E4F1
Developmental stage
Expressed in a variety of fetal tissues.
Function
May function as a transcriptional repressor. May also function as a ubiquitin ligase mediating ubiquitination of chromatin-associated TP53. Functions in cell survival and proliferation through control of the cell cycle. Functions in the p53 and pRB tumor suppressor pathways and regulates the cyclin CCNA2 transcription.
Identified as a cellular target of the adenoviral oncoprotein E1A, it is required for both transcriptional activation and repression of viral genes.
Pathway
Protein modification; protein ubiquitination.
Post-translational modifications
Proteolytic cleavage produces a 50 kDa N-terminal peptide (p50E4F) which has a DNA-binding activity and activates transcription in presence of the adenoviral E1A protein. The major full-length protein (p120E4F) functions as a repressor of transcription.
Phosphorylated; p120E4F and p50E4F are both phosphorylated. Phosphorylation is cell cycle-dependent and differentially regulates DNA-binding activity and function of both forms.
May be sumoylated by UBE2I upon interaction with CDKN2A.
Tissue Specificity
Ubiquitously expressed.
Cellular localization
- Nucleus
- Nucleoplasm
- Cytoplasm
- A small fraction is detected in the cytoplasm. Excluded from the nucleolus where it is targeted upon CDKN2A overexpression. Localizes to the mitotic spindle during embryogenesis.
Alternative names
E4F, E4F1, Transcription factor E4F1, E4F transcription factor 1, Putative E3 ubiquitin-protein ligase E4F1, RING-type E3 ubiquitin transferase E4F1, Transcription factor E4F, p120E4F, p50E4F