Insights into beta2-adrenergic receptor binding from structures of the N-terminal lobe of ARRDC3.
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Qi S, O'Hayre M, Gutkind JS, Hurley JH
Insights into beta2-adrenergic receptor binding from structures of the N-terminal lobe of ARRDC3.
Protein Sci. 2014 Dec;23(12):1708-16. doi: 10.1002/pro.2549. Epub 2014 Sep 26.
- PubMed ID
- 25220262 [ View in PubMed]
- Abstract
ARRDC3 is one of six known human alpha-arrestins, and has been implicated in the downregulation of the beta2-adrenergic receptor (beta2AR). ARRDC3 consists of a two-lobed arrestin fold and a C-terminal tail containing two PPYX motifs. In the current model for receptor downregulation by ARRDC3, the arrestin fold portion is thought to bind the receptor, while the PPXY motifs recruit ubiquitin ligases of the NEDD4 family. Here we report the crystal structures of the N-terminal lobe of human ARRDC3 in two conformations, at 1.73 and 2.8 A resolution, respectively. The structures reveal a large electropositive region that is capable of binding phosphate ions of crystallization. Residues within the basic patch were shown to be important for binding to beta2AR, similar to the situation with beta-arrestins. This highlights potential parallels in receptor recognition between alpha- and beta-arrestins.