We previously reported that UV induced rapid proteasomal degradation of p21 protein in an ubiquitination-independent manner. Here, UV-induced p21 proteolysis was found to occur in the cytosol. Before cytosolic degradation, however, p21 protein translocated to and transiently accumulated in the nucleus. Nuclear translocation of p21 was not required for its degradation, but rather promoted DNA repair and cell survival. Overexpression of the wild type p21, but not the one with defective nuclear localization signal (NLS), reduced UV-induced DNA damage and cell death. Some of p21 protein translocated to the nucleus were associated with chromatin-bound PCNA and saved from UV-induced proteolysis. These data together show that p21 translocates to the nucleus to participate in DNA repair, while the rest is rapidly degraded in the cytosol. We propose that our findings reflect a mechanism to facilitate removal of damaged cells, enhancing DNA repair at the same time.
|Number of pages||6|
|Journal||Biochemical and biophysical research communications|
|Publication status||Published - 2009 Dec 25|
Bibliographical noteFunding Information:
This work was supported by a KOSEF Grant ( 2009-0080582 ), a grant from Korea University and ACE program through the National Research Foundation of Korea (NRF) grant funded by the Korean Ministry of Education, Science and Technology ( R0809661 ).
- DNA repair
- Nuclear translocation
- Protein degradation
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology