Structural and Functional Analysis of a β2-Adrenergic Receptor Complex with GRK5
Konstantin E. Komolov, Yang Du, Nguyen Minh Duc, Robin M. Betz, João P.G.L.M. Rodrigues, Ryan D. Leib, Dhabaleswar Patra, Georgios Skiniotis, Christopher M. Adams, Ron O. Dror, Ka Young Chung, Brian K. Kobilka, Jeffrey L. Benovic
The phosphorylation of agonist-occupied G-protein-coupled receptors (GPCRs) by GPCR kinases (GRKs) functions to turn off G-protein signaling and turn on arrestin-mediated signaling. While a structural understanding of GPCR/G-protein and GPCR/arrestin complexes has emerged in recent years, the molecular architecture of a GPCR/GRK complex remains poorly defined. We used a comprehensive integrated approach of cross-linking, hydrogen-deuterium exchange mass spectrometry (MS), electron microscopy, mutagenesis, molecular dynamics simulations, and computational docking to analyze GRK5 interaction with the β2-adrenergic receptor (β2AR). These studies revealed a dynamic mechanism of complex formation that involves large conformational changes in the GRK5 RH/catalytic domain interface upon receptor binding. These changes facilitate contacts between intracellular loops 2 and 3 and the C terminus of the β2AR with the GRK5 RH bundle subdomain, membrane-binding surface, and kinase catalytic cleft, respectively. These studies significantly contribute to our understanding of the mechanism by which GRKs regulate the function of activated GPCRs.
Circular dichroism, Secondary structure, Thermal stability, Thermodynamics, Biochemistry