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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)
In this work we characterize some acidic nuclear substrates of protein kinase C (PKC) and
cyclic AMP-dependent protein kinase
(
PKA
), using intact anterior pituitary corticotrophic tumor cells (AtT-20/D16-16). It was found that, as in the cytosolic fraction, substrates for both PKC and
PKA
exist in the nucleus and that changes in the phosphorylation states of a few of these phosphoproteins are mediated by both kinases. One of the phosphoproteins examined, a 14 kDa phosphoprotein (pp14) described previously, exhibited a phorbol-ester induced translocation from nucleus to cytosol in pulse-chase experiments utilizing 35S-methionine labeling. These results suggest that pp14 may be involved in signal transduction in AtT-20 cells. Although its identity remains to be determined, a 14 kDa
DNA-binding protein
was also seen in nuclear extracts of AtT-20 cells.
...
PMID:Nuclear protein kinase substrates in AtT-20 cells: translocation of a 14 kDa phosphoprotein. 321 70
The transcriptional activator ADR1 from Saccharomyces cerevisiae is a postulated
DNA-binding protein
that controls the expression of the glucose-repressible alcohol dehydrogenase (ADH2). Carboxy-terminal deletions of the ADR1 protein (1,323 amino acids in length) were used to localize its functional regions. The transcriptional activation region was localized to the N-terminal 220 amino acids of ADR1 containing two DNA-binding zinc finger motifs. In addition to the N terminus, a large part of the ADR1 sequence was shown to be essential for complete activation of ADH2. Deletion of the putative phosphorylation region, defined by ADR1c mutations that overcome glucose repression, did not render ADH2 expression insensitive to glucose repression. Instead, this region (amino acids 220 through 253) was found to be required by ADR1 to bypass glucose repression. These results suggest that ADR1c mutations enhance ADR1 function, rather than block an interaction of the putative phosphorylation region with a repressor molecule. Furthermore, the
protein kinase
CCR1 was shown to affect ADH2 expression when the putative phosphorylation region was removed, indicating that CCR1 does not act solely through this region. A functional ADR1 gene was also found to be necessary for growth on glycerol-containing medium. The N-terminal 506 amino acids of ADR1 were required for this newly identified function, indicating that ADH2 activation and glycerol growth are controlled by separate regions of ADR1.
...
PMID:Identification of functional regions in the yeast transcriptional activator ADR1. 329 Jun 50
Injection of whole adenovirus DNA into Xenopus oocytes results in the synthesis of large amounts of the early region 2A
DNA-binding protein
(E2A-DBP) and smaller amounts of polypeptide IX. The lack of synthesis of any functional messenger RNAs transcribed from the major late promotor at 16.3 map units is remarkable. Cleavage of the adenovirus DNA outside the E2A gene proper by restriction enzymes decreases synthesis of the DBP to about 10% of the amount produced after injection of intact DNA. On the other hand, presence of the terminal (Bellett) protein on the injected template enhances DBP synthesis considerably. Experiments with injected DNA restriction fragments, as well as reconstructed genes cloned into pBR322, indicate that efficient synthesis of DBP in oocytes requires the presence of either or both of the two main promoters from which the E2A gene is transcribed plus an intact 3' end of the gene. In the absence of any known promotor, 100-fold lower amounts of otherwise normal DBP are produced. Unlike in a regular infection, synthesis of DBP in oocytes does not require the product of the E1A gene. The same series of experiments also demonstrates that the DBP, a phosphoprotein, is the substrate of a cellular rather than a virus-encoded
protein kinase
. Two minor E2A proteins, although colinear with the major DBP, are synthesized independently. Synthesis of a 44,000 Mr protein, probably corresponding to the carboxy-terminal 360 amino acid residues of the DBP, is not decreased after injection of "promotorless" E2A genes. Unlike the 44,000 Mr protein, production of a 67,000 Mr protein (carboxy-terminal 483 amino acid residues) by one DNA-construct is probably directed by a T-A-T-A-A-A-T-A sequence in the vector DNA.
...
PMID:Analysis of expression of adenovirus DNA (fragments) by microinjection in Xenopus oocytes. Independent synthesis of minor early region 2 proteins. 630 67
Protein kinase activities copurifying with the 72000-Mr
DNA-binding protein
of adenovirus on DNA-cellulose chromatography and gel filtration in acrylamide/agarose have been partially characterized and purified. One of these kinases was found to phosphorylate efficiently the viral
DNA-binding protein
in vitro and to be stimulated severalfold by the addition of histones, protamine, or polyamines. The kinase does not, however, phosphorylate histones, protamine, casein, or phosvitin. A second
protein kinase
was also recovered from single-stranded DNA-cellulose which is able to phosphorylate the 72000-Mr
DNA-binding protein
, but which is inhibited by the addition of histones. Phosphorylation in vitro of the 72000-Mr
DNA-binding protein
from the ts125 mutants of adenovirus by the histone-stimulated
protein kinase
was found to be thermosensitive.
...
PMID:Protein kinases associated with the adenovirus single-stranded DNA-binding protein. 689
We have previously described a Chironomus tentans nuclear 42 kDa phosphoprotein preferentially associated with transcriptionally active chromatin. In an attempt to purify and identify the kinase responsible for the phosphorylation of the 42 kDa protein, a casein-phosvitin affinity chromatography was used. Unexpectedly, in the eluted kinase fraction, a novel 42 kDa
casein kinase
, designated
protein kinase
CK42, with a kinase activity similar, but not identical, to
protein kinase
CKII
, could be identified. In other studies, a nuclear protein that comigrates with
protein kinase
CK42 in electrophoresis and is capable to bind different gene promoters in single-stranded forms in a sequence-selective manner was found. The observations that both
protein kinase
and ssDNA-binding activities could be ascribed to a 42 kDa protein raised the possibility that the ssDNA-binding 42 kDa phosphoprotein is a
protein kinase
. By specific ssDNA-binding affinity chromatography, using a biotinylated oligodeoxyribonucleotide promoter probe and Streptavidine-agarose matrix, evidence that both activities arise from the same protein molecules was obtained. The similarity in the enzyme activities between
protein kinase
CK42 and
CKII
raised the question of whether the former was an alpha subunit of the latter. To provide an answer to this issue,
CKII
, isolated and purified from an epithelial cell line of C. tentans, was characterized and compared with
protein kinase
CK42 purified from the same cell system. Like other purified
CKII
preparations,
CKII
from Chironomus is able to use ATP or GTP for phosphorylation of casein and phosvitin, and its activity is strongly inhibited by heparin and the transcription inhibitor 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB). However, the heparin and DRB sensitivities of
protein kinase
CKII
were substantially higher than those of the
protein kinase
CK42. Due to their differential solubilities in NaCl and (NH4)2SO4 solutions, individual alpha and beta subunit pools of
CKII
could be detected. More than 80% of the nuclear alpha subunit was insoluble in 0.35 M NaCl, while all individual beta subunit were solubilized under the same conditions suggesting that a major portion of the nuclear CKII alpha subunit does not form heterooligomeric structures with the beta subunit, but binds tightly to nuclear components, probably to chromatin. The biochemical and immunological data taken together strongly suggest that CK42 is a novel
DNA-binding protein
kinase that is not the alpha subunit of
CKII
.
...
PMID:Analysis of a novel DNA-binding protein kinase CKII-like enzyme of Chironomus cells. 773 20
To analyze regulation of the human T-cell leukemia virus type I (HTLV-I) long terminal repeat (LTR), cell lines were generated from LTR-tax x LTR-beta-galactosidase (beta-Gal) doubly transgenic mouse fibroblastic tumors. The HTLV-I LTR directs expression of both the tax and lacZ genes, and Tax up-modulates both promoters in primary cells. However, once cells were transformed by tax, beta-Gal but not tax expression was suppressed. Supertransformation of these cells with v-src suppressed both beta-Gal and tax expression. This suppression was reversed by treatment with the tyrosine kinase inhibitor herbimycin A or
protein kinase A
inhibitor H8. Electrophoretic mobility shift assays demonstrated augmented binding in the R but not U3 region. This binding was competitively inhibited by a high-affinity CREB oligodeoxynucleotide and super-shifted with a specific CREB antibody. Treatment of cells with the cyclic AMP analog dibutyryl cyclic AMP also transiently increased the R region binding dramatically. In vitro DNase I footprint analysis identified a protein-binding sequence in the R region which corresponded with suppression. However, this target sequence lacked a conventional CREB-binding site. A 70.5-kDa
DNA-binding protein
was partially purified by affinity chromatography, along with a 49-kDa protein which reacted with CREB-specific sera. These data demonstrate that HTLV-I LTR suppression is associated with CREB factor binding in the R region, probably by direct interaction with a 70.5-kDa protein, and provide a novel mechanism for maintenance of viral latency.
...
PMID:Transcriptional suppression of the human T-cell leukemia virus type I long terminal repeat occurs by an unconventional interaction of a CREB factor with the R region. 803 15
In the yeast Saccharomyces cerevisiae, glucose repression of SUC2 transcription requires the SSN6-TUP1 repressor complex. It has been proposed that the
DNA-binding protein
MIG1 secures SSN6-TUP1 to the SUC2 promoter. Here we show that a mig1 deletion does not cause nearly as dramatic a loss of repression as ssn6: glucose-grown mig1 mutants display 20-fold lower SUC2 expression than ssn6 mutants. Thus, repression by SSN6-TUP1 is not mediated solely by MIG1, but also involves MIG1-independent mechanisms. We report that mig1 partially restores SUC2 expression in mutants lacking the SNF1
protein kinase
and show that mig1 is allelic to ssn1, a mutation selected as a suppressor of snf1. Other SSN genes identified in this selection were therefore candidates for a role in repression of SUC2. We show that mig1 acts synergistically with ssn2 through ssn5, ssn7, and ssn8 to relieve glucose repression of SUC2 and to suppress the requirement for SNF1. These findings indicate that the SSN proteins contribute to repression of SUC2, and the pleiotropic phenotypes of the ssn mutants suggest global roles in repression. Finally, the regulated SUC2 expression observed in snf1 mig1 mutants indicates that signals regarding glucose availability can be transmitted independently of the SNF1
protein kinase
.
...
PMID:Synergistic release from glucose repression by mig1 and ssn mutations in Saccharomyces cerevisiae. 805 22
The human single-stranded-
DNA-binding protein
(HSSB, also called RP-A) is a trimeric complex (p70, p34, and p14) required for multiple functions in DNA transactions. We report here that the p34 subunit of HSSB was hyperphosphorylated by kinase activities present in G1 extract (obtained from HeLa cells in G1 phase) preincubated with human cyclin A. This hyperphosphorylated HSSB product included at least four species of p34 that migrated more slowly through denaturing polyacrylamide gels than the hypophosphorylated form. Fractionation of cyclin A-activated G1 extract identified two kinases involved in the hyperphosphorylation of HSSB p34: cdk-cyclin A complex and DNA-dependent p350
protein kinase
(DNA-PK). Kinetic analysis revealed that in cyclin A-activated G1 extract, p34 was first phosphorylated by cdk-cyclin A prior to the action of DNA-PK. Addition of p21cip1, a specific inhibitor of cdk-cyclin A but not DNA-PK, nearly abolished the hyperphosphorylation of HSSB p34 in G1 extract preincubated with cyclin A. This suggests a requirement of the cdk-cyclin A activity for the phosphorylation of p34 by DNA-PK in G1 extract.
...
PMID:Phosphorylation of the p34 subunit of human single-stranded-DNA-binding protein in cyclin A-activated G1 extracts is catalyzed by cdk-cyclin A complex and DNA-dependent protein kinase. 807 85
The nonactivated estrogen receptor (naER) has been isolated and purified to absolute homogeneity from the goat uterine cytosol. It is a 66-kDa protein, sedimenting at 4.2 S on linear sucrose density gradients and having a Stokes radius of 36 A. It displays high affinity and specificity for estradiol and diethyl stilbestrol with a Kd of 1 x 10(-10) M. CNBr peptide analysis reveals that it has a primary structure distinctly different from that of the regular estrogen receptor even though anti-ER antibody cross-reacts with the nonactivated ER. The protein gains access to the DNA only upon dimerization with the estrogen receptor activation factor (E-RAF), a
DNA-binding protein
having no capacity to bind estradiol. Analysis reveals that both naER and E-RAF are protein kinases. While the E-RAF is a
serine kinase
, naER functions as a tyrosine kinase. No
protein kinase
activity is displayed by the regular estrogen receptor. The
protein kinase
activity of the naER is inhibited in the presence of estradiol. Similarly, the
protein kinase
activities associated with the proteins disappear when the naER and E-RAF are brought together.
...
PMID:The nonactivated estrogen receptor (naER) of the goat uterus is a tyrosine kinase. 813 28
We have identified in mammalian cells a novel cyclic AMP response element (CRE)-binding protein of molecular mass 47 kDa. This protein was not recognized by either the CREB-327/341 or c-Jun antisera, and its tissue distribution did not overlap with those of the CREB and Jun families. For example, hepatoma and placental tissue did not contain the 47-kDa
DNA-binding protein
, but did contain the CREB isoforms. On the other hand, S49 lymphoma cells contained a high level of the 47-kDa
DNA-binding protein
but did not contain a 47-kDa Jun-related protein which was found in normal liver and hepatoma. This new 47-kDa factor bound to the CRE in the dephosphorylated form, and phosphorylation of the protein by the catalytic subunit of
protein kinase A
completely abolished its DNA-binding activity. The isoforms of the CREB-327/341 family, on the other hand, bound to DNA in the phosphorylated form, and alkaline phosphatase treatment reduced significantly their interaction with CRE sequence. This reverse effect of phosphorylation/dephosphorylation on the DNA-binding property of this new 47-kDa protein in particular distinguishes it from other known CREB factors and suggests that the protein might play a unique role in the regulation of cAMP-mediated transcription.
...
PMID:Identification of a new cAMP response element-binding factor by southwestern blotting. 836 1
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