Protein / target

Estrogen receptor

ESR1P03372Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
37
Approved medicines
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Sequence-specific double-stranded DNA binding

Primary system

Nervous system

Strongest disease association

breast cancer

Genetic evidence · score 0.78

Therapeutic maturity

Clinically validated target

37 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

37 approved · 13 in clinical development

30 linked trials

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

Nuclear hormone receptor. The steroid hormones and their receptors are involved in the regulation of eukaryotic gene expression and affect cellular proliferation and differentiation in target tissues. Ligand-dependent nuclear transactivation involves either direct homodimer binding to a palindromic estrogen response element (ERE) sequence or association with other DNA-binding transcription factors, such as AP-1/c-Jun, c-Fos, ATF-2, Sp1 and Sp3, to mediate ERE-independent signaling. Ligand binding induces a conformational change allowing subsequent or combinatorial association with multiprotein coactivator complexes through LXXLL motifs of their respective components. Mutual transrepression occurs between the estrogen receptor (ER) and NF-kappa-B in a cell-type specific manner. Decreases NF-kappa-B DNA-binding activity and inhibits NF-kappa-B-mediated transcription from the IL6 promoter and displace RELA/p65 and associated coregulators from the promoter. Recruited to the NF-kappa-B response element of the CCL2 and IL8 promoters and can displace CREBBP. Present with NF-kappa-B components RELA/p65 and NFKB1/p50 on ERE sequences. Can also act synergistically with NF-kappa-B to activate transcription involving respective recruitment adjacent response elements; the function involves CREBBP. Can activate the transcriptional activity of TFF1. Also mediates membrane-initiated estrogen signaling involving various kinase cascades. Essential for MTA1-mediated transcriptional regulation of BRCA1 and BCAS3 (PubMed:17922032). Maintains neuronal survival in response to ischemic reperfusion injury when in the presence of circulating estradiol (17-beta-estradiol/E2) (By similarity)

Subcellular location

NucleusCytoplasmCell membraneGolgi apparatus
Domains and Gene Ontology detail (61)

Domains & features

NR LBD

Gene Ontology

  • Cchromatin
  • Ccytoplasm
  • Ccytosol
  • Ceuchromatin
  • CGolgi apparatus
  • Cmembrane
  • Cnucleoplasm
  • Cnucleus
  • Cplasma membrane
  • Cprotein-containing complex
  • F14-3-3 protein binding
  • FATPase binding

595 aa · 66 kDa · 4 isoforms

Biological roles

Reactome v97

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

Transcriptional regulationUniProt · GO · ReactomeNuclear receptor signallingGO · ReactomeG protein-coupled signallingGOKinase signallingGOImmune signallingUniProtProteolysisReactome
View supporting evidence

Transcriptional regulation

  • ·Nuclear hormone receptor. The steroid hormones and their receptors are involved in the r…
  • ·DNA-binding transcription activator activity, RNA polymerase II-specific
  • ·DNA-binding transcription factor activity
  • ·DNA-binding transcription factor activity, RNA polymerase II-specific

Nuclear receptor signalling

  • ·DNA-binding transcription factor activity
  • ·DNA-binding transcription factor activity, RNA polymerase II-specific
  • ·nuclear receptor activity
  • ·nuclear receptor-mediated steroid hormone signaling pathway

G protein-coupled signalling

  • ·phospholipase C-activating G protein-coupled receptor signaling pathway

Kinase signalling

  • ·protein kinase binding

Immune signalling

  • ·Nuclear hormone receptor. The steroid hormones and their receptors are involved in the r…

Proteolysis

  • ·Ovarian tumor domain proteases
View underlying pathways (17)

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.

SRCJUNHSP90A…NCOA1IGF1RBRCA1NRIP1NCOA3NCOR1SP1ESR1

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.

Drugs targeting this protein

7

Whether each drug engages this protein directly or through a complex, and how many other targets are recorded for it. Direct binders with few recorded targets are listed first.

Estradiol
Narrow target profileApprovedAgonist

Estrogen receptor alpha agonist

Appears in clinical studies involving menopause, Atrophy, hypogonadism, Premature ovarian insufficiency

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

fulvestrant
Narrow target profileApprovedAntagonist

Estrogen receptor alpha antagonist

Appears in clinical studies involving breast cancer, breast carcinoma, breast neoplasm, neoplasm

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

Diethylstilbestrol
Narrow target profileApprovedAgonist

Estrogen receptor alpha agonist

Appears in clinical studies involving neoplasm, prostate cancer

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

Estrone
Narrow target profileApprovedAgonist

Estrogen receptor alpha agonist

Appears in clinical studies involving premenstrual tension

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

elacestrant
Narrow target profileApprovedDegrader

Estrogen receptor alpha degrader

Appears in clinical studies involving breast cancer, breast neoplasm, neoplasm, Hot flashes

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

Lasofoxifene
ApprovedModulator

Estrogen receptor modulator

Appears in clinical studies involving osteoporosis, breast cancer, viral infectious disease

Acts on a complex — shared with ESR2 · 1 of 2 recorded protein targets — narrow recorded profile

Ospemifene
ApprovedModulator

Estrogen receptor modulator

Appears in clinical studies involving menopause, Dyspareunia, Atrophy, postmenopausal atrophic vaginitis

Acts on a complex — shared with ESR2 · 1 of 2 recorded protein targets — narrow recorded profile

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

Translational evidence

Open Targets 26

Why this target matters therapeutically — disease associations, drugs in development, tractability and safety, from Open Targets.

Strongest genetic associations

Human genetic evidence — the most direct causal link between this target and a disease.

breast cancer0.78

Genetic · overall 0.74

Estrogen resistance syndrome0.76

Genetic · overall 0.66

breast carcinoma0.69

Genetic · overall 0.71

endometriosis0.65

Genetic · overall 0.67

osteoporosis0.65

Genetic · overall 0.71

Highest-confidence therapeutic associations

Diseases where a drug acting on this target has already reached clinical development.

hypogonadism0.99

Clinical · overall 0.60

menopause0.98

Clinical · overall 0.60

acne0.98

Clinical · overall 0.61

neoplasm0.93

Clinical · overall 0.66

breast neoplasm0.91

Clinical · overall 0.66

Show all associations
breast cancer0.74
breast carcinoma0.71
osteoporosis0.71
endometriosis0.67
breast neoplasm0.66
neoplasm0.66
Estrogen resistance syndrome0.66
acne0.61
hypogonadism0.60
menopause0.60

Open Targets ranks 3,206 associations for this target and we store the top 10 by aggregated score. The long tail is largely literature co-mention and RNA-expression evidence, not evidence that this target drives those diseases.

Known drugs · 51 total

MESTRANOLApproval

contraception

ARZOXIFENEApproval

breast cancer · osteoporosis

SYNTHETIC CONJUGATED ESTROGENS, BApproval

Atrophy · menopause

GTX-758Phase 2

prostate cancer

ESTRIOLApproval

Atrophic Vaginitis · Atrophic Vaginitis · urgency urinary incontinence

ESTRADIOL ACETATEApproval

menopause · Atrophy

CLOMIPHENEApproval

female infertility · hypogonadism · hypogonadotropic hypogonadism

TOREMIFENEApproval

breast cancer · neoplasm · mastodynia

ESTROGENS, ESTERIFIEDApproval

breast cancer · menopause · Atrophy

TOREMIFENE CITRATEApproval

breast cancer · breast carcinoma · breast neoplasm

Tractability

SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · High-Quality PocketSM · Druggable FamilyAB · UniProt loc high confAB · GO CC high confAB · UniProt loc med confPR · Advanced ClinicalPR · LiteraturePR · UniProt UbiquitinationPR · Database Ubiquitination

Safety liabilities

azoospermiabone density lossmethamphetamine-induced psychosisAltered, Larval developmentN/A, Breast Cancerless bone mineral lossbreast atrophyPromotion, ovarian adenomasIncrease, Endometrial adenocarcinomaslarger tamoxifen-induced decrease in total cholesterolvaginal atrophyregulation of steroid biosynthetic process

Clinical trials

30

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein.

Show remaining trials (24)

COMPLETED · via Estradiol · NCT01046643

ClinicalTrials.gov via the drug-target graph.

Related literature

35

Papers indexed under “Receptors, Estrogen” — a subject heading that covers this protein without being specific to it. Shown as context; not counted as this protein's own research activity.

Biomarkers in breast cancer 2024: an updated consensus statement by the Spanish Society of Medical Oncology and the Spanish Society of Pathology.

Colomer R · Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico · 2024

Rat Models of Hormone Receptor-Positive Breast Cancer.

Nicotra R · Journal of mammary gland biology and neoplasia · 2024

Europe PMC literature, reached through a MeSH descriptor linked to this protein.

Forefront confidence

Synthesis

Our own weighting of the evidence behind each disease association. Human genetics and clinical evidence count for most; literature co-mention counts for little, because two entities sharing an abstract is not evidence that one drives the other.

breast carcinomaWell supported
0.96
agreement 0.871.00
Genetic33%Clinical32%Somatic mutation19%Pathway8%Literature7%RNA expression1%

Open Targets aggregate 0.71 · 6 independent evidence families

breast cancerWell supported
0.95
agreement 0.841.00
Genetic47%Clinical45%Literature9%

Open Targets aggregate 0.74 · 3 independent evidence families

osteoporosisWell supported
0.93
agreement 0.841.00
Clinical44%Genetic39%Animal model10%Literature7%

Open Targets aggregate 0.71 · 4 independent evidence families

endometriosisWell supported
0.91
agreement 0.801.00
Clinical46%Genetic44%Literature9%

Open Targets aggregate 0.67 · 3 independent evidence families

breast neoplasmWell supported
0.90
agreement 0.791.00
Clinical47%Genetic43%Literature10%

Open Targets aggregate 0.66 · 3 independent evidence families

This ranking differs from Open Targets' own: re-weighting moves genetically-evidenced diseases above more heavily co-mentioned ones. 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 underlying per-type scores are shown above so the calculation can be checked.

What's happening now

60

Recent activity around this target, drawn from one canonical event stream. Every item is reached through 7 drugs that target this protein, so each event is news about that drug rather than about the protein directly.

  1. Trial status changed2026-07-06

    PIKture-01: First-in-Human Study of the PI3KαH1047R Mutant-Selective Inhibitor OKI-219 as Monotherapy in Participants With Advanced Solid Tumors and as Part of Combination Therapy in Participants With Advanced Breast Cancer

    Status changed to Active, not recruiting · ClinicalTrials.gov · via fulvestrant

  2. Industry development2026-06-29
    Sorption and desorption of 17α−ethinylestradiol (EE2) and β−estradiol (E2) to nylon microparticles

    Nature — Environmental Sciences · news · via Estradiol

  3. Label change2026-06-24

    Label change: ELACESTRANT (NDA217639)

    fda · regulatory · fda · via elacestrant

  4. Label change2026-06-08

    Label change: ESTRADIOL (ANDA075182)

    fda · regulatory · fda · via Estradiol

  5. Label change2026-06-08

    Label change: ESTRADIOL (ANDA075182)

    fda · regulatory · fda · via Estradiol

  6. Label change2026-06-08

    Label change: ESTRADIOL (ANDA075182)

    fda · regulatory · fda · via Estradiol

  7. New publication2025-02-14
    The association between sex hormones and bone mineral density in US females.

    Scientific reports · 2025 · 6 citations · Europe PMC · via Estradiol

  8. Label change2025-02-07

    Label change: OSPEMIFENE (NDA203505)

    fda · regulatory · fda · via Ospemifene

  9. 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

  10. New publication2024-09-03
    Metabolic benefits afforded by estradiol and testosterone in both sexes: clinical considerations.

    The Journal of clinical investigation · 2024 · 39 citations · Europe PMC · via Estradiol

  11. New publication2024-08-01
    Sex hormones differently regulate lipid metabolism genes in primary human hepatocytes.

    BMC endocrine disorders · 2024 · 8 citations · Europe PMC · via Estradiol

  12. New publication2024-07-04
    TFEB controls syncytiotrophoblast formation and hormone production in placenta.

    Cell death and differentiation · 2024 · 14 citations · Europe PMC · via Estradiol

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.