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)

Syntheses and biological activities of 12 N6-substituted adenosine 5'-phosphates and 15 cyclic 3',5'-phosphates are described. Included among these are the cyclic phosphates of the naturally occurring anticodon adjacent modified nucleosides, N6-(delta2-isopentenyl)adenosine and N-(purin-6-ylcarbamoyl)-L-threonine ribonucleoside. Also reported in this paper are the 5'-phosphates and cyclic phosphates of the cytokinins, N6-benzyladenosine, kinetin ribonucleoside, 3-(chloro-trans-2-buten-2-yl)adenosine,6-o-chlorophenylureidopurine ribonucleoside, and 6-allylureidopurine ribonucleoside. The 5'-nucleotides were prepared by direct phosphorylation of the corresponding ribonucleosides with POCl3 and triethyl phosphate. These compounds were converted to the cyclic 3',5'-phosphates by cyclization of the corresponding 5'-nucleotides with dicyclohexylcarbodiimide. Comparison of the cytotoxicity of the ribonucleosides with their 5'-nucleotides and cyclic 3',5'-nucleotides showed that some of the 5'-phosphates and cyclic phosphates were almost as active as the parent nucleosides. The 5'-nucleotides and the cyclic phosphates were more soluble than the parent nucleosides. The cyclic 3',5'-nucleotides were examined as alternate activators of cAMP-dependent protein kinase from beef heart. While all of the analogs studied showed some activity toward this enzyme, several compounds were more effective than cAMP itself. The analogs were also tested as substrates for cyclic 3',5'-nucleotide phosphodiesterase from beef heart. The N6-alkyl-cAMP analogs were poor substrates for the enzyme, while N6-carbamoyl-cAMP derivatives were inert toward this enzyme. These compounds did not inhibit the phosphodiesterase. Some of the cyclic phosphates exhibited marginal effect in the inhibition of glycogen synthesis in skin slices.
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PMID:Synthesis and antitumor activity of 5'-phosphates and cyclic 3',5'-phosphates derived from biologically active nucleosides. 16 81

The mechanism of inhibition of adenosine 3':5'-monophosphate (cyclic AMP)-dependent protein kinase was studied using a protein inhibitor isolated by a non-denaturing procedure from bovine heart. This protein inhibitor interacts with the catalytic subunit of protein kinase and binds to some substrates of the kinase. Protein kinase activity can also be inhibited by polyanions which, like the protein inhibitor, bind to basic substrates but do not bind to the catalytic subunit of protein kinase. Peptides such as L-lysyl-L-tyrosyl-L-threonine that resemble the phosphate accepting site of protein kinase substrates competitively inhibit phosphorylation of histone. Protein kinase activity can thus be inhibited in vitro by interaction of the protein inhibitor with substrates, and/or the catalytic subunit of the kinase, by competition of substrate analogs with "natural" substrates and by direct interaction of polyanions with basic protein substrates for the phosphotransferase reaction.
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PMID:Inhibition of adenosine 3':5'-monophosphate-dependent protein kinase: comparison of a protein inhibitor with polyanions and substrate analogs. 20 15

The BCR gene (Groffen et al., 1984) plays a critical role in the pathogenesis of human leukemias that involve the Philadelphia chromosome (Ph1) (Rowley, 1973; Nowell & Hungerford, 1960). Cells containing the Ph1 contain a chimeric gene formed from the fusion of BCR (Collins et al., 1987; Lifshitz et al. 1988) and ABL genes that results from the reciprocal translocation of segments of chromosomes 9 and 22 (Shtivelman et al., 1985). The product of this chimera is a 210 kDa protein, termed P210 BCR-ABL, that possesses an activated tyrosine kinase activity (Konopka et al., 1984; Kloetzer et al., 1985). Studies using long-term marrow culture systems and retrovirus-mediated gene transfer have documented that P210 BCR-ABL can stimulate the growth of immature hematopoietic precursor cell types (McLaughlin et al., 1987; Young & Witte, 1984). We have previously reported that P210 BCR-ABL exists in cytoplasmic complexes in association with a 53 kDa protein termed ph-P53 (Maxwell et al., 1987; Li et al. 1988). Similarly, BCR proteins have been found in cytoplasmic complexes containing ph-P53 in cells lacking the Ph1 (Li et al., 1989). These BCR protein complexes possess an associated ser/thr protein kinase activity. In this same study, we found that P210-containing complexes phosphorylate BCR proteins on tyrosine residues in vitro (Li et al., 1989). We now present results which demonstrate that P210 BCR-ABL is tightly associated with P160 BCR and ph-P53 proteins in cytoplasmic complexes from cells containing the Ph1.
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PMID:P210 BCR-ABL is complexed to P160 BCR and ph-P53 proteins in K562 cells. 214 May 98

We previously isolated a novel human transforming gene from a primary stomach cancer and identified it as an activated version of the c-raf-1 gene which is the human homologue of v-raf, a viral oncogene encoding a serine/threonine-specific protein kinase. Analyses of cDNA and genomic clones of this gene revealed that it was generated by substitution of 5'-sequence (exons 1-5) of the normal c-raf-1 gene with an unrelated human sequence. We identified the region in the genomic clone where the rearrangement had occurred. The rearranged EcoRI fragment was detected in all the primary transformants obtained from two independent transfections, suggesting that the recombination had occurred in the primary cancer. By sequence analysis of cDNA, the putative product of the transforming gene was inferred to have a hydrophobic stretch ahead of the ser/thr-protein kinase domain of the c-raf-1 gene product. We introduced one of the cDNA which contains the 1.6-kb open reading frame into the pUC9 vector. An autophosphorylating, 58 kd protein was induced in Escherichia coli cells bearing the plasmid upon induction. Since ser/thr-protein kinase activity of the normal c-raf protein has not been evidenced, these results suggest that the truncation/replacement of the amino-terminal domain of the c-raf-1 protein leads to constitutive activation of the protein kinase probably residing on the downstream domain.
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PMID:Structure of the activated c-raf-1 gene from human stomach cancer. 284 97

During cellular remodeling that accompanies cornification of epidermal cells, the highly phosphorylated protein, profilaggrin, is dephosphorylated and proteolytically cleaved to filaggrin, the keratin matrix protein. Using rat filaggrin phosphorylated by bovine casein kinase II (CK II) as a substrate, we have partially purified a phosphatase from rat epidermis which dephosphorylates rat profilaggrin in vitro. Anion exchange, hydroxylapatite, and gel filtration chromatography yielded a 100-fold purification of phosphatase from a low-salt extract. Further purification led to loss of activity; therefore, only the partially purified phosphatase was characterized. Two forms of the phosphatase, with molecular weights of approximately 170 and 40 kDa, were resolved during gel filtration. The 170-kDa form could be converted to the 40-kDa form in the presence of dithiothreitol. Both forms had pH optima of 6.6, and were strongly inhibited by NaCl (50% inhibition at 35-40 mM). Neither form hydrolyzed para-nitrophenylphosphate or dephosphorylated casein or the synthetic peptide arg3-glu3-thr-glu3, which were phosphorylated by casein kinase II. The two forms were similarly inhibited by known inorganic phosphatase inhibitors, with 22%-36% inhibition by 0.1 mM Na+/K+ tartrate, 55%-60% inhibition by 0.1 mM NaF, and 75% inhibition by 0.1 mM Na pyrophosphate. Para-chloromercuribenzoate also inhibited the activity, suggesting that reduced thiols may be important in catalysis. One mM calcium chloride altered the activity in a complex manner depending on the pH, suggesting a possible role for calcium in regulating enzyme activity.
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PMID:Characterization of an epidermal phosphatase specific for filaggrin phosphorylated by casein kinase II. 284 73

Rat tissue levels of Ca2+ . calmodulin-dependent protein kinase II (protein kinase II) and Ca2+ . phospholipid-dependent protein kinase (protein kinase C) were selectively assayed using the synthetic peptide syntide-2 as substrate. The sequence of syntide-2 (pro-leu-ala-arg-thr-leu-ser-val-ala-gly-leu-pro-gly-lys-lys) is homologous to phosphorylation site 2 in glycogen synthase. The relative Vmax/Km ratios of the known Ca2+-dependent protein kinases for syntide-2 were determined to be as follows: protein kinase II, 100; protein kinase C, 22; phosphorylase kinase, 2; myosin light chain kinase, 0.005. Levels of protein kinase II were highest in cerebrum (3.36 units/g tissue) and spleen (0.85 units/g) and lowest in testis (0.05 units/g) and kidney (0.04 units/g). Protein kinase II activity was localized predominantly in the 100,000g particulate fraction of cerebrum and testis, in the supernatant fraction of heart, liver, adrenal, and kidney, and about equally distributed between particulate and supernatant in spleen and lung. Likewise, protein kinase C activity was highest in cerebrum (0.56 units/g) and spleen (0.47 units/g), and the majority of activity was present in the cytosolic fraction for all tissues measured except for cerebrum and testis in which the kinase activity was equal in both fractions. Finally, the ratios of protein kinase II to protein kinase C were different in various rat tissues and between particulate and supernatant fractions. These results suggest somewhat different functions for these two Ca2+-regulated, multifunctional protein kinases.
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PMID:Calcium . calmodulin-dependent protein kinase II and calcium . phospholipid-dependent protein kinase activities in rat tissues assayed with a synthetic peptide. 302 65

A synthetic peptide ArgThrProProProSerGly with sequence similar to the threonine sites of phosphorylation in both myelin basic protein and simian virus 40 T antigen could be phosphorylated in vitro by a purified rat brain Ca2+-activated and phospholipid-dependent protein kinase, protein kinase C. The apparent Km and Vm values of this heptapeptide for the enzyme were determined to be 240 microM and 60 nmol/min/mg, respectively. Up to 0.8 mol 32P could be incorporated into the peptide, mainly at the threonine residue. Substitution of the L-threonine residue in the heptapeptide by its D-enantiomer abolished the phosphorylatability of the peptide by protein kinase C. However, this (D)Thr-containing peptide could act as a competitive inhibitor for the kinase with an apparent Ki value of approximately 320 microM. These findings suggest that a triprolyl sequence may act as a recognition site for protein kinase C.
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PMID:Substrate specificity of rat brain calcium-activated and phospholipid-dependent protein kinase. 308 Oct 2

We previously isolated a novel human transforming sequence from a primary stomach cancer and identified the gene as an activated version of the c-raf-1 gene which is the human homologue of v-raf, a viral oncogene encoding a serine/threonine-specific protein kinase. Of 57 kbp of the human sequence isolated, a region of 40 kbp was found to be the minimum functional unit for the transforming activity, because a cosmid clone harboring this region was capable of inducing foci upon transfection. The size of the transcript of the transforming c-raf-1 gene was estimated to be about 2.8kb. Analyses of cDNA clones of this gene revealed that the gene was generated by substitution of the 5'-sequence (exons 1-5) of the normal c-raf-1 gene with an unrelated human sequence. We identified a region in the genomic clone where the rearrangement had occurred. The rearranged EcoRI fragment was detected in all the primary transformants obtained from two independent transfections, suggesting that the recombination had occurred in the primary cancer. The substituted cDNA sequence is composed of an open reading frame, which joins to exon 6 of the c-raf-1 gene in an in-phase manner. The substituted open reading frame encodes an extremely hydrophobic polypeptide. Thus, the putative product of the transforming gene seems to have a hydrophobic stretch ahead of the ser/thr-protein kinase domain of the c-raf-1 gene product. These results suggest that the truncation or replacement of the amino-terminal domain of the c-raf-1 protein leads to constitutive activation of the protein kinase residing in the downstream domain.
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PMID:[Activated c-raf-1 gene from human stomach cancer]. 330 May 56

raf oncogenes were shown to act synergistically with myc in transformation. The contribution of myc was identified as that of a "second messenger" in signal transduction of at least some, competence inducing, growth factors. The role of raf appears to be that of a cytosolic ser/thr specific protein kinase which was placed downstream of ras in the signal transduction of serum growth factors by ras and raf antibody microinjection experiments. Because of the inability of raf to abrogate a cells need for myc inducing competence factors, as well as its synergistic effect with myc, raf was placed downstream of ras in the progression pathway of cellular growth control. We speculate that the basis for synergism with myc might be the ability of raf to activate competence factor induced myc protein or a myc induced protein by phosphorylation. The role of raf in lung tumors was examined by the development of a high incidence mouse model system using ethylnitrosourea as carcinogen and butylated hydroxytoluene as promoter. raf proteins of normal size were expressed at high levels, raf protein vaccination was apparently effective in eliminating the promoted phase of tumor induction.
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PMID:Transformation by raf and myc oncogenes. 333 21

Protein kinase CK2 (also known as casein kinase II) is a ubiquitous eukaryotic ser/thr protein kinase present in the nucleus and cytoplasm. CK2 is known to phosphorylate more than 100 substrates, many of which are involved in the control of cell division and in signal transduction. The review centers on the structure and function of CK2 alpha and beta subunits and on the regulation of its activity, a topic that remains to be elucidated. An analogy is drawn between CK2 and the cyclin-dependent kinases (cdks); both types of protein kinases share many substrates and are activated by regulatory subunits.
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PMID:Protein kinases. 4. Protein kinase CK2: an enzyme with multiple substrates and a puzzling regulation. 789


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