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)

Human DNA-PK is a nuclear, serine/threonine protein kinase that, when activated by DNA, phosphorylates several DNA-binding substrates, including the tumor suppressor protein p53. To identify which p53 residues are phosphorylated, we examined DNA-PK's ability to phosphorylate synthetic peptides corresponding to human p53 sequences. Serines 15 and 37 in the amino-terminal transactivation domain of human p53, and serines 7 and 18 of mouse p53, were phosphorylated by DNA-PK in the context of synthetic peptides. Other serines in these p53 peptides, and serines in other p53 peptides, including peptides containing the serine 315 p34cdc2 site and the serine 392 casein kinase II site, were not recognized by DNA-PK or were phosphorylated less efficiently. Phosphorylation of the conserved serine 15 in human p53 peptides depended on the presence of an adjacent glutamine, and phosphorylation was inhibited by the presence of a nearby lysine. Phosphorylation of recombinant wild-type mouse p53 was inhibited at high DNA concentrations, suggesting that DNA-PK may phosphorylate p53 only when both are bound to DNA at nearby sites. Our study suggests that DNA-PK may have a role in regulating cell growth and indicates how phosphorylation of serine 15 in DNA-bound p53 could alter p53 function.
...
PMID:Human DNA-activated protein kinase phosphorylates serines 15 and 37 in the amino-terminal transactivation domain of human p53. 140 79

Isolated transcription complexes contain a protein kinase that phosphorylates the heptapeptide repeats of the carboxy-terminal domain (CTD) of the RNA polymerase II (RNAP II) large subunit in an apparently promoter-dependent manner. We now show that the essential features of this reaction can be reproduced in a reconstituted system containing three macromolecular components: a fusion protein consisting of the CTD of RNAP II fused to a heterologous DNA-binding domain, an activating DNA fragment containing the recognition sequence for the fusion protein, and a protein kinase that binds nonspecifically to DNA. This kinase closely resembles a previously known DNA-dependent protein kinase. Evidently, the association of the CTD with DNA provides a key signal for phosphorylation. There appears to be no absolute requirement for specific contacts with other DNA-bound transcription factors.
...
PMID:DNA binding provides a signal for phosphorylation of the RNA polymerase II heptapeptide repeats. 154 41

DNA-PK is a moderately abundant serine/threonine protein kinase found in the nucleus of a wide range of eukaryotic cells. It is one of the few known cellular enzymes whose activity is regulated directly by DNA. Many DNA binding proteins, including a number of transcription factors, are substrates for DNA-PK in vitro. We suggest that this kinase may coordinate signal transduction pathways and nuclear events, including transcription, in response to changes in DNA or chromatin state.
...
PMID:The DNA-activated protein kinase, DNA-PK: a potential coordinator of nuclear events. 175 Dec 87

HeLa cells contain a serine/threonine protein kinase (DNA-PK) that is strongly activated in vitro by low concentrations of double-stranded DNA (dsDNA). Activation was specific for dsDNA; both natural DNAs and synthetic oligonucleotides functioned as kinase activators. The fact that DNA-PK activity was rapidly inhibited by incubation with dsDNA and ATP suggests that DNA-PK activity also may be regulated by autophosphorylation. During gel filtration, DNA-PK activity behaved as a 350-kDa protein, and highly purified DNA-PK contained a dsDNA-binding, 350-kDa polypeptide that was phosphorylated in a dsDNA-dependent manner. We conclude that this 350-kDa polypeptide is likely to be DNA-PK. Previously we showed that the dsDNA-activated kinase phosphorylates two threonines at the N terminus of hsp90 alpha (S. P. Lees-Miller and C. W. Anderson, J. Biol. Chem. 264:17275-17280, 1989). Here we show that DNA-PK also phosphorylates the simian virus 40 large tumor antigen, the mouse tumor-suppressor protein p53, the human Ku autoantigen, and two unidentified HeLa DNA-associated polypeptides of 52 and 110 kDa. Identification of these and other newly identified DNA-binding substrates suggest that the dsDNA-activated kinase may regulate transcription, DNA replication, or cell growth.
...
PMID:Human cells contain a DNA-activated protein kinase that phosphorylates simian virus 40 T antigen, mouse p53, and the human Ku autoantigen. 224 67

The DNA-activated serine/threonine protein kinase (DNA-PK) is composed of a large (approximately 460 kDa) catalytic polypeptide (DNA-PKcs) and Ku, a heterodimeric DNA-binding component (p70/p80) that targets DNA-PKcs to DNA. A 41-kbp segment of the DNA-PKcs gene was isolated, and a 7902-bp segment was sequenced. The sequence contains a polymorphic Pvu II restriction enzyme site, and comparing the sequence with that of the cDNA revealed the positions of nine exons. The DNA-PKcs gene was mapped to band q11 of chromosome 8 by in situ hybridization. This location is coincident with that of XRCC7, the gene that complements the DNA double-strand break repair and V(D)J recombination defects (where V is variable, D is diversity, and J is joining) of hamster V3 and murine severe combined immunodeficient (scid) cells.
...
PMID:Gene for the catalytic subunit of the human DNA-activated protein kinase maps to the site of the XRCC7 gene on chromosome 8. 763 22

The trimeric human single-stranded DNA-binding protein (HSSB; also called RP-A) plays an essential role in DNA replication, nucleotide excision repair, and homologous DNA recombination. The p34 subunit of HSSB is phosphorylated at the G1/S boundary of the cell cycle or upon exposure of cells to DNA damage-inducing agents including ionizing and UV radiation. We have previously shown that the phosphorylation of p34 is catalyzed by both cyclin-dependent kinase-cyclin A complex and DNA-dependent protein kinase. In this study, we investigated the effect of phosphorylation of p34 by these kinases on the replication and repair function of HSSB. We observed no significant difference with the unphosphorylated and phosphorylated forms of HSSB in the simian virus 40 DNA replication or nucleotide excision repair systems reconstituted with purified proteins. The phosphorylation status of the p34 subunit of HSSB was unchanged during the reactions. We suggest that the phosphorylated HSSB has no direct effect on the basic mechanism of DNA replication and nucleotide excision repair reactions in vitro, although we cannot exclude a role of p34 phosphorylation in modulating HSSB function in vivo through a yet poorly understood control pathway in the cellular response to DNA damage and replication.
...
PMID:Phosphorylated and unphosphorylated forms of human single-stranded DNA-binding protein are equally active in simian virus 40 DNA replication and in nucleotide excision repair. 775 55

The radiosensitive rodent mutant cell line xrs-5 is defective in DNA double-strand break repair and lacks the Ku component of the DNA-activated protein kinase, DNA-PK. Here radiosensitive human cell lines were analyzed for DNA-PK activity and for the presence of related proteins. The radiosensitive human malignant glioma M059J cell line was found to be defective in DNA double-strand break repair, but fails to express the p350 subunit of DNA-PK. These results suggest that DNA-PK kinase activity is involved in DNA double-strand break repair.
...
PMID:Absence of p350 subunit of DNA-activated protein kinase from a radiosensitive human cell line. 785 2

To investigate the effect of phosphorylation on the transcription activity of p53, ten phosphorylation mutants were constructed covering all the identified phosphorylation sites of rat p53. These included mutants of two casein kinase I sites (Ser6 and Ser9), two DNA-PK sites (Ser15 and Ser39), a p34cdc2 site (Ser313), the adjacent Ser312 and a casein kinase II site (Ser390). Two double phosphorylation mutants (Ser4, 6 and Ser15, 390) and one triple phosphorylation mutant (Ser4, 6 and 15) were also constructed. The transcription activity of all the p53 phosphorylation mutants was tested by transfection into two different types of cells, Saos-2 cells and p53(-/-) fibroblasts derived from p53 knock out mice, which both lack endogenouse p53. Surprisingly, all the p53 phosphorylation mutants retain transcription activity and the seven mutants tested can also suppress cell growth.
...
PMID:p53 phosphorylation mutants retain transcription activity. 786 59

We report here that the human estrogen receptor (hER) overexpressed in Sf9 insect cells is phosphorylated similarly to hER from the human MCF-7 mammary carcinoma cell line. The recombinant and native hER labeled to steady-state with [32P]phosphate were purified to homogeneity using specific DNA-affinity chromatography followed by SDS-gel electrophoresis. Resolution of the hER tryptic digests by reverse phase-high performance liquid chromatography revealed that five [32P]phosphopeptides from the hER expressed in the Sf9 cells had retention times identical to five of the seven [32P]phosphopeptides from the hER in MCF-7 cells. Uniquely, a dephosphorylation of a single 32P-labeled peptide occurred in response to estradiol treatment of MCF-7 cells. In vitro protein kinase assays with the purified recombinant hER revealed that the DNA-dependent protein kinase (DNA-PK) phosphorylated the receptor and induced a decrease in the receptor's mobility as demonstrated by SDS-gel electrophoresis. In contrast, protein kinases A and C did not phosphorylate the purified recombinant hER. These results suggest that in the process of becoming transcriptionally active the estrogen receptor undergoes a dephosphorylation after estrogen-binding and subsequent phosphorylations, in part by the DNA-PK.
...
PMID:In vivo and in vitro phosphorylation of the human estrogen receptor. 787 51

DNA-PK is a DNA-activated serine/threonine protein kinase capable of phosphorylating a number of nuclear DNA-binding proteins. Purified human DNA-PK has two subunits, a 350-kDa polypeptide, Prkdc, which binds ATP and is presumed to contain the catalytic site, and the Ku autoantigen which mediates DNA binding and activation. Previous studies have shown that DNA-PK is activated in vitro by linear double-stranded DNA fragments; however, the Ku subunit binds a broader range of DNA structures. Here we show that EBP-80, a protein originally isolated as a transcription factor for a retroviral long terminal repeat element and subsequently found to be similar to if not identical with Ku, also mediates kinase activation. The EBP-80-Prkdc complex is activated by nanomolar concentrations of DNA constructs containing single-to-double strand transitions, including a closed stem-loop structure and single strand gaps of 0 (nick), 6, and 30 nucleotides. Kinase activation parallels the ability of EBP-80 to bind these and other constructs. Our results extend the range of DNA configurations known to activate DNA-PK and are consistent with the participation of this enzyme complex in several nuclear functions.
...
PMID:DNA-dependent protein kinase is activated by nicks and larger single-stranded gaps. 820 88


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

---