Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human adult lung fragments removed from macroscopically undamaged and anthracosis exempted zones of lungs of 20 pneumonectomies made for cancer, were tested for 25 enzymic activities. The location and intensities of these enzymic activities were different in the lung tissue components; The bronchial epithelia contained highly active LDH, MDH, SDH, NADH-TR and NADPH-TR, glucose-6-phosphate dehydrogenase, active hydroxyproline-2-epimerase, alkaline phosphatase. Ca2+-activated ATP-ase, and beta-galactosidase. Bronchial and vascular muscles presented intense activities of LDH, MDH and SDH of alkalinephosphatase, AMP-ase and Ca2+-activated ATP-ase, as well as of beta-galactosidase. The alveolar walls presented high activities of SDH, MDH and LDH, of alkaline and acid phosphatases, of beta-galactosidase and of Tween-40 and 60-esterases, of HEP, cytochrome-oxidase and peroxidase. The free alveolar macrophages were active for LDH, MDH, SDH, NADH-TR and NADPH-TR, G1-6-ph-DH, acid and alkaline phosphatase, cytochrome-oxidase and peroxidase, HEP, AMP-ase and Mg2+-activated ATP-ase, Tween-esterases, naphthol-ASD-acetate esterase, and beta-galactosidase. The endothelia contained high activities of alkaline phosphatase, of AMP-ase and Mg2+-activated ATPase, of LDH, MDH and SDH, and of beta-galactosidase. In bronchial lymphoid nodules it was the LDH, MDH, SDH, cytochrome-oxidase and peroxidase, HEP, alkaline phosphatase and AMP-ase, Tween-60-esterase and beta-galactosidase that were active. The interlobular areas of the lung presented intense activities of SDH, MDH, LDH, HEP and cytochrome-oxidase. The activities of the other tested enzymes were weaker or absent in the adult human lung components, the same as those of aminopeptidases which were present only in some free alveolar macrophages. The discussion of some relationships between these enzymic actitivies and the morphology of the human adult lung tissue asserted that the latter could not be considered as a "normal" tissue but as one overstrained by the components of blood and polluted air.
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PMID:Histoenzymology of the lung. I. Enzyme activities of the lung tissue of acult humans; relationships between structure and functions. 14 Mar 14

The ATP-ADP exchange activity previously described in a membrane farction of Escherichia coli appeared after a cold osmotic shock according to Neu and Heppel ((1965) J. Biol. Chem. 240, 3685--3692) in the shock fluid. Membranes derived from shocked cells had no activity. The enzyme responsible for this activity has been purified 125-fold and catalyzed the transfer of a phosphoryl radical from ribonucleosidetriphosphates (NTPs) to ribonucleosidediphosphates (NDPs); this is, therefore, a non-specific nucleosidediphosphate kinase (ATP:nucleosidediphosphate phosphotransferase, EC 2.7.4.6). The activity required the presence of a divalent cation, Mg2+, Mn2+ or Ca2+ at a unity mol/mol ratio of nucleotide for maximal activation. The enzyme exhibited simple saturation kinetics with respect to the phosphate donor but inhibition by excess substrate was observed upon increasing phosphate acceptor. The kinetics of the reaction indicated an ordered bi-molecular ping-pong reaction mechanism. Differential heat sensitivity of the enzyme whether it is heated alone with ATP, ADP or Mg2+ opens possibilities to study different enzyme-substrate complexes.
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PMID:Nucleosidediphosphate kinase of Escherichia coli, a periplasmic enzyme. 21 26

The troponin I peptide N alpha-acetyl TnI (104-115) amide (TnIp) represents the minimum sequence necessary for inhibition of actomyosin ATPase activity of skeletal muscle (Talbot, J.A. & Hodges, R.S. 1981, J. Biol. Chem. 256, 2798-3802; Van Eyk, J.E. & Hodges, R.S., 1988, J. Biol. Chem. 263, 1726-1732; Van Eyk, J.E., Kay, C.M., & Hodges, R.S., 1991, Biochemistry 30, 9974-9981). In this study, we have used 1H NMR spectroscopy to compare the binding of this inhibitory TnI peptide to a synthetic peptide heterodimer representing site III and site IV of the C-terminal domain of troponin C (TnC) and to calcium-saturated skeletal TnC. The residues whose 1H NMR chemical shifts are perturbed upon TnIp binding are the same in both the site III/site IV heterodimer and TnC. These residues include F102, I104, F112, I113, I121, I149, D150, F151, and F154, which are all found in the C-terminal domain hydrophobic pocket and antiparallel beta-sheet region of the synthetic site III/site IV heterodimer and of TnC. Further, the affinity of TnIp binding to the heterodimer (Kd = 192 +/- 37 microM) was found to be similar to TnIp binding to TnC (48 +/- 18 microM [Campbell, A.P., Cachia, P.J., & Sykes, B.D., 1991, Biochem. Cell Biol. 69, 674-681]). The results indicate that binding of the inhibitory region of TnI is primarily to the C-terminal domain of TnC. The results also indicate how well the synthetic peptide heterodimer mimics the C-terminal domain of TnC in structure and functional interactions.
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PMID:A 1H NMR study of a ternary peptide complex that mimics the interaction between troponin C and troponin I. 130 91

A truncated form of the type 1 fibroblast growth factor receptor (FGFR1) lacking most of its cytoplasmic domain was tested for its ability to inhibit signal transduction by each of three different wild-type FGFRs (FGFR1, 2, and 3). When the truncated FGFR1 was expressed in Xenopus oocytes in excess of each wild-type FGFR, mobilization of intracellular calcium mediated by the wild-type FGFRs was completely blocked. The truncated FGFR did not inhibit signal transduction by the co-expressed platelet-derived growth factor beta-receptor. A form of truncated FGFR1 which lacked the first immunoglobulin-like domain also inhibited signal transduction by wild-type FGFRs. Truncated FGFR formed complexes with wild-type FGFR in the presence of basic FGF in intact cells. These observations were consistent with the hypothesis that the truncated FGFR interacted with wild-type FGFRs to form nonfunctional heterodimers, thus eliminating the signaling by the wild-type FGFRs. The observation that signaling by multiple types of FGFR can be blocked by a single type of truncated FGFR suggests that the different types of FGFR can interact with each other in ligand-mediated complexes. These findings provide a molecular basis for inhibiting the actions of FGFs in vivo.
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PMID:A truncated form of fibroblast growth factor receptor 1 inhibits signal transduction by multiple types of fibroblast growth factor receptor. 130 84

Prostaglandin E2 (PGE2), PTH, and epidermal growth factor (EGF) are potent regulators of osteoblast proliferation. In UMR 106-01 rat osteosarcoma cells with osteoblast-like features, PGE2 and PTH inhibit, while EGF stimulates, mitogenesis. Both PGE2 and PTH increase intracellular cAMP levels, cytosolic calcium, and inositol phosphate turnover. In a variety of cell types, EGF mediates its effects in part via activation of receptor protein-tyrosine kinase and other protein kinases, such as protein kinase-C. The nuclear mechanisms of PGE2, PTH, and EGF regulation of osteoblast proliferation are unknown. Accordingly, we have examined the effects of these agents on mitogenesis, second messenger generation, and primary response genes, which may link second messenger activation to subsequent alterations in gene expression. Northern blot analysis of mRNA from UMR 106-01 cells treated for 3 h with 2 microM PGE2, 10 nM PTH, or 10 ng/ml EGF in the presence of cycloheximide demonstrated that all three agents induced the expression of c-fos and c-jun mRNA. In contrast, only EGF stimulated cellular proliferation and induced Egr-1 mRNA. Also, unlike PGE2 and PTH, EGF did not increase intracellular cAMP levels. c-fos mRNA was induced by treatment with 50 ng/ml tetradecanoyl phorbol acetate or by 40 ng/ml forskolin, while induction of Egr-1 mRNA was stimulated by treatment with tetradecanoyl phorbol acetate, but not forskolin. Thus, EGF signal transduction differs from that of PGE2 and PTH in UMR 106-01 osteoblast-like cells, in that EGF does not stimulate the protein kinase-A second messenger system, but causes activation of Egr-1, a primary response gene that may play a role in the mitogenic effect of EGF.
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PMID:The effects of prostaglandin E2, parathyroid hormone, and epidermal growth factor on mitogenesis, signaling, and primary response genes in UMR 106-01 osteoblast-like cells. 133 Apr 91

To elucidate the relationship between the high concentration of taurine in platelets and platelet aggregation in patients with EPH gestosis (gestosis with edema, proteinuria and hypertension), platelet aggregation and the platelet release response (release of ATP and beta-thromboglobulin) were studied in the washed platelet suspension (PS) obtained from normal pregnant or non-pregnant women and EPH gestosis patients. Platelet aggregation and platelet release response were significantly lower in EPH gestosis patients than in normal pregnant and non-pregnant women. Platelet aggregation, platelet release response induced by ADP and collagen and the aggregation induced by A23187 were inhibited in taurine-loaded PS from non-pregnant women. These results suggest that the decrease of platelet aggregation in EPH gestosis patients was caused by high concentrations of taurine in platelets, which may inhibit the intracellular Ca2+ movement and platelet release response. Therefore, taurine appears to have a protective effect against the hyper-coagulative state in EPH gestosis.
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PMID:Effect of taurine concentration on platelet aggregation in gestosis patients with edema, proteinuria and hypertension. 144 48

Engagement of MHC class II (Ia) molecules on B cells induces tyrosine phosphorylation, phosphoinositide turnover, elevation of intracellular calcium concentrations, and a rise in cAMP levels. However, a role for these biochemical signals in mediating functional responses induced by Ia ligands remains largely undefined. In this study, we utilized the induction of B cell adhesion by Ia ligands to demonstrate a role for signals transduced via Ia molecules in the generation of a functional response. Ia ligands that induced B cell aggregation induced tyrosine phosphorylation, whereas Ia ligands that did not induce B cell aggregation failed to induce any detectable tyrosine phosphorylation. Ia-induced B cell aggregation and tyrosine phosphorylation were inhibited by genistein and by herbimycin A, inhibitors of tyrosine kinases (PTK). Sphingosine and calphostin C, inhibitors of protein kinase C (PKC), also inhibited Ia-induced adhesion whereas HA1004, an inhibitor of cyclic nucleotide-dependent kinases, did not. Ia ligands induced both LFA-1-dependent and LFA-1-independent B cell adhesion. These two pathways of cell adhesion differed in their requirement for activation signals. PKC activation was sufficient for LFA-1-dependent adhesion, whereas LFA-1-independent adhesion required independent phosphorylation events mediated by PKC and by PTK. These results provide functional relevance for biochemical signals transduced via Ia molecules by demonstrating that Ia-induced B cell adhesion is mediated by the activation of PKC and by one or more PTK.
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PMID:Role of protein kinase activation in the induction of B cell adhesion by MHC class II ligands. 151 59

Application of 10 nM Epidermal Growth Factor (EGF) to single EGFR-T17 fibroblasts induced a marked hyperpolarization that could last for tens of minutes; in many cases the first transient was followed by a series of oscillations of the membrane potential. The outward current responsible for the hyperpolarizing response could be recorded simultaneously to an increase in the intracellular calcium concentration, as measured with the fluorescent indicator fura-2. The conductance was nearly linear in the voltage range from -100 to +50 mV. While the EGF-induced current had many characteristics of a K+ current and was strongly reduced by 50 nM charybdotoxin (ChTx), its reversal potential was apparently more negative than the potassium equilibrium potential (VK). The application of 2 microM ouabain prior to EGF stimulation produced responses that were similar to those obtained without ouabain; however, under these conditions the EGF-induced current showed a reversal potential of -96.6 +/- 3.2 mV, very close to VK. Simultaneous application of both 2 microM ouabain and 50 nM ChTx completely abolished the response. It can be concluded that the response to EGF stimulation in EGFR-T17 cells consists of two components: the first is a current carried through Ca(2+)-activated K+ channels; the second is due to the acceleration of the operation of the Na+/K(+)-ATPase.
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PMID:Two currents activated by epidermal growth factor in EGFR-T17 fibroblasts. 155 Aug 55

We investigated regulation of atrial natriuretic factor (ANF)-stimulated cellular cGMP accumulation (ANF-s-cGMP) in an ANF-responsive human renal cell line, SK-NEP-1. Dose-response data indicated that the EC50 for ANF(99-126) was 1.1 x 10(-9) M. Brain natriuretic peptide (10(-6) M) increased cGMP to a level indistinguishable from that of ANF (10(-6) M). [Met-(O)]ANF was only half as potent as ANF, and atriopeptin I (10(-6) M) did not increase cGMP over basal levels. Preincubation of SK-NEP-1 cells with ANF, but not atriopeptin I (API), for two hours or longer, caused a concentration-dependent down-regulation of ANF-s-cGMP. Phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, and A23187 and its 4-bromo derivative, calcium ionophores, inhibited ANF-s-cGMP in a dose-dependent manner. A23187 inhibition was calcium dependent and promoted net cGMP degradation. Thirty-six hour preincubation with PMA, a procedure used to down-regulate PKC, abolished acute PMA inhibition of ANF-s-cGMP without having an effect on ANF-s-cGMP or on 4-bromo-A23187 inhibition thereof. These data indicate that PKC activation specifically inhibited ANF-s-cGMP but that PKC was not required for ANF-s-cGMP in SK-NEP-1 cells. Thus structurally related ANF peptides, protein kinase C (PKC) activators, calcium ionophores are potential modulators of ANF-s-cGMP in cells from this human renal cell line.
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PMID:Phorbol and calcium decreased atriopeptin response in a human renal cell line. 164 14

Previous work (Gandino, L., Di Renzo, M. F., Giordano, S., Bussolino, F., and Comoglio, P.M. (1990) Oncogene 5, 721-725) has shown that the tyrosine kinase activity of the receptor encoded by the MET protooncogene is negatively modulated by protein kinase C (PKC). We now show that an increase of intracellular Ca2+ has a similar inhibitory effect in vivo, via a PKC-independent mechanism. In GTL-16 cells the p145MET kinase is overexpressed and constitutively phosphorylated on tyrosine. A rapid and reversible decrease of p145MET tyrosine phosphorylation was induced by treatment with the calcium ionophores A23187 or ionomycin. Experiments performed with the ionophores in absence of extracellular calcium showed that a rise in cytoplasmic Ca2+ concentration to 450 nM (due to release from intracellular stores) resulted in a similar effect. These Ca2+ concentrations had no effect on p145MET autophosphorylation in an in vitro kinase assay. This suggests that the effect of Ca2+ on p145MET tyrosine phosphorylation is not direct but may be mediated by Ca(2+)-activated proteins(s). Involvement of Ca(2+)-dependent tyrosine phosphatases was ruled out by experiments carried out in presence of Na2VO4. In vivo labeling with [32P]orthophosphate showed that the rise of intracellular Ca2+ induces serine phosphorylation of p145MET on a specific phosphopeptide. This suggests that Ca2+ negatively modulates p145MET kinase through the phosphorylation of a critical serine residue by a Ca(2+)-activated serine kinase distinct from PKC.
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PMID:Intracellular calcium regulates the tyrosine kinase receptor encoded by the MET oncogene. 165 34


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