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

---

Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Autophosphorylation of a DNA-activated protein kinase (DNA-PK) in Raji Burkitt's lymphoma cells generated a band that corresponded to a phosphoprotein of about 300 kDa on SDS/PAGE. This band corresponds to a 300-350-kDa DNA-PK found previously in HeLa cells. In addition to the 300-kDa phosphoprotein, the band of a highly phosphorylated 58-kDa protein was detected by SDS/PAGE of partially purified DNA-PK preparations after the phosphorylation reaction in the presence of double-stranded DNA. This phosphoprotein was specifically immunoprecipitated by phosphoprotein nor detectable activities of other kinases, phosphorylated recombinant c-Myc proteins in the presence of DNA. The c-Myc phosphorylation by DNA-PK was markedly stimulated by relaxed, double-stranded DNA, but neither by single-stranded DNA nor by RNA. Phosphopeptide mapping and phosphoamino acid analysis indicated that DNA-PK phosphorylates c-Myc in vitro at several serine residues.
...
PMID:DNA-activated protein kinase in Raji Burkitt's lymphoma cells. Phosphorylation of c-Myc oncoprotein. 159 96

UBF is a DNA binding protein which interacts with both the promoter and the enhancer of various vertebrate ribosomal RNA genes and functions as a transcription initiation factor for RNA polymerase I (pol I). We have purified murine UBF to apparent molecular homogeneity and demonstrate that its transactivating potential, but not its DNA binding activity, is modulated in response to cell growth. In vivo labelling experiments demonstrate that UBF is a phosphoprotein and that the phosphorylation state is different in growing and quiescent cells. We show that UBF is phosphorylated in vitro by a cellular protein kinase which by several criteria closely resembles casein kinase II (CKII). A major modification involves serine phosphoesterifications in the carboxy terminal hyperacidic tail of UBF. Deletions of this C-terminal domain severely decreases the UBF directed activation of transcription. The data suggest that phosphorylation of UBF by CKII may play an important role in growth dependent control of rRNA synthesis.
...
PMID:The nucleolar transcription factor mUBF is phosphorylated by casein kinase II in the C-terminal hyperacidic tail which is essential for transactivation. 160 Sep 46

Mammalian DNA ligase I has been shown to be a phosphoprotein. Dephosphorylation of purified DNA ligase I causes inactivation, an effect dependent on the presence of the N-terminal region of the protein. Expression of full-length human DNA ligase I in Escherichia coli yielded soluble but catalytically inactive enzyme whereas an N-terminally truncated form expressed activity. Incubation of the full-length preparation from E. coli with purified casein kinase II (CKII) resulted in phosphorylation of the N-terminal region and was accompanied by activation of the DNA ligase. Of a variety of purified protein kinases tested, only CKII stimulated the activity of calf thymus DNA ligase I. Tryptic phosphopeptide analysis of DNA ligase I revealed that CKII specifically phosphorylated a major peptide also apparently phosphorylated in cells, implying that CKII is a protein kinase acting on DNA ligase I in the cell nucleus. These data suggest that DNA ligase I is negatively regulated by its N-terminal region and that this inhibition can be relieved by post-translational modification.
...
PMID:Activation of mammalian DNA ligase I through phosphorylation by casein kinase II. 163 65

The effect of increasing concentrations of Zn2+ (1 microM-5 mM) on protein phosphorylation was investigated in cytosol (S3) and crude synaptic plasma membrane (P2-M) fractions from rat cerebral cortex and purified calmodulin-stimulated protein kinase II (CMK II). Zn2+ was found to be a potent inhibitor of both protein kinase and protein phosphatase activities, with highly specific effects on CMK II. Only one phosphoprotein band (40 kDa in P2-M phosphorylated under basal conditions) was unaffected by addition of Zn2+. The vast majority of phosphoprotein bands in both basal and calcium/calmodulin-stimulated conditions showed a dose-dependent inhibition of phosphorylation, which varied with individual phosphoproteins. Two basal phosphoprotein bands (58 and 66 kDa in S3) showed a significant stimulation of phosphorylation at 100 microM Zn2+ with decreased stimulation at higher concentrations, which was absent by 5 mM Zn2+. A few Ca2+/calmodulin-stimulated phosphoproteins in P2-M and S3 showed biphasic behavior; inhibition at less than 100 microM Zn2+ and stimulation by millimolar concentrations of Zn2+ in the presence or absence of added Ca2+/calmodulin. The two major phosphoproteins in this group were identified as the alpha and beta subunits of CMK II. Using purified enzyme, Zn2+ was shown to have two direct effects on CMK II: an inhibition of Ca2+/calmodulin-stimulated autophosphorylation and substrate phosphorylation activity at low concentrations and the creation of a new Zn(2+)-stimulated, Ca2+/calmodulin-independent activity at concentrations of greater than 100 microM that produces a redistribution of activity biased toward autophosphorylation and an alpha subunit with an altered mobility on sodium dodecyl sulfate-containing gels.
...
PMID:Effect of zinc on calmodulin-stimulated protein kinase II and protein phosphorylation in rat cerebral cortex. 164 55

Engagement of membrane IgM on a number of human and murine B-cell lines induced activation of a Mn(2+)-preferring serine/threonine kinase that phosphorylated microtubule-associated protein-2 (MAP-2) in vitro. B-cell MAP-2 kinase (MAP-2K) activity could be fractionated into two peaks by sequential DEAE and hydrophobic chromatography. Although peak I included two tyrosine phosphoproteins of molecular mass 36 and 38 kDa, peak II showed a single 42-kDa tyrosine phosphoprotein (pp42). Since all kinase activity could be removed from peak II material over an antiphosphotyrosine immune affinity column, it suggests that pp42 is identical with lymphoid MAP-2K. Although peak I activity showed a similarity to peak II with regard to its preference for Mn2+, sensitivity to phosphatase exposure, and resistance to a range of common serine kinase inhibitors, it is not clear whether these activities are related. MAP-2 kinase activity could also be induced by treatment with the phorbol ester, phorbol myristate 13-acetate, suggesting that protein kinase C may also be involved with MAP-2K regulation. Although MAP-2K activity reached a peak response within minutes of receptor ligation, there were differences in the rates of dephosphorylation of pp42 and decline of MAP-2K activity in different B-cell lines. The tyrosine phosphatase inhibitor, vanadate, transformed a rapidly reversible MAP-2K response in BAL 17.2 cells into a sustained state of activation that resembled the kinetics of activation in WEHI-231 cells. The latter finding implies involvement of a tyrosine phosphatase, which opposes the effect of an inducing tyrosine kinase.
...
PMID:Stimulation of B-cells via the membrane immunoglobulin receptor or with phorbol myristate 13-acetate induces tyrosine phosphorylation and activation of a 42-kDa microtubule-associated protein-2 kinase. 165 69

Earlier studies have shown that a herpes simplex virus 1 (HSV-1) open reading frame, US3, encodes a novel protein kinase and have characterized the cognate amino acid sequence which is phosphorylated by this enzyme. This report identifies an apparently essential viral phosphoprotein whose posttranslational processing involves the viral protein kinase. Analyses of viral proteins phosphorylated in the course of productive infection revealed a phosphoprotein whose mobility was viral protein kinase and serotype dependent. Thus, the corresponding HSV-1 and HSV-2 phosphoproteins differ in their electrophoretic mobilities, and the phosphoprotein specified by the HSV-1 mutant deleted in US3 (R7041) differs from that of the corresponding HSV-1 and HSV-2 proteins. Analyses of HSV-1 x HSV-2 recombinants mapped the phosphoprotein between 0.42 and 0.47 map units on the prototype HSV-1 DNA map. Within this region, the UL34 open reading frame was predicted to encode a protein of appropriate molecular weight which would also contain the consensus target site for phosphorylation by the viral protein kinase as previously defined with synthetic peptides. Replacement of the native UL34 gene with a UL34 gene tagged with a 17-amino-acid epitope from the alpha 4 protein identified this gene as encoding the phosphoprotein. Finally, mutagenesis of the predicted phosphorylation site on UL34 in the viral genome, and specifically the substitution of threonine or serine with alanine in the product of the UL34 gene, yielded phosphoproteins whose electrophoretic mobilities could not be differentiated from that of the US3- mutant. We conclude that the posttranslational processing of the UL34 gene product to its wild-type phenotype requires the participation of the viral protein kinase. While the viral protein kinase is not essential for viral replication in cells in culture, the UL34 gene product itself may not be dispensable.
...
PMID:The herpes simplex virus 1 protein kinase encoded by the US3 gene mediates posttranslational modification of the phosphoprotein encoded by the UL34 gene. 165 69

Changes of phosphoprotein patterns in HL-60 cells were studied during short exposures to 1 alpha, 25-dihydroxyvitamin D3 [1,25(OH)2D3]. One hundred nanometers 1,25(OH)2D3 dephosphorylated at least three proteins in 6 h: phosphoproteins with molecular weights of 82 kD (pp82), 33 kD (pp33), and 31 kD (pp31). Phosphorylation of pp33 and pp31 was also suppressed by 1 mM dbcAMP, and dephosphorylation of the two protein by 1,25(OH)2D3 was inhibited by 8 microM H-8, an inhibitor of cAMP-dependent protein kinase (PKA). Furthermore, 8 microM H-8 inhibited dephosphorylation of the two proteins when it was added with 1,25(OH)2D3. On the other hand, 10 nM TPA gave no significant change to these two phosphoproteins. These results suggest the possibility that PKA is involved in the early stages of 1,25(OH)2D3-induced HL-60 cell differentiation through specific protein dephosphorylation.
...
PMID:Dephosphorylation of specific proteins in HL-60 cells by 1 alpha, 25-dihydroxyvitamin D3: possible involvement of cAMP-dependent protein kinase. 165 50

Sequences encoded by the first exon of BCR that bind to the ABL SH2 domain are essential for the activation of the ABL tyrosine kinase and transforming potential of the chimeric BCR-ABL oncogene. The normal cellular BCR gene encodes a 160,000 dalton phosphoprotein associated with a serine/threonine kinase activity, but it shows only weak dispersed homologies to protein kinases. p160c-BCR was purified to apparent homogeneity as an oligomer of greater than 600,000 daltons that contains autophosphorylation activity and transphosphorylation activity for several protein substrates. A region containing paired cysteine residues within the 426 amino acids encoded by the first exon of BCR is essential for its novel phosphotransferase activity, which overlaps with the strong SH2-binding regions. The recent demonstration of a GTPase-activating function within the C-terminal portion of BCR suggests that the protein kinase and SH2-binding domains may work in concert with other regions of the molecule in intracellular signalling processes.
...
PMID:The BCR gene encodes a novel serine/threonine kinase activity within a single exon. 165 98

Antibodies that recognize the alpha 2 delta and alpha 1 subunits of skeletal muscle L-type calcium channels have been used to investigate the subunit components and phosphorylation of omega-conotoxin (omega-CgTx)-sensitive N-type calcium channels from rabbit brain. Photolabeling of the N-type channel with a photoreactive derivative of 125I-omega-CgTx results in the identification of a single polypeptide of 240 kDa. MANC-1, a monoclonal antibody recognizing alpha 2 delta subunits of L-type calcium channels from skeletal muscle, immunoprecipitates the omega-CgTx-labeled 240-kDa polypeptide and approximately 6% of the digitonin-solubilized 125I-omega-CgTx-labeled N-type channels. MANC-1 also immunoprecipitates a phosphoprotein of 240 kDa that comigrates with 125I-omega-CgTx-labeled N-type calcium channels, but not with L-type calcium channels, in sucrose gradients. Both cAMP-dependent protein kinase and protein kinase C are effective in the phosphorylation of this polypeptide. Similar to the alpha 1 subunits of skeletal muscle L-type calcium channels, the immunoprecipitation of the 240-kDa phosphoprotein by MANC-1 is prevented by the detergent Triton X-100. Anti-CP-(1382-1400), an antipeptide antibody against a highly conserved segment of the alpha 1 subunits of calcium channels, immunoprecipitates the 240-kDa phosphopeptide in Triton X-100. The 240-kDa protein is phosphorylated to a stoichiometry of approximately 1 mol of phosphate/mol of omega-CgTx-binding N-type calcium channels by both cAMP-dependent protein kinase and protein kinase C. Our results show that the 240-kDa polypeptide is an alpha 1-like subunit of an omega-CgTx-sensitive N-type calcium channel. The N-type calcium channels containing this subunit are phosphorylated by cAMP-dependent protein kinase and protein kinase C and contain noncovalently associated alpha 1-like and alpha 2 delta-like subunits as part of their oligomeric structure.
...
PMID:Phosphorylation of an alpha 1-like subunit of an omega-conotoxin-sensitive brain calcium channel by cAMP-dependent protein kinase and protein kinase. 165 16

MEKA is an acidic 33-kilodalton phosphoprotein found in the retina and pineal gland. It is of interest because it forms a cytoplasmic heterotrimer with the beta gamma-complex of GTP-binding regulatory proteins (G proteins). Accordingly, MEKA may play a role in signal transduction. MEKA is phosphorylated on Ser73 by cAMP-dependent protein kinase. In the present report, MEKA was studied using an antiserum (Anti-32) against MEKA65-96, which can be used to estimate total MEKA and the phosphorylation state of MEKA. It was confirmed that MEKA is rapidly phosphorylated by adrenergic stimulation of pineal glands in organ culture. In addition, total (dephosphorylated) MEKA was observed to increase after a 6-h treatment with norepinephrine or (Bu)2 cAMP, an effect which was dependent upon new protein synthesis. In in vivo studies, it was found that the total amount of MEKA and MEKA phosphorylation were increased at night in the dark, a time when the pineal gland is adrenergically stimulated. The high level of phosphorylation was rapidly reduced when animals were exposed to light, which blocks neural stimulation of the gland. This report provides the first in vivo evidence that MEKA phosphorylation is under physiological control, and that MEKA synthesis is controlled by an adrenergic----cAMP mechanism which requires protein synthesis.
...
PMID:Photoneural control of the synthesis and phosphorylation of pineal MEKA (phosducin). 165 28


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---