ARR3 Recombinant Rabbit mAb (S-3290-27)

ARR3 (Arrestin-C, also known as X-arrestin or Cone Arrestin) is a 45-kDa protein belonging to the arrestin family of regulatory proteins, specifically expressed in retinal cone photoreceptors and pinealocytes, where it plays a critical role in terminating G protein-coupled receptor (GPCR) signaling through high-affinity binding to light-activated, phosphorylated cone opsins. Structurally, ARR3 shares the characteristic two-domain arrestin fold with β-strand-dominated N- and C-domains connected by a flexible hinge region, enabling the protein to undergo a conformational change upon receptor engagement that precludes further G protein coupling while promoting receptor internalization and trafficking. Unlike the ubiquitously expressed ARR2 (β-arrestin-1) and ARR3's rod-specific counterpart SAG (S-antigen/arrestin-1), ARR3 demonstrates preferential affinity for short-wavelength cone opsins and exhibits distinct phosphorylation-dependent regulatory mechanisms that modulate its subcellular localization between the photoreceptor outer segment and synaptic terminal. Genetic mutations in the ARR3 gene have been associated with various retinal dystrophies, including Oguchi disease and certain forms of cone-rod dystrophy, underscoring its essential function in maintaining cone photoreceptor health and proper visual cycle regulation.