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 product of the c-raf-1 proto-oncogene, Raf-1, is a 74,000-dalton cytoplasmic serine/threonine protein kinase that has been implicated as an intermediate in signal transduction mechanisms. In the human factor-dependent myeloid cell line MO7, both granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-3 (IL-3) were found to induce rapid, dose-dependent phosphorylation of Raf-1, which resulted in altered Raf-1 mobility in sodium dodecyl sulfate-polyacrylamide gels. The increase in phosphorylation was due primarily to an increase in phosphoserine, with only a minor component (less than 2%) of phosphotyrosine. PMA (12-phorbol 13-myristic acid) also induced Raf-1 phosphorylation in MO7 cells, but the resulting alteration in electrophoretic mobility was different than that observed after GM-CSF or IL-3. GM-CSF and IL-3 rapidly and transiently increased Raf-1 kinase activity using Histone H1 as a substrate in an immune complex kinase assay in vitro. These results suggest that phosphorylation of Raf-1 could play a role in some aspect of GM-CSF and IL-3 signal transduction.
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PMID:Granulocyte-macrophage colony-stimulating factor and interleukin-3 induce rapid phosphorylation and activation of the proto-oncogene Raf-1 in a human factor-dependent myeloid cell line. 184 31

We have previously found and characterized a mitogen-activated, serine/threonine-specific protein kinase that specifically phosphorylates microtubule-associated protein 2 (MAP2) in vitro, which we call here MAP2 kinase [Hoshi, M., Nishida, E. & Sakai, H. (1988) J. Biol. Chem. 263, 5396-5401; Hoshi, M., Nishida, E. & Sakai, H. (1989) Eur. J. Biochem. 184, 477-486]. In this study, we have found another serine/threonine-specific protein kinase that is activated by various mitogens. The activated kinase utilized microtubule-associated protein 1B (MAP1B) as the major substrate in vitro, so we tentatively call it MAP1B kinase (M1BK). M1BK was maximally activated 20-30 min after treatment of quiescent rat fibroblastic 3Y1 cells with epidermal growth factor (EGF), while MAP2 kinase was maximally activated within 5-10 min of EGF treatment. The EGF-activated M1BK was eluted at about 0.15 M NaCl on a DEAE-cellulose column, while the activated MAP2 kinase was eluted at about 0.1 M NaCl under the conditions used. The EGF-activated M1BK was eluted as a single peak just after the activated MAP2 kinase on an HPLC gel-filtration column. Histone, casein and ribosomal protein S6 were very poor substrates for the M1BK, while MAP2 and myelin basic protein were moderate substrates. The M1BK activity in cell extracts was inhibited by Ca2+, glycerol 2-phosphate and Zn2+, and slightly enhanced by heparin. These data suggested that M1BK is distinct from previously described mitogen-activated kinases such as MAP2 kinase, casein kinase II and S6 kinase. Pretreatment with cycloheximide or puromycin did not block the M1BK activation by EGF. Furthermore, incubation of the EGF-activated M1BK with acid phosphatase inactivated the kinase activity. Therefore, M1BK may be activated by phosphorylation in EGF-treated cells. In addition to EGF, 12-O-tetradecanoylphorbol 13-acetate, platelet-derived growth factor and insulin-like growth factor-I also induced the activation of M1BK in quiescent cells.
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PMID:Activation of a serine/threonine kinase that phosphorylates microtubule-associated protein 1B in vitro by growth factors and phorbol esters in quiescent rat fibroblastic cells. 222 68

Histone H1 kinase (H1K) undergoes a transient activation at each early M phase of both meiotic and mitotic cell cycles. The mechanisms underlying the transient activation of this protein kinase were investigated in mitotic sea urchin eggs. Translocation of active H1K from particulate to soluble fraction does not seem to be responsible for this activation. H1K activation cannot be accounted for by the transient disappearance of a putative H1K inhibitor present in soluble fractions of homogenates. Aphidicolin, an inhibitor of DNA synthesis, and actinomycin D, an inhibitor of RNA synthesis, do not impede the transient appearance of H1K activity. H1K activation therefore does not require DNA or RNA synthesis. Fertilization triggers a rise in intracellular pH responsible for the increase of protein synthesis. H1K activation is highly dependent on the intracellular pH. Ammonia triggers an increase of intracellular pH and stimulates protein synthesis and H1K activation. Acetate lowers the intracellular pH, decreases protein synthesis, and blocks H1K activation. Protein synthesis is an absolute requirement for H1K activation as demonstrated by their identical sensitivities to emetine concentration and to time of emetine addition. About 60 min after fertilization, H1K activation and cleavage become independent of protein synthesis. The concentration of p34, a homolog of the yeast cdc2 gene product which has been recently shown to be a subunit of H1K, does not vary during the cell cycle and remains constant in emetine-treated cells. H1K activation thus requires the synthesis of either a p34 postranslational modifying enzyme or another subunit. Finally, phosphatase inhibitors and ATP slow down in the in vitro inactivation rate of H1K. These results suggest that a subunit or an activator of H1K is stored as an mRNA in the egg before mitosis and that full activation of H1K requires a phosphorylation.
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PMID:M-phase-specific protein kinase from mitotic sea urchin eggs: cyclic activation depends on protein synthesis and phosphorylation but does not require DNA or RNA synthesis. 247 56

Protein kinases I (PK I) and II (PK II) were purified 253- and 13.5-fold, respectively, from an extract of sonically disrupted cells of Legionella micdadei by ion-exchange chromatography on QAE-Sephadex, by histone affinity chromatography, and by HPLC-gel filtration chromatography. Both enzymes catalysed the phosphorylation of calf thymus histones, with a Km of 2.7 mg ml-1 for PK I and 2.9 mg ml-1 for PK II. Histone H2b was the best protein kinase substrate for both PK I and PK II. The pH optima were 6.8 and 7.0 for PK I and PK II respectively. The Km for ATP was 0.29 mM for PK I and 0.33 mM for PK II. PK II activity was stimulated by either cAMP or cGMP, whereas PK I was inhibited by both cyclic nucleotides. The activity of PK I was unaffected by addition of calmodulin, diacylglycerol and mixtures of Ca2+ and acidic phospholipids, but these additions increased PK II activity threefold. The activity of PK II was stimulated by spermine and spermidine, but PK I was inhibited by these compounds. PK I and PK II were both strongly inhibited by heparin.
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PMID:Demonstration of two protein kinases in extracts of Legionella micdadei. 284 25

Five protein kinases are shown to serve as specific phosphatases in the absence of ADP. Although the rates of hydrolysis are very slow compared to the forward phosphorylation rates under optimal conditions, they are of the same order as the reverse reaction in the presence of ADP. Because cells contain approximately equal to 3 mM ATP, neither the reverse reaction nor the phosphatase is likely to play a physiological role. beta-casein B phosphorylated by the catalytic subunit of cAMP-dependent protein kinase (protein kinase A) is specifically dephosphorylated by protein kinase A but not by polypeptide-dependent protein kinase (protein kinase P). beta-casein B phosphorylated by protein kinase P is specifically dephosphorylated by protein kinase P but not by protein kinase A. Histone H1 phosphorylated by protein kinase C is dephosphorylated by the same enzyme in the absence of ADP. In all cases tested addition of ADP and F1-ATPase accelerates moderately the rate of dephosphorylation. Native H+-ATPase from yeast plasma membranes is isolated mainly in the phosphorylated form. It is dephosphorylated and rephosphorylated by protein kinase P but not by protein kinase A. Protein-tyrosine kinase of the epidermal growth factor receptor phosphorylates the random synthetic polypeptide poly(Glu80Tyr20). The phosphorylated polymer is specifically dephosphorylated in the absence of ADP by epidermal growth factor receptor preparations but not by insulin receptor preparations. The same polymer phosphorylated by insulin receptor is dephosphorylated by insulin receptor but not by epidermal growth factor receptor preparations. By using a cycle of dephosphorylation-rephosphorylation, it is possible to identify proteins that are phosphorylated by these protein kinases in vivo. Should this method be applicable to additional protein kinases, it should be possible to estimate the quantitative contribution of each protein kinase to a single phosphoprotein.
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PMID:Specific dephosphorylation of phosphoproteins by protein-serine and -tyrosine kinases. 290 Oct 92

At least twelve 32P-labeled stromal proteins were detected by electrophoresis under denaturing conditions when intact chloroplasts were incubated with 32Pi, in the light but only three were detected in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) or in the dark. Incubation of isolated stroma with [gamma-32P]ATP resulted in the preferential phosphorylation of one of them, a 70-kDa polypeptide, in serine residues. Thylakoid membranes in the dark promoted the phosphorylation of two additional stromal polypeptides of 55 and 40 kDa. Illumination during the phosphorylation of stroma in the presence of thylakoids stimulated severalfold the labeling of the 40-kDa polypeptide but not when DCMU was added. The protein kinase activity present in isolated stroma phosphorylated exogenous substrates like histone III, phosvitin, histone II, and casein with specific activities of 3, 1.8, 0.7, and 0.2 pmol X mg-1 X min-1. Histone III polypeptides were phosphorylated differently by stroma and by thylakoids in the dark. Moreover, histone III phosphorylated by thylakoids in the dark yielded a pattern of phosphopeptides after V8 protease treatment that was different from the pattern obtained when histone III was phosphorylated by stroma.
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PMID:Stromal serine protein kinase activity in spinach chloroplasts. 295 8

Protein kinase activity of lymphocytes isolated from human subjects was assayed using histone as substrate. The activity was stimulated about twofold by cyclic AMP and total enzyme activity, determined in the presence of cyclic AMP, was inhibited by 65% by the specific heat-stable inhibitor of cyclic AMP-dependent protein kinase. Histone phosphorylation was not stimulated by cyclic GMP in the presence of the inhibitor. Cyclic AMP-dependent protein kinase could be activated in vitro by incubating intact cells with isoproterenol or with forskolin and was reflected by a significant (P less than 0.05) increase in the protein kinase activity ratio. In contrast to these well-characterized adenylate cyclase activators, incubating cells for up to 2 hr in vitro in the presence of the specific beta-blocker propranolol had no significant effect on the amount of cyclic AMP-dependent protein kinase that was in the activated state. When compared in subjects between the ages of 21 and 74 years, lymphocyte protein kinase activity was unaltered by age or gender. These results indicate that cyclic nucleotide-dependent protein kinase is of the cyclic AMP-dependent variety in the human lymphocyte. A low amount of the cyclic AMP-dependent activity (about 15%) is in the already activated state in freshly isolated cells, and this is not further reduced by incubation in vitro or by beta-blockade. In contrast to previously reported changes in the capacity to synthesize cyclic AMP, lymphocyte protein kinase is unaltered by gender or age in human subjects.
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PMID:Lymphocyte protein kinase activity in cells from young and elderly men and women. 300 43

Nuclear histone kinase activity, specifically histone H1 phosphotransferase activity, was shown to increase in synchronous Chinese hamster cells from the G1/S boundary to late G2/early M phase. Chromatin extracts purified by DEAE-Sephacel chromatography showed a cAMP-independent kinase activity that demonstrated cell cycle dependence and high specificity for histone H1 as the phosphate acceptor in the presence of [gamma-32P] ATP. This activity was purified approximately 40-fold. Using as substrates calf thymus histone H1 subfractions resolved by Bio-Rex 70 ion exchange chromatography, phosphorylation by the nuclear histone H1 kinase indicated that 32P incorporation into H1-2 was at least twice that for H1-1 and H1-3 subfractions. Both amino- and carboxy-terminal fragments generated by N-bromosuccinimide cleavage were phosphorylated. Phosphoamino acid analysis showed phosphothreonine to be approximately twice as abundant as phosphoserine. Histone H1 kinase activity was not activated by cyclic nucleotides, nor inhibited by cAMP-dependent protein kinase inhibitors or regulatory subunits. There was no effect on activity by Ca2+ alone or in the presence of calmodulin or diacylglycerol. Kinase activity was inhibited by nonhydrolyzable analogs of ATP such as adenyl-5'-yl imidodiphosphate, by 5'-p-fluorosulfonylbenzoyladenosine which binds to the ATP binding site of the enzyme, and by quercetin. Column fractions enriched in histone H1 kinase were labeled with 5'-p-fluorosulfonylbenzoyl[8-14C]adenosine, and peptides were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. One band, Mr 67,000, was specifically labeled and may represent the H1 kinase catalytic subunit.
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PMID:Histone H1 kinase in exponential and synchronous populations of Chinese hamster fibroblasts. 300 70

We have examined protein phosphatase activities that are present during the cellular differentiation of Dictyostelium. Utilizing differential centrifugation, ion exchange, gel filtration, and concanavalin A affinity chromatography we found a number of distinct protein phosphatase activities. Three peaks of soluble Kemptide phosphatase activity and a very broad and heterogeneous soluble histone phosphatase activity were resolved by anion exchange chromatography. Histone phosphatase was associated with the particulate fraction, while Kemptide phosphatase was not. The protein phosphatase activities were able to dephosphorylate sites that had been phosphorylated by the cyclic AMP-dependent protein kinase. Therefore it is possible that their function in vivo may be to oppose the action of the cAMP-dependent protein kinase. In addition several paranitrophenyl phosphate phosphatase activities are shown to be largely separable from the protein phosphatases. An apparent heat-stable inhibitor of histone phosphatase is shown to be artifactual in that instead of interacting with the enzyme it acts by complexing with histone.
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PMID:Chromatographic resolution of soluble and particulate protein phosphatases from Dictyostelium discoideum. 301 27

The activity of histone kinase II was determined on the basis of its ability to phosphorylate the nonapeptide Ala-Ala-Ala-Ser-Phe-Lys-Ala-Lys-Lys-amide designed previously as a specific substrate for this enzyme. Histone kinase II was purified from calf thymus extract by DEAE-cellulose chromatography followed by hydroxylapatite chromatography and high-performance liquid chromatography on a Protein Analysis column (I-125). The Mr value of histone kinase II estimated by the latter method was 50,000-55,000, but several observations indicated that histone kinase II was a product of a proteolytic process. Since the substrate specificity determinants for histone kinase II known from our previous investigations are very similar to those for protein kinase C, it was presumable that histone kinase II was the proteolytic fragment of protein kinase C. Therefore, the nonapeptide was tested as a substrate for protein kinase C prepared from rabbit brain extract by DEAE-cellulose chromatography. The activity of histone kinase II was also detected in brain extract. Histone kinase II was eluted from the DEAE-cellulose in the known position of the proteolytic fragment of protein kinase C. The nonapeptide Ala-Ala-Ala-Ser-Phe-Lys-Ala-Lys-Lys-amide proved to be a better substrate than H1 histone for the detection of the activity of protein kinase C because it was not phosphorylated by the cAMP-dependent protein kinase and the Vmax of protein kinase C was about one order of magnitude higher with the peptide than with H1 histone. The apparent Km of protein kinase C for the peptide was identical with that of histone kinase II (0.2 mM).
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PMID:The assay of the activity of protein kinase C with the synthetic oligopeptide substrate designed for histone kinase II. 301 24


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