The α-Arrestin ARRDC3 Regulates the Endosomal Residence Time and Intracellular Signaling of the β2-Adrenergic Receptor

Arrestin domain-containing protein 3 (ARRDC3) is a member of the mammalian -arrestin family, which is predicted to share similar tertiary structure with visual-/-arrestins and also contains C-terminal PPXY motifs that mediate interaction with E3 ubiquitin ligases. Recently, ARRDC3 has been proposed to play a role in regulating the trafficking of G protein-coupled receptors, although mechanistic insight into this process is lacking. Here, we focused on characterizing the role of ARRDC3 in regulating the trafficking of the (2)-adrenergic receptor ((2)AR). We find that ARRDC3 primarily localizes to EEA1-positive early endosomes and directly interacts with the (2)AR in a ligand-independent manner. Although ARRDC3 has no effect on (2)AR endocytosis or degradation, it negatively regulates (2)AR entry into SNX27-occupied endosomal tubules. This results in delayed recycling of the receptor and a concomitant increase in (2)AR-dependent endosomal signaling. Thus, ARRDC3 functions as a switch to modulate the endosomal residence time and subsequent intracellular signaling of the (2)AR.