Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Poly(ADP-ribose) polymerase-1 (PARP-1) is a mammalian enzyme that attaches long branching chains of ADP-ribose to specific nuclear proteins, including itself. Because its activity in vitro is dependent upon interaction with broken DNA, it has been postulated that PARP-1 plays an important role in DNA strand-break repair in vivo. The exact mechanism of binding to DNA and the structural determinants of binding remain to be defined, but regions of transition from single-stranded to double-strandedness may be important recognition sites. Here we employ surface plasmon resonance (SPR) to investigate this hypothesis. Oligodeoxynucleotide (ODN) substrates that mimic DNA with different degrees of single-strandedness were used for measurements of both PARP-1/DNA binding kinetics and PARP-1's enzyme activities. We found that binding correlated with activity, but was unrelated to single-strandedness of the ODN. Instead, PARP-1 binding and activity were highest on ODNs that modeled a DNA double-strand break (DSB). These results provide support for PARP-1 recognizing and binding DSBs in a manner that is independent of single-stranded features, and demonstrate the usefulness of SPR for simultaneously investigating both PARP-1 binding and PARP-1 auto-poly(ADP-ribosyl)ation activities within the same in vitro system.
J Mol Recognit
PMID:Binding kinetics and activity of human poly(ADP-ribose) polymerase-1 on oligo-deoxyribonucleotide substrates. 1958 41

Many established cancer therapies involve DNA-damaging chemotherapy or radiotherapy. Gain of DNA repair capacity of the tumor represents a common mechanism used by cancer cells to survive DNA-damaging therapy. Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme that is activated by DNA damage and plays a critical role in base excision repair. Inhibition of PARP represents an attractive approach for the treatment of cancer. Previously, we have described the discovery and characterization of a potent PARP inhibitor, ABT-888. ABT-888 potentiates the activity of DNA-damaging agents such as temozolomide (TMZ) in a variety of preclinical models. We report here the generation of HCT116 cells resistant to treatment with TMZ and ABT-888 (HCT116R cells). HCT116R cells exhibit decreased H2AX phosphorylation in response to treatment with TMZ and ABT-888 relative to parental HCT116 cells. Microarray and Western blot studies indicate that HCT116R cells have decreased PARP-1 and elevated Rad51 expression levels. HCT116R cells are dependent on Rad51 for proliferation and survival, as shown by inhibition of proliferation and induction of apoptosis upon treatment with Rad51 small interfering RNA. In addition, HCT116R cells are more resistant to radiation than the parental HCT116 cells. Our study suggests that cancer cells upregulate the homologous recombination DNA repair pathway to compensate for the loss of base excision repair, which may account for the observed resistance to treatment with TMZ and ABT-888.
Mol Cancer Res 2009 Oct
PMID:Acquired resistance to combination treatment with temozolomide and ABT-888 is mediated by both base excision repair and homologous recombination DNA repair pathways. 1982 92

In this issue of Molecular Cell, Stilmann et al. (2009) demonstrate a new mode of prosurvival NF-kappaB activation through the formation of a PARP-1-poly(ADP-ribose) signaling scaffold in response to DNA damage.
Mol Cell 2009 Nov 13
PMID:A PAR-SUMOnious mechanism of NEMO activation. 1991 46

Upon genotoxic stresses, cells activate IkappaB kinases (IKKs) and the transcription factor NF-kappaB to modulate apoptotic responses. The SUMO-1 ligase PIASy and the kinase ataxia talengiectasia mutated (ATM) have been implicated to SUMOylate and phosphorylate nuclear IKKgamma (NEMO) in a consecutive mode of action, which in turn results in activation of cytoplasmic IKK holocomplexes. However, the nuclear signals and scaffold structures that initiate IKKgamma recruitment and activation are unknown. Here, we show that poly(ADP-ribose)-polymerase-1 (PARP-1) is the DNA proximal regulator, which senses DNA strand breaks and, through poly(ADP-ribose) (PAR) synthesis, assembles IKKgamma, PIASy, and ATM in a dynamic manner. Signalosome formation involves direct protein-protein interactions and binding to ADP-ribose polymers through PAR binding motifs (PARBM). Activated PARP-1 and a PARBM in PIASy are required to trigger IKKgamma SUMOylation, which in turn permits IKK and NF-kappaB activation, as well as NF-kappaB-regulated resistance to apoptosis.
Mol Cell 2009 Nov 13
PMID:A nuclear poly(ADP-ribose)-dependent signalosome confers DNA damage-induced IkappaB kinase activation. 1991 42

The enzyme poly(ADP-ribose) polymerase-1 (PARP-1) is a global monitor of chromatin structure and DNA damage repair. PARP-1 binds to nucleosomes and poly(ADP-ribosylates) histones and several chromatin-associated factors to expose specific DNA sequences to the cellular machinery involved in gene transcription and/or DNA damage repair. While these processes are critical to genomic stability, the molecular mechanisms of how DNA damage induces PARP-1 activation are poorly understood. We have used biochemical and thermodynamic measurements in conjunction with small-angle X-ray scattering to determine the stoichiometry, affinity, and overall structure of a human PARP-1 construct containing the entire DNA binding region, the zinc ribbon domain, and automodification domains (residues 1-486). The interaction of this PARP-1 protein construct with three different DNA damage models (DNA constructs containing a nick, a blunt end, or a 3' extension) was evaluated. Our data indicate that PARP-1 binds each DNA damage model as a monomer and with similar affinity, in all cases resulting in robust activation of the catalytic domain. Using small-angle X-ray scattering, we determined that the N-terminal half of PARP-1 behaves as an extended and flexible arrangement of individually folded domains in the absence of DNA. Upon binding DNA, PARP-1 undergoes a conformational change in the area surrounding the zinc ribbon domain. These data support a model in which PARP-1, upon binding DNA, undergoes a conformational change to become an active nuclear enzyme.
J Mol Biol 2010 Feb 05
PMID:Structural and biophysical studies of human PARP-1 in complex with damaged DNA. 1996 92

Poly(ADP-ribosyl)ation of the conserved multifunctional transcription factor CTCF was previously identified as important to maintain CTCF insulator and chromatin barrier functions. However, the molecular mechanism of this regulation and also the necessity of this modification for other CTCF functions remain unknown. In this study, we identified potential sites of poly(ADP-ribosyl)ation within the N-terminal domain of CTCF and generated a mutant deficient in poly(ADP-ribosyl)ation. Using this CTCF mutant, we demonstrated the requirement of poly(ADP-ribosyl)ation for optimal CTCF function in transcriptional activation of the p19ARF promoter and inhibition of cell proliferation. By using a newly generated isogenic insulator reporter cell line, the CTCF insulator function at the mouse Igf2-H19 imprinting control region (ICR) was found to be compromised by the CTCF mutation. The association and simultaneous presence of PARP-1 and CTCF at the ICR, confirmed by single and serial chromatin immunoprecipitation assays, were found to be independent of CTCF poly(ADP-ribosyl)ation. These results suggest a model of CTCF regulation by poly(ADP-ribosyl)ation whereby CTCF and PARP-1 form functional complexes at sites along the DNA, producing a dynamic reversible modification of CTCF. By using bioinformatics tools, numerous sites of CTCF and PARP-1 colocalization were demonstrated, suggesting that such regulation of CTCF may take place at the genome level.
Mol Cell Biol 2010 Mar
PMID:Mutational analysis of the poly(ADP-ribosyl)ation sites of the transcription factor CTCF provides an insight into the mechanism of its regulation by poly(ADP-ribosyl)ation. 2003 29

Poly(ADP-ribose) polymerase-1 (PARP-1) inhibition is toxic to cells with mutations in the breast and ovarian cancer susceptibility genes BRCA1 or BRCA2, a concept termed synthetic lethality. However, whether this approach is applicable to other human cancers with defects in other DNA repair genes has yet to be determined. The ataxia telangiectasia mutated (ATM) gene is altered in several human cancers including mantle cell lymphoma (MCL). Here, we characterize a panel of MCL cell lines for ATM status and function and investigate the potential for synthetic lethality in MCL in the presence of small-molecule inhibitors of PARP-1. We show that Granta-519 and UPN2 cells have low levels of ATM protein, are defective in DNA damage-induced ATM-dependent signaling, are radiation sensitive, and have cell cycle checkpoint defects: all characteristics of defective ATM function. Significantly, Granta-519 and UPN2 cells were more sensitive to PARP-1 inhibition than were the ATM-proficient MCL cell lines examined. Furthermore, the PARP-1 inhibitor olaparib (known previously as AZD2281/KU-0059436) significantly decreased tumor growth and increased overall survival in mice bearing s.c. xenografts of ATM-deficient Granta-519 cells while producing only a modest effect on overall survival of mice bearing xenografts of the ATM-proficient cell line, Z138. Thus, PARP inhibitors have therapeutic potential in the treatment of MCL, and the concept of synthetic lethality extends to human cancers with ATM alterations.
Mol Cancer Ther 2010 Feb
PMID:ATM deficiency sensitizes mantle cell lymphoma cells to poly(ADP-ribose) polymerase-1 inhibitors. 2012 59

c-Jun N-terminal kinase (JNK) is activated by cellular stress and plays critical roles in diverse types of cell death. However, role of JNK in beta-cell injury is obscure. We investigated the role for JNK in streptozotocin (STZ)-induced beta-cell death. STZ induced JNK activation in insulinoma or islet cells. JNK inhibitors attenuated insulinoma or islet cell death by STZ. STZ-induced JNK activation was decreased by PARP inhibitors, suggesting that JNK activation is downstream of PARP-1. Phosphatase inhibitors induced activation of JNK and abrogated the suppression of STZ-induced JNK activation by PARP inhibitors, suggesting that the inhibition of phosphatases is involved in the activation of JNK by STZ. STZ induced production of reactive oxygen species (ROS) as potential inhibitors of phosphatases, which was suppressed by PARP inhibitors. PARP-1 siRNA attenuated insulinoma cell death and JNK activation after STZ treatment, which was reversed by MKP (MAP kinase phosphatase)-1 siRNA. These results suggest that JNK is activated by STZ downstream of PARP-1 through inactivation of phosphatases such as MKP, which plays important roles in STZ-induced beta-cell death.
Mol Cell Endocrinol 2010 Jun 10
PMID:Role of JNK activation in pancreatic beta-cell death by streptozotocin. 2017 78

The biological roles of poly(ADP-ribose) polymers (PAR) and poly(ADP-ribosyl)ation of proteins in the central nervous system are diverse. The homeostasis of PAR orchestrated by poly(ADP-ribose) polymerase-1 (PARP-1) and poly(ADP-ribose) glycohydrolase (PARG) is crucial for cell physiology and pathology. Both enzymes are ubiquitously distributed in neurons and glia; however, they are segregated at the subcellular level. PARP-1 serves as a "nick sensor" for single- or double-stranded breaks in DNA and is involved in long and short patch base-excision repair, while PARG breaks down PAR. The stimulation of PARP-1 and PAR formation can activate proinflammatory transcription factors, including nuclear factor kappa B. However, hyperactivation of PARP-1 can result in depletion of NAD/ATP, and in PAR-dependent mitochondrial pore formation leading to release of apoptosis inducing factor and cell death. The role of PAR as a death signaling molecule in brain ischemia-reperfusion and inflammation as well as the effect of gender and aging is presented in this review. Modulating the PAR level through pharmacological or genetic intervention on PARP-1/PARG activity and gene expression should be a valuable way for neuroprotective strategy.
Mol Neurobiol 2010 Jun
PMID:Poly(ADP-ribose) metabolism in brain and its role in ischemia pathology. 2041 56

Recently, the massively parallel computation of absolute binding free energy with a well-equilibrated system (MP-CAFEE) has been developed. The present study aimed to determine whether the MP-CAFEE method is useful for drug discovery research. In the drug discovery process, it is important for computational chemists to predict the binding affinity accurately without detailed structural information for protein/ligand complex. We investigated the absolute binding free energies for Poly (ADP-ribose) polymerase-1 (PARP-1)/inhibitor complexes, using the MP-CAFEE method. Although each docking model was used as an input structure, it was found that the absolute binding free energies calculated by MP-CAFEE are well consistent with the experimental ones. The accuracy of this method is much higher than that using molecular mechanics Poisson-Boltzmann/surface area (MM/PBSA). Although the simulation time is quite extensive, the reliable predictor of binding free energies would be a useful tool for drug discovery projects.
J Mol Model 2011 Feb
PMID:Docking study and binding free energy calculation of poly (ADP-ribose) polymerase inhibitors. 2048 Mar 80


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