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The association of arrestin-3 with the human lutropin/choriogonadotropin receptor depends mostly on receptor activation rather than on receptor phosphorylation
Journal article   Open access   Peer reviewed

The association of arrestin-3 with the human lutropin/choriogonadotropin receptor depends mostly on receptor activation rather than on receptor phosphorylation

Le Min, Colette Galet and Mario Ascoli
The Journal of biological chemistry, Vol.277(1), pp.702-710
01/04/2002
DOI: 10.1074/jbc.M106082200
PMID: 11696538
url
https://doi.org/10.1074/jbc.M106082200View
Published (Version of record) Open Access

Abstract

Although the involvement of the nonvisual arrestins in the agonist-induced internalization of the human lutropin receptor (hLHR) has been documented previously with the use of dominant-negative mutants, a physical association of the nonvisual arrestins with the hLHR in intact cells has not been established. In the studies presented herein, we used a cross-linking/coimmunoprecipitation/immunoblotting approach as well as confocal microscopy to document the association of the hLHR with the nonvisual arrestins in co-transfected 293 cells. We also used this approach to examine the relative importance of receptor activation and receptor phosphorylation in the formation of this complex. Using hLHR mutants that impair phosphorylation, activation, or both, we show that the formation of the hLHR-nonvisual arrestin complex depends mostly on the agonist-induced activation of the hLHR rather than on the phosphorylation of the hLHR. These results stand in contrast to those obtained with several other G protein-coupled receptors (i.e. the β2-adrenergic receptor, the m2 muscarinic receptor, rhodopsin, and the type 1A angiotensin receptor) where arrestin binding depends mostly on receptor phosphorylation rather than on receptor activation. We have also examined the association of the nonvisual arrestins with naturally occurring gain-of-function mutations of the hLHR found in boys with Leydig cell hyperplasia or Leydig cell adenomas. Our results show that these mutants associate with the nonvisual arrestins in an agonist-independent fashion.

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