Functions as an adapter recruiting ubiquitin-protein ligases to their specific substrates (PubMed:27462458). Plays a role in endocytosis of activated G protein-coupled receptors (GPCRs) (By similarity). Through an ubiquitination-dependent mechanism also plays a role in the incorporation of SLC11A2 into extracellular vesicles (PubMed:27462458). May play a role in glucose uptake (By similarity). Interacts with ADRB2. Interacts (via PPxY motifs) with ITCH, NEDD4L and WWP2. Interacts with AVPR2. Identified in a complex containing at least ARRDC4, AVPR2 and HGS (By similarity). Interacts with SLC11A2; controls the incorporation of SLC11A2 into extracellular vesicles through an ubiquitination-dependent mechanism (PubMed:27462458). Also found in extracellular vesicles different from exosomes. Up-regulated by high iron diet. Belongs to the arrestin family.