Regulation of DNA topoisomerase IIalpha stability by the ECV ubiquitin ligase complex.
In this study, we attempted to elucidate the E3 ubiquitin ligase for topo IIalpha. When cullins and VHL were ectopically expressed in HT1080 and HEK293T cells, topo IIalpha was degraded most prominently in cullin 2- and VHL-expressing cells. Cullin 2 and the beta domain (aa 114-123) of VHL, a subunit of the ECV (Elongin B/C-cullin 2-VHL protein) complex, specifically interact with the ATPase domain of topo IIalpha. We identified that topo IIalpha associated with endogenous Elongin C. In HT1080 cells co-transfected with deletion mutants of topo IIalpha GRDD (glucose-regulated destruction domain) and VHL, topo IIalpha was degraded by VHL expression. These results demonstrate that ECV acts as E3 ubiquitin ligase targeting GRDD-independent topo IIalpha to the ubiquitin-proteasome pathway.
Yun
Jisoo
J
Research Center for Resistant Cells, Chosun University, Gwangju 501-759, Republic of Korea.
Kim
Yong-Il
YI
Tomida
Akihiro
A
Choi
Cheol-Hee
CH
D000251:Adenosine Triphosphatases; D000951:Antigens, Neoplasm / Q000378:metabolism*; D002460:Cell Line; D044842:Cullin Proteins / Q000378:metabolism*; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D000075065:Elongin; D004795:Enzyme Stability; D006801:Humans; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000378:metabolism*
D000951:Antigens, Neoplasm; C105153:CUL2 protein, human; D044842:Cullin Proteins; D004268:DNA-Binding Proteins; C000616396:ELOB protein, human; C000616395:ELOC protein, human; D000075065:Elongin; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D000251:Adenosine Triphosphatases; D004250:DNA Topoisomerases, Type II; C497446:VHL protein, human