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Protein / target

Estrogen receptor beta

Encoded byESR2Q92731Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
20
Approved medicines
Open Targets target-level
View by indication →
29
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Nuclear estrogen receptor

Strongest disease association

Osteoporosis

Via encoding gene ESR2 · Clinical evidence · score 0.61

Therapeutic position

Established drug target

Small molecules

Research activity

Emerging research

3 papers · latest 2020

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function overview

Nuclear hormone receptor.

View complete UniProt function annotation

Nuclear hormone receptor. Binds estrogens with an affinity similar to that of ESR1/ER-alpha, and activates expression of reporter genes containing estrogen response elements (ERE) in an estrogen-dependent manner (PubMed:20074560)

Subcellular location

Nucleus
Domains and Gene Ontology detail (27)

Domains & features

NR LBD

Gene Ontology

  • Cchromatin
  • Cmitochondrion
  • Cnucleoplasm
  • Cnucleus
  • FDNA binding
  • FDNA-binding transcription factor activity, RNA polymerase II-specific
  • Fenzyme binding
  • Festrogen response element binding
  • Fnuclear estrogen receptor activity
  • Fnuclear receptor activity
  • Fnuclear steroid receptor activity
  • Freceptor antagonist activity

530 aa · 59 kDa · 9 isoforms

Biological roles

Reactome v97

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Nuclear receptor signallingGO · ReactomeCell proliferation & survivalReactomeOncogenic signallingReactomeTranscriptional regulationGO · Reactome
View supporting evidence

Nuclear receptor signalling

  • ·nuclear receptor activity
  • ·Nuclear Receptor transcription pathway

Cell proliferation & survival

  • ·PIP3 activates AKT signaling
  • ·PI5P, PP2A and IER3 Regulate PI3K/AKT Signaling

Oncogenic signalling

  • ·Constitutive Signaling by Aberrant PI3K in Cancer

Transcriptional regulation

  • ·DNA-binding transcription factor activity, RNA polymerase II-specific
  • ·RNA polymerase II cis-regulatory region sequence-specific DNA binding
  • ·DNA-templated transcription
  • ·negative regulation of transcription by RNA polymerase II
View underlying pathways (6)

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Interaction neighbourhood

STRING v12.0

Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.

NCOA1ESR1NCOA3SRCNCOA2SP1MED1CAV1NCOR1JUNESR2

10 strongest partners — larger node and heavier line mean higher confidence

Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.

Approved medicines with mapped indications

1 medicine · 2 areas

Approved therapies targeting this protein, grouped by what they are approved to treat — the disease-first view of the medicines below. Relationships come from the canonical approved-indication graph (ChEMBL phase-4), the same source as the drug cards.

Atrophy1 medicine
Dyspareunia1 medicine

20 medicines meet Open Targets' target-level approved-medicine definition; the 1 shown here are those on this page with a canonical approved disease indication in the graph. Approved indications from ChEMBL (phase-4), via the canonical drug→disease graph.

Drugs targeting this protein

4

How approved and investigational drugs engage this protein — mechanism and action type, direct vs complex targeting, and how broadly each acts across other targets. A drug-first view (the section above groups the approved ones disease-first); direct binders with few recorded targets are listed first.

equol
Narrow target profileAgonist

Estrogen receptor beta agonist

Direct interaction with this protein · Only this protein recorded as a target

Lasofoxifene
ApprovedModulator

Estrogen receptor modulator

Acts on a complex — shared with ESR1 · 1 of 2 recorded protein targets — narrow recorded profile

Ospemifene
ApprovedModulator

Estrogen receptor modulator

Indicated for Atrophy, Dyspareunia

Acts on a complex — shared with ESR1 · 1 of 2 recorded protein targets — narrow recorded profile

Afimoxifene
Phase 2Modulator

Estrogen receptor modulator

Acts on a complex — shared with ESR1 · 1 of 3 recorded protein targets — narrow recorded profile

ChEMBL mechanism, action type, target identity and approved indications. Open Targets clinical status.

Translational evidence

Open Targets 26

Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.

Strongest disease associations · via encoding gene ESR2

Gene-level evidence surfaced through the gene ESR2 that encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.

Osteoporosis
0.75Well supported

Clinical evidence dominant · Open Targets 0.61

Osteoporosis, Postmenopausal
0.72Moderately supported

Clinical evidence dominant · Open Targets 0.58

Atrophy
0.68Moderately supported

Clinical evidence dominant · Open Targets 0.55

Primary Ovarian Insufficiency
0.65Moderately supported

Clinical evidence dominant · Open Targets 0.48

Neoplasms
0.63Moderately supported

Clinical evidence dominant · Open Targets 0.49

View evidence synthesis (5)
OsteoporosisWell supported
0.75
agreement 0.600.91
Clinical90%Literature10%

Open Targets aggregate 0.61 · 2 independent evidence families

Osteoporosis, PostmenopausalModerately supported
0.72
agreement 0.560.87
Clinical97%Literature3%

Open Targets aggregate 0.58 · 2 independent evidence families

AtrophyModerately supported
0.68
agreement 0.530.84
Clinical99%Literature1%

Open Targets aggregate 0.55 · 2 independent evidence families

Primary Ovarian InsufficiencyModerately supported
0.65
agreement 0.520.78
Clinical75%Animal model24%Literature1%

Open Targets aggregate 0.48 · 3 independent evidence families

NeoplasmsModerately supported
0.63
agreement 0.480.79
Clinical80%Literature21%

Open Targets aggregate 0.49 · 2 independent evidence families

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.

Show all associations
Osteoporosis0.61
Osteoporosis, Postmenopausal0.58
Atrophy0.55
Neoplasms0.49
Primary Ovarian Insufficiency0.48

Drug development

35 compounds recorded · 20 approved · 14 in clinical development · 1 earlier-stage

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 4 drugs that target this protein in Forefront's canonical graph (1 with a mapped approved indication, shown above): these count different sets and are not a subset relation.

View all recorded compounds (10)
LASOFOXIFENE TARTRATEApproval
OSPEMIFENEApproval
ERTEBERELPhase 2
ESTRIOLApproval
DROLOXIFENEPhase 2
ACOLBIFENEPhase 3
ESTRAMUSTINE PHOSPHATE SODIUMApproval
AFIMOXIFENEPhase 2
PRINABERELPhase 2
IDOXIFENEPhase 3

Open Targets known-drugs universe. Drug name and highest clinical stage only — the disease relationship is NOT read from this slice (it carries trial-context noise); approved indications come from the canonical graph above.

Tractability

Small moleculesStrong

Approved Drug and Structure with Ligand support this modality.

Protein degradersEmerging

Feasibility evidence (small molecule binder) — no clinical-stage drug of this modality recorded.

Other modalitiesStrong

Approved Drug support this modality.

View underlying tractability evidence (7)
SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · High-Quality PocketSM · Druggable FamilyPR · Small Molecule BinderOC · Approved Drug

Raw Open Targets tractability assessment buckets, by modality.

Safety-related annotations

regulation of transcription factor activityToxCastprotein stabilizationToxCastregulation of steroid biosynthetic processToxCastbone density lossClinPGxregulation of steroid hormone biosynthetic processToxCasttamoxifen-induced increase in triglyceridesClinPGx

Terms indexed against this target in Open Targets' safety data, with their datasource. These are annotations, not causal claims: the direction of effect (whether activation or inhibition is implicated), species and evidence strength are not captured here, so an entry does not mean that modulating this target is known to cause that condition.

Clinical trials

29

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein. Ranked by active status, then clinical phase and recency, and spread across the targeting drugs.

View all trials (25)

ACTIVE_NOT_RECRUITING · via equol · NCT05741060

COMPLETED · via Lasofoxifene · NCT00141323

ClinicalTrials.gov via the drug-target graph.

What's happening now

12

Recent therapeutic activity around this target — regulatory actions, clinical trials and safety signals for 3 drugs that target this protein, plus publications where such a drug is a genuine subject. Every item is reached indirectly through the drug, not the protein itself; incidental mentions (a paper that merely measures a drug) and press items are excluded.

  1. Label change2025-02-07

    Label change: OSPEMIFENE (NDA203505)

    fda · regulatory · fda · via Ospemifene

  2. New publication2024-09-10
    Hormonal Treatments and Vaginal Moisturizers for Genitourinary Syndrome of Menopause : A Systematic Review.

    Annals of internal medicine · 2024 · 14 citations · Europe PMC · via Ospemifene

  3. Label change2024-02-15

    Label change: OSPEMIFENE (NDA203505)

    fda · regulatory · fda · via Ospemifene

  4. New publication2024-02-11
    From Gut to Hormones: Unraveling the Role of Gut Microbiota in (Phyto)Estrogen Modulation in Health and Disease.

    Molecular nutrition & food research · 2024 · 50 citations · Europe PMC · via equol

  5. New publication2023-12-01
    Lasofoxifene versus fulvestrant for ER+/HER2- metastatic breast cancer with an ESR1 mutation: results from the randomized, phase II ELAINE 1 trial.

    Annals of oncology : official journal of the European Society for Medical Oncology · 2023 · 33 citations · Europe PMC · via Lasofoxifene

  6. New publication2023-12-01
    Open-label, phase II, multicenter study of lasofoxifene plus abemaciclib for treating women with metastatic ER+/HER2- breast cancer and an ESR1 mutation after disease progression on prior therapies: ELAINE 2.

    Annals of oncology : official journal of the European Society for Medical Oncology · 2023 · 37 citations · Europe PMC · via Lasofoxifene

  7. Indication expanded2019-01-25

    Indication expansion: OSPEMIFENE (NDA203505)

    fda · regulatory · fda · via Ospemifene

  8. Supplemental approval2017-03-17

    Supplemental approval: OSPEMIFENE (NDA203505)

    fda · regulatory · fda · via Ospemifene

  9. Supplemental approval2016-11-03

    Supplemental approval: OSPEMIFENE (NDA203505)

    fda · regulatory · fda · via Ospemifene

  10. Supplemental approval2015-08-24

    Supplemental approval: OSPEMIFENE (NDA203505)

    fda · regulatory · fda · via Ospemifene

  11. Regulatory approval2015-01-14

    Approval: Senshio (EMA)

    ema · regulatory · ema · via Ospemifene

  12. Regulatory approval2013-02-26

    Approval: OSPEMIFENE (NDA203505)

    fda · regulatory · fda · via Ospemifene

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.

Research activity

3 papers · to 2020

Papers linked directly to this protein. This is the protein's own literature — descriptor-derived papers are kept separate below.

Most cited

Li LC · Bioinformatics (Oxford, England) · 2002

Wang Y · Annual review of pathology · 2020

Recent

The Origin and Pathogenesis of Endometriosis.

Wang Y · Annual review of pathology · 2020

MethPrimer: designing primers for methylation PCRs.

Li LC · Bioinformatics (Oxford, England) · 2002

Europe PMC papers linked directly to this protein.

Related family literature

35

Papers about “Receptors, Estrogen” — a broader family this protein belongs to. Shown as context; not counted as papers specifically about this protein.

Biomarkers of response and resistance to immune checkpoint inhibitors in breast cancer.

Li M · Breast (Edinburgh, Scotland) · 2025

via Receptors, Estrogen

Landscape of Baseline and Acquired Genomic Alterations in Circulating Tumor DNA with Abemaciclib Alone or with Endocrine Therapy in Advanced Breast Cancer.

Goetz MP · Clinical cancer research : an official journal of the American Association for Cancer Research · 2024

via Receptors, Estrogen

Datopotamab Deruxtecan in Advanced or Metastatic HR+/HER2- and Triple-Negative Breast Cancer: Results From the Phase I TROPION-PanTumor01 Study.

Bardia A · Journal of clinical oncology : official journal of the American Society of Clinical Oncology · 2024

via Receptors, Estrogen

Abemaciclib plus a nonsteroidal aromatase inhibitor as initial therapy for HR+, HER2- advanced breast cancer: final overall survival results of MONARCH 3.

Goetz MP · Annals of oncology : official journal of the European Society for Medical Oncology · 2024

via Receptors, Estrogen

Europe PMC literature, reached through curated HGNC family membership. Membership is a taxonomic relationship — it does not imply this protein participates in every mechanism these papers discuss.