Towards Profiling of G protein-biased Ligands of the Parathyroid hormone 1 receptor using a Streamlined Bioluminescence-based Binding

Abstract

We have generated and characterized a NanoLuc-parathyroid hormone 1 receptor (PTH1R) fusion protein that enables improved equilibrium and kinetic competition binding assays. We examined both the truncated endogenous parathyroid hormone (PTH) and a previously described α/-amino acid-containing, G protein-biased analogue (PTH-P2). Using our new assay system, we report that PTH-P2 binds PTH1R with lower affinity and induces less receptor internalization by endocytosis than PTH. However, PTH-P2 activates G protein-dependent cAMP generation to a comparable degree as PTH, meaning that it is both selective towards activation of a specific signaling cascade, and selective towards membrane localization.