ERβ

ERβ (estrogen receptor beta, ESR2) is a ligand-activated nuclear receptor that regulates transcriptional programs controlling cellular differentiation, proliferation, and tissue homeostasis through estrogen-responsive gene networks^[1]. Mechanistically, ERβ functions as a transcription factor and can modulate estrogen signaling by interacting with target promoters and forming heterodimers with related estrogen receptor isoforms^[2]. Through these activities, ERβ influences gene expression patterns associated with cell-cycle regulation and cellular growth control, making it an important regulator of physiological and pathological processes^[1][2]. In disease contexts, reduced ERβ expression has been reported in multiple tumor types, and accumulating evidence supports a tumor-suppressive role for ERβ in cancer biology^[1]. Experimental studies further demonstrate that ERβ activation can suppress proliferation and alter migration-associated transcriptional programs, supporting its utility in mechanistic cancer models^[3]. Compared with the closely related isoform ERα, ERβ displays distinct transcriptional properties and can inhibit ERα-driven transcriptional activity under specific conditions, thereby reducing cellular sensitivity to estradiol signaling^[2]. Structural analyses additionally indicate that ERβ adopts ligand-binding domain conformations that differ from ERα, providing a molecular basis for subtype-specific functional responses and pharmacological selectivity^[4]. For experimental applications, several ERβ-selective agonists have been developed and are widely used to investigate ERβ-dependent signaling pathways, isoform-specific biology, and therapeutic mechanisms while minimizing ERα-mediated proliferative effects^[5].