arrestiinien
Arrestins are a small family of cytosolic proteins that regulate signaling by G protein–coupled receptors (GPCRs). In vertebrates, the arrestin family includes visual arrestins (arrestin-1, also known as S-arrestin, expressed in rod photoreceptors, and cone arrestin, sometimes called arrestin-4) and non-visual arrestins (beta-arrestin-1 and beta-arrestin-2). The primary role of arrestins is to desensitize GPCR signaling: when a GPCR is phosphorylated by GPCR kinases (GRKs), arrestins bind to the receptor and prevent further activation of G proteins. This binding also promotes receptor internalization via clathrin-coated pits, aiding receptor endocytosis and trafficking to endosomes.
Beyond termination of G protein signaling, arrestins function as scaffolds that assemble signaling complexes. This scaffolding
Different arrestins have specialized roles. Visual arrestins regulate phototransduction in the retina, helping to terminate light-evoked
Structural studies reveal a two-domain conformation with a polar core that recognizes phosphorylated receptor tails. Genetic