Protein / target

Sodium-dependent serotonin transporter

SLC6A4P31645Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
53
Approved medicines
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Neurotransmitter transmembrane transporter activity

Primary system

Nervous system

Strongest disease association

obsessive-compulsive disorder

Genetic evidence · score 0.54

Therapeutic maturity

Clinically validated target

53 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

53 approved · 11 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

Serotonin transporter that cotransports serotonin with one Na(+) ion in exchange for one K(+) ion and possibly one proton in an overall electroneutral transport cycle. Transports serotonin across the plasma membrane from the extracellular compartment to the cytosol thus limiting serotonin intercellular signaling (PubMed:10407194, PubMed:12869649, PubMed:21730057, PubMed:27049939, PubMed:27756841, PubMed:34851672). Essential for serotonin homeostasis in the central nervous system. In the developing somatosensory cortex, acts in glutamatergic neurons to control serotonin uptake and its trophic functions accounting for proper spatial organization of cortical neurons and elaboration of sensory circuits. In the mature cortex, acts primarily in brainstem raphe neurons to mediate serotonin uptake from the synaptic cleft back into the pre-synaptic terminal thus terminating serotonin signaling at the synapse (By similarity). Modulates mucosal serotonin levels in the gastrointestinal tract through uptake and clearance of serotonin in enterocytes. Required for enteric neurogenesis and gastrointestinal reflexes (By similarity). Regulates blood serotonin levels by ensuring rapid high affinity uptake of serotonin from plasma to platelets, where it is further stored in dense granules via vesicular monoamine transporters and then released upon stimulation (PubMed:17506858, PubMed:18317590). Mechanistically, the transport cycle starts with an outward-open conformation having Na1(+) and Cl(-) sites occupied. The binding of a second extracellular Na2(+) ion and serotonin substrate leads to structural changes to outward-occluded to inward-occluded to inward-open, where the Na2(+) ion and serotonin are released into the cytosol. Binding of intracellular K(+) ion induces conformational transitions to inward-occluded to outward-open and completes the cycle by releasing K(+) possibly together with a proton bound to Asp-98 into the extracellular compartment. Na1(+) and Cl(-) ions remain bound throughout the transport cycle (PubMed:10407194, PubMed:12869649, PubMed:21730057, PubMed:27049939, PubMed:27756841, PubMed:34851672). Additionally, displays serotonin-induced channel-like conductance for monovalent cations, mainly Na(+) ions. The channel activity is uncoupled from the transport cycle and may contribute to the membrane resting potential or excitability (By similarity)

Subcellular location

Cell membraneEndomembrane systemEndosome membraneSynapseCell junction, focal adhesionCell projection, neuron projection
Domains and Gene Ontology detail (54)

Gene Ontology

  • Cendomembrane system
  • Cendosome membrane
  • Cfocal adhesion
  • CGolgi apparatus
  • Cmembrane raft
  • Cneuron projection
  • Cplasma membrane
  • Cpostsynaptic membrane
  • Cpresynaptic membrane
  • Cserotonergic synapse
  • Csynapse
  • Factin filament binding

630 aa · 70 kDa · 2 isoforms

Biological roles

Reactome v97

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

Synaptic signallingUniProt · GOHaemostasisUniProt · GOIon channel gatingGOExcitatory neurotransmissionUniProtCell adhesionUniProtTranscriptional regulationGO
View supporting evidence

Synaptic signalling

  • ·Serotonin transporter that cotransports serotonin with one Na(+) ion in exchange for one…
  • ·Synapse
  • ·postsynaptic membrane
  • ·presynaptic membrane

Haemostasis

  • ·Serotonin transporter that cotransports serotonin with one Na(+) ion in exchange for one…
  • ·platelet aggregation

Ion channel gating

  • ·monoatomic cation channel activity
  • ·sodium ion transmembrane transport

Excitatory neurotransmission

  • ·Serotonin transporter that cotransports serotonin with one Na(+) ion in exchange for one…

Cell adhesion

  • ·Cell junction, focal adhesion

Transcriptional regulation

  • ·positive regulation of gene expression
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.

DRD4HTR1AHTR2ATPH1COMTMAOAHTR1BSTX1ATPH2BDNFSLC6A4

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

1

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.

Duloxetine Hydrochloride
Narrow target profileApprovedInhibitor

Serotonin transporter inhibitor

Appears in clinical studies involving major depressive disorder, fibromyalgia, muscular disease, neuropathic pain

Direct interaction with this protein · 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.

obsessive-compulsive disorder0.54

Genetic · overall 0.68

Highest-confidence therapeutic associations

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

major depressive disorder1.00

Clinical · overall 0.64

depressive disorder0.99

Clinical · overall 0.63

fibromyalgia0.99

Clinical · overall 0.60

panic disorder0.99

Clinical · overall 0.60

anxiety disorder0.98

Clinical · overall 0.60

Highest overall evidence

Remaining associations by Open Targets' aggregated evidence score.

post-traumatic stress disorder0.59

Clinical

social phobia0.59

Clinical

attention deficit-hyperactivity disorder0.58

Clinical

bipolar disorder0.58

Clinical

Show all associations
obsessive-compulsive disorder0.68
major depressive disorder0.64
depressive disorder0.63
panic disorder0.60
fibromyalgia0.60
anxiety disorder0.60
post-traumatic stress disorder0.59
social phobia0.59
attention deficit-hyperactivity disorder0.58
bipolar disorder0.58

Open Targets ranks 1,176 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 · 67 total

VILAZODONEApproval

major depressive disorder · generalized anxiety disorder · depressive disorder

DESVENLAFAXINE FUMARATEApproval

major depressive disorder

METHAMPHETAMINEApproval

attention deficit-hyperactivity disorder · Pain · obsessive-compulsive disorder

NEFAZODONEApproval

major depressive disorder · cocaine abuse · cocaine use disorder

DESVENLAFAXINE SUCCINATEApproval

major depressive disorder · major depressive episode · fibromyalgia

FLUVOXAMINE MALEATEApproval

obsessive-compulsive disorder · anxiety disorder · panic disorder

ESCITALOPRAMApproval

major depressive disorder · schizophrenia · pulmonary hypertension

CITALOPRAMApproval

depressive disorder · major depressive disorder · Agitation

NEFAZODONE HYDROCHLORIDEApproval

major depressive disorder

VENLAFAXINE HYDROCHLORIDEApproval

major depressive disorder · melancholia · depressive disorder

Tractability

SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · Druggable FamilyAB · UniProt loc high confAB · GO CC high confAB · UniProt SigP or TMHMMPR · Small Molecule BinderOC · Advanced Clinical

Safety liabilities

nausea and vomitingDecrease, Population growth rateinsomniadecreased sleepgastrointestinal crampsdizzinessanxietyincreased gastrointestinal motilityinsomniasexual dysfunctiondecreased upper gastrointestinal transitdiarrhea

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.

COMPLETED · via Duloxetine Hydrochloride · NCT00058968

COMPLETED · via Duloxetine Hydrochloride · NCT00673452

Show remaining trials (24)

COMPLETED · via Duloxetine Hydrochloride · NCT01425827

COMPLETED · via Duloxetine Hydrochloride · NCT00067912

COMPLETED · via Duloxetine Hydrochloride · NCT00036309

COMPLETED · via Duloxetine Hydrochloride · NCT00479726

COMPLETED · via Duloxetine Hydrochloride · NCT05508516

COMPLETED · via Duloxetine Hydrochloride · NCT00071695

UNKNOWN · via Duloxetine Hydrochloride · NCT03110172

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.

obsessive-compulsive disorderWell supported
0.91
agreement 0.811.00
Clinical48%Genetic35%Animal model15%Literature1%

Open Targets aggregate 0.68 · 4 independent evidence families

major depressive disorderWell supported
0.79
agreement 0.630.94
Clinical84%Literature16%

Open Targets aggregate 0.64 · 2 independent evidence families

depressive disorderWell supported
0.78
agreement 0.630.94
Clinical84%Literature16%

Open Targets aggregate 0.63 · 2 independent evidence families

panic disorderModerately supported
0.75
agreement 0.590.90
Clinical97%Literature3%

Open Targets aggregate 0.60 · 2 independent evidence families

fibromyalgiaModerately supported
0.74
agreement 0.590.90
Clinical99%Literature1%

Open Targets aggregate 0.60 · 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

8

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

  1. Product recall2026-06-04

    Recall (Class II): DULOXETINE HYDROCHLORIDE

    fda · safety · fda · via Duloxetine Hydrochloride

  2. Product recall2026-06-04

    Recall (Class II): DULOXETINE HYDROCHLORIDE

    fda · safety · fda · via Duloxetine Hydrochloride

  3. Product recall2025-07-15

    Recall (Class II): DULOXETINE HYDROCHLORIDE

    fda · safety · fda · via Duloxetine Hydrochloride

  4. Product recall2024-12-06

    Recall (Class II): DULOXETINE HYDROCHLORIDE

    fda · safety · fda · via Duloxetine Hydrochloride

  5. New publication2014-04-14
    Prevention and management of chemotherapy-induced peripheral neuropathy in survivors of adult cancers: American Society of Clinical Oncology clinical practice guideline.

    Journal of clinical oncology : official journal of the American Society of Clinical Oncology · 2014 · 831 citations · Europe PMC · via Duloxetine Hydrochloride

  6. New publication2010-11-01
    Duloxetine versus placebo in the treatment of patients with diabetic neuropathic pain in China.

    Chinese medical journal · 2010 · 27 citations · Europe PMC · via Duloxetine Hydrochloride

  7. New publication2010-09-21
    Efficacy and safety of duloxetine 60 mg and 120 mg daily in patients hospitalized for severe depression: a double-blind randomized trial.

    The Journal of clinical psychiatry · 2011 · 11 citations · Europe PMC · via Duloxetine Hydrochloride

  8. Regulatory approval2004-08-11

    Approval: Yentreve (EMA)

    ema · regulatory · ema · via Duloxetine Hydrochloride

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.