title: PARG is recruited to DNA damage sites through poly(ADP-ribose)- and PCNA-dependent mechanisms.
abstract: Post-translational poly(ADP-ribosyl)ation has diverse essential functions in the cellular response to DNA damage as it contributes to avid DNA damage detection and assembly of the cellular repair machinery but extensive modification eventually also induces cell death. While there are 17 human poly(ADP-ribose) polymerase (PARP) genes, there is only one poly(ADP-ribose) glycohydrolase (PARG) gene encoding several PARG isoforms located in different subcellular compartments. To investigate the recruitment of PARG isoforms to DNA repair sites we locally introduced DNA damage by laser microirradiation. All PARG isoforms were recruited to DNA damage sites except for a mitochondrial localized PARG fragment. Using PARP knock out cells and PARP inhibitors, we showed that PARG recruitment was only partially dependent on PARP-1 and PAR synthesis, indicating a second, PAR-independent recruitment mechanism. We found that PARG interacts with PCNA, mapped a PCNA binding site and showed that binding to PCNA contributes to PARG recruitment to DNA damage sites. This dual recruitment mode of the only nuclear PARG via the versatile loading platform PCNA and by a PAR dependent mechanism likely contributes to the dynamic regulation of this posttranslational modification and ensures the tight control of the switch between efficient DNA repair and cell death.
authors.affiliation: Ludwig Maximilians University Munich, Department of Biology, Center for Integrated Protein Science Munich, 82152 Planegg-Martinsried, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Mortusewicz
authors.forename: Elise
authors.initials: E
authors.lastname: Fouquerel
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Amé
authors.forename: Heinrich
authors.initials: H
authors.lastname: Leonhardt
authors.forename: Valérie
authors.initials: V
authors.lastname: Schreiber
mesh_terms: D000818:Animals; D055162:Biocatalysis; D002478:Cells, Cultured; D004249:DNA Damage; D006026:Glycoside Hydrolases / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007834:Lasers; D051379:Mice; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D017434:Protein Structure, Tertiary
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D020033:Protein Isoforms; D011064:Poly Adenosine Diphosphate Ribose; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase