Arrestin-3/β-Arrestin 2

Arrestin-3/β-arrestin 2 is a ubiquitously expressed cytosolic adaptor protein that regulates GPCR signaling by limiting heterotrimeric G protein activity, promoting receptor endocytosis, and supporting kinase activation pathways^[1]. Mechanistically, β-arrestins act as endocytic adaptors and signaling scaffolds for seven-transmembrane receptors, linking receptor trafficking with alternate downstream signaling pathways^[2]. In lysophosphatidic acid receptor models, β-arrestin 2 expression attenuated EGFR transactivation-dependent signaling and promoted a distinct subset of ERK1/2-mediated transcriptional responses^[3]. In PAR-2 signaling, β-arrestin 2 mediated delayed receptor internalization and membrane-associated ERK1/2 activation, whereas β-arrestin 1 mediated early internalization and lysosomal receptor degradation^[4]. In inflammatory disease models, β-arrestin 2 overexpression decreased TNFα and IL-6 production in fibroblast-like synoviocytes, and β-arrestin 2 knockout mice developed more severe collagen antibody-induced arthritis^[5]. Compared with β-arrestin 1, β-arrestin 2 showed opposite regulation of IGF-1R by promoting unstimulated receptor degradation while protecting against agonist-induced degradation^[6]. For experimental applications, biased ligands that block G protein activation while promoting β-arrestin binding enable pathway-selective analysis of GPCR signaling^[1][7].