Modulation of ETS-1 transcriptional activity by huUBC9, a ubiquitin-conjugating enzyme.
Ets transcription factors have Ets DNA binding domains, that have a winged helix-turn-helix structure. ETS-1, the founding member of the family, is regulated by the Ras and Ca2+ signaling pathways and is implicated in various physiological processes leading to cell growth, differentiation and apoptosis. We have identified ETS-1 interacting factors with a yeast two-hybrid screen. The majority of the positive clones turned out to encode the human homologue of the yeast ubiquitin-conjugating enzymes UBC9 and Hus5. In two different yeast assays, ETS-1 interacted with huUBC9. In an in vitro GST 'pull-down' assay, ETS-1 and several other Ets family members complexed with huUBC9. Interestingly, in mammalian cells, coexpression of huUBC9 resulted in a substantial increase in the transcriptional activity of ETS-1. Coexpressed huUBC9 did not affect the ETS-1 protein level, and moreover, a point mutation at Cys93, an amino acid known to be essential for ubiquitination, did not abolish the stimulation of the ETS-1 transcriptional activity. Our results indicate that the modulation of ETS-1 activity by huUBC9 results from processes other than ubiquitination and ETS-1 stabilization.
Pubmed ID: 9333025 RIS Download
Amino Acid Sequence | Base Sequence | Binding Sites | Cloning, Molecular | Humans | Ligases | Molecular Sequence Data | Protein-Tyrosine Kinases | Proto-Oncogene Protein c-ets-1 | Proto-Oncogene Proteins | Proto-Oncogene Proteins c-ets | Recombinant Fusion Proteins | Sequence Alignment | Sequence Homology, Amino Acid | Transcription Factors | Transcription, Genetic | Ubiquitin-Conjugating Enzymes