Beta-arrestin 2 (ARRB2) (ARRB2)

Beta-arrestin 2 is a ubiquitous intracellular scaffold protein that plays a dual role in G protein-coupled receptor (GPCR) signaling [1, 2]. It was originally identified for its role in the desensitization and internalization of activated GPCRs, effectively terminating G protein-mediated signaling by sterically hindering receptor-G protein coupling [3, 14]. Beyond this regulatory role, Beta-arrestin 2 acts as a versatile signal transducer by scaffolding various intracellular signaling cascades, such as the MAPK/ERK, PI3K/AKT, and NF-κB pathways, independent of G protein activation [6, 12]. This dual functionality has led to the development of 'biased ligands' that selectively modulate either G protein or Beta-arrestin 2 pathways to achieve therapeutic specificity [9, 11]. For example, G protein-biased opioid agonists are designed to avoid Beta-arrestin 2 recruitment to minimize side effects like respiratory depression and constipation [8]. Conversely, Beta-arrestin-biased ligands for the angiotensin II type 1 receptor are being explored for their potential cardioprotective benefits [20, 22]. Beta-arrestin 2 is also implicated in the pathogenesis of inflammatory diseases, cancer, and neurodegeneration, where it can modulate immune cell infiltration and tumor progression [4, 5, 16]. Its involvement in such a wide array of physiological processes makes it a high-value target for drug discovery, though its ubiquitous expression presents challenges for tissue-specific targeting [16]. Current therapeutic strategies include both the indirect modulation of its recruitment via biased GPCR agonists and the direct inhibition of its scaffolding functions using experimental small molecules or aptamers [7, 16].

Other names

Arrestin beta-2ARRB2Arrestin-3Non-visual arrestin-3BARR2

Biased agonism (selective recruitment or avoidance of Beta-arrestin 2), direct scaffold inhibition, and modulation of GPCR desensitization and internalization.