Acetylation-mediated transcriptional activation of the ETS protein ER81 by p300, P/CAF, and HER2/Neu.
The regulated expression of the ETS transcription factor ER81 is a prerequisite for normal development, and its dysregulation contributes to neoplasia. Here, we demonstrate that ER81 is acetylated by two coactivators/acetyltransferases, p300 and p300- and CBP-associated factor (P/CAF) in vitro and in vivo. Whereas p300 acetylates two lysine residues (K33 and K116) within the ER81 N-terminal transactivation domain, P/CAF targets only K116. Acetylation of ER81 not only enhances its ability to transactivate but also increases its DNA binding activity and in vivo half-life. Furthermore, oncogenic HER2/Neu, which induces phosphorylation and thereby activation of ER81, was less able to activate acetylation-deficient ER81 mutants, indicating that both acetyltransferase and protein kinase-specific regulatory mechanisms control ER81 activity. Importantly, HER2/Neu overexpression stimulates the ability of p300 to acetylate ER81, likely by inducing phosphorylation of p300 through the Ras-->Raf-->mitogen-activated protein kinase pathway. This represents a novel mechanism by which oncogenic HER2/Neu, Ras, or Raf may promote tumor formation by enhancing acetylation not only of ER81 but also of other downstream effector transcription factors as well as histones.
Pubmed ID: 12917345 RIS Download
Acetylation | Acetyltransferases | Cell Cycle Proteins | Cells, Cultured | DNA | DNA-Binding Proteins | Histone Acetyltransferases | Histone Deacetylase 1 | Histone Deacetylase 2 | Histone Deacetylases | Humans | Lysine | Macromolecular Substances | Mutation | Nuclear Proteins | Phosphorylation | Proto-Oncogene Proteins | Proto-Oncogene Proteins c-ets | Receptor, ErbB-2 | Recombinant Fusion Proteins | Repressor Proteins | Trans-Activators | Transcription Factors | Transcription, Genetic | Transcriptional Activation | p300-CBP Transcription Factors