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 present study describes hyper-phosphorylation of E7-oncoprotein of human papillomavirus (HPV) type 16 in epidermal keratinocytes. We found that highly phosphorylated E7-oncoprotein was present in epidermal keratinocytes but little in fibroblasts. The E7 oncoprotein contains serine residues (Ser-Ser-Glu-Glu-Glu) capable of being phosphorylated by casein kinase II (CK II). Extracts from various cell lines including human origins transformed by HPV 16 were examined for the casein kinase activity. The results showed that CK II activity was present at significantly high levels in keratinocytes but little or no detectable levels of the activity in human fibroblasts. These differential CK II activities in host cells may play a part in the differential transforming activity by E7-oncoprotein.
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PMID:Casein kinase II activities related to hyperphosphorylation of human papillomavirus type 16-E7 oncoprotein in epidermal keratinocytes. 217 86

Casein kinase II (CK II) is a ubiquitous protein kinase that has been found in both nuclear and soluble subcellular fractions and whose precise cellular functions and mechanisms of control remain to be clarified. Using immunocytochemical localization, it was observed that the intracellular distribution of CK II exhibited a striking shift toward an increased nuclear concentration during active proliferation of bovine adrenocortical cells in primary culture. The interaction of CK II with purified adrenocortical cell nuclear preparation was thus examined in vitro. CK II was found to rapidly associate with nuclei in a temperature-dependent and saturable process, resulting in a tight binding of the kinase to nuclear components, as shown by various extraction procedures. This association resulted in a concentration of the kinase in the nuclear preparation about 100-fold that in the medium and exhibited two types of binding sites with Ka of 10(9) and 10(7) M-1, respectively. The nuclear CK II uptake was dependent upon the presence of ATP and was stimulated by a kinase activator such as spermine, although the enzyme activity did not appear to be required for the process. These observations would be in line with a pore-mediated, energy-dependent nuclear uptake of the kinase. Since a number of potential nuclear CK II targets have been reported, including the oncoprotein myc, it is suggested that the nuclear translocation of the kinase as characterized in vitro may have a biological significance in living cell, especially in the control of nuclear activities related to cell proliferation and the mechanism of action of growth factors.
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PMID:Cytoplasmic and nuclear distribution of casein kinase II: characterization of the enzyme uptake by bovine adrenocortical nuclear preparation. 227 31

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

Two cyclic-nucleotide independent soluble casein kinase activities (CK I and CK II) from the fungus Mucor rouxii have been isolated, characterized and found to fit in the general classification of type 1 (CK I) and 2 (CK II) casein kinases, according to their enzymatic and structural properties. Both enzymes phosphorylate acidic substrates, require Mg2+ and have a chromatographic behaviour on DEAE-Sepharose and phosphocellulose similar to their mammalian counterparts. CK I has a sedimentation coefficient of 3.5 S, uses ATP as a phosphate donor (Km = 40 microM), phosphorylates casein mainly on serine residues, its activity is strongly inhibited by KCl and polyamines. CK II has a sedimentation coefficient of 7.4 S, uses ATP and GTP as phosphate donors (Km ATP = 10 microM; Km GTP = 40 microM), phosphorylates casein in serine and threonine, its activity is stimulated by KCl and by polyamines and is inhibited by heparin (I50 = 0.5 micrograms/ml). Casein kinase activity associated to particulate fraction (40% of total) has been partially characterized and shown to be similar to the soluble CK I activity.
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PMID:Characterization of two casein kinase activities in the fungus Mucor rouxii. 324 73

The peptide Arg-Arg-Arg-Glu-Glu-Glu-Thr-Glu-Glu-Glu was shown to be a specific substrate for casein kinase II (CK II) in extracts of 3T3-L1 cells. Fractionation of a cell extract on DEAE-cellulose revealed only one peptide kinase and it eluted at the same salt concentration required to elute CK II. Consistent with the properties of CK II, the peptide kinase activity was inhibited by very low concentrations of heparin (Ki less than 6 nM) and it used GTP efficiently as a substrate. A Western blot, developed with antiserum to bovine thymus CK II, demonstrated the presence of CK II protein in 3T3-L1 extracts and that peptide kinase activity was directly related to the amount of CK II protein. The peptide was used to assay CK II activity in extracts of 3T3-L1 cells stimulated to differentiate into adipocytes. Differentiation produced a transient increase in CK II activity that reached a maximum (4-fold) on day 4. The increased activity was accounted for by increased CK II protein. Induction of CK II preceded the increase in total protein and was not the result of cell proliferation. CK II induction was coincident with induction of the insulin receptor, but, whereas insulin binding remained elevated, CK II activity declined after day 4. Agents that stimulate differentiation of 3T3-L1 cells did not cause induction of CK II in 3T3-C2 cells that do not differentiate. The transient nature of the induction of CK II suggests that the kinase may contribute to the process of differentiation rather than being a phenotypic change like that of the insulin receptor.
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PMID:Induction of casein kinase II during differentiation of 3T3-L1 cells. 346 3

2,3,7,8-Tetrachloro-p-dioxin (TCDD) induced a modest stimulation of nuclear protein phosphorylation in explant tissue cultures in 10 min, followed by a substantial decrease in the level of total protein phosphorylation activity in the nucleus. Curiously, this TCDD-induced decline in nuclear protein phosphorylation was accompanied by an increase in cytosolic and extranuclear protein phosphorylation activity. One of the main causes for such a decrease in the protein phosphorylation activity in the nucleus appears to be related to some increase in protein phosphatase activities as judged by the counteractions of okadaic acid and Na3VO4 to the above effect. In addition, TCDD induced changes in nuclear protein kinase activities as well. Manganese-stimulated protein kinase was found to be the predominant type of nuclear protein phosphorylating activity affected by TCDD, with 60% of the total activity due to heparin-sensitive casein kinase II (CK II), a major nuclear protein kinase. The level of CK II activity in the nuclear protein preparation from adipose tissue of TCDD-treated guinea pigs (1 microgram/kg) in the presence of 100 nM heparin was only 35% of the control value after 24 hr. In addition, TCDD was found to increase the protein kinase C and microtubule-associated protein 2 kinase activities as early as 15 min after treatment in isolated adipose tissues in culture. Under in situ incubation conditions with explant tissues in culture, TCDD rapidly enhanced the DNA binding activity of the transcriptional factor AP-1, whereas the same treatment reduced c-Myc DNA binding activity. Genistein, a specific protein tyrosine kinase inhibitor, abolished the stimulatory effect of TCDD on AP-1 binding activity, but not on DNA binding activity of c-Myc. Phorbol ester (TPA) increased the binding activity of AP-1 and c-Myc, as expected. However, TCDD in combination with TPA caused a slight reduction in binding activity of both transcriptional factors. On the other hand, in the presence of forskolin, the stimulatory effect of TCDD on AP-1 binding activity and the inhibitory effect on c-Myc were still apparent. Okadaic acid almost abolished the binding activity of c-Myc, whereas in combination with TCDD a stimulatory effect was found. These observations are consistent with the idea that TCDD regulates the DNA binding activity of AP-1 and c-Myc mainly through modulating their states of phosphorylation by altering protein kinase and phosphatase activities.
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PMID:Regulation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) of the DNA binding activity of transcriptional factors via nuclear protein phosphorylation in guinea pig adipose tissue. 748 34

The distribution of microtubule-associated protein lB (MAPlB) phosphorylated by either proline-directed protein kinase (PDPK) or casein kinase II (CK II) in neuroblastoma cells and hippocampal neurons has been studied by immunofluorescence using specific antibodies to distinct phosphorylation-sensitive epitopes. A proximo-distal gradient of increasing PDPK-catalyzed phosphorylation of MAPlB is superimposed on a proximo distal gradient of decreasing CK II-catalyzed MAPlB phosphorylation within growing axon-like neurites. Additionally, CK II-phosphorylated MAPlB is present in cell bodies and dendrites where no PDPK-phosphorylated MAPlB is observed. These results suggest distinct roles for both types of modifications of MAPlB in developing neurons.
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PMID:Role of phosphorylated MAPlB in neuritogenesis. 751 12

Several derivatives of K-252a, a protein kinase inhibitor isolated from Nocardiopsis sp., were investigated for their effects on the replication of vesicular stomatitis virus (VSV) in BHK-21 cell cultures. Among those we tested, KT5926, which preferentially inhibits the myosin light chain kinase (MLCK), suppressed the viral replication by 95-99% at 15 microM. K-252a, which inhibits a broad spectrum of cellular protein kinase, similarly affected the viral replication. Other derivatives, KT5720 and KT5823, that are known to inhibit the cAMP-dependent protein kinase (PKA) and cGMP-dependent protein kinase (PKG), respectively, did not suppress VSV replication even at a high concentration as 15 microM. None of these inhibitors affected the Sindbis virus replication in BHK-21 cells under similar assay conditions as used for VSV. KT5926 and K-252a seemed to affect the VSV replication at the step(s) after the viral invasion, resulting in decreased viral RNA synthesis. Neither substance inhibited cellular casein kinase (CK) II which is known to be involved in phosphorylation of the nonstructural (NS) protein, a non-catalytic subunit of the viral RNA polymerase. These results suggest that the inhibition of VSV replication by KT5926 and K-252a is not a secondary effect due to generalized suppression of host cell activities, and that the VSV replication requires the KT5926-sensitive function(s) in the cell which would be performed by an enzyme(s) other than CK II.
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PMID:Studies on the antiviral activity of protein kinase inhibitors against the replication of vesicular stomatitis virus. 755 Jan 28

Phosphorylation of the polyomavirus major capsid protein VP1 plays a role in virus assembly and may function in virus-cell recognition. Previous mapping of the in vivo phosphorylation sites on VP1 identified phosphorylation of threonine residues Thr-63 and Thr-156 (Li, M., and Garcea, R. L. (1994) J. Virol. 68, 320-327). Phosphoserine was detected in a tryptic phosphopeptide encompassing residues 58-78. Because of consensus casein kinase II (CK II) sites in this peptide, we examined the in vitro phosphorylation of the purified recombinant VP1 protein by CK II. CK II phosphorylated VP1 on serine, and the resulting tryptic phosphopeptide eluted in a 30-31 min high performance liquid chromatography fraction corresponding to residues 58-78. The VP1 tryptic phosphopeptide also co-migrated in two-dimensional peptide analysis with one of the tryptic peptides obtained from VP1 isolated after in vivo 32P labeling of virus-infected cells. A site-directed mutant VP1 protein, Ser-66 to Ala, was phosphorylated poorly by CK II in vitro. As determined by electron microscopy, all of the mutant proteins were isolated in pentameric form similar to the wild-type protein, although the Ala-66 pentamers had a tendency to self-assemble in vitro into tubular as well as capsid-like structures. These findings identify Ser-66 as a site of VP1 phosphorylation in vitro, and suggest that VP1 may serve as a substrate for CK II in vivo.
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PMID:In vitro phosphorylation of the polyomavirus major capsid protein VP1 on serine 66 by casein kinase II. 759 92

The purified casein kinase II (CK II) from Arabidopsis thaliana phosphorylates wheat elongation factor 1 beta (EF-1 beta), but not elongation factor 1 beta' (EF-1 beta'), which lacks a serine residue in the conserved phosphorylation site. Both EF-1 beta and beta' subunits, with similar functions, seem to undergo different regulation despite the partial amino acid sequence of EF-1 beta being similar to that of EF-1 beta'.
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PMID:Analysis of phosphorylation of wheat elongation factor 1 beta and beta' by casein kinase II. 776 71


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