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Phosphorylation represses Ets-1 DNA binding by reinforcing autoinhibition
1Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112-5550, USA.
Genes & Development
|February 16, 2000
Summary
Calcium-dependent phosphorylation inhibits Ets-1 transcription factor DNA binding by reinforcing an autoinhibitory mechanism. This reveals a structural role for inhibitory modules in negative signaling pathways.
Area of Science:
- Molecular Biology
- Cell Signaling
- Gene Expression Regulation
Background:
- Transcription factors control gene expression by binding DNA.
- Phosphorylation is a key post-translational modification linking cell signaling to gene regulation.
Purpose of the Study:
- To investigate the role of phosphorylation in regulating the DNA binding activity of the Ets-1 transcription factor.
- To elucidate the structural mechanism by which phosphorylation affects Ets-1 function.
Main Methods:
- Quantitative DNA-binding assays to measure Ets-1 binding affinity.
- Site-directed mutagenesis to identify key phosphorylation sites.
- Partial proteolysis to assess conformational changes.
Main Results:
- Calcium-dependent phosphorylation inhibits Ets-1 DNA binding by 50-fold.
- Four specific serine residues, distant from the DNA-binding domain, mediate this inhibition.
- An intact inhibitory module is essential for phosphorylation-dependent regulation.
- Phosphorylation stabilizes an inhibitory conformation of Ets-1.
Conclusions:
- Phosphorylation provides a structural mechanism to inhibit Ets-1 DNA binding via autoinhibition.
- Inhibitory modules can act as structural mediators for negative signaling events.
- This study reveals a novel regulatory function for phosphorylation in transcription factor activity.