G-protein-coupled receptors(GPCRs)convert extracellular stimuli to intracellular signaling cascades primarily through G proteins or arrestin-mediated pathways 1-4.G proteins transduce signals by regulating the levels of second messengers,whereas arrestins recruit distinct downstream proteins to either desensitise receptors or initiate their own signaling pathways by recognising different GPCR conformations and phosphorylation states 5-10.