β-Arrestin
β-Arrestins (β-arrestin-1 and β-arrestin-2), proteins involved in the turn-off of G protein-coupled receptor (GPCR) activation, bind to the β2-adaptin subunit of the clathrin adaptor AP-2. The interaction of β2-adaptin with β-arrestin involves critical arginine residues in the C-terminal domain of β-arrestin and plays an important role in initiating clathrin-mediated endocytosis of the β2-adrenergic receptor (β2AR).[1]
[1] S.A. Laporte et al. beta-Arrestin/AP-2 interaction in G protein-coupled receptor internalization: identification of a beta-arrestin binging site in beta 2-adaptin. J Biol Chem. 2002 Mar 15;277(11):9247-54.