title: APC/C (Cdh1)  controls the proteasome-mediated degradation of E2F3 during cell cycle exit.
abstract: E2F transcription factors regulate gene expression in concert with the retinoblastoma tumor suppressor family. These transcriptional complexes are master regulators of cell cycle progression and, in addition, control the expression of genes involved in DNA repair, G 2/M checkpoint and differentiation. E2F3 has recently attracted particular attention, because it is amplified in various human tumors. Here we show that E2F3 becomes unstable as cells exit the cell cycle. E2F3 degradation is mediated by the anaphase-promoting complex/cyclosome and its activator Cdh1 (APC/C (Cdh1) ). E2F3 interacts with Cdh1 but not Cdc20, the other APC/C activator. Enforced expression of Cdh1 results in proteasome-dependent degradation of E2F3, whereas the overexpression of Cdc20 has no effect on E2F3 turnover. Finally, silencing of Cdh1 by RNA interference stabilizes E2F3 in differentiating neuroblastoma cells. These findings indicate that the APC/C (Cdh1)  ubiquitin ligase targets E2F3 for proteasome-dependent degradation during cell cycle exit and neuronal differentiation.
authors.affiliation: Hubrecht Institute-KNAW and University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Ping
authors.forename: Ratna
authors.initials: R
authors.lastname: Lim
authors.forename: Tarig
authors.initials: T
authors.lastname: Bashir
authors.forename: Michele
authors.initials: M
authors.lastname: Pagano
authors.forename: Daniele
authors.initials: D
authors.lastname: Guardavaccaro
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D015703:Antigens, CD; D015820:Cadherins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D050699:E2F3 Transcription Factor / Q000378:metabolism*; D059565:G2 Phase Cell Cycle Checkpoints; D057809:HEK293 Cells; D006801:Humans; D059566:M Phase Cell Cycle Checkpoints; D055495:Neurogenesis; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; D015820:Cadherins; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D050699:E2F3 Transcription Factor; C098319:E2F3 protein, human; D034741:RNA, Small Interfering; C577488:CDC20 protein, human; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D046988:Proteasome Endopeptidase Complex