Structure of the Neurotensin Receptor 1 in complex with β-arrestin 1

Arrestin proteins bind to active, phosphorylated G protein coupled receptors (GPCRs), thereby preventing G protein coupling, triggering receptor internalization, and affecting various downstream signaling pathways(1,2). While there exists a wealth of structural information delineating the interactions between GPCRs and G proteins, less is known about how arrestins engage GPCRs. Here we report a cryoEM structure of full-length human neurotensin receptor 1 (NTSR1) in complex with truncated human β-arrestin 1 (βarr1(ΔCT)). We found that phosphorylation of NTSR1 was critical for obtaining a stable complex with βarr1(ΔCT), and identified phosphorylated sites in both the third intracellular loop and the C-terminus that may promote this interaction. In addition, we observed a phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) molecule forming a bridge between the membrane side of NTSR1 transmembrane segments 1 and 4 and the C-lobe of arrestin. Compared to a structure of rhodopsin-arrestin-1, our structure displays an ~85° rotation of arrestin relative to the receptor. These findings highlight both conserved aspects but also the plasticity of arrestin-receptor interactions.