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Protein / target

Adenosine receptor A3

Encoded byADORA3P0DMS8Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
6
Approved medicines
Open Targets target-level
View by indication →
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

G protein-coupled adenosine receptor

Strongest disease association

Migraine Disorders

Via encoding gene ADORA3 · Clinical evidence · score 0.61

Therapeutic position

Established drug target

Small molecules

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

G protein-coupled receptor (GPCR) for adenosine that plays significant roles in various physiological processes including immune regulation, cardioprotection and neuroprotection.

View complete UniProt function annotation

G protein-coupled receptor (GPCR) for adenosine that plays significant roles in various physiological processes including immune regulation, cardioprotection and neuroprotection (PubMed:38627384, PubMed:40825947, PubMed:9837869). Also acts as a receptor for adenosines containing N(6)-methylated adenine (m6A) post-transcriptional modification, which are derived from the degradation of RNAs (mRNAs, rRNAs and tRNAs): activated by N(6)-methyladenosine (m6A), N(6),N(6)-dimethyladenosine (m6,6A) and N(6)-isopentenyladenosine (i6A) (PubMed:33472058, PubMed:39511145). Preferentially couples to the inhibitory G protein (Gi), leading to the suppression of adenylate cyclase activity and a reduction in intracellular cyclic AMP levels (PubMed:33472058, PubMed:38627384). Upon adenosine binding, mediates cardioprotection in cardiomyocytes through anti-apoptotic effects primarily via the ERK1/2 pathway as well as the PI3K pathway (PubMed:9837869). In the central nervous system, participates in the modulation of synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD) in the hippocampus (By similarity). In lung mast cells, receptor activation contributes to the type I allergic response by facilitating mast cell degranulation and histamine release (By similarity). Highly expressed in inflammatory cells such as neutrophils and mast cells, inhibits neutrophil degranulation and reduces superoxide production, thereby modulating inflammatory responses (PubMed:9164961)

Subcellular location

Cell membrane
Domains and Gene Ontology detail (18)

Gene Ontology

  • Cdendrite
  • Cplasma membrane
  • Cpresynaptic membrane
  • CSchaffer collateral - CA1 synapse
  • Csynapse
  • FG protein-coupled adenosine receptor activity
  • Pactivation of adenylate cyclase activity
  • Padenylate cyclase-inhibiting G protein-coupled receptor signaling pathway
  • PG protein-coupled adenosine receptor signaling pathway
  • Pinflammatory response
  • Pnegative regulation of cell migration
  • Pnegative regulation of cell population proliferation

318 aa · 36 kDa · 3 isoforms

Biological roles

Reactome v97

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

Synaptic signallingGOCell proliferation & survivalGOCell migrationGOG protein-coupled signallingUniProt · GOImmune signallingUniProt · GO
View supporting evidence

Synaptic signalling

  • ·presynaptic membrane
  • ·Schaffer collateral - CA1 synapse
  • ·synapse
  • ·presynaptic modulation of chemical synaptic transmission

Cell proliferation & survival

  • ·negative regulation of cell population proliferation

Cell migration

  • ·negative regulation of cell migration

G protein-coupled signalling

  • ·G protein-coupled receptor (GPCR) for adenosine that plays significant roles in various…
  • ·G protein-coupled adenosine receptor activity
  • ·adenylate cyclase-inhibiting G protein-coupled receptor signaling pathway
  • ·G protein-coupled adenosine receptor signaling pathway

Immune signalling

  • ·G protein-coupled receptor (GPCR) for adenosine that plays significant roles in various…
  • ·inflammatory response
  • ·positive regulation of mast cell degranulation
View underlying pathways (2)

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.

GNAI2GNAI1KNG1GNAI3ADORA1GPR34LTBP2LTBP3LTBP1ADAADORA3

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 · 1 area

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.

Cardiovascular Diseases1 medicine

6 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

1

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.

Adenosine
ApprovedAgonist

Adenosine receptor agonist

Indicated for Cardiovascular Diseases

Acts on a complex — shared with ADORA1, ADORA2B, ADORA2A · 1 of 4 recorded protein targets

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 ADORA3

Gene-level evidence surfaced through the gene ADORA3 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.

Migraine Disorders
0.75Moderately supported

Clinical evidence dominant · Open Targets 0.61

Asthma
0.75Moderately supported

Clinical evidence dominant · Open Targets 0.61

Pulmonary Disease, Chronic Obstructive
0.61Moderately supported

Clinical evidence dominant · Open Targets 0.49

View evidence synthesis (3)
Migraine DisordersModerately supported
0.75
agreement 0.590.90
Clinical100%Literature1%

Open Targets aggregate 0.61 · 2 independent evidence families

AsthmaModerately supported
0.75
agreement 0.610.88
Clinical97%Literature3%RNA expression0%

Open Targets aggregate 0.61 · 3 independent evidence families

Pulmonary Disease, Chronic ObstructiveModerately supported
0.61
agreement 0.460.77
Clinical98%Literature3%

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
Migraine Disorders0.61
Asthma0.61
Pulmonary Disease, Chronic Obstructive0.49

Drug development

8 compounds recorded · 6 approved · 2 in clinical development

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 1 drug that targets 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 (8)
THEOPHYLLINEApproval
OXTRIPHYLLINEApproval
NAMODENOSONPhase 3
CAFFEINEApproval
ADENOSINEApproval
CAFFEINE CITRATEApproval
PICLIDENOSONPhase 3
AMINOPHYLLINEApproval

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.

AntibodiesEmerging

Feasibility evidence (go cc high conf and uniprot loc med conf) — no clinical-stage drug of this modality recorded.

Protein degradersEmerging

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

View underlying tractability evidence (8)
SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · Druggable FamilyAB · GO CC high confAB · UniProt loc med confAB · UniProt SigP or TMHMMPR · Small Molecule Binder

Raw Open Targets tractability assessment buckets, by modality.

Safety-related annotations

angiogenesisUrban et al. (2012)decreased convulsionsLynch et al. (2017)interference with the regulation of cell growth (inferred by author)Urban et al. (2012)cell proliferationUrban et al. (2012)decreased locomotor activityLynch et al. (2017)increased bronchoconstrictionLynch et al. (2017)hypotensionUrban et al. (2012)myocardial ischemia (inferred by author)Urban et al. (2012)increased convulsionsLynch et al. (2017)decreased painLynch et al. (2017)cell necrosisUrban et al. (2012)antiischaemic (cardioprotective)Urban et al. (2012)

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

30

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 (26)

RECRUITING · via Adenosine · NCT04600115

COMPLETED · via Adenosine · NCT03557385

COMPLETED · via Adenosine · NCT01234870

COMPLETED · via Adenosine · NCT00944970

COMPLETED · via Adenosine · NCT00944294

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 a drug that targets 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. New publication2025-10-11
    Adenosine Receptors in Neuroinflammation and Neurodegeneration.

    Cells · 2025 · 2 citations · Europe PMC · via Adenosine

  2. New publication2025-01-01
    REDIportal: toward an integrated view of the A-to-I editing.

    Nucleic acids research · 2025 · 16 citations · Europe PMC · via Adenosine

  3. New publication2024-12-27
    Advances in A-to-I RNA editing in cancer.

    Molecular cancer · 2024 · 17 citations · Europe PMC · via Adenosine

  4. New publication2024-11-28
    Microglia regulate motor neuron plasticity via reciprocal fractalkine and adenosine signaling.

    Nature communications · 2024 · 16 citations · Europe PMC · via Adenosine

  5. New publication2024-10-05
    Astrocytic neuroligin 3 regulates social memory and synaptic plasticity through adenosine signaling in male mice.

    Nature communications · 2024 · 15 citations · Europe PMC · via Adenosine

  6. New publication2024-09-01
    WTAP participates in neuronal damage by protein translation of NLRP3 in an m6A-YTHDF1-dependent manner after traumatic brain injury.

    International journal of surgery (London, England) · 2024 · 41 citations · Europe PMC · via Adenosine

  7. New publication2024-06-18
    Adenosine and adenosine receptors in metabolic imbalance-related neurological issues.

    Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · 2024 · 17 citations · Europe PMC · via Adenosine

  8. New publication2024-05-21
    Astrocytic ALKBH5 in stress response contributes to depressive-like behaviors in mice.

    Nature communications · 2024 · 50 citations · Europe PMC · via Adenosine

  9. New publication2024-03-18
    Adenosine and Cortical Plasticity.

    The Neuroscientist : a review journal bringing neurobiology, neurology and psychiatry · 2025 · 1 citation · Europe PMC · via Adenosine

  10. New publication2023-11-08
    m<sup>1</sup>A in CAG repeat RNA binds to TDP-43 and induces neurodegeneration.

    Nature · 2023 · 60 citations · Europe PMC · via Adenosine

  11. New publication2023-10-05
    The Immune Regulatory Role of Adenosine in the Tumor Microenvironment.

    International journal of molecular sciences · 2023 · 34 citations · Europe PMC · via Adenosine

  12. New publication2023-06-30
    Monocytic MDSCs exhibit superior immune suppression via adenosine and depletion of adenosine improves efficacy of immunotherapy.

    Science advances · 2023 · 57 citations · Europe PMC · via Adenosine

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.