Divergent β-Arrestin-dependent Signaling Events Are Dependent upon Sequences within G-protein-coupled Receptor C Termini

β-Arrestins are multifunctional adaptor proteins that, upon recruitment to an activated G-protein-coupled receptor, can promote desensitization of G-protein signaling and receptor internalization while simultaneously eliciting an independent signal. The result of β-arrestin signaling depends upon the activating receptor. For example, activation of two Gα q -coupled receptors, protease-activated receptor-2 (PAR 2 ) and neurokinin-1 receptor (NK1R), results in drastically different signaling events. PAR 2 promotes β-arrestin-dependent membrane-sequestered extracellular signal-regulated kinase (ERK1/2) activation, cofilin activation, and cell migration, whereas NK1R promotes nuclear ERK1/2 activation and proliferation. Using bioluminescence resonance energy transfer to monitor receptor/β-arrestin interactions in real time, we observe that PAR 2 has a higher apparent affinity for both β-arrestins than does NK1R, recruits them at a faster rate, and exhibits more rapid desensitization of the G-protein signal. Furthermore, recruitment of β-arrestins to PAR 2 does not require prior Gα q signaling events, whereas inhibition of Gα q signaling intermediates inhibits recruitment of β-arrestins to NK1R. Using chimeric receptors in which the C terminus of PAR 2 is fused to the N terminus of NK1R and vice versa and a critical Ser/Thr mutant of PAR 2 , we demonstrate that interactions between β-arrestins and specific phosphoresidues in the C termini of each receptor are crucial for determining the rate and magnitude of β-arrestin recruitment as well as the ultimate signaling outcome. Background: Many GPCRs that utilize β-arrestins differ with respect to downstream signaling and cellular consequences. Results: Exchanging the C termini of two GPCRs switches the β-arrestin responses and relative affinities for the two receptors. Conclusion: Sequences within the C termini of different GPCRs are important for determining the nature of β-arrestin recruitment and signaling. Significance: These studies provide new insight regarding receptor-specific β-arrestin signals.