Biophysical characterization of the ETV6 PNT domain polymerization interfaces

Area of Science:

• Molecular biology
• Biophysics
• Protein-protein interactions

Background:

• ETV6 is a transcriptional repressor involved in cancer via fusion oncoproteins.
• Its PNT domain self-associates, forming polymers that are difficult to target therapeutically.
• Understanding these interactions is crucial for developing new cancer therapies.

Purpose of the Study:

• To characterize the ETV6 PNT domain interaction interfaces biophysically.
• To identify key regions for drug discovery targeting ETV6 polymerization.
• To elucidate the mechanism of transcriptional repression via self-association.

Main Methods:

• NMR spectroscopy
• X-ray crystallography
• Molecular dynamics simulations
• Amide hydrogen exchange
• Surface plasmon resonance (SPR) with alanine scanning mutagenesis

Main Results:

• ETV6 PNT domain variants maintain stable helical folds upon self-association.
• Identified hot spot regions within the interfaces, including hydrophobic and salt-bridging residues.
• Demonstrated that these interfaces are relatively rigid and do not undergo conformational changes.

Conclusions:

• Small molecules targeting identified hot spots could inhibit ETV6 polymerization.
• This research aids drug discovery for ETV6-related cancers.
• Provides mechanistic insights into ETV6-mediated transcriptional repression.