Protein / target

Melatonin receptor type 1A

MTNR1AP48039Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
4
Approved medicines
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

G protein-coupled receptor activity

Strongest disease association

insomnia

Clinical evidence · score 0.60

Therapeutic maturity

Clinically validated target

4 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

4 approved · 1 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

High affinity receptor for melatonin. Likely to mediate the reproductive and circadian actions of melatonin. The activity of this receptor is mediated by pertussis toxin sensitive G proteins that inhibit adenylate cyclase activity. Possibly involved in sleep induction, by melatonin activation of the potassium channel KCNMA1/BK and the dissociation of G-beta and G-gamma subunits, thereby decreasing synaptic transmission (By similarity)

Subcellular location

Cell membrane
Domains and Gene Ontology detail (9)

Gene Ontology

  • Cplasma membrane
  • Creceptor complex
  • FG protein-coupled receptor activity
  • Fhormone binding
  • Fmelatonin receptor activity
  • Padenylate cyclase-inhibiting G protein-coupled receptor signaling pathway
  • Pcircadian rhythm
  • PG protein-coupled receptor signaling pathway, coupled to cyclic nucleotide second messenger
  • Pmating behavior

350 aa · 39 kDa

Biological roles

Reactome v97

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

G protein-coupled signallingGOSynaptic signallingUniProt
View supporting evidence

G protein-coupled signalling

  • ·G protein-coupled receptor activity
  • ·adenylate cyclase-inhibiting G protein-coupled receptor signaling pathway
  • ·G protein-coupled receptor signaling pathway, coupled to cyclic nucleotide second messen…

Synaptic signalling

  • ·High affinity receptor for melatonin. Likely to mediate the reproductive and circadian a…
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.

GNB1GNAI1GPR50MTNR1BGNG2FAT1GNAI2GNAI3FAT3GNB4MTNR1A

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

2

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.

Melatonin
ApprovedAgonist

Melatonin receptor agonist

Appears in clinical studies involving insomnia, autism, Sleep disturbance, insomnia

Acts on a complex — shared with MTNR1B · 1 of 2 recorded protein targets — narrow recorded profile

agomelatine
ApprovedAgonist

Melatonin receptor agonist

Appears in clinical studies involving major depressive disorder, treatment resistant depression, obsessive-compulsive disorder, depressive disorder

Acts on a complex — shared with MTNR1B · 1 of 3 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.

Highest-confidence therapeutic associations

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

insomnia0.98

Clinical · overall 0.60

major depressive disorder0.95

Clinical · overall 0.58

sleep-wake disorder0.79

Clinical · overall 0.48

Sleep disturbance0.66

Clinical · overall 0.40

circadian rhythm sleep disorder0.64

Clinical · overall 0.39

Highest overall evidence

Remaining associations by Open Targets' aggregated evidence score.

autism0.39

Clinical

sleep disorder0.39

Clinical

Chromosomal anomaly0.37

Clinical

Anxiety0.37

Clinical

neurodegenerative disease0.36

Pathway

Show all associations
insomnia0.60
major depressive disorder0.58
sleep-wake disorder0.48
Sleep disturbance0.40
circadian rhythm sleep disorder0.39
autism0.39
sleep disorder0.39
Chromosomal anomaly0.37
Anxiety0.37
neurodegenerative disease0.36

Open Targets ranks 609 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 · 5 total

MELATONINApproval

insomnia · autism · Sleep disturbance

AGOMELATINEApproval

major depressive disorder · treatment resistant depression · obsessive-compulsive disorder

PIROMELATINEPhase 2 3

Alzheimer disease · dementia · Alzheimer disease

TASIMELTEONApproval

Chromosomal anomaly · sleep-wake disorder · insomnia

RAMELTEONApproval

insomnia · bipolar I disorder · depressive disorder

Tractability

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

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)

RECRUITING · via Melatonin · NCT06226025

UNKNOWN · via Melatonin · NCT05857046

ACTIVE_NOT_RECRUITING · via Melatonin · NCT00262470

UNKNOWN · via Melatonin · NCT03013790

ClinicalTrials.gov via the drug-target graph.

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.

insomniaModerately supported
0.74
agreement 0.590.90
Clinical97%Literature3%

Open Targets aggregate 0.60 · 2 independent evidence families

major depressive disorderModerately supported
0.72
agreement 0.560.87
Clinical97%Literature3%

Open Targets aggregate 0.58 · 2 independent evidence families

sleep-wake disorderModerately supported
0.59
agreement 0.430.76
Clinical100%

Open Targets aggregate 0.48 · 1 independent evidence family

Sleep disturbanceLimited support
0.49
agreement 0.330.66
Clinical100%

Open Targets aggregate 0.40 · 1 independent evidence family

sleep disorderLimited support
0.48
agreement 0.330.64
Clinical97%Literature3%

Open Targets aggregate 0.39 · 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 underlying per-type scores are shown above so the calculation can be checked.

What's happening now

23

Recent activity around this target, drawn from one canonical event stream. Every item is reached through 2 drugs that target this protein, so each event is news about that drug rather than about the protein directly.

  1. Trial status changed2026-07-14

    The Effect of Preoperative Oral Melatonin on Postoperative Pain Control After Cesarean Section: A Dose Comparison Study

    Status changed to Completed · ClinicalTrials.gov · via Melatonin

  2. New publication2025-12-22
    STAT3 Signaling Mediates Agomelatine Restoration of Prefrontal Cortex Synaptic Plasticity in Chronic Social Defeat Stress Mice.

    Molecular neurobiology · 2025 · 1 citation · Europe PMC · via agomelatine

  3. New publication2025-04-23
    Molecular Links Between Circadian Rhythm Disruption, Melatonin, and Neurodegenerative Diseases: An Updated Review.

    Molecules (Basel, Switzerland) · 2025 · 12 citations · Europe PMC · via Melatonin

  4. New publication2024-09-03
    Dysfunctional mitochondria in age-related neurodegeneration: Utility of melatonin as an antioxidant treatment.

    Ageing research reviews · 2024 · 37 citations · Europe PMC · via Melatonin

  5. New publication2024-09-01
    Melatonin Regulates Neuronal Synaptic Plasticity in the Supramammillary Nucleus and Attenuates Methamphetamine-Induced Conditioned Place Preference and Sensitization in Mice.

    Journal of pineal research · 2024 · 7 citations · Europe PMC · via Melatonin

  6. New publication2024-08-02
    Transcriptomic Plasticity of the Circadian Clock in Response to Photoperiod: A Study in Male Melatonin-Competent Mice.

    Journal of biological rhythms · 2024 · 9 citations · Europe PMC · via Melatonin

  7. New publication2024-07-13
    The Role of Gut Microbiome in Sleep Quality and Health: Dietary Strategies for Microbiota Support.

    Nutrients · 2024 · 31 citations · Europe PMC · via Melatonin

  8. New publication2024-06-28
    Presence of melatonin in foods of daily consumption: The benefit of this hormone for health.

    Food chemistry · 2024 · 7 citations · Europe PMC · via Melatonin

  9. New publication2024-04-19
    Melatonin: a ferroptosis inhibitor with potential therapeutic efficacy for the post-COVID-19 trajectory of accelerated brain aging and neurodegeneration.

    Molecular neurodegeneration · 2024 · 15 citations · Europe PMC · via Melatonin

  10. New publication2023-12-01
    The European Insomnia Guideline: An update on the diagnosis and treatment of insomnia 2023.

    Journal of sleep research · 2023 · 489 citations · Europe PMC · via Melatonin

  11. New publication2023-08-17
    The role of Neurochemicals, Stress Hormones and Immune System in the Positive Feedback Loops between Diabetes, Obesity and Depression.

    Frontiers in endocrinology · 2023 · 12 citations · Europe PMC · via Melatonin

  12. Regulatory approval2022-11-07

    Approval: Melatonin Neurim (EMA)

    ema · regulatory · ema · via Melatonin

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.