Open AccessSUMO-1 conjugation to intact DNA topoisomerase I amplifies cleavable complex formation induced by camptothecin
Author(s) -
Koji Horie,
Akihiro Tomida,
Yoshikazu Sugimoto,
Toshiharu Yasugi,
Hiroyuki Yoshikawa,
Yuji Taketani,
Takashi Tsuruo
Publication year - 2002
Publication title -
oncogene
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 3.395
H-Index - 342
eISSN - 1476-5594
pISSN - 0950-9232
DOI - 10.1038/sj.onc.1205917
Subject(s) - sumo protein , camptothecin , biology , topoisomerase , dna , ubiquitin , dna damage , microbiology and biotechnology , dna ligase , biochemistry , mutation , gene
DNA topoisomerase I (Topo1) manages the topological state of DNA. Cleavable complexes, the covalent Topo1-DNA intermediates, become DNA damaged when the catalytic cycles are inhibited by the anti-tumor drug camptothecin (CPT). Intriguingly, Topo1 is modified rapidly and extensively with SUMO-1, a ubiquitin-like protein, in response to CPT. This study shows that the sumoylation enhances the cleavable complex formation and apoptosis induced by CPT. Indeed, substitutions of Lys117 and Lys153, identified as Topo1 sumoylation sites, reduced the CPT-induced cleavable complexes without influencing its in vitro catalytic activity. Consistent with this observation, CPT-induced cleavable complexes of wild-type Topo1 increased in a sumoylation-dependent manner. We also found that Topo1 sumoylation occurred independently of CPT when Topo1 was inactivated by mutation of the catalytic Tyr723. These findings suggested that Topo1 inactivation by CPT treatment can trigger Topo1 sumoylation, leading to enhanced cleavable complex formation.