Molecular interactions between poly(ADP‐ribose) polymerase (PARP I) and topoisomerase I (Topo I): identification of topology of binding

Abstract

The molecular interactions of poly(ADP-ribose) polymerase I (PARP I) and topoisomerase I (Topo I) have been determined by the analysis of physical binding of the two proteins and some of their polypeptide components and by the effect of PARP I on the enzymatic catalysis of Topo I. Direct association of Topo I and PARP I as well as the binding of two Topo I polypeptides to PARP I are demonstrated. The effect of PARP I on the`global' Topo I reaction (scission and religation), and the activation of Topo I by the 36 kDa polypeptide of PARP I and catalytic modifications by poly(ADP-ribosyl)ation are also shown. The covalent binding of Topo I to circular DNA is activated by PARP I similar to the degree of activation of thè global' Topo I reaction, whereas the religation of DNA is unaffected by PARP I. The geometry of PARP I^Topo I interaction compared to automodified PARP I was reconstructed from direct binding assays between glutathione S-transferase fusion polypeptides of Topo I and PARP I demonstrating highly selective binding, which was correlated with amino acid sequences and with the`C clamp' model derived from X-ray crystallography. ß 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

Enhanced Killing of Cancer Cells by Poly(ADP-ribose) Polymerase Inhibitors and Topoisomerase I Inhibitors Reflects Poisoning of Both Enzymes

“…Previous experiments using purified proteins under cell-free conditions demonstrated a potential role for pADPr generated by PARP1 in the modulation of topo I activity (33)(34)(35)(36)(37). These experiments predicted that PARP inhibition would alter the kinetics of topo I-mediated strand religation, thereby shifting the cleavage-religation equilibrium (Fig.…”

“…3E, third panel) (33)(34)(35)(36)(37). This model would predict that increased Topo1cc covalent complexes would be formed in the presence of PARP inhibitors.…”

“…First, studies with purified enzymes have shown that PARP1 can covalently attach pADPr to topo I. The presence of this pADPr polymer alters the affinity of topo I for DNA, shifting the cleavage/religation equilibrium of the enzyme toward sealed DNA (33)(34)(35)(36)(37).…”

Poly(ADP-ribosyl)ation as a DNA Damage-induced Post-translational Modification Regulating Poly(ADP-ribose) Polymerase-1-Topoisomerase I Interaction

“…Other lines of evidence suggest that PARP-1 plays a role in DNA repair through interaction with XRCC-1 (36,37), DNA ligase III (19), and Werner syndrome protein (38). Finally, PARP-1 has been reported to bind to topoisomerase I (Topo I) (39,40), which is an enzyme required for DNA replication and transcription (41,42). Taken together, these observations suggest that PARP-1 is an enzyme playing roles in transcription initiation, DNA replication, and DNA repair through interaction with several different factors and enzymes.…”

“…Taken together, these observations suggest that PARP-1 is an enzyme playing roles in transcription initiation, DNA replication, and DNA repair through interaction with several different factors and enzymes. Interestingly, in some cases, the interacting domain of PARP-1 with these factors and enzymes has been identified; the interactions between PARP-1 and XRCC-1 (37), NF-B (25), YY1 (24), and Topo I (40) occur through the automodification domain of PARP-1. Thus, ADP-ribose polymer formation on the automodification domain is likely to have an effect on the interactions between PARP-1 and these factors and enzymes.…”