The interactions between β-Arrestin 1 and Gαs or Gαi1: functional and structural insights

ABSTRACT: G proteins and arrestins are key G protein-coupled receptor (GPCR) signaling transducers, mediating distinct downstream pathways. Recent evidence suggests that G proteins and β-arrestins (βarrs) can directly or functionally interact through GPCR–G protein–βarr megaplexes, direct βarr1–Gαs interactions, and Gαi–βarr complexes that regulate ERK activation. However, the molecular details and functional consequences of βarr–Gα interactions remain poorly understood. Here, we quantified the binding affinities between βarr1 and Gαs or Gαi1 in various activation states using microscale thermophoresis (MST). βarr1 active state favored binding, whereas Gα activation state was less determinant. To assess functional outcomes, we employed a BODIPY-FL–GTPγS assay for Gα activation and a βarr1 β-strand XX (βXX) release assay for arrestin activation. βarr1 did not affect GDP/GTP turnover of Gα; however, Gαs enhanced V2Rpp-induced βarr1 activation. Hydrogen/deuterium exchange mass spectrometry revealed conformational changes in both the Ras-like and α-helical domains of Gα subunits upon βarr1 binding, and localized changes in the βarr1 lariat loop. These findings define domain-level interfaces and support a cooperative mechanism by which Gαs facilitates GPCR-driven βarr1 activation.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Longhan Duan  

LAB HEAD: Longhan Duan, Ka Young Chung

PROVIDER: PXD065019 | Pride | 2026-02-23

REPOSITORIES: Pride