Allosteric Antibody Modulation of EGFR Activity: Bridging Experiment and In Silico Modeling.

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Allosteric regulation is crucial for modulating receptor tyrosine kinase (EGFR) signaling, which is often dysregulated in cancer.
• EGFR activation involves conformational changes linking extracellular ligand binding to intracellular kinase activity.

Purpose of the Study:

• To investigate how camelid-derived VHH antibodies can inhibit EGFR function by exploiting its allosteric architecture.
• To dissect the effects of VHH antibodies on EGFR signaling and internalization using experimental and computational approaches.

Main Methods:

• Utilized a panel of monospecific and biparatopic VHH antibodies targeting distinct EGFR epitopes.
• Combined experimental assays (signaling, internalization) with structure-based modeling (AlphaFold3, SBSMMA) to analyze allosteric modulation.
• Computed residue-level allosteric changes induced by antibody binding to EGFR.

Main Results:

• Only specific VHH antibody epitope combinations induced long-range allosteric responses affecting the EGFR juxtamembrane and kinase domains.
• These effective allosteric modulations correlated with inhibited downstream ERK and AKT signaling.
• High EGFR internalization capacity did not always correlate with significant allosteric propagation or signaling suppression.

Conclusions:

• Defined distinct allosteric mechanisms by which VHH antibodies modulate EGFR.
• Demonstrated that computational modeling of energetic propagation can guide the development of targeted allosteric biologics.
• Highlighted the mechanistic uncoupling of receptor internalization from allosteric conformational regulation.