ESR2 (estrogen receptor beta) is a nuclear receptor that mediates estrogen signaling in various tissues, though the provided UniProt summary notes it has reduced ligand binding and ERE binding capacity compared to ESR1. In normal physiology, ESR2 is predominantly expressed in the brain and regulates reproductive and non-reproductive functions 1. ESR2 operates through the estrogen receptor signaling pathway, controlling transcription via RNA polymerase II binding to estrogen response elements and regulating both positive and negative transcriptional processes [Gene Ontology annotations]. In reproductive tissues, ESR2 contributes to endometriosis pathogenesis; endometriotic stromal cells show abnormally elevated ESR2 levels relative to ESR1, promoting estrogen-driven inflammation and prostaglandin formation that facilitates lesion development and progression 23. ESR2 signaling also regulates ferroptosis in fibroblast-like synoviocytes through the ESR2/LPAR3/Nrf2 axis, with therapeutic implications for knee osteoarthritis pain management 4. Genetically, ESR2 polymorphisms show population-specific associations: the rs4986938 variant exhibits protective effects against dementia in Asian populations 5, while rs1256030 associates with breast cancer susceptibility in the Mexican population 6. ESR2 variants also influence assisted reproduction outcomes, with the AluI GG genotype associated with ovarian hyperstimulation syndrome 7. These diverse functions establish ESR2 as a clinically relevant target for endometriosis, dementia prevention, and cancer risk stratification.