CHO-R cells, insulin caused a specific, time-, and concentration-dependent activation of NF-kappa B. The insulin-induced DNA-binding complex was identified as the p50/p65 heterodimer. Insulin activation of NF-kappa B: 1) was related to insulin receptor number and tyrosine kinase activity since it was markedly reduced in parental CHO cells which proved to respond to insulin growth factor-1 and phorbol 12-myristate 13-acetate (PMA) activation, and was dramatically decreased in CHO-Y2 cells; 2) persisted in the presence of cycloheximide and was blocked by pyrrolidine dithiocarbamate, aspirin and sodium salicylate, three compounds interfering with I kappa B degradation and/or NF-kappa B.I kappa B complex dissociation; 3) was independent of both PMA-sensitive and atypical (zeta) protein kinases C; and 4) was dependent on Raf-1 kinase activity since insulin-stimulated NF-kappa B DNA binding activity was inhibited by 8-bromo-cAMP, a Raf-1 kinase inhibitor. Moreover, insulin activation of NF-kappa B-driven luciferase reporter gene expression was blocked in CHO-R cells expressing a Raf-1 dominant negative mutant. This is the first evidence that insulin activates NF-kappa B in mammalian cells through a post-translational mechanism requiring both insulin receptor tyrosine kinase and Raf-1 kinase activities.
...
PMID:Insulin activates nuclear factor kappa B in mammalian cells through a Raf-1-mediated pathway. 759 58

T-cell activation requires two different signals. The T-cell receptor's recognition of a specific antigen on antigen-presenting cells provides one, and the second signal comes from costimulatory molecules such as CD28. In contrast, T cells that are stimulated with antigen in the absence of the CD28 costimulatory signal can become anergic (nonresponsive). The CD28 response element (CD28RE) has been identified as the DNA element mediating interleukin 2 (IL-2) gene activation by CD28 costimulation. Our previous work demonstrates that the Rel/NF-kappa B family proteins c-Rel, RelA (p65), and NFKB1 (p50) are involved in the complex that binds to the CD28RE. We also showed that c-Rel, but not NFKB1 (p50), can bind to the CD28RE and activate CD28RE-driven transcription in cotransfection assays. However, the role of RelA (p65) in CD28 signaling has not yet been addressed. We provide evidence that RelA (p65) itself bound directly to the CD28RE of the IL-2 promoter and other lymphokine promoters. In addition, RelA (p65) was a potent transcriptional activator of the CD28RE in vivo. We show that a RelA (p65)-c-Rel heterodimer bound to the CD28RE and synergistically activated the CD28RE enhancer activity. We also demonstrate that activated Raf-1 kinase synergized with RelA (p65) in activating the CD28RE enhancer activity. Interestingly, a soluble anti-CD28 monoclonal antibody alone, in the absence of other stimuli, also synergized with RelA (p65) in activating the CD28RE. Furthermore, we show that RelA (p65) activated expression of the wild-type IL-2 promoter but not the CD28RE-mutated IL-2 promoter. A combination of RelA (p65) and NFKB1 (p50) also activated the IL-2 promoter through the CD28RE site. These results demonstrate the functional regulation of the CD28RE, within the IL-2 promoter, by Rel/NF-kappa B transcription factors.
...
PMID:RelA is a potent transcriptional activator of the CD28 response element within the interleukin 2 promoter. 762 20

Protein hyper- or hypophosphorylation induced by okadaic acid (OA) treatment was examined using quiescent cultures of the BALB/MK-2 mouse epidermal keratinocytes. Treatment with OA enhanced the phosphorylation of five proteins with molecular weights of 65,000, 55,000, 50,000, 28,000 and 15,000 (p65, p55, p50, p28, and p15, respectively) and decreased that of two proteins with molecular weights of 22,000 and 20,000 (p22 and p20, respectively). The two major phosphorylated proteins, p65 and p55, were identified as type II and type I keratins, respectively, by immunoblotting and immunoprecipitation with keratin specific antibodies. Serine was the only phosphoamino acid residue in hydrolysates of the 32P-labeled keratins purified from OA-treated cells. Two-dimensional tryptic peptide maps of the phosphorylated keratins showed that the hyperphosphorylation was largely due to phosphorylation at several additional sites in both keratins. The hyperphosphorylation of keratins induced by OA treatment resulted in a drastic change in their solubility. This change closely correlated with reorganization of the keratin filament network, which finally collapsed into large perinuclear aggregates. Concomitantly the cells changed from a typical epithelial shape to a round shape. Of several protein kinase inhibitors tested, only staurosporine interfered with this OA-induced morphological change and reorganization of the keratin network.
...
PMID:Hyperphosphorylation of keratins by treatment with okadaic acid of BALB/MK-2 mouse keratinocytes. 769 89

Stimulation of the protein kinase A (PKA) signalling pathway exerts an inhibitory effect on the proliferation of numerous cells, including T lymphocytes. In CD4+ T helper cells, stimulation of PKA leads to suppression of interleukin 2 (IL-2) induction, while induction of the genes coding for the lymphokines IL-4 and IL-5 is enhanced. We show that the differential effect of PKA activity on induction of the IL-2 and IL-4 genes is mediated through their promoters. One major target of the suppressive effect of PKA is the kappa B site in the IL-2 promoter. A kappa B site is missing in the IL-4 promoter. Mutations preventing factor binding to the IL-2 kappa B site result in a loss of PKA-mediated suppression of IL-2 promoter activity. Furthermore, activation of the PKA signalling pathway impairs the inducible activity of multiple kappa B sites of the IL-2 promoter, but not of other factor binding sites. The reduction in activity of kappa B sites in activated and PKA-stimulated T cells is accompanied by changes in the concentration and DNA binding of Rel/NF-kappa B factors. Stimulation of the PKA pathway in Jurkat T cells with the PKA activator forskolin leads to an increase in synthesis of c-Rel and p105/p50, while synthesis of p65/RelA remains unchanged. However, nuclear translocation and DNA binding of p65 is distinctly impaired, probably due to a retarded degradation of I kappa B-alpha. In a similar way, stimulation of the PKA signalling pathway inhibits nuclear translocation of p65 and generation of nuclear kappa B complexes in peripheral T lymphocytes from murine lymph nodes. These results indicate that PKA-mediated suppression of NF-kappa B activity plays an important role in the control of activation of peripheral T lymphocytes.
...
PMID:RelA/p65 is a molecular target for the immunosuppressive action of protein kinase A. 774 6

A lymphocyte-specific protein, p50, is phosphorylated on Ser and Thr residues in mitogen-activated T cells, suggesting that this molecule plays some role in the T cell activation cascade. p50 was identified as lymphocyte specific protein 1 (LSP1), which is a putative calcium-binding protein. In the present study, to clarify the role of p50 protein in the cascade, in vivo and in vitro phosphorylation of this molecule, and the effect of the phosphorylation on its distribution in activated T cells were examined. First, to obtain a sufficient amount of p50 as a phosphorylation substrate, p50 cDNA, which encodes a protein of 330 amino acid residues with a molecular mass of 36,728 Da, was cloned from an ICR mouse thymocyte cDNA library and expressed in Escherichia coli. When the putative coding region of p50 cDNA was expressed in E. coli, the product showed an apparent molecular mass of 50 kDa on SDS-PAGE. The recombinant p50 was phosphorylated in vitro by rabbit protein kinase C (PKC) and by murine cytosolic protein kinase, that was activated by a combination of phosphatidylserine and diacylglycerol. Furthermore, p50 was shown to be phosphorylated on the same sites in T cells upon stimulation with Con A as when phosphorylated in vitro by rabbit PKC, indicating that p50 is phosphorylated by PKC in Con A-stimulated T cells. On subcellular fractionation followed by immunoblotting analysis, membrane-bound p50 was shown to be released from the membrane following activation of PKC in T cells. These results and the recent finding that p50 binds to actin fibers raise the possibility that p50 controls the binding of actin fibers to the plasma membrane under regulation by PKC in T cells.
...
PMID:Protein kinase C phosphorylates p50 LSP1 and induces translocation of p50 LSP1 in T lymphocytes. 777 93

Nuclear factor kappa B (NF-kappa B), consisting of p50 and p65, is bound to a cytoplasmic retention protein, I kappa B, in a resting state, and the stimulation of cells with a variety of inflammatory stimuli induces the dissociation of NF-kappa B from I kappa B and the nuclear translocation of NF-kappa B, thereby activating several genes involved in inflammatory responses, such as interleukin (IL)-6, IL-8, and tumor necrosis factor alpha. In order to elucidate the precise mechanism of NF-kappa B activation, we have established lipopolysaccharide (LPS)-dependent NF-kappa B activation in a cell-free system using plasma membrane-enriched, cytosol, and nuclear fractions extracted from a human monocytic cell line, THP-1, by disruption with sonication followed by a differential centrifugation. The combination of plasma membrane-enriched fraction and cytosol was sufficient to activate NF-kappa B in a LPS/CD14-dependent manner only in the presence of ATP as judged by the binding of NF-kappa B to the IL-8 gene kappa B site on an electrophoretic mobility shift assay. LPS-dependent NF-kappa B activation was inhibited by protein kinase inhibitors, such as staurosporine, herbimycin A, tyrphostin, and genistein, but not mitogen-activated protein kinase substrate, cGMP-dependent protein kinase, cAMP-dependent protein kinase, protein kinase C, and calmodulin-dependent protein kinase II inhibitory peptides, suggesting that staurosporine-sensitive kinase(s) as well as tyrosine kinase(s) are involved in LPS-mediated NF-kappa B activation. In addition, LPS induced the phosphorylation of I kappa B-alpha, starting at 5 min after the stimulation in a cell-free system. Moreover, the phosphorylation was inhibited by herbimycin A and tyrphostin, but not staurosporine, suggesting that these protein kinase inhibitors act at distinct steps of signal transmission. Establishment of ligand-dependent activation of NF-kappa B in a cell-free system will facilitate identification of protein kinase(s) and its substrate(s) involved in LPS-mediated NF-kappa B activation.
...
PMID:Establishment of lipopolysaccharide-dependent nuclear factor kappa B activation in a cell-free system. 787 68


1 2 3 4 5 6 7 8 9 10 Next >>

---