Differences in degradation lead to asynchronous expression of cyclin E1 and cyclin E2 in cancer cells.
Cyclin E1 is expressed at the G 1/S phase transition of the cell cycle to drive the initiation of DNA replication and is degraded during S/G2M. Deregulation of its periodic degradation is observed in cancer and is associated with increased proliferation and genomic instability. We identify that in cancer cells, unlike normal cells, the closely related protein cyclin E2 is expressed predominantly in S phase, concurrent with DNA replication. This occurs at least in part because the ubiquitin ligase component that is responsible for cyclin E1 downregulation in S phase, Fbw7, fails to effectively target cyclin E2 for proteosomal degradation. The distinct cell cycle expression of the two E-type cyclins in cancer cells has implications for their roles in genomic instability and proliferation and may explain their associations with different signatures of disease.
['Caldon|C Elizabeth|CE|', 'Sergio|C Marcelo|CM|', 'Sutherland|Robert L|RL|', 'Musgrove|Elizabeth A|EA|']
D018797:Cell Cycle Proteins D045744:Cell Line, Tumor D019927:Cyclin E D016213:Cyclins D004261:DNA Replication D044783:F-Box Proteins D000073979:F-Box-WD Repeat-Containing Protein 7 D059585:G1 Phase Cell Cycle Checkpoints D059565:G2 Phase Cell Cycle Checkpoints D015972:Gene Expression Regulation, Neoplastic D015894:Genome, Human D042822:Genomic Instability D006801:Humans D015513:Oncogene Proteins D046988:Proteasome Endopeptidase Complex D059748:Proteolysis D044767:Ubiquitin-Protein Ligases
cyclin E1 cyclin E2 cell cycle proliferation Fbw7