The DNA topoisomerase IIbeta binding protein 1 (TopBP1) interacts with poly (ADP-ribose) polymerase (PARP-1).
We investigated the physical association of the DNA topoisomerase IIbeta binding protein 1 (TopBP1), involved in DNA replication and repair but also in regulation of apoptosis, with poly(ADP-ribose) polymerase-1 (PARP-1). This enzyme plays a crucial role in DNA repair and interacts with many DNA replication/repair factors. It was shown that the sixth BRCA1 C-terminal (BRCT) domain of TopBP1 interacts with a protein fragment of PARP-1 in vitro containing the DNA-binding and the automodification domains. More significantly, the in vivo interaction of endogenous TopBP1 and PARP-1 proteins could be shown in HeLa-S3 cells by co-immunoprecipitation. TopBP1 and PARP-1 are localized within overlapping regions in the nucleus of HeLa-S3 cells as shown by immunofluorescence. Exposure to UVB light slightly enhanced the interaction between both proteins. Furthermore, TopBP1 was detected in nuclear regions where poly(ADP-ribose) (PAR) synthesis takes place and is ADP-ribosylated by PARP-1. Finally, cellular (ADP-ribosyl)ating activity impairs binding of TopBP1 to Myc-interacting zinc finger protein-1 (Miz-1). The results indicate an influence of post-translational modifications of TopBP1 on its function during DNA repair.
Wollmann
Yvonne
Y
Department of Cell and Molecular Biology, Leibniz Institute for Natural Product Research and Infection Biology (Hans Knoell Institute), Beutenbergstrasse 11a, D-07745 Jena, Germany.
Schmidt
Uta
U
Wieland
Gerhard D
GD
Zipfel
Peter F
PF
Saluz
Hans-Peter
HP
Hänel
Frank
F
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D001665:Binding Sites; D002352:Carrier Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D002467:Cell Nucleus / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism; D009687:Nuclear Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000032:analysis / Q000378:metabolism*; D017434:Protein Structure, Tertiary
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D051741:Kruppel-Like Transcription Factors; D009687:Nuclear Proteins; C110513:TOPBP1 protein, human; C107961:ZBTB17 protein, human; D000246:Adenosine Diphosphate Ribose; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases