Exploring human rare disease variants from a multidimensional perspective illuminates receptor – G protein coupling diversity

Abstract

G protein-coupled receptors (GPCRs) are transmembrane proteins capable of detecting signals as diverse as odours, neurotransmitters, and hormones. Upon activation, receptor signalling converges onto four Gα protein subtypes to regulate intracellular responses. Therefore, variation in a single Gα protein gene can potentially impact the function of numerous receptors. In this work, we have performed a multidimensional study of rare disease mutations in Gαs, a prototypical Gα protein. By integrating data from 3D structures, GPCR / G protein functional pairings, transcriptomics, biophysics, and molecular dynamics with systems pharmacology modelling, our results reveal why mutations impairing receptor / Gαs coupling result in highly specific context-based signalling defects. Furthermore, we show that mutations leading to the same rare disease can alter different signal transduction steps, highlighting the importance of patient-specific treatment strategies. By closely dissecting G protein coupling, our study provides a blueprint to interrogate GPCR pathway signalling diversity in different (patho)physiological contexts.