VCP/p97 works as a segregase to extract the ubiquitylated proteins from protein complexes, lipid membranes and chromosomes, thereby promoting their degradation or recycling. VCP/p97 plays essential roles in ubiquitin-dependent proteasome degradation, ERAD, autophagy, endocytosis, reassembly of ER, Golgi and nuclear envelop, and cell cycle regulation. In ubiquitin dependent proteasome degradation pathway, VCP/p97, as a special ubiquitin binding-shuttle factor, is required for the successful cell cycle progression in regulating IκB, CDT-1, Aurora B, and CDC25A. Here, we studied the role of VCP/p97 in G1 to S phase transition in MCF-7 human breast cancer cells. We found that VCP/p97 knockdown or inhibition by DBeQ, a potent VCP/p97 inhibitor, decreased cell proliferating rates and reduced S phase cell percentages in asynchronized MCF-7 cells.VCP/p97 inhibition by DBeQ also arrested cells at G1 phase in synchronized MCF-7 cells. These data suggest that VCP/p97 is required for G0/G1 to S phase transition in MCF-7 cells. In addition, in either asynchronized or synchronized MCF-7 cells, VCP/p97 knockdown or DBeQ treatment resulted in the accumulation of p21 and p27, two CDK inhibitors. Moreover, p27, not p21, knockdown in MCF-7 cells rescued the defects of S phase entry caused by VCP/p97 knockdown or DBeQ treatment. Taken together, our results suggest that VCP/p97 regulates the timely degradation of p27 to promote G1 to S phase transition in MCF-7 cells. / published_or_final_version / Physiology / Master / Master of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/208005 |
| Date | January 2014 |
| Creators | Shi, Xianli, 石现丽 |
| Contributors | Yue, J |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Rights | Creative Commons: Attribution 3.0 Hong Kong License, The author retains all proprietary rights, (such as patent rights) and the right to use in future works. |
| Relation | HKU Theses Online (HKUTO) |
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