Catching a complex for optimal signaling

Area of Science:

• Immunology
• Molecular Biology
• Structural Biology

Background:

• Agonistic antibodies can dimerize cell surface receptors to trigger signaling pathways.
• Accurate receptor activation requires antibodies to precisely mimic the native dimeric state.
• Existing methods may not perfectly recapitulate native receptor conformations.

Purpose of the Study:

• To develop a high-fidelity method for activating cell surface receptors using engineered antibodies.
• To create a tool that selectively targets and dimerizes specific receptor complexes.
• To enable receptor signaling in the absence of endogenous ligands.

Main Methods:

• Engineered a monovalent single-chain variable fragment (scFv) termed a "stapler."
• Selected for antibodies that bind the IL-4Rα/γc heterodimeric complex in its native signaling conformation.
• Utilized the scFv to bind at the receptor dimerization interface.

Main Results:

• Developed a stapler scFv that binds the IL-4Rα/γc heterodimeric complex.
• The stapler successfully recapitulates the native dimeric state for receptor activation.
• Demonstrated a method for precise receptor dimerization and signaling.

Conclusions:

• The stapler approach provides a powerful and specific method for receptor activation.
• This technique can be applied to various homo- and heterodimeric receptors.
• Enables controlled receptor signaling, particularly when endogenous ligands are absent.