β-arrestin recruitment facilitates a direct association with G proteins
- Claudia Y. Lee
- Jeffrey S. Smith
- Taylor Kohlmann
- Emily M. Meara
- Uyen Pham
- Frank Kwarcinski
- Andrew N. Dates
- Jessica K. Orofino
- Issac Choi
- Ari S. Hilibrand
- Chanpreet Jassal
- Abigail Gilmer
- Stephen C. Blacklow
- Gregory G. Tall
- Andrew C. Kruse
- Sudarshan Rajagopal
2026-07-17
G protein-coupled receptors (GPCRs) are targets for almost a third of all FDA-approved drugs. GPCRs are known to signal through both heterotrimeric G proteins and β-arrestins. Traditionally these pathways were viewed as largely separable, with G proteins primarily initiating downstream signaling while β-arrestins modulate receptor trafficking and desensitization in addition to regulating their own signaling events. Recent studies suggest an integrated role of G proteins and β-arrestins in GPCR signaling, however the cellular and biochemical requirements for G protein:β-arrestin interactions remain unclear. Here, we show that G proteins and β-arrestins can directly interact. Through utilization of β-arrestin-biased receptors and artificially enforced β-arrestin relocalization, we demonstrate that recruitment of β-arrestin to the plasma membrane is sufficient to interact with the G protein Gαi. Using purified proteins, we show that Gαi directly interacts with β-arrestin. In addition, we find that Gαi family members differ in their degree of association with β-arrestin, and that a large degree of this selectivity resides within the alpha helical domain of Gαi. These findings delineate the cellular and biochemical conditions that drive direct interactions between G proteins and β-arrestins and illuminate the molecular basis for how they interact.