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

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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)

C-protein, a thick filament-associated protein, has been isolated from bovine myocardium and found to be a substrate in vitro of the Ca2+- and phospholipid-dependent protein kinase (protein kinase C). Incorporation of approximately 1.6 mol Pi/mol C-protein was observed. This phosphorylation was dependent on both Ca2+ and a phospholipid (L-alpha-phosphatidyl-L-serine was used). Phosphate incorporation specifically into C-protein was verified by SDS-polyacrylamide gel electrophoresis and autoradiography and was almost exclusively into serine residues (86.9%), with only a small amount of phosphothreonine (13.1%) and no phosphotyrosine being detected. Two-dimensional thin-layer electrophoresis of a chymotryptic digest of phosphorylated C-protein indicated site specificity of phosphorylation. Cardiac C-protein is known to be a substrate of cAMP-dependent protein kinase both in vitro and in vivo (Jeacocke, S.A. and England, P.J. (1980) FEBS Lett. 122, 129-132). Isolated bovine cardiac C-protein was rapidly phosphorylated, to the extent of 5 mol/mol, by the purified catalytic subunit of cAMP-dependent protein kinase. Phosphorylation catalyzed by these two protein kinases was not additive, suggesting that the sites phosphorylated by protein kinase C are also phosphorylated by cAMP-dependent protein kinase. Chicken cardiac muscle has also been shown to contain a Ca2+, calmodulin-dependent protein kinase which phosphorylates C-protein (Hartzell, H.C. and Glass, D.B. (1984) J. Biol. Chem. 259, 15587-15596). The physiological role of cardiac C-protein may therefore be subject to regulation by multiple protein kinases.
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PMID:Phosphorylation of bovine cardiac C-protein by protein kinase C. 384 Sep 98

A simple and economical procedure, capable of routine application, is described for the labelling of cerebral phosphoproteins in vivo. [32P]Orthophosphate, in high concentration, was infused into selected brain areas of anaesthetised rats under stereotaxic control. The animals were frozen with liquid N2 and the labelled tissue punched out of frozen thick sections. [32P]Polypeptides were analysed by high-resolution two-dimensional gel electrophoresis. Several phosphoproteins on the gels were provisionally identified, including synapsin I, MAP-2 and an 82-87 kdalton substrate of protein kinase 'C'.
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PMID:A simple and economical method for studying protein phosphorylation in vivo in the rat brain. 399 5

Phosphate uptake by brush-border membrane (BBM) vesicles prepared from hypophosphatemic mice (Hyp) is reduced by half relative to BBM vesicles from normal mice. To investigate this abnormality, we studied the protein composition of BBM, their capacity to bind inorganic phosphate, and their protein kinase activity with and without the addition of exogenous cAMP, in normal and Hyp mice. Gradient polyacrylamide gel electrophoresis of BBM proteins showed 27 bands which were identical in normal and Hyp mice. Incubation of the membranes with ortho[32P]phosphate at 0 degrees C revealed a phosphate binding protein with an apparent molecular weight (Mr) of 79000, which has been previously identified in rats as the monomer of alkaline phosphatase. In normal mice, the Scatchard plot of phosphate binding was not linear, suggesting heterogeneity of the binding sites with two major components. At high substrate concentrations, the affinity (K) was 1.42 mM and maximal binding (Bmax) was 83 pmol/mg protein. At low substrate concentrations, these values were 0.07 mM and 10.9 pmol/mg, respectively. In Hyp mice BBM, only one binding system was found with K and Bmax values of 0.38 mM and 53.8 pmol/mg. Incubation of the membranes with 25 microM[gamma-32P]ATP resulted in the phosphorylation of 11 proteins. The major band (Mr: 79000) corresponded to the inorganic phosphate binding protein, i.e., to the alkaline-phosphatase monomer. The 11 proteins showed maximal phosphorylation at pH 10. The protein of 79000 Mr showed a second peak of phosphorylation at pH 7.5.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Renal brush border membranes from mice with X-linked hypophosphatemia: protein composition, phosphate binding capacity, and protein kinase activity. 609 82

6-Phosphofructo-2-kinase (PFK2) is activated by a cAMP-dependent protein kinase, and inactivated by phosphatase, indicating the interconversion of PFK2. Inorganic phosphate also activates PFK2, and the optimum pH for the PFK2 activity varies with the concentration of phosphate. Phosphate also enhances the inactivation of PFK2 by citrate, suggesting that phosphate acts as a regulator of PFK2.
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PMID:Activation of yeast 6-phosphofructo-2-kinase by protein kinase and phosphate. 609 66

Acetyl CoA carboxylase was purified from liver of fasted-refed rats to near homogeneity, based on electrophoretic analysis and biotin content. These preparations contained an endogenous protein kinase that catalyzed the transfer of radioactive phosphate from [gamma-32P]ATP to acetyl CoA carboxylase, accompanied by a decrease in acetyl CoA carboxylase activity. Phosphate incorporated into acetyl CoA carboxylase was removed when the preparation was incubated with partially purified phosphorylase phosphatase catalytic subunit with regain of enzymatic activity. This endogenous protein kinase was shown not to be affected by either cyclic-AMP-dependent protein kinase inhibitor, EGTA, or trifluoperazine. The addition of either cyclic-AMP or purified cyclic-AMP-dependent protein kinase catalytic subunit to the purified acetyl CoA carboxylase preparation increased protein phosphorylation but had no further effect on acetyl CoA carboxylase activity. Purified acetyl CoA carboxylase was shown to act as an ATPase during the phosphorylation reaction.
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PMID:Regulation of purified rat liver acetyl CoA carboxylase by phosphorylation. 613 2

The Ca2+- and phospholipid-dependent protein kinase (protein kinase C) has been found to phosphorylate and inactivate glycogen synthase. With muscle glycogen synthase as a substrate, the reaction was stimulated by Ca2+ and by phosphatidylserine. The tumor-promoting phorbol esters 12-O-tetradecanoyl phorbol 13-acetate was also a positive effector, half-maximal activation occurring at 6 nM. Phosphorylation of glycogen synthase, but not histone, was partially inhibited by glycogen, half-maximally at 0.05 mg/ml, probably via a substrate-directed mechanism. The rate of glycogen synthase phosphorylation was approximately half that for histone; the apparent Km for glycogen synthase was 0.25 mg/ml. Protein kinase C also phosphorylated casein, the preferred substrate among the individual caseins being alpha s1-casein. Glycogen synthase was phosphorylated to greater than 1 phosphate/subunit with an accompanying reduction in the -glucose-6-P/+glucose-6-P activity ratio from 0.9 to 0.5. Phosphate was introduced into serine residues in both the NH2-terminal and COOH-terminal CNBr fragments of the enzyme subunit. The two main tryptic phosphopeptides mapped in correspondence with the peptides that contain site 1a and site 2. Lesser phosphorylation in an unidentified peptide was also observed. Rabbit liver and muscle glycogen synthases were phosphorylated at similar rates by protein kinase C. The above results are compatible with a role for protein kinase C in the regulation of glycogen synthase as was suggested by a recent study of intact hepatocytes.
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PMID:Phosphorylation of glycogen synthase by the Ca2+- and phospholipid-activated protein kinase (protein kinase C). 623 16

The regulatory subunit of the type I cAMP-dependent protein kinase (RI) can be separated into multiple forms on isoelectric focusing gels. RI from bovine skeletal muscle gives rise to bands at pI = 5.57 and 5.45. Phosphate determinations indicate that the more acidic band contains protein-bound phosphate. RI from rat skeletal muscle can be separated into three bands of pI = 5.57, 5.45, and 5.35. The two acidic forms comigrate with labeled RI isolated from rat soleus muscles that were incubated with [32P]orthophosphate. RI from bovine muscle is isolated mainly in the unphosphorylated state while that from rat muscle is primarily phosphorylated. At lest 4 mol of phosphate can be incorporated into each RI dimer following extensive phosphorylation by cGMP-dependent protein kinase in vitro. Two phosphopeptides are observed on polyacrylamide gels following partial proteolysis of in vitro phosphorylated rat RI. One of these peptides is also observed following proteolysis of rat RI phosphorylated in intact soleus muscles.
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PMID:Studies on the phosphorylation of the type I cAMP-dependent protein kinase. 625 Oct 86

Phosphorylation and synthesis of type I regulatory subunit (RI) of cAMP-dependent protein kinase were studied using two-dimensional polyacrylamide gel electrophoresis of [35S]methionine-labeled proteins from intact S49 mouse lymphoma cells. [32P]Phosphate labeling, peptide mapping, and acid hydrolysis confirm that charge heterogeneity in RI results from phosphorylation of a single serine residue. In drug-free cells, phosphorylation proceeds to a steady state proportion of 90 to 95% of total RI with a half-time of about 25 min. The rate and steady state extent of RI phosphorylation are reduced by some, but not all, agents causing intracellular kinase activation. These results suggest that RI might assume different conformations in association with different amounts of cAMP or different analogs of cAMP. Endogenous kinase activation has no immediate effect on RI synthesis but leads to a moderate increase in RI synthesis after several hours; this induction occurs with all agents tested. Mutants of S49 cells lacking catalytic activity of cAMP-dependent protein kinase exhibit reduced phosphorylation and synthesis of RI. Comparative studies suggest that the phosphorylation of RI and its induction by kinase activation are fairly general phenomena; the extent of RI phosphorylation and the relative rate of RI synthesis are variable among cell types.
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PMID:Studies on the phosphorylation and synthesis of type I regulatory subunit of cyclic AMP-dependent protein kinase in intact S49 mouse lymphoma cells. 627 Jan 51

A novel peptide mapping approach has been used to map sites of charge modification to major structural domains of regulatory subunit (R) of type I cAMP-dependent protein kinase from S49 mouse lymphoma cells. Proteolytic fragments of crude, radiolabeled R were purified by cAMP affinity chromatography and displayed by two-dimensional polyacrylamide gel electrophoresis. [35S]methionine-labeled peptides containing sites of mutation or phosphorylation exhibited charge heterogeneity attributable to the modification. Phosphate-containing fragments were also labeled with [32P]orthophosphate to confirm their phosphorylation. Major fragments from [35S]methionine-labeled S49 cell R corresponded in size to carboxyterminal cAMP-binding fragments reported from proteolysis of purified type I Rs from various mammalian species; additional fragments were also visualized. End-specific markers in Rs from some mutant S49 sublines confirmed that cAMP-binding fragments extended to the carboxyterminus of R. Aminoterminal endpoints of fragments could be deduced, therefore, from peptide molecular weights. Clustering of proteolytic cleavage sites within the "hinge-region" separating aminoterminal and carboxyterminal domains of R permitted high resolution mapping in this region: the endogenous phosphate and a "phenotypically-silent" electrophoretic marker mutation fell within a 2.5-kdalton interval at its aminoterminal end. On the other hand, Ka mutations that increase the apparent constant for activation of kinase by cAMP mapped within the large cAMP-binding region of R. A map of charge density distribution within the hinge-region of R was constructed to facilitate structural comparisons between Rs from S49 cells and from other mammalian sources.
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PMID:Sites of phosphorylation and mutation in regulatory subunit of cyclic AMP-dependent protein kinase from S49 mouse lymphoma cells: mapping to structural domains. 631 40

A protein kinase, able to phosphorylate casein, phosvitin, and glycogen synthase, was purified approximately 9000-fold from rabbit liver, and appeared analogous to an enzyme studied by Itarte and Huang (Itarte, E., and Huang, K.-P. (1979) J. Biol. Chem. 254, 4052-4057). This enzyme, designated here casein kinase-1, was shown to be a distinct glycogen synthase kinase and in particular to be different from the protein kinase GSK-3 (Hemmings, B.A., Yellowlees, D., Kernohan, J.C., and Cohen, P. (1981) Eur. J. Biochem. 119, 443-451). Casein kinase-1 had native molecular weight of 30,000 as judged by gel filtration. The enzyme phosphorylated beta-casein A or B better than kappa-casein or alpha s1-casein, and modified only serine residues in beta-casein B and phosvitin. The apparent Km for ATP was 11 microM, and GTP was ineffective as a phosphoryl donor. The phosphorylation of glycogen synthase by casein kinase-1 was inhibited by glycogen, half-maximally at 2 mg/ml, and by heparin, half-maximally at 0.5-1.0 microgram/ml, but was unaffected by Ca2+ and/or calmodulin, or by cyclic AMP. Phosphorylation of muscle glycogen synthase proceeded to a stoichiometry of at least 6 phosphates/subunit with reduction in the +/- glucose-6-P activity ratio to less than 0.4. Phosphate was introduced into both a COOH-terminal CNBr fragment (CB-2) as well as a NH2-terminal fragment (CB-1). At a phosphorylation stoichiometry of 6 phosphates/subunit, 84% of the phosphate was associated with CB-2 and 6.5% with CB-1. The remainder of the phosphate was introduced into another CNBr fragment of apparent molecular weight 16,500. Phosphorylation by casein kinase-1 correlated with reduced electrophoretic mobilities, as analyzed on polyacrylamide gels in the presence of sodium dodecyl sulfate, of the intact glycogen synthase subunit, as well as the CNBr fragments CB-1 and CB-2.
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PMID:Glycogen synthase kinases. Classification of a rabbit liver casein and glycogen synthase kinase (casein kinase-1) as a distinct enzyme. 632 24


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