Allosteric Nanobodies Modulate EGFR Functioning by Tuning Receptor Dynamics

Membrane-spanning receptors are crucial for sensing and transducing signals across the plasma membrane. While increasing evidence suggests that these processes are characterized by distinct conformations and ligand binding properties, the role of receptor dynamics in signal transduction remains elusive. An example refers to the epidermal growth factor receptor, that activates signaling pathways crucial for the regulation of cell proliferation, migration and differentiation. We employed nanobodies to directly examine the relationship between EGFR dynamics and function. Using a combination of cell biology and solid-state NMR methods, we find that allosteric nanobody binding reduces extracellular domain (ECD) motion and EGF binding affinity, leading to inhibition of kinase activation and receptor internalization. By introducing point mutations, we can increase the dynamic state of the ECD, thereby enhancing kinase activity and receptor internalization. Our findings suggest that EGFR functioning can not only be controlled by activating ligands, but also by modulation of receptor dynamics.