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)

The pyruvate dehydrogenase complex has been demonstrated in high speed pellet preparations from sonicated ribbed mussel gill mitochondria. The activity of the complex is inhibited by low chloride (less than 100 mM) concentrations, EDTA (1 mM), succinate, ATP, and NAD/NADH ratios below 4. Inhibition by EDTA is relieved by addition of 10 mM MgCl2-1 mM CaCl2. ATP inhibition was enhanced by NaF and reversed by high Mg++ concentrations in the absence of NaF. Pyruvate and thiamine pyrophosphate inhibited the inactivation by ATP. The nonhydrolyzable ATP analog AMP-PNP caused inhibition of the overall catalytic activity that was identical to ATP. Factors involved in the ATP inhibition and Mg++ reversal are lost with freezing or cold storage. Preliminary results using gamma-32P-ATP indicate that a protein kinase that phosphorylates the alpha subunit of E1 (pyruvate dehydrogenase) from the mammalian PDC is associated with the gill PDC. The activity of the complex may be regulated by a phosphorylation/dephosphorylation mechanism and by the relative levels of substrates, products, and other metabolites in the mitochondria.
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PMID:Pyruvate dehydrogenase complex from ribbed mussel gill mitochondria. 408 84

The protein kinase activity associated with pp60src of a mutant of RSV temperature sensitive for transformation was shown to be sixfold more labile than that of its wild-type parent at 45 degrees C when pp60src's synthesized in vitro were compared. Thus, a mutant that is temperature sensitive for transformation has a temperature-sensitive protein kinase activity. Analysis of the levels of protein kinase activity in immunoprecipitates from cells infected with four different temperature-sensitive mutants of RSV led to the surprising finding that two mutants had barely detectable levels of protein kinase activity even at the permissive temperature, whereas two others had levels of activity at the nonpremissive temperatures that were as great as 40% that of wild-type pp60src. Protein kinase activity of pp60src of NY68 was partially renatured when cells were shifted from 41 degrees C to 36 degrees C. This reactivation occurred in less than an hour and did not require protein synthesis. It was found that pp60src synthesized in vitro is phosphorylated. Finally, the methionine-containing tryptic peptides of pp60sarc immunoprecipitated from uninfected chick cells were very similar to those of viral pp60src.
Cold Spring Harb Symp Quant Biol 1980
PMID:Studies on the structure and function of the avian sarcoma virus transforming-gene product. 625 24

The hormonal response of viable mouse thymocytes is radically dependent of their ambient temperature. While at 37 degrees C the cells respond to isoproterenol by an abrupt rise (within 30 s) followed by a exponential decline in the level of intracellular cAMP, at 4 degrees C the level of cAMP remains high, i.e. there is an inhibition of the hormone-induced refractory state. These distinctly different patterns of response are reflected also in both the state of activation of cAMP-dependent protein kinase and the activity of adenylate cyclase. The inhibition of cellular refractoriness in the cold is shown to be fully reversible, lasting only as long as the hormone is present in the extracellular medium. Washing out the hormone or displacing it by a specific antagonist (propranolol) results in a decline of cAMP, of the activity ratio of the kinase, and of the activity of the adenylate cyclase back to basal values. Evidence is presented to show that at 4 degrees C there is no significant hormone-dependent decreases in cAMP degradation or efflux. On the other hand, the activity of adenylate cyclase remains persistently high, through neither the hormone-binding site of the receptor nor the active site of the catalytic subunit of the cyclase seem to be impaired. The different response pattern observed at 4 degrees C appears, therefore, to be associated with the transfer and the signal between these two sites and probably with the G/F protein (s). The possibility to dissect in a selective and reversible manner the process of hormonal stimulation (coupling) from the process of desensitization, which, under normal physiological conditions constitute consecutive and inseparable chain of events, leads us to a propose that the signal transfer which enables activation of adenylate cyclase is, somewhere along its way, distinct from the signal transfer which brings about the onset of the refractory state, and to conclude that these two processes are partially autonomous and regulated by either two different proteins or two different sites on the same protein. The postulated proteins (or sites) should, therefore, differ in their sensitivity to temperature changes, a difference which may be most useful in the identification and isolation of the molecular species involved and in the study of their properties and their mechanism of action.
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PMID:Exposure of thymocytes to a low temperature (4 degrees C) inhibits the onset of their hormone-induced cellular refractoriness. 627 31

We recently reported the partial purification of a cAMP-independent and Ca2+-calmodulin-independent glycogen synthase kinase from porcine renal cortex (Schlender, K. K., Beebe, S. J., and Reimann, E. M. (1981) Cold Spring Harbor Conf. Cell Proliferation, 389-400). Subsequent purification indicated that the enzyme preparation consisted of at least three forms of glycogen synthase kinase which could be resolved by ATP gradient elution from aminoethylphosphate-agarose (AEP-agarose). The predominant form of glycogen synthase kinase, which eluted from AEP-agarose between 2 and 6 mM ATP, was purified approximately 800-fold and is designated GSK-A1. It had a molecular weight of 45,000-50,000 as determined by gel filtration and sucrose density gradient centrifugation. It catalyzed the transfer of 1 mol of 32P/mol of synthase subunit into a low molecular weight (10,000) CNBr peptide which was tentatively identified as Ser-7 (site 2) by high performance liquid chromatography. This phosphorylation decreased the activity ratio (activity in the absence of glucose-6-P divided by activity in the presence of 7.2 mM glucose-6-P) from 0.95 to about 0.55. GSK-A1 appeared to be specific for and had low s0.5 values for both substrates, ATP (13 microM) and glycogen synthase (0.3-0.4 microM). The enzyme could not use GTP as the phosphate donor. GSK-A1 was not affected by the protein kinase inhibitor, cAMP, cGMP, Ca2+-calmodulin, EGTA, or trifluoperazine and had a broad pH optimum (pH 7.0-8.5). A second form, GSK-A2, was eluted from AEP-agarose between 7 and 9 mM ATP. GSK-A2 could transfer a 2nd mol of 32P/mol of synthase subunit and decreased the activity ratio to 0.30. The interrelation among these multiple forms is not clear, but the data suggest that multiple kinases are required to form the highly inactivated glycogen synthase in renal tissues.
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PMID:Purification and characterization of a cAMP- and Ca2+-calmodulin-independent glycogen synthase kinase from porcine renal cortex. 631 98

We mutagenized a cloned fragment of polyoma DNA encoding portions of the middle size (MT) and large T antigens. We regenerated infectious viral genomes containing the mutagenized DNA and tested their transforming ability at 32 and 39 degrees C. We isolated three nontransforming mutants and two mutants which were cold sensitive for the maintenance of cell transformation. The nontransforming mutants contained amber termination codons in the reading frame for the MT antigen. They synthesized truncated MT antigens which lacked MT-associated protein kinase activity. The cold-sensitive mutants synthesized MT antigens indistinguishable from wild type with regard to size, stability at 32 and 39 degrees C, intracellular location, and associated protein kinase activity. One of the mutants was shown by nucleotide sequence analysis to contain a single amino acid change in the MT antigen, located two residues upstream from the C-terminal hydrophobic region, and no changes in the large T antigen. The other mutant contained two amino acid changes in the MT antigen and two amino acid changes in the large T antigen.
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PMID:Characterization of viable mutants of polyomavirus cold sensitive for maintenance of cell transformation. 632 64

Cold-labile microtubule protein can be rendered cold-stable by addition of a fraction containing a small number of polypeptides that are derived from cold-stable microtubules. These polypeptides can be obtained from purified cold-stable microtubules by passage through a DEAE-cellulose (DE-52) ion exchange column from which they emerge in the first eluate fraction. The stabilizing activity of these proteins is abolished by phosphorylation catalyzed by two types of protein kinases, one dependent on calmodulin and the other independent of that regulatory protein. The calmodulin-dependent reaction appears to phosphorylate mainly two polypeptides, 56 and 72 kilodaltons; the reaction is blocked by trifluoperazine. The calmodulin-independent reaction appears to phosphorylate different cold-stable microtubule-associated proteins. That reaction is observed only in purified material obtained from vigorously homogenized brain tissue. Gently homogenization yields cold-stable microtubules that are responsive only to the calmodulin-dependent protein kinase. A distinguishing feature of the calmodulin-independent reaction is that it does not occur on polypeptides while they are bound to the microtubules.
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PMID:Regulation of microtubule cold stability by calmodulin-dependent and -independent phosphorylation. 657 83

Saccharomyces cerevisiae CTDK-I is a protein kinase complex that specifically and efficiently hyperphosphorylates the carboxyl-terminal repeat domain (CTD) of RNA polymerase II and is composed of three subunits of 58, 38, and 32 kDa. The kinase is essential in vivo for normal phosphorylation of the CTD and for normal growth and differentiation. We have now cloned the genes for the two smaller kinase subunits, CTK2 and CTK3, and found that they form a unique, divergent cyclin-cyclin-dependent kinase complex with the previously characterized largest subunit protein CTK1, a cyclin-dependent kinase homolog. The CTK2 gene encodes a cyclin-related protein with limited homology to cyclin C, while CTK3 shows no similarity to other known proteins. Copurification of the three gene products with each other and CTDK-I activity by means of conventional chromatography and antibody affinity columns has verified their participation in the complex in vitro. In addition, null mutations of each of the genes and all combinations thereof conferred very similar growth-impaired, cold-sensitive phenotypes, consistent with their involvement in the same function in vivo. These characterizations and the availability of all of the genes encoding CTDK-I and reagents derivable from them will facilitate investigations into CTD phosphorylation and its functional consequences both in vivo and in vitro.
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PMID:The yeast carboxyl-terminal repeat domain kinase CTDK-I is a divergent cyclin-cyclin-dependent kinase complex. 756 23

p53 is an allosterically regulated protein with a latent DNA-binding activity. Posttranslational modification of a carboxy-terminal regulatory site in vitro, by casein kinase II and protein kinase C, can activate the sequence-specific DNA-binding function of the wild-type protein. The latent form of p53 is produced in a variety of eukaryotic and prokaryotic cell lines, including E. coli, Sf9 insect cells, and C6 cells, indicating that the activation of p53 in vivo is rate-limiting. In addition, phosphorylation of p53 at the protein kinase C site and activation in vivo correlate with the loss of reactivity of active p53 protein to the carboxy-terminal antibody, PAb421. These results suggest that two highly conserved protein kinases modify polypeptide structure through a common biochemical mechanism and that different enzymatic pathways may channel information into the carboxy-terminal regulatory site of p53, allosterically activating its function as a tumor suppressor.
Cold Spring Harb Symp Quant Biol 1994
PMID:Regulation of the cryptic sequence-specific DNA-binding function of p53 by protein kinases. 758 70

During brain development, the microtubule-associated protein tau presents a transient state of high phosphorylation. We have investigated the developmental distribution of the phosphorylated fetal-type tau in the developing rat cortex and in cultures of embryonic cortical neurons, using antibodies which react with tau in a phosphorylation-dependent manner. The phosphorylated fetal-type tau was present in the developing cortex at 20 days but not at 18 days of embryonic life and was not detected before four to five days in neuronal culture. The cyclin-dependent kinase p34cdc2 was expressed only in germinal layers in the embryonic brain and was not co-localized with phosphorylated tau. After 10 days of postnatal life, the phosphorylated tau progressively disappeared from cortical neurons, disappearing first from the deepest cortical layers where neurons are ontogenetically the oldest. Phosphorylated tau was found in axons and dendrites of cortical neurons at all developmental stages whereas unphosphorylated tau tended to disappear from dendrites during development. The timing of appearance of phosphorylated tau in the cortex, by comparison with the expression of other developmental markers, indicates that phosphorylated tau is present at a high level only during the period of intense neuritic outgrowth and that it disappears during the period of neurite stabilization and synaptogenesis, concomitantly to the expression of adult tau isoforms. In control cultures and in cultures treated with colchicine, the phosphorylated tau was not associated to cold-stable and to colchicine-resistant microtubules. These in vivo results suggest that the high expression of phosphorylated tau species is correlated with the presence of a dynamic microtubule network during a period of high plasticity in the developing brain.
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PMID:Distribution of the phosphorylated microtubule-associated protein tau in developing cortical neurons. 789 84

LTE1 belongs to the CDC25 family that encodes a guanine nucleotide exchange factor for GTP-binding proteins of the ras family. Previously we have shown that LTE1 is essential for termination of M phase at low temperatures. We have identified TEM1 as a gene that, when present on a multicopy plasmid, suppresses the cold-sensitive phenotype of lte1. Sequence analysis of TEM1 and GTP-binding analysis of the gene product revealed that TEM1 encodes a novel low-molecular-weight GTP-binding protein. The defect of TEM1 was lethal, and the tem1-defective cells were arrested at telophase with high H1-kinase activity under restrictive conditions, indicating that TEM1 is required to exit from M phase. The defect of TEM1 was suppressed by a high dose of CDC15, which encodes a protein kinase homologous to mitogen-activated protein kinase kinase kinases. The genetic interaction among LTE1, TEM1, and CDC15 indicates that they cooperatively play an essential role for termination of M phase.
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PMID:The yeast TEM1 gene, which encodes a GTP-binding protein, is involved in termination of M phase. 793 62


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