Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Addition of acetate to a stationary phase culture of Escherichia coli in glycerol mineral salts medium containing phosphorus-32-labeled orthophosphate results in rapid loss of isocitrate dehydrogenase activity and concomitant incorporation of phosphorus-32 into the enzyme. This is the first example of protein phosphorylation in a bacterium in which the endogenous substrate for the protein kinase has been identified.
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PMID:Phosphorylation of Isocitrate dehydrogenase of Escherichia coli. 3 15

A nucleoside-dependent protein kinase (EC 2.7.1.37) was partially purified from Trypanosoma gambiense, the pathogenic agent of sleeping sickness. This enzyme catalyzes the phosphorylation of histone and protamine. Various nucleosides at the concentration of 10(-4) M stimulated the histone kinase activity about two-fold, whereas cyclic AMP and cyclic GMP were without effect. The pH-optimum for histone phosphorylation was at about pH 7.0. The enzyme activity absolutely depends on Mg2+, Mn2+ or Co2+. The apparent Km-value for histone was 0.3 mg/ml and those for ATP were 2 - 10(-4) M and 6 - 10(-5) M in the absence or presence of 10(-4) M adenosine respectively. IDP and ADP complete with ATP. The inhibition constants were calculated to be 2 - 10(-4) M and 2.5 - 10(-4) M, respectively. The molecular weight of the histone kinase was found to be 95 000 by gel filtration and 88 000 by sedimentation in a sucrose gradient.
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PMID:Nucleoside-dependent protein kinase from Trypanosoma gambiense. 17 63

Addition of triiodothyronine (T3) to chick-embryo hepatocytes in culture causes increased accumulations of malic enzyme, fatty acid synthase, acetyl-CoA carboxylase and their mRNAs. H-8 and other protein kinase inhibitors inhibited the T3-induced accumulations of these lipogenic enzymes and their mRNAs but had no effect on the activities of 6-phosphogluconate dehydrogenase and isocitrate dehydrogenase, enzymes not induced by T3 in chick-embryo hepatocytes. H-8 also had no effect on the activities of malic enzyme, fatty acid synthase, and acetyl-CoA carboxylase in hepatocytes not treated with T3. Synthesis of soluble protein, levels of mRNAs for beta-actin and glyceraldehyde-3-phosphate dehydrogenase, and induction of metallothionein mRNA by Zn2+ were unaffected by H-8 at concentrations that inhibited the T3-induced accumulation of lipogenic enzymes and their mRNAs. H-8 inhibited T3-induced transcription of the genes for both malic enzyme and fatty acid synthase but had little effect on transcription of the beta-actin or glyceraldehyde-3-phosphate dehydrogenase genes or on total RNA synthesis in isolated nuclei. H-8 also had no effect on binding of T3 to its nuclear receptor. In isolated nuclei, H-8 inhibited phosphorylation of total protein by 15-20%. Phosphorylation of only one major protein was consistently and substantially inhibited, indicating that the effect of H-8 was selective. These results suggest that on-going protein phosphorylation is required specifically for stimulation of transcription of the lipogenic genes by T3.
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PMID:Triiodothyronine-induced accumulations of malic enzyme, fatty acid synthase, acetyl-coenzyme A carboxylase, and their mRNAs are blocked by protein kinase inhibitors. Transcription is the affected step. 168 Jan 29

Dehydroepiandrosterone (DHEA) treatment is effective in preventing or delaying the onset of various genetic and induced disorders of mice and rats. Associated with the beneficial therapeutic effects exerted by action of this steroid is the development of hepatomegaly. To determine whether the changes associated with hepatomegaly also involve alterations in activities of tissue enzymes, we evaluated the effects of DHEA (0.45% in food, w/w) on hepatic protein kinases, phosphatases, and lipogenic enzymes in mice of various strains. The rates of fatty acid and cholesterol syntheses also were evaluated. DHEA administration resulted in profound changes in the sodium dodecylsulfate-polyacrylamide gel electrophoresis patterns of endogenous radiophosphorylated proteins obtained by incubation of liver homogenates with (gamma-32P]ATP. These changes were dependent upon the medium used for homogenization. Thus, when homogenates of liver tissue of DHEA-treated mice were prepared in Tris buffer containing sucrose (0.25 M) there was a marked decrease in phosphorylation of the proteins of relative molecular weight approximately 116,000 (Mr approximately 116,000), approximately 82,000, approximately 80,000, approximately 58,000, approximately 56,000, approximately 48,000, approximately 34,000, and approximately 31,000 compared with controls. With liver homogenates of DHEA-treated mice prepared in Tris buffer alone, there was a marked increase in phosphorylation of the proteins of Mr approximately 70,000, approximately 49,000, approximately 34,000, approximately 31,000, and 28,000 compared with controls. Moreover, the specific activity of kinases for endogenous protein acceptors in liver of control mice was higher than that in liver of DHEA-treated animals. The specific activities of casein kinase, cAMP-dependent protein kinase, and cGMP-dependent protein kinase remained unchanged with DHEA treatment, but the specific activity of histone kinase was increased approximately 30%. Long-term administration of DHEA also was associated with increases in the specific activities of liver AMPase and GTPase (approximately two times), but not of other nucleotidases, alkaline phosphatase, acid phosphatase, glucose-6-phosphatase, or phosphotyrosine phosphatase. The activity of hepatic NADP-linked malic enzyme was increased significantly (two to three times) by DHEA treatment of female mice of three different strains, but was unchanged in male C57BL/6 mice. The specific activities of hepatic glucose-6-phosphate dehydrogenase, NADP-linked isocitrate dehydrogenase, and ATP-citrate lyase were not affected significantly by DHEA treatment of mice. The rate of hepatic lipogenesis, determined by incorporation of tritium from 3H2O into fatty acids, was decreased approximately 70% in DHEA-treated mice, while the rate of cholesterol synthesis was increased approximately 44% compared with controls.
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PMID:Dehydroepiandrosterone feeding and protein phosphorylation, phosphatases, and lipogenic enzymes in mouse liver. 215 82

In Escherichia coli, the phosphorylation and dephosphorylation of isocitrate dehydrogenase (IDH) are catalyzed by a bifunctional protein kinase/phosphatase. We have determined the nucleotide sequence of aceK, the gene encoding IDH kinase/phosphatase. This gene consists of a single open reading frame of 1,734 base pairs preceded by a Shine-Dalgarno ribosome-binding site. Examination of the deduced amino acid sequence of IDH kinase/phosphatase revealed sequences which are similar to the consensus sequence for ATP-binding sites. This protein did not, however, exhibit the extensive sequence homologies which are typical of other protein kinases. Multiple copies of the REP family of repetitive extragenic elements were found within the intergenic region between aceA (encoding isocitrate lyase) and aceK. These elements have the potential for combining to form an exceptionally stable stem-loop structure (delta G = -54 kcal/mol [ca. -226 kJ/mol]) in the mRNA. This structure, which masks the ribosome-binding site and start codon for aceK, may contribute to the downshift in expression observed between aceA and aceK. Another potential stem-loop structure (delta G = -29 kcal/mol [ca. 121 kJ/mol]), unrelated to the REP sequences, was found within aceK.
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PMID:Nucleotide sequence of aceK, the gene encoding isocitrate dehydrogenase kinase/phosphatase. 283 70

The reversibility of the reactions catalyzed by the wheat germ kinase and the cyclic AMP independent protein kinases isolated from human erythrocytes (casein kinases A and G) and rabbit skeletal muscle (casein kinases I and II) has been investigated. The reverse reaction requires ADP, Mg2+, phosphoprotein, and kinase and results in the formation of ATP from the phosphoprotein and ADP. The requirement for ADP in the wheat germ kinase and casein kinases II and G catalyzed reactions appears to be nonspecific. These kinases can also utilize GDP, IDP, and UDP as phosphoryl acceptors. Studies with the wheat germ protein T-substrate indicate that the phosphorylation of this protein substrate by the kinases is fully reversible. By contrast, the phosphorylation of phosvitin and casein is only partially reversible. Since the T-substrate is found to contain multiple phosphorylation sites and can serve as phosphoryl acceptor for the various kinases, the specificity of the phosphorylation of the substrate by the kinases is examined by way of the reverse reaction. The wheat germ kinase, casein kinase G, and casein kinase II appear to phosphorylate the same sites on the T-substrate as they are capable of completely dephosphorylating each other's 32P-T-substrate. Each of these kinases can catalyze the incorporation of 12 mol of 32P/48 000 g of T-substrate. In contrast, casein kinases A and I can incorporate only 6 mol of 32P/48 000 g of T-substrate. Studies on the reverse reactions suggest that these phosphorylation sites may be the same for both enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reversible phosphorylation of T-substrate by wheat germ, human erythrocyte, and rabbit skeletal muscle protein kinases. 665 66

(1) Pyruvate kinase type M2 from rat lung has been purified 840-fold with an overall yield of 20%. The enzyme gave a single band upon SDS-electrophoresis and isoelectrofocusing and had a specific activity of 1340 U/mg protein. The homotetramer of Mr = 224000 and an isoelectric point of pH 5.8 had an amino acid composition closely resembling that of other pyruvate kinase isoenzymes type M2, except that of the chicken liver. The enzyme was crystallized. (2) The enzyme has its pH optimum at pH 6.5. The K0.5 value for phosphoenolpyruvate is 0.26 mM (nH = 1.81) which decreases in the presence of 0.2 mM fructose 1,6-bisphosphate to 0.056 mM (nH = 1.06). 1 microM fructose 1,6-bisphosphate activates the enzyme at 0.1 mM phosphoenolpyruvate half-maximally. The Km value for ADP at 1 mM phosphoenolpyruvate is 0.4 mM. The Km value for other nucleoside diphosphates increases in the order ADP less than GDP less than IDP less than UDP. (3) No evidence for an interconversion of pyruvate kinase type M2 from rat or chicken lung was found. The enzyme was neither a substrate for the cAMP-dependent protein kinase from rabbit muscle nor for the cAMP-independent protein kinase from chicken liver. Since pyruvate kinase type M2 from chicken liver is inactivated by phosphorylation catalyzed by a cAMP-independent protein kinase (Eigenbrodt, E., Abdel-Fattah Mostafa, M. and Schoner, W. (1977) Hoppe-Seyler's Z. Physiol. Chem. 358, 1047-1055) we suggest that the interconvertible form of pyruvate kinase type M2 may represent a separate form of the pyruvate kinase type M2 family.
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PMID:Purification and properties of pyruvate kinase type M2 from rat lung. 711 73

Dissociated single fibers from the mouse flexor digitorum brevis (FDB) muscle were used in patch clamp experiments to investigate the mechanisms of activation and inactivation of KATP in mammalian skeletal muscle. Spontaneous rundown of channel activity, in many excised patches, occurred gradually over a period of 10-20 min. Application of 1.0 mM free-Ca2+ to the cytoplasmic side of the patch caused irreversible inactivation of KATP within 15 sec. Ca(2+)-induced rundown was not prevented by the presence of 1.0 microM okadaic acid or 2.0 mg ml-1 of an inhibitor of calcium-activated neutral proteases, a result consistent with the conclusion that phosphatases or calcium-activated neutral proteases were not involved in the rundown process. Application of 1.0 mM Mg.ATP to Ca(2+)-inactivated KATP caused inhibition of residual activity but little or no reactivation of the channels upon washout of ATP, even in the presence of the catalytic subunit of cyclic AMP-dependent protein kinase (10 U ml-1). Mg.ATP also failed to reactivate KATP, even after only partial spontaneous rundown, despite the presence of channels that could be activated by the potassium channel opener BRL 38227. Nucleotide diphosphates (500 microM; CDP, UDP, GDP and IDP) caused immediate and reversible opening of Ca(2+)-inactivated KATP. Reactivation of KATP by ADP (100 microM) increased further upon removal of the nucleotide. In contrast to KATP from cardiac and pancreatic cells, there was no evidence for phosphorylation of KATP from the surface sarcolemma of dissociated single fibers from mouse skeletal muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Rundown and reactivation of ATP-sensitive potassium channels (KATP) in mouse skeletal muscle. 780 25

The isocitrate dehydrogenase kinase/phosphatase (IDHK/P) of E. coli is a bifunctional enzyme responsible for the reversible phosphorylation of isocitrate dehydrogenase (IDH) on a seryl residue. As such, it belongs to the serine/threonine protein kinase family. However, only a very limited homology with the well-characterized eukaryotic members of that family was identified so far in its primary structure. In this report, a new region of amino acids including three putative residues involved in the kinase activity of IDHK/P was identified by sequence comparison with eukaryotic protein kinases. In IDHK/P, these residues are Asp-371, Asn-377, and Asp-403. Their counterpart eukaryotic residues have been shown to be involved in either catalysis (former residue) or magnesium binding (the two latter residues). Site-directed mutagenesis was performed on these three IDHK/P residues, and also on the Glu-439 residue equivalent to that of the Ala-Pro-Glu motif found in the eukaryotic protein kinases. Mutations of Asp-371 into either Ala, Glu, or Gln residues drastically lowered the yield and the quality of the purification. Nevertheless, the recovered mutant enzymes were barely able to phosphorylate IDH either in vitro or after expression in an aceK (-) mutant strain. In contrast, mutation of either Asn-377, Asp-403, or Glu-439 into an Ala residue altered neither the yield of purification nor the maximal phosphorylating capacity of the enzyme. However, when IDH was phosphorylated in the presence of increasing concentrations of magnesium ions, the two former mutants displayed a much lower affinity for this cation, with a K(m) value of 0.6 or 0.8 mM, respectively, as compared to 0.1 mM for the wild-type enzyme. On the other hand, the Glu439Ala mutant has an affinity for magnesium essentially unaffected. Therefore, and in contrast to the current opinion, our results suggest that the catalytic mechanism of IDHK/P exhibits some similarities with that found in the eukaryotic members of the protein kinase family.
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PMID:The "catalytic" triad of isocitrate dehydrogenase kinase/phosphatase from E. coli and its relationship with that found in eukaryotic protein kinases. 1125 18

Depolarization, growth factors, neurotrophins, and other stimuli induce expression of immediate early genes (IEGs) in neurons. We identified a subset of IEGs, IPD-IEGs, which are induced preferentially by depolarization, but not by neurotrophins or growth factors, in PC12 cells. The "promiscuous" IEGs Egr1 and c-fos, induced by growth factors and neurotrophins, in addition to depolarization, require activation of the MAP kinase signaling pathway for induction in response to KCl depolarization in PC12 cells; MEK1/2 inhibitors block KCl-induced Egr1 and c-fos expression. In contrast, MEK1/2 inhibition has no effect on KCl-induced expression of the known IPD-IEGs in PC12 cells. Additional "candidate" IDP-IEGs were identified by a microarray comparison of genes induced by KCl in the presence vs. the absence of an MEK1/2 inhibitor in PC12 cells. Northern blot analyses demonstrated that representative newly identified candidate IPD-IEGs, as with the known IPD-IEGs, are also induced by a MAP kinase- independent pathway in response to depolarization, both in PC12 cells and in rat primary cortical neurons. Nerve growth factor and epidermal growth factor are unable to induce the expression of the Crem/Icer, Nur77, Nor1, Rgs2, Dusp1 (Mkp1), and Dscr1 genes in PC12 cells, validating their identification as IPD-IEGs. Inhibiting calcium/calmodulin-dependent kinase II (CaMKII), calcineurin, or protein kinase A (PKA) activity prevents KCl-induced IPD-IEG mRNA accumulation, suggesting that the IPD-IEG genes are induced by depolarization in neurons via a combination of calcineurin/PKA- and CaMKII-dependent pathways.
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PMID:The MAPK pathway is required for depolarization-induced "promiscuous" immediate-early gene expression but not for depolarization-restricted immediate-early gene expression in neurons. 1794 Oct 51


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