G protein-coupled receptor kinase 2 and β-arrestins are recruited to FSH receptor in stimulated rat primary Sertoli cells

Abstract

FSH-receptor (FSH-R) signaling is regulated by agonistinduced desensitization and internalization. It has been shown, in a variety of overexpression systems, that G protein-coupled receptor kinases (GRKs) phosphorylate the activated FSH-R, promote b-arrestin recruitment and ultimately lead to internalization. The accuracy of this mechanism has not yet been demonstrated in cells expressing these different molecules at physiological levels. Using sucrose gradient fractionation, we show that FSH induces the recruitment of the endogenous GRK 2 and b-arrestin 1/2 from the cytoplasm to the plasma membrane of rat primary Sertoli cells. As assessed by ligand binding, the FSH-R was found expressed in the fractions where GRK 2 and b-arrestins were recruited upon FSH treatment. In addition, the endogenous b-arrestin 1 was found dephosphorylated in an agonist-dependent manner. Finally, a significant FSH-binding activity was co-immunoprecipitated with the endogenous b-arrestins from agonist-stimulated but not from untreated Sertoli cell extracts. This FSH-R interaction with b-arrestins was sustained for up to 30 min. In conclusion, our data strongly suggest that the GRK/b-arrestin machinery plays a physiologically relevant role in the regulation of the FSH signaling.

G protein‐dependent signaling triggers a β‐arrestin‐scaffolded p70S6K/ rpS6 module that controls 5'TOP mRNA translation

“…7C, D). In addition, as expected, b-arrestins were recruited to the FSHR in an FSH-dependent manner (23)(24)(25). However, we observed that p70S6K was not part of the complex (Fig.…”

“…Our previous data indicated that the FSHR recruits b-arrestins upon ligand binding, promoting its desensitization, internalization (23,24), and ERK MAP kinase activation (25). Another FSHR-targeted signaling effector is p70S6K, as we and others had shown (6,7,47).…”

“…When considering activation of the ERK MAP kinase pathway, in several instances, G protein-and b-arrestindependent signaling have been shown to operate independently, after GPCR activation (19,20). Similarly, agonist-bound FSHR couples to Gs, leading to cAMP production and PKA activation, and it recruits b-arrestins for its desensitization, internalization, and signaling (21)(22)(23)(24). This receptor also stimulates ERK MAPKs through the sequential action of G proteins and b-arrestins (25).…”

RGS22, A Novel Testis-Specific Regulator of G-protein Signaling Involved in Human and Mouse Spermiogenesis along with GNA12/13 Subunits1

“…For instance, G protein-coupled receptor kinases (GRKs) and dual-specific A kinase-anchoring protein 2, AKAP10 (also known as D-AKAP2), are expressed in the mouse testis [4][5][6]. Further studies demonstrated that ADRBK1 (also known as GRK2) is recruited to FSH receptors in stimulated primary rat Sertoli cells [5], and GRK4 is expressed in spermatozoa and germinal cells, where it is associated with mitochondrial and acrosomal membranes [4]. Here, we report a new RGS gene, regulator of G-protein signaling 22 (RGS22), that is specifically expressed in the human and mouse testis during different stages of development.…”

Novel pathways in gonadotropin receptor signaling and biased agonism

“…β-arrestins are proteins endowed with regulatory scaffolding properties, which are generic to most GPCRs [46]. Recently, data have pointed to the instrumental role of β-arrestins as direct interactors with the FSH-R involved in the spatial and temporal organization of these signaling events [47][48][49]. These observations led to the concept that ligands with FSH activity could select only part of the signaling repertoire induced by the natural hormone, either G protein-dependent or β-arrestin-dependent [50,51].…”