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Development of a binding assay for p53/HDM2 by using homogeneous time-resolved fluorescence
S A Kane1, C A Fleener, Y S Zhang
1Department of Cancer Research, Merck Research Laboratories, West Point, Pennsylvania 19486, USA. stefanie_kane@merck.com
Analytical Biochemistry
|January 21, 2000
Summary
A new HTRF assay monitors p53/HDM2 binding, crucial for tumor suppressor regulation. This method assesses how p53 N-terminus phosphorylation and p73 peptide affinity affect HDM2 binding.
Area of Science:
- Molecular Biology
- Biochemistry
- Cancer Research
Background:
- p53 is a tumor suppressor protein regulated by HDM2.
- HDM2 binding leads to p53 degradation, inhibiting its tumor-suppressive functions.
- Disrupting the p53-HDM2 complex can activate p53 signaling.
Purpose of the Study:
- To develop and validate a homogeneous time-resolved fluorescence (HTRF) assay for monitoring p53/HDM2 binding.
- To investigate the impact of p53 N-terminus serine phosphorylation on HDM2 binding.
- To determine the binding affinity of a p73 peptide to HDM2.
Main Methods:
- Development of a site-specific biotinylated p53/GST-HDM2 HTRF assay.
- Utilized fluorophore-conjugated reagents (streptavidin-XL665, Eu(K)-anti-GST) for FRET detection.
- Compared HTRF assay performance against traditional ELISA.
Main Results:
- A robust HTRF assay was established for quantifying p53-HDM2 interactions.
- Serine phosphorylation in the p53 N-terminus was shown to influence HDM2 binding.
- The relative affinity of a p73 peptide for HDM2 was determined using the HTRF assay.
Conclusions:
- The developed HTRF assay provides a sensitive method for studying p53-HDM2 interactions.
- p53 phosphorylation status significantly modulates its binding to HDM2.
- The assay is valuable for screening compounds that disrupt the p53-HDM2 complex and for characterizing protein-protein interactions in cancer research.