Radiation induces cell cycle arrest and/or cell death in mammalian cells. In the present study, we show that Hip2, a ubiquitin-conjugating enzyme, can overcome radiation-induced G2/M cell cycle arrest and trigger the entry into mitosis. Ionizing radiation increased the levels of Hip2 by preventing its degradation but not its gene transcription. The stability of Hip2 in irradiated cells was further confirmed using live cell fluorescence imaging. Flow cytometric and molecular analyses revealed that Hip2 abrogated radiation-induced G2/M arrest, promoting entry into mitosis. Bimolecular fluorescence complementation assays and co-immunoprecipitation experiments showed that Hip2 interacted with and targeted p53 for degradation via the ubiquitin proteasome system, resulting in the activation of cdc2-cyclin B1 kinase to promote mitotic entry. These results contribute to our understanding of the mechanisms that regulate cell cycle progression and DNA damage-induced G2/M checkpoint cellular responses.
|Number of pages
|Biochimica et Biophysica Acta - Molecular Cell Research
|Published - 2013 Dec
Bibliographical noteFunding Information:
We thank Dr. SG Chi (Division of Life Sciences, Korea University) for helpful discussion. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. R1203241 ).
- G2/M arrest
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology