Learn More
The p27 mammalian cell cycle protein is an inhibitor of cyclin-dependent kinases. Both in vivo and in vitro, p27 was found to be degraded by the ubiquitin-proteasome pathway. The human ubiquitin-conjugating enzymes Ubc2 and Ubc3 were specifically involved in the ubiquitination of p27. Compared with proliferating cells, quiescent cells exhibited a smaller(More)
Many DNA tumor viruses express a protein that inhibits transcriptional activation by the tumor-suppressing transcription factor p53. We report that adenovirus E1B 55K represses p53-mediated activation by a mechanism not described previously. E1B 55K binds p53 without displacing it from its DNA-binding site. A fusion of E1B 55K to the GAL4 DNA-binding domain(More)
The cellular phosphoprotein p53 inhibits progression through the mammalian cell cycle. Both p53 alleles are frequently mutated in human tumours, indicating that p53 is a tumour suppressor. Recent studies have suggested that p53 functions as a transcriptional activator, but the significance of this activity in cell-cycle control has not been established. The(More)
  • P. Yew
  • Journal of cellular physiology
  • 2001
Cell-cycle progression in all eukaryotes is driven by cyclin-dependent kinases (CDKs) and their cyclin partners. In vertebrates, the proper and timely duplication of the genome during S-phase relies on the coordinated activities of positive regulators such as CDK-cyclins and E2F, and negative regulators such as CDK inhibitors of the Cip/Kip and INK4(More)
The cell division cycle gene, CDC34, is required for ubiquitin-mediated degradation of G1 regulators and cell cycle progression through the transition from G1 to S phase in budding yeast. A CDC34 requirement for S phase onset in higher eukaryotes has not been established. Studies of the simple embryonic cell cycle of Xenopus laevis eggs demonstrated that(More)
The regulation of the vertebrate cell cycle is controlled by the function of cyclin-dependent kinases (CDKs), cyclins, and CDK inhibitors. The Xenopus laevis kinase inhibitor, p27(Xic1) (Xic1) is a member of the p21(Cip1)/p27(Kip1)/p57(Kip2) CDK inhibitor family and inhibits CDK2-cyclin E in vitro as well as DNA replication in Xenopus egg extracts. Xic1 is(More)
Estrogen receptor (ER) signaling plays an important role in breast cancer progression, and ER functions are influenced by coregulatory proteins. PELP1 (proline-, glutamic acid-, and leucine-rich protein 1) is a nuclear receptor coregulator that plays an important role in ER signaling. Its expression is deregulated in hormonal cancers. We identified PELP1 as(More)
To determine whether the viral replication functions of the adenovirus E1B 55K protein play a role in its ability to transform cloned rat embryo fibroblast cells in culture, we constructed an extensive series of insertion mutations throughout the 55K gene. The mutations were recombined into infectious virus and characterized for their abilities to produce(More)
During DNA polymerase switching, the Xenopus laevis Cip/Kip-type cyclin-dependent kinase inhibitor Xic1 associates with trimeric proliferating cell nuclear antigen (PCNA) and is recruited to chromatin, where it is ubiquitinated and degraded. In this study, we show that the predominant E3 for Xic1 in the egg is the Cul4-DDB1-XCdt2 (Xenopus Cdt2) (CRL4(Cdt2))(More)
The ubiquitin-conjugating enzyme CDC34 (UBC3) is linked to cell cycle progression in diverse cell types; however, its role in multiple myeloma (MM) pathogenesis is unclear. Here, we show that CDC34 is highly expressed in patient MM cells and MM cell lines versus normal cells. Blocking CDC34 using a dominant-negative strategy enhances the anti-MM activity of(More)