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Protein / target

Adenosine receptor A1

Encoded byADORA1P30542Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
7
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

Asthma

Via encoding gene ADORA1 · Genetic evidence · score 0.78

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

Receptor for adenosine.

View complete UniProt function annotation

Receptor for adenosine (PubMed:29925945). The activity of this receptor is mediated by G proteins such as GNAI2 which inhibit adenylyl cyclase

Subcellular location

Cell membrane
Domains and Gene Ontology detail (67)

Gene Ontology

  • Casymmetric synapse
  • Caxolemma
  • Cbasolateral plasma membrane
  • Ccalyx of Held
  • Cdendrite
  • Cdendritic spine
  • Cintracellular protein-containing complex
  • Cneuronal cell body
  • Cplasma membrane
  • Cpostsynaptic membrane
  • Cpresynaptic active zone
  • Cpresynaptic membrane

326 aa · 37 kDa · 2 isoforms

Biological roles

Reactome v97

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

Excitatory neurotransmissionGOLipid & lipoprotein metabolismGOInhibitory neurotransmissionGOGrowth-factor signallingGOCell proliferation & survivalGOG protein-coupled signallingGO
View supporting evidence

Excitatory neurotransmission

  • ·excitatory postsynaptic potential
  • ·negative regulation of synaptic transmission, glutamatergic

Lipid & lipoprotein metabolism

  • ·fatty acid homeostasis
  • ·triglyceride homeostasis

Inhibitory neurotransmission

  • ·negative regulation of synaptic transmission, GABAergic

Growth-factor signalling

  • ·epidermal growth factor receptor signaling pathway

Cell proliferation & survival

  • ·negative regulation of cell population proliferation

G protein-coupled signalling

  • ·G protein-coupled adenosine receptor activity
  • ·G protein-coupled receptor binding
  • ·adenylate cyclase-inhibiting G protein-coupled receptor signaling pathway
  • ·G protein-coupled purinergic nucleotide receptor signaling pathway
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.

GNAI2GNB1GNAI1KNG1GNAI3ADORA3SLC29A1ADAGNG2ADORA2AADORA1

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

7 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

2

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.

defibrotide
ApprovedAgonist

Adenosine A1 receptor agonist

Direct interaction with this protein · 1 of 5 recorded protein targets

Adenosine
ApprovedAgonist

Adenosine receptor agonist

Indicated for Cardiovascular Diseases

Acts on a complex — shared with ADORA2B, ADORA3, 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 ADORA1

Gene-level evidence surfaced through the gene ADORA1 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.

Asthma
0.94Well supported

Genetic evidence dominant · Open Targets 0.72

Migraine Disorders
0.75Well supported

Clinical evidence dominant · Open Targets 0.61

Pulmonary Disease, Chronic Obstructive
0.74Moderately supported

Clinical evidence dominant · Open Targets 0.54

View evidence synthesis (3)
AsthmaWell supported
0.94
agreement 0.841.00
Genetic51%Clinical48%Literature2%

Open Targets aggregate 0.72 · 3 independent evidence families

Migraine DisordersWell supported
0.75
agreement 0.590.91
Clinical98%Literature2%

Open Targets aggregate 0.61 · 2 independent evidence families

Pulmonary Disease, Chronic ObstructiveModerately supported
0.74
agreement 0.630.85
Clinical64%Genetic35%Literature2%

Open Targets aggregate 0.54 · 3 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
Asthma0.72
Migraine Disorders0.61
Pulmonary Disease, Chronic Obstructive0.54

Drug development

22 compounds recorded · 7 approved · 15 in clinical development

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 2 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)
T-62Phase 2
ADENOSINEApproval
CAFFEINEApproval
GW493838Phase 2
CAPADENOSONPhase 2
ROLOFYLLINEPhase 3
AMP579Phase 2
PBF-680Phase 2
TONAPOFYLLINEPhase 3
DEFIBROTIDEApproval

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 (uniprot loc high conf and go cc high 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 (9)
SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · Druggable FamilyAB · UniProt loc high confAB · GO CC high confAB · UniProt SigP or TMHMMAB · Human Protein Atlas locPR · Small Molecule Binder

Raw Open Targets tractability assessment buckets, by modality.

Safety-related annotations

decreased blood pressureLynch et al. (2017)aspirin-intolerant asthmaClinPGxbronchoconstrictionUrban et al. (2012)heart failureLynch et al. (2017)induction of sleepUrban et al. (2012)natriuresisUrban et al. (2012)deathLynch et al. (2017)diuresisUrban et al. (2012)atrioventricular blockLynch et al. (2017)convulsionsLynch et al. (2017)increased urinary sodium excretionLynch et al. (2017)bradycardiaUrban 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

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 2 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. 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. Regulatory approval2013-10-18

    Approval: Defitelio (EMA)

    ema · regulatory · ema · via defibrotide

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.