Europe PMC requires Javascript to function effectively.
Either your web browser doesn't support Javascript or it is currently turned off. In the latter case, please
turn on Javascript support in your web browser and reload this page.
This website requires cookies, and the limited processing of your
personal data in order to function. By using the site you are agreeing
to this as outlined in our
privacy notice and cookie policy.
1.
Institute of Molecular Life Sciences, Centre of Excellence of the Hungarian Academy of Sciences, HUN-REN Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary.
Authors
Tóth AD
1,
2
Szalai B
1,
2
Soltész-Katona E
1
Turu G
1,
2
Hunyady L
1,
2
(5 authors)
2.
Department of Physiology, Faculty of Medicine, Semmelweis University, Tűzoltó utca 37-47, H-1094 Budapest, Hungary.
Authors
Tóth AD
1,
2
Szalai B
1,
2
Kovács OT
2
Garger D
2
Prokop S
2
Balla A
2
Várnai P
2
Turu G
1,
2
Hunyady L
1,
2
(9 authors)
3.
Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578 Japan.
Share this article
Share with emailShare with twitterShare with linkedinShare with facebook
Abstract
The stabilization of different active conformations of G protein-coupled receptors is thought to underlie the varying efficacies of biased and balanced agonists. Here, profiling the activation of signal transducers by angiotensin II type 1 receptor (AT1R) agonists revealed that the extent and kinetics of β-arrestin binding exhibited substantial ligand-dependent differences, which were lost when receptor internalization was inhibited. When AT1R endocytosis was prevented, even weak partial agonists of the β-arrestin pathway acted as full or near-full agonists, suggesting that receptor conformation did not exclusively determine β-arrestin recruitment. The ligand-dependent variance in β-arrestin translocation was much larger at endosomes than at the plasma membrane, showing that ligand efficacy in the β-arrestin pathway was spatiotemporally determined. Experimental investigations and mathematical modeling demonstrated how multiple factors concurrently shaped the effects of agonists on endosomal receptor-β-arrestin binding and thus determined the extent of functional selectivity. Ligand dissociation rate and G protein activity had particularly strong, internalization-dependent effects on the receptor-β-arrestin interaction. We also showed that endocytosis regulated the agonist efficacies of two other receptors with sustained β-arrestin binding: the V2 vasopressin receptor and a mutant β2-adrenergic receptor. In the absence of endocytosis, the agonist-dependent variance in β-arrestin2 binding was markedly diminished. Our results suggest that endocytosis determines the spatiotemporal bias in GPCR signaling and can aid in the development of more efficacious, functionally selective compounds.