Role of β-arrestins and arrestin domain-containing proteins in G protein-coupled receptor trafficking

The arrestin clan can now be broadly divided into three structurally similar subgroups: the originally identified arrestins (visual and beta-arrestins), the alpha-arrestins and a group of Vps26-related proteins. The visual and beta-arrestins selectively bind to agonist-occupied phosphorylated G protein-coupled receptors (GPCRs) and inhibit GPCR coupling to heterotrimeric G proteins while the beta-arrestins also function as adaptor proteins to regulate GPCR trafficking and G protein-independent signaling. The alpha-arrestins have also recently been implicated in regulating GPCR trafficking while Vps26 regulates retrograde trafficking. In this review, we provide an overview of the alpha-arrestins and beta-arrestins with a focus on our current understanding of how these adaptor proteins regulate GPCR trafficking.