Single-Molecule Fluorescence Detection of the Epidermal Growth Factor Receptor in Membrane Discs

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• Epidermal growth factor receptor (EGFR) is crucial for cell signaling and implicated in cancer.
• EGFR is a key target for anticancer drugs, but its molecular dynamics are poorly understood.
• Lack of molecular-level insight hinders the design and development of effective EGFR-targeting therapies.

Purpose of the Study:

• To create a functional, fluorescently labeled, full-length EGFR system for in vitro studies.
• To investigate ATP-EGFR interactions and EGFR conformational dynamics.
• To establish a novel single-molecule assay for studying EGFR interactions in real-time.

Main Methods:

• Construction and characterization of full-length, fluorescently labeled EGFR within nanolipoprotein particles (NLPs).
• Utilized Förster resonance energy transfer (FRET) to measure distances between the EGFR catalytic site and C-terminus.
• Investigated ATP binding to the EGFR catalytic site.

Main Results:

• Successfully created functional, fluorescently labeled EGFR in NLPs for in vitro studies.
• Observed ATP binding at the EGFR catalytic site.
• Measured distances between the catalytic site and C-terminus, suggesting conformational flexibility.
• ATP-based experiments indicated a range of C-terminus conformations potentially linked to EGFR phosphorylation state.

Conclusions:

• Demonstrated a proof-of-principle for single-molecule studies as a non-crystallographic assay for EGFR.
• The developed system allows real-time, near-physiological investigation of EGFR interactions.
• This approach has significant potential for advancing understanding of EGFR in disease and cancer drug discovery.