(157ad) Allosteric Regulation of GPCRs Driven By Engineered Protein Scaffolds

Improper regulation and function of G protein-coupled receptors (GPCRs) is associated with several diseases and disorders such as diabetes, obesity, and neurological abnormalities. As the largest class of receptor proteins in the human body, there are substantial opportunities for improving health by correcting the behavior of GPCRs. In this project, novel protein ligands are engineered to selectively target and regulate GPCRs. We will overcome limitations of traditional ligands (e.g. monoclonal antibodies and small molecules) by using small protein scaffolds with diverse topologies to not only bind specific proteins, but unique conformations. Conformationally selective binding proteins provide the opportunity to allosterically regulate GPCRs through precise binding interfaces to enhance or alter protein activity, as well as facilitating structural studies within this class of challenging transmembrane proteins. The high affinity binders generated in this study have the potential to a make a profound impact on the availability of new therapeutics for pervasive diseases.

The small, stable engineered proteins used in this study (e.g. affibody, Gp2 and monobody) have multiple advantages over traditional antibodies not only due to their small size, but their diverse paratope geometries and conformations enable them to recognize epitopes that are inaccessible to bulky antibodies. Moreover, small proteins have excellent biodistribution properties making them well suited for cancer and disease diagnostic agents.

This project will: 1) Identify an efficient combination of protein scaffolds having multiple distinct paratopes which can bind a diverse collection of model GPCRs; 2) Discover conformationally selective binders from within populations of strategically mutated protein scaffolds; 3) Apply the lessons learned in generating binders to the model systems to design libraries capable of binding more challenging and exciting GPCRs. The protein ligands discovered in this body of work will provide incredible opportunities for the future of high-performance therapeutics and diagnostics.