Premium
Dynamic Formation of a Ternary PTH receptor−Arrestin−Gβγ Complex required for sustained Signaling
Author(s) -
Wehbi Vanessa Leila,
Stevenson Hilary Paige,
Feinstein Timothy Nathan,
Romero Guillermo,
Calero Guillermo,
Vilardaga Jean-Pierre
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.665.3
Subject(s) - g protein coupled receptor , heterotrimeric g protein , g protein , arrestin , microbiology and biotechnology , chemistry , receptor , internalization , g protein coupled receptor kinase , gq alpha subunit , signal transduction , protein subunit , parathyroid hormone , biophysics , biology , biochemistry , calcium , gene , organic chemistry
Arrestins and heterotrimeric G proteins (Gαβγ) regulate G‐protein‐coupled receptors (GPCRs) signaling and trafficking. Arrestin binding to an activated GPCR terminates receptor and G protein coupling, and promotes receptor internalization. The binding of the β‐arrestins and G‐proteins on agonist‐bound GPCRs is thought to be mutually exclusive. Here we show that β‐arrestins prolong rather that desensitize parathyroid hormone (PTH) receptor (PTHR) signaling. By using optical approaches (confocal microscopy, FRAP, TIRF, fluorescence correlation spectroscopy, and FRET) in live cells in real time we found that PTHR forms a ternary complex with β‐arrestin1/2 and Gβγ subunits in response to PTH stimulation. Additionally, we found that the rapid (t 1/2 < 60 s) assembly/disassembly dynamics formation of a receptor microdomain that contains PTH, PTHR, arrestin and Gβγ subunits increases the levels of G‐protein activation and cAMP accumulation in magnitude and duration. These data contradicted established tenets of the regulation of GPCR signaling and raise the emerging concept that the formation of a long‐lived GPCR‐Gβγ‐arrestin ternary complex contributes to prolonged receptor signaling by mechanisms that presumably permit multiple rounds of Gα S subunit coupling and activation.