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:2.4.2.30 (PARP)
13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Poly(ADP-ribosyl)ation is a eukaryotic posttranslational protein modification catalyzed by poly(ADP-ribose) polymerase (PARP), a highly conserved nuclear enzyme which uses NAD as substrate. We have previously tested PARP activity in permeabilized mononuclear blood cells (MNC) from 13 mammalian species as a function of the species-specific life span. A direct and maximal stimulus of PARP activation was provided by including saturating amounts of a double-stranded oligonucleotide in the PARP-reaction buffer. The data yielded a strong positive correlation between PARP activities and the species' maximal life spans (r = 0.84; p << 0.001). Here, we investigated the formation of poly(ADP-ribose) in living MNC from two mammalian species with widely differing longevity (rat and man) by immunofluorescence detection of poly(ADP-ribose). The fraction of positive cells was recorded, following gamma-irradiation of intact MNC, as a semiquantitative estimation of poly(ADP-ribose) formation. Human samples displayed a significantly higher percentage of positivity than did those from rats, consistent with our previous results on permeabilized cells. While rat MNC had a higher NAD content than human MNC, the number of radiation-induced DNA strand breaks was not significantly different in the two species. Since poly(ADP-ribosyl)ation is apparently involved in DNA repair and the cellular recovery from DNA damage, we speculate that the higher poly(ADP-ribosyl)ation capacity of long-lived species might more efficiently help to slow down the accumulation of unrepaired DNA damage and of genetic alterations, as compared with short-lived species.
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PMID:Poly(ADP-ribose) polymerase activity in intact or permeabilized leukocytes from mammalian species of different longevity. 789 80

Cyclophosphamide (CYC) is a metabolically activated, DNA-alkylating, antitumor agent that causes pulmonary fibrosis. BALB/cN (B) mice are sensitive and C57Bl/6N (C) mice are resistant to CYC-induced fibrosis. Pulmonary bioactivation may contribute to strain sensitivity. Therefore, we tested the intrinsic susceptibility of murine lung slices to cell injury by direct exposure to CYC for 2-8 hr. Injury was measured by release of lactate dehydrogenase (LDH). DNA damage activates the nuclear enzyme poly(ADP-ribose) polymerase (PAP, EC 2.4.2.30), causing depletion of its substrate, NAD. NAD can also be decreased by phosphorylation to NADP, as seen with oxidative stress. Depletion of NAD can lead to loss of ATP. Thus, we measured LDH release, PAP activation, NAD, NADP and ATP in slices incubated with or without the PAP-inhibitor, 3-aminobenzamide (3-AB). CYC (0.1 to 1.0 mg/mL for 4-8 hr) caused LDH release in slices from both murine strains, but LDH release was significantly greater in B lung slices than in C slices. After an 8-hr incubation 63.9 +/- 3.7% (mean +/- SEM) of total LDH was released from B lung slices with 1.0 mg CYC/mL, whereas only 45.8 +/- 2.6% was released from C lung slices (P < 0.05). 3-AB reduced LDH release to 44.7 +/- 2.4% in B slices and 28.1 +/- 2.0% in C slices (P < 0.05 vs CYC only). PAP activity in nuclei isolated from CYC-treated B lung slices was increased 2- to 4-fold after 2 hr of incubation with 0.5 and 1.0 mg CYC/mL. PAP activation was delayed and reduced with incubation in 3-AB. PAP was activated 2-fold in nuclei from C slices treated with 0.5 mg CYC/mL for 2 hr. NAD was decreased at 2 and 4 hr in B slices treated with 0.5 and 1.0 mg CYC/mL, and at 4 hr with 0.1 mg CYC/mL. NAD depletion occurred only at 4 hr in the resistant C slices treated with 1.0 mg CYC/mL. CYC increased NADP by a similar extent in B and C lung slices. In B slices, NAD losses were approximately 4 times the increases in NADP. CYC did not decrease ATP in B slices and ATP dropped 25% only after 4 hr in the resistant C slices. We conclude that CYC is directly toxic to lung tissue and observe that strain sensitivity in vitro mirrors the sensitivity to fibrosis in vivo. PAP activation and oxidative stress may contribute to this toxicity.
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PMID:Acute pneumocyte injury, poly(ADP-ribose) polymerase activity, and pyridine nucleotide levels after in vitro exposure of murine lung slices to cyclophosphamide. 798 Jun 45

Recent studies suggest that proteases of the interleukin 1-beta-converting enzyme (ICE)/ced-3 family are involved in initiating the active phase of apoptosis. Here we identify a novel protease resembling ICE (prICE) that is active in a cell-free system that reproduces the morphological and biochemical events of apoptosis. prICE cleaves the nuclear enzyme poly(ADP-ribose) polymerase (PARP) at a tetrapeptide sequence identical to one of two ICE sites in pro-interleukin-1-beta. However, prICE does not cleave purified pro-interleukin-1-beta, and purified ICE does not cleave PARP, indicating that the two activities are distinct. Inhibition of prICE abolishes all manifestations of apoptosis in the extracts including morphological changes, cleavage of PARP and production of an oligonucleosomal ladder. These studies suggest that prICE might be pivotal in initiating the active phase of apoptosis in vitro and in intact cells.
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PMID:Cleavage of poly(ADP-ribose) polymerase by a proteinase with properties like ICE. 809 Feb 5

A cDNA spanning the entire coding region for poly(ADP-ribose) polymerase (PARP) of Sarcophaga peregrina was isolated and the nucleotide sequence was determined. The longest open reading frame encodes a polypeptide of 996 amino acid residues with a molecular mass of 113,033 Da. The similarities to the human PARP in amino acid sequence were relatively low in the DNA-binding and auto-modification domains, but very high in the C-terminal catalytic domain: identity of amino acids is 34% in the N-terminal DNA-binding domain (residues 1-369), 27% in the auto-modification domain (residues 370-507), and 56% in the C-terminal NAD-binding domain (residues 508-996). Two zinc-fingers (C-X2-C-X28-H-X2-C and C-X2-C-X31-H-X2-C)2 and a basic region in the N-terminal DNA-binding domain recognized in other PARP are conserved. Downstream of the basic region, another cysteine-rich motif (C-X2-C-X13-C-X9-C), a putative zinc-finger, was found to be well conserved in the PARP of Sarcophaga, Drosophila and human. A leucine-zipper motif (L-X6-L-X6-L-X6-L) which was found in the auto-modification domain of Drosophila PARP, is disrupted in the Sarcophaga enzyme: the second leucine is replaced by proline, and the third leucine by valine. Full-length cDNA for Sarcophaga PARP was cloned into an expression plasmid and expressed in Escherichia coli. A lysate of E. coli cells containing expressed protein reacted with antibody against Sarcophaga PARP, and PARP activity was detected. Thus, we conclude that isolated cDNA encodes a functional Sarcophaga PARP cDNA.
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PMID:Cloning and functional expression of poly(ADP-ribose) polymerase cDNA from Sarcophaga peregrina. 812 21

After weaning, the mammary gland ceases lactation and involutes. The wet weight of the gland decreases by 70% within 4 days of weaning. This involves significant tissue remodelling as the ducts regress and return to the resting state. The presence of apoptotic bodies in the luminal epithelial compartment 2 to 3 days after weaning provides clear evidence that a substantial proportion of the regression is attributable to the induction of active cell death (ACD) of the epithelial cells. These changes in the architecture of the gland were found to be mirrored by changes in gene expression. The steady-state level of beta-casein mRNA decreased rapidly after weaning from the high levels seen during lactation to undetectable levels by 8 days after weaning. The steady-state levels of expression of a number of genes associated with ACD, including TRPM-2, tissue transglutaminase (TGase) and poly(ADP-ribose) polymerase (PARP), increased transiently during this time-frame. The steady-state level of TRPM-2 mRNA increased 2 days after weaning, reaching a peak on day 4, and decreasing to undetectable levels by day 8 after weaning. The steady-state levels of two other mRNAs, TGase and PARP, showed very similar kinetics. In contrast, the mRNA for Hsp 27, which has been shown to be induced during prostate regression, was not significantly induced in the regressing mammary gland. In-situ hybridization demonstrated that the TRPM-2, TGase and PARP genes were expressed predominantly in the luminal epithelial cells of the ducts. These cells expressed beta-casein mRNA during lactation, and underwent ACD after weaning. While the ultrastructural changes in the mammary gland after weaning, and the induction of TRPM-2, TGase and PARP mRNAs, are reminiscent of apoptosis in the prostate, several features of the process are different. Most notably, the disruption of the secretory processes and the lack of increased expression of Hsp 27 in the regressing mammary gland suggest that there may be a number of important events in ACD that are not common to all cells.
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PMID:Induction of gene expression during involution of the lactating mammary gland of the rat. 818 14

We have determined the molecular mechanism of the automodification reaction of poly(ADP-ribose) polymerase (PARP) (EC 2.4.2.30). While PARP-mono(ADP-ribose) conjugates were the predominant products of automodification at 200 nM NAD, enzyme-bound branched polymers were preferentially synthesized at 200 microM NAD. Thus, the initiation, elongation, and branching reactions catalyzed by PARP appear to be [NAD]-dependent. Initial rates of automodification increased with second order kinetics as a function of [PARP] at both 200 nM and 200 microM NAD. Therefore, 2 molecules of PARP, i.e. a catalytic dimer, are required for the auto-mono(ADP-ribosyl)ation and the auto-poly(ADP-ribosyl)ation reactions. Initial rates of automodification also increased with second order kinetics at low NAD concentrations. Therefore, the catalytic dimer also requires 2 molecules of NAD. These results are consistent with the conclusion that the automodification reaction of PARP is intermolecular and that the 2 monomeric units of PARP may simultaneously function as catalyst and acceptor molecules in the automodification reaction. Confirmatory evidence for the catalytic role of protein-protein interactions in the automodification reaction was manifested by a marked inhibition of auto-poly(ADP-ribosyl)ation at 40 nM or higher [PARP].
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PMID:Poly(ADP-ribose) polymerase is a catalytic dimer and the automodification reaction is intermolecular. 822 68

Previous studies suggest that heavy chain isotype switch (S) recombination is directed by cytokine-induced transcription of the unrearranged CH gene before recombination. In studies aimed at identifying other signaling pathways that promote switching, we discovered that inhibitors of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) increase LPS-induced switching to IgA in the B cell lymphoma 1.29 mu and to IgG1 in LPS + IL-4-treated splenic B cells. PARP, which binds to and is activated by DNA strand breaks, catalyzes the removal of ADP-ribose from NAD+ and poly(ADP-ribosylation) of chromatin-associated acceptor proteins. This enzyme is believed to function in cellular processes involving DNA strand breaks as well as in modulating chromatin structure. In 1.29 mu cells, PARP inhibitors increase IgA switching by day 2 and cause a fivefold increase in switching on day 3 as assayed by immunofluorescence microscopy. In spleen B cells, the PARP inhibitor nicotinamide increases IgG1 switching by about twofold. Nicotinamide also causes a reduced intensity of hybridization of C mu- and C alpha-specific probes to genomic DNA fragments containing the expressed VDJ-C mu and the unrearranged S alpha-C alpha segments, respectively, in 1.29 mu cells, indicating that PARP inhibition increases rearrangement of these fragments. Induction of switching by PARP inhibitors is not mimicked by treatment with cAMP analogues or reduced by inhibitors of protein kinase A. Induction of switching by PARP inhibitors does not appear to involve increased levels of transcription of the unrearranged C alpha gene.
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PMID:Inhibitors of poly(ADP-ribose) polymerase increase antibody class switching. 825 3

At a concentration of 2.5 mM, nicotinamide (NA), an inhibitor of poly(ADP-ribose) polymerase (PARP), significantly potentiated the cytotoxicity of cisplatin (DDP) in a DDP-resistant rat ovarian tumor cell line (O-342/DDP) in vitro, whereas the same treatment had no substantial effect on DDP's cytotoxic activity against the DDP-sensitive parental line (O-342). Furthermore, in a nude mouse model where the O-342/DDP tumor grew intraperitoneally, whereas DDP given alone at 1 mg/kg x 3 exhibited no antitumor activity as compared with control values due to the resistance, NA given at a nontoxic dose (5 mmol/kg x3) significantly increased the mean survival time (MST) of the tumor-bearing NMRI nude mice from 20.7 days in the DDP-treated group to 29.0 days in the combination group. Mechanism studies showed that endogenous PARP activity (incorporation of tritiated nicotinamide adenine dinucleotide, [3H]-NAD) was 2.6 times higher in O-342/DDP than in O-342 cells and that the presence of 2.5 mM NA during the incubation with the isotope resulted in 73.3% inhibition of the enzyme activity in O-342/DDP cells but in only about 30% inhibition in the sensitive line. However, treatment with NA during and after DDP exposure failed to produce any significant effect on the formation of DNA single-strand breaks (SSB) but decreased the induction of DNA interstrand cross-links (ISCL) by DDP in the sensitive and resistant cell lines. These results suggest that NA might have some clinical potential in reversing DDP resistance, and further studies are therefore warranted to confirm the resistance-reversing effect of NA in other DDP-resistant cell lines.
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PMID:Reversal of acquired cisplatin resistance by nicotinamide in vitro and in vivo. 826 76

The complete nucleotide (nt) sequence of the Xenopus laevis poly(ADP-ribose) polymerase (PARP)-encoding cDNA was determined. The putative X. laevis PARP protein consists of 1008 amino acids (aa) with a molecular weight of 113 kDa. X. laevis PARP shares 74, 83, 73, 78 and 42% aa sequence homology with the human, bovine, mouse, chicken and Drosophila melanogaster PARPs, respectively. Comparison of the PARP aa sequences among these species showed conservation of two zinc-finger motifs in the DNA-binding domain, and an NAD-binding motif and a Rossmann fold in the catalytic domain. The first Leu of the putative leucine zipper of D. melanogaster PARP is substituted to Lys in X. laevis PARP. All the Glu residues in the leucine zipper are conserved in these six species.
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PMID:Isolation of the poly(ADP-ribose) polymerase-encoding cDNA from Xenopus laevis: phylogenetic conservation of the functional domains. 829 62

A novel affinity-purification scheme based on the tight binding of NAD+:ADP-ribosyltransferase (polymerizing) [pADPRT; poly(ADP-ribose) polymerase; EC 2.4.2.30] to single-strand nicks in DNA, single-stranded patches and DNA ends has been developed to facilitate the purification of this enzyme from the lower eukaryote Dictyostelium discoideum. Two homogeneous forms of the enzyme, with M(r) values of 116,000 and 90,000, were prepared from D. discoideum by using poly(A) hybridized to oligo(dT)-cellulose as affinity material. The Km is 20 microM NAD+ for the 90,000-M(r) protein and 77 microM NAD+ for the 116,000-M(r) protein. The optimum conditions for the enzyme activity in vitro are 6-10 degrees C and pH 8. The time course is linear during the first 10 min of the reaction only. As in enzymes of higher eukaryotes, the activity is dependent on DNA and histone H1 and is inhibited by 3-methoxybenzamide, nicotinamide, theophylline, caffeine and thymidine.
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PMID:Purification and characterization of NAD+:ADP-ribosyltransferase (polymerizing) from Dictyostelium discoideum. 832 67


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