Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The post-translational poly ADP-ribosylation of proteins by the nuclear enzyme poly(ADP-ribose) polymerase (EC 2.4.2.30) involves a complex pattern of ADP-ribose polymers. We have determined how this enzyme produces the various polymer size patterns responsible for altered protein function. The results show that histone H1 and core histones are potent regulators of both the numbers and sizes of ADP-ribose polymers. Each histone induced the polymerase to synthesize a specific polymer size pattern. Various other basic and/or DNA binding proteins as well as other known stimulators of poly(ADP-ribose) polymerase (spermine, MgCl2, nicked DNA) were ineffective as polymer size modulators. Testing specific proteolytic fragments of histone H1, the polymer number and polymer size modulating activity could be mapped to specific polypeptide domains. The results suggest that histones specifically regulate the polymer termination reaction of poly(ADP-ribose) polymerase.
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PMID:Regulation of poly(ADP-ribose) polymerase. Histone-specific adaptations of reaction products. 190 93

Poly(ADP-ribose) polymerase (EC 2.4.2.30) is a zinc-binding protein that specifically binds to a DNA strand break in a zinc-dependent manner. We describe here the cloning and expression in Escherichia coli of a cDNA fragment encoding the two putative zinc fingers (FI and FII) domain of the human poly(ADP-ribose) polymerase. Using site-directed mutagenesis, we identified the amino acids involved in metal coordination and analyzed the consequence of altering the proposed zinc-finger structures on DNA binding. Disruption of the metal binding ability of the second zinc finger, FII, dramatically reduced target DNA binding. In contrast, when the postulated Zn(II) ligands of FI were mutated, the DNA binding activity was only slightly affected. DNase I protection studies showed that the FII is involved in the specific recognition of a DNA strand break. These results demonstrate that poly(ADP-ribose) polymerase contains a type of zinc finger that differs from previously recognized classes in terms of both structure and function.
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PMID:The second zinc-finger domain of poly(ADP-ribose) polymerase determines specificity for single-stranded breaks in DNA. 210 22

The nuclear enzyme poly(ADP-ribose) polymerase (EC 2.4.2.30) participates in DNA excision repair by post-translational selfmodification ("automodification") and the modification of other chromatin proteins ("heteromodification") with ADP-ribose polymers. We have studied the molecular mechanism of these reactions in a reconstituted in vitro system. After activation by DNA, poly(ADP-ribose) polymerase produces polymers with a distinct size pattern. These polymers are attached to a small subfraction of enzyme molecules. As the reaction progresses, more enzyme molecules are recruited for modification with an identical polymer size pattern. Likewise, the auto- and heteromodification reaction in nucleosomal core particles involves the consecutive addition of a highly conserved polymer size pattern to the acceptor proteins. Thus, a highly conserved polymer size pattern may constitute the molecular signal priming chromatin proteins for a role in DNA excision repair in vivo. The priming reaction is processive.
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PMID:Poly ADP-ribosylation of proteins. Processivity of a post-translational modification. 250 17

The level of mRNA encoding the nuclear enzyme poly(ADP-ribose) polymerase (ADP-ribosyltransferase, EC 2.4.2.30) was found to be very low in quiescent human lymphocytes and to increase at least 10-fold between 1 and 2 dyas after stimulation with the mitogen phytohaemagglutinin, staying high for several days thereafter. This increase was inhibited by 3-methoxybenzamide (a competitive inhibitor of poly(ADP-ribose) polymerase) but was not affected significantly by aphidicolin. Incubation of activated cells with cycloheximide for 2 h increased the expression slightly. These data demonstrate that, during lymphocyte activation, the level of mRNA of the poly(ADP-ribose) polymerase gene correlates with, and hence is presumably responsible for, the increase in poly(ADP-ribose) polymerase protein detectable by enzyme assay or immunochemistry.
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PMID:Changes in mRNA levels of poly(ADP-ribose) polymerase during activation of human lymphocytes. 250 50

To analyze a possible involvement of ADP-ribosylation reactions in 3T3-L1 pre-adipocyte differentiation. ADP-ribosyltransferase activities is permeabilized cells as well as endogenous amounts of protein-bound mono- and poly(ADP-ribose) residues were determined. Also, in vivo labeling with [3H]adenosine of ADP-ribose residues linked to high-mobility-group (HMG) proteins was performed. As an additional probe, the effects of ADP-ribosylation inhibitors and non-inhibitory analogs were studied. Basal and total poly(ADP-ribose) polymerase activities markedly increased prior to the appearance of the differentiation marker glycerol-3-phosphate dehydrogenase. Despite these apparent changes in activity, however, neither protein-bound poly(ADP-ribose) residue nor mono(ADP-ribosyl) groups in histones, nor the NAD content, changed significantly under these conditions. Furthermore, although HMG protein-associated [3H]ADP-ribose was reduced in differentiating [3H]adenosine-labeled cells, the data suggest altered precursor pool labeling rather than a specific decrease in ADP-ribosylated HMG proteins. Non-participation of ADP-ribosylation reactions in 3T3-L1 differentiation is further supported by experiments with inhibitors and non-inhibitory analogs. Benzamide at 0.3-3 mM per se without effect on differentiation, was able to induce specific gene expression when combined with insulin (10(-12)-10(-7) M). Similar effects were seen with benzoate as well as with nicotinamide, 3-aminobenzamide and their corresponding acids. The data indicate that benzamide and analogs have profound effects on chromatin functions that are not mediated by ADP-ribosylation reactions.
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PMID:Differentiation of 3T3-L1 pre-adipocytes induced by inhibitors of poly(ADP-ribose) polymerase and by related noninhibitory acids. 252 99

In HL-60 cells, a human promyelocytic leukemia cell line, the human c-myc gene, designated MYC, is amplified about 16-fold. On differentiation of the HL-60 cells into granulocytes induced by several inhibitors of poly(ADP-ribose) polymerase [NAD+ poly(adenosine diphosphate D-ribose)ADP-D-ribosyltransferase, EC 2.4.2.30] including benzamide, nicotinamide, coumarin, and 4-hydroxyquinazoline or dimethyl sulfoxide, some MYC loss was observed. In contrast, benzoic acid, a noninhibitory analogue of benzamide, did not induce either granulocytic differentiation or loss of MYC. Loss of MYC seems to be associated with granulocytic differentiation because the time course of its loss was similar to that of appearance of nitroblue tetrazolium-positive cells, mature granulocytes, and its loss was not observed on differentiation of HL-60 cells into macrophages induced by phorbol 12-myristate 13-acetate or teleocidin. The loss of MYC is not the reason for the down regulation of MYC expression observed within 1 hr after addition of inducers, since the loss of MYC was not detected by 1-day treatment with inducers.
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PMID:Loss of the MYC gene amplified in human HL-60 cells after treatment with inhibitors of poly(ADP-ribose) polymerase or with dimethyl sulfoxide. 252 40

H2O2, in concentrations achieved in the proximity of stimulated leukocytes, induces injury and lysis of target cells. This may be an important aspect of inflammatory injury of tissues. Cell lysis in two target cells, the murine macrophage-like tumor cell line P388D1 and human peripheral lymphocytes, was found to be associated with activation of poly(ADP-ribose) polymerase (EC 2.4.2.30), a nuclear enzyme. This enzyme is activated under various conditions of DNA damage. Poly(ADP-ribose) polymerase utilizes nicotinamide adenine dinucleotide (NAD) as substrate and has been previously shown to consume NAD during exposure of cells to oxidants that was associated with inhibition of glycolysis, a decrease in cellular ATP, and cell death. In the current studies, inhibition of poly(ADP-ribose) polymerase by 3-aminobenzamide, nicotinamide, or theophylline in cells exposed to lethal concentrations of H2O2 prevented the sequence of events that eventually led to cell lysis--i.e., the decrease in NAD, followed by depletion of ATP, influx of extracellular Ca2+, actin polymerization and, finally, cell death. DNA damage, the initial stimulus for poly(ADP-ribose) polymerase activation, occurred despite the inhibition of this enzyme. Cells exposed to oxidant in the presence of the poly(ADP-ribose) polymerase inhibitor 3-aminobenzamide failed to demonstrate repair of DNA strand breaks.
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PMID:Hydrogen peroxide-induced injury of cells and its prevention by inhibitors of poly(ADP-ribose) polymerase. 294 60

In mammalian cells, NAD+ serves a dual role as a respiratory coenzyme and as a substrate for the posttranslational poly(ADP-ribose) modification of chromatin proteins, catalyzed by the nuclear enzyme poly(ADP-ribose) polymerase [NAD+ ADP-ribosyltransferase, EC 2.4.2.30]. Biological evidence strongly suggests that poly(ADP-ribosyl)ation modulates chromatin functions, although the precise molecular mechanisms involved have not yet been elucidated. Here we describe conditions for the rapid uptake of exogenously supplied NAD+ by living hepatocytes in primary monolayer culture. Raising the intracellular NAD+ concentration by 70% caused a 5-fold increase of chromatin-bound poly(ADP-ribose). We conclude that the constitutive level of posttranslational poly(ADP-ribose) modifications of chromatin proteins in mammalian cells is related to the availability of NAD+, which varies in different physiological and pathological states. We propose that poly-(ADP-ribose) may serve a hitherto unrecognized function by signaling altered metabolic conditions to the chromatin and thus modulate its functions in tune with changing metabolic states.
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PMID:Poly(ADP-ribose) may signal changing metabolic conditions to the chromatin of mammalian cells. 310 32

a1-1 cells, a transformant line obtained by transfection of NIH 3T3 cells with human c-Ha-rasT24 (hc-Ha-rasT24), were converted to morphologically normal flat cells following a 2-week culture in the presence of benzamide (BA), an inhibitor of poly(ADP-ribose) polymerase [ADP-ribosyltransferase (polymerizing); EC 2.4.2.30]. Concomitant with these morphological changes was the loss of the exogenous hc-Ha-rasT24 sequence. When cells were cultured without transfer, multiple clusters of flat revertant cells surrounded by transformed cells within single colonies of a1-1 cells were observed. This, together with the slow growth rate of flat cells in the presence of BA, indicated that flat revertants were induced rather than selected by BA. Flat cells isolated from mixed colonies completely lost the exogenous and amplified hc-Ha-rasT24 gene. In contrast, the endogenous mouse c-Ha-ras in flat revertant cells was not lost during culture with BA. Similarly, the endogenous hc-Ha-rasT24 in human bladder carcinoma T24 cells was not affected by BA. By using various chemicals, it was suggested that inhibition of poly(ADP-ribose) polymerase induces an efficient and specific loss of the exogenous transforming genes including Ki-ras, N-ras, c-raf, and ret-II.
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PMID:Deletion of transfected oncogenes from NIH 3T3 transformants by inhibitors of poly(ADP-ribose) polymerase. 314 13

To investigate the origin of DNA repair in rat pleural mesothelial cells (RPMC) exposed to asbestos fibers, poly(ADP-ribose) polymerase (PARP) activity was measured in the asbestos-treated cells. As bleomycin has been shown to activate poly(ADP-ribose) synthesis in several cell systems, the response to bleomycin with regard to PARP assay was first investigated. Bleomycin produced a dose-dependent increase of poly(ADP-ribose) synthesis in RPMC. Likewise both chrysotile and crocidolite fibers produced a concentration-dependent PARP activation indicating that the formation of DNA strand breaks is one type of damage produced by asbestos in RPMC. Enhancement of DNA repair, assessed by the measurement of [3H] methylthymidine incorporation in growth arrested cells, was not detectable in the presence of 3-methoxybenzamide (3-MBA), a PARP inhibitor, confirming a relation between PARP activation and DNA repair. The participation of DNA breakage in asbestos toxicity on RPMC was determined by the colorimetric 3-4(5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. There was no relationship between DNA breakage and cytotoxicity since the use of PARP inhibitors did not change cell viability. These results indicate that asbestos produce DNA damage that is repaired in RPMC.
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PMID:Synthesis of poly(ADP-ribose) in asbestos treated rat pleural mesothelial cells in culture. 750 Sep 78


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