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Protein / target

Sodium channel protein type 4 subunit alpha

Encoded bySCN4AP35499Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
63
Approved medicines
Open Targets target-level
View by indication →
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Voltage-gated sodium channel

Strongest disease association

Potassium-aggravated myotonia

Via encoding gene SCN4A · Genetic evidence · score 0.96

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

Pore-forming subunit of Nav1.4, a voltage-gated sodium (Nav) channel that directly mediates the depolarizing phase of action potentials in excitable membranes.

View complete UniProt function annotation

Pore-forming subunit of Nav1.4, a voltage-gated sodium (Nav) channel that directly mediates the depolarizing phase of action potentials in excitable membranes. Navs, also called VGSCs (voltage-gated sodium channels) or VDSCs (voltage-dependent sodium channels), operate by switching between closed and open conformations depending on the voltage difference across the membrane. In the open conformation they allow Na(+) ions to selectively pass through the pore, along their electrochemical gradient. The influx of Na+ ions provokes membrane depolarization, initiating the propagation of electrical signals throughout cells and tissues (PubMed:12766226, PubMed:15318338, PubMed:16890191, PubMed:17898326, PubMed:18690054, PubMed:19347921, PubMed:25707578, PubMed:26659129, PubMed:26700687, PubMed:29992740, PubMed:30190309). Highly expressed in skeletal muscles, Nav1.4 generates the action potential crucial for muscle contraction (PubMed:16890191, PubMed:19347921, PubMed:25707578, PubMed:26659129, PubMed:26700687)

Subcellular location

Cell membrane
Domains and Gene Ontology detail (9)

Domains & features

IQ

Gene Ontology

  • Cplasma membrane
  • Cvoltage-gated sodium channel complex
  • Fvoltage-gated sodium channel activity
  • Pcardiac muscle cell action potential involved in contraction
  • Pmuscle contraction
  • Pregulation of skeletal muscle contraction by action potential
  • Psodium ion transmembrane transport
  • Psodium ion transport

1836 aa · 208 kDa

Biological roles

Reactome v97

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

Ion channel gatingGOMuscle contractionUniProt · GO
View supporting evidence

Ion channel gating

  • ·sodium ion transmembrane transport

Muscle contraction

  • ·Pore-forming subunit of Nav1.4, a voltage-gated sodium (Nav) channel that directly media…
  • ·muscle contraction
  • ·regulation of skeletal muscle contraction by action potential
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.

SCN1BCALM3SCN4BCLCN1SCN3BSCN2ACALM2SCN2BSCNN1BSCNN1ASCN4A

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

12 medicines · 19 areas

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.

Epilepsies, Partial3 medicines
Pain2 medicines
Acute Pain1 medicine
Amyotrophic Lateral Sclerosis1 medicine
Angina Pectoris1 medicine
Arrhythmias, Cardiac1 medicine
Arthritis1 medicine
Back Pain1 medicine
Bipolar Disorder1 medicine
Depressive Disorder1 medicine
Inflammation1 medicine
Migraine Disorders1 medicine
Neuralgia1 medicine
Neuralgia, Postherpetic1 medicine
Osteoarthritis1 medicine
Pruritus1 medicine
Broader indication categories (1)
Cardiovascular Diseases1 medicine

Broad umbrella indications (e.g. “Neoplasms”). Shown here because every medicine also appears under a more specific disease above — kept for completeness, de-emphasised for clarity.

63 medicines meet Open Targets' target-level approved-medicine definition; the 12 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

12

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.

Bupivacaine
Narrow target profileApprovedBlocker

Sodium channel protein type IV alpha subunit blocker

Indicated for Acute Pain, Pain

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

ranolazine
Narrow target profileApprovedBlocker

Sodium channel protein type IV alpha subunit blocker

Indicated for Angina Pectoris, Cardiovascular Diseases

Direct interaction with this protein · 1 of 2 recorded protein targets — narrow recorded profile

Riluzole
ApprovedBlocker

Sodium channel alpha subunit blocker

Indicated for Amyotrophic Lateral Sclerosis

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 10 recorded protein targets — broad pharmacology

lamotrigine
ApprovedBlocker

Sodium channel alpha subunit blocker

Indicated for Bipolar Disorder, Depressive Disorder, Epilepsies, Partial, Epilepsy

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 10 recorded protein targets — broad pharmacology

lidocaine
ApprovedBlocker

Sodium channel alpha subunit blocker

Indicated for Arrhythmias, Cardiac, Arthritis, Back Pain, Inflammation

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 10 recorded protein targets — broad pharmacology

lacosamide
ApprovedBlocker

Sodium channel alpha subunit blocker

Indicated for Epilepsies, Partial, Epilepsy, Seizures

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 10 recorded protein targets — broad pharmacology

View all 12 targeting drugs
phenytoin
ApprovedBlocker

Sodium channel alpha subunit blocker

Indicated for Epilepsy, Seizures

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 10 recorded protein targets — broad pharmacology

topiramate
ApprovedBlocker

Sodium channel alpha subunit blocker

Indicated for Epilepsy, Migraine Disorders, Seizures

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 37 recorded protein targets — broad pharmacology

cenobamate
ApprovedInhibitor

Sodium channel alpha subunit inhibitor

Indicated for Epilepsy, Seizures

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 26 recorded protein targets — broad pharmacology

Sodium channel alpha subunit blocker

Indicated for Epilepsy, Seizures

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 10 recorded protein targets — broad pharmacology

rufinamide
ApprovedBlocker

Sodium channel alpha subunit blocker

Indicated for Epilepsy, Seizures

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 10 recorded protein targets — broad pharmacology

zonisamide
ApprovedBlocker

Sodium channel alpha subunit blocker

Indicated for Epilepsies, Partial, Epilepsy, Seizures

Acts on a complex — shared with SCN5A, SCN7A, SCN2A +6 more · 1 of 10 recorded protein targets — broad pharmacology

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 SCN4A

Gene-level evidence surfaced through the gene SCN4Athat 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.

paramyotonia congenita of Von Eulenburg
0.97Well supported

Genetic evidence dominant · Open Targets 0.84

Potassium-aggravated myotonia
0.97Well supported

Genetic evidence dominant · Open Targets 0.81

Hypokalemic periodic paralysis, type 2
0.95Well supported

Genetic evidence dominant · Open Targets 0.74

Hyperkalemic periodic paralysis
0.94Well supported

Genetic evidence dominant · Open Targets 0.83

Congenital myasthenic syndrome 16
0.93Well supported

Genetic evidence dominant · Open Targets 0.69

View evidence synthesis (5)
paramyotonia congenita of Von EulenburgWell supported
0.97
agreement 0.871.00
Genetic59%Clinical21%Animal model18%Literature2%Genetic literaturedup

Open Targets aggregate 0.84 · 4 independent evidence families · 1 not counted as duplicate

Potassium-aggravated myotoniaWell supported
0.97
agreement 0.851.00
Genetic78%Animal model21%Literature1%Genetic literaturedup

Open Targets aggregate 0.81 · 3 independent evidence families · 1 not counted as duplicate

Hypokalemic periodic paralysis, type 2Well supported
0.95
agreement 0.831.00
Genetic79%Animal model20%Literature1%Genetic literaturedup

Open Targets aggregate 0.74 · 3 independent evidence families · 1 not counted as duplicate

Hyperkalemic periodic paralysisWell supported
0.94
agreement 0.821.00
Genetic77%Animal model20%Literature3%Genetic literaturedup

Open Targets aggregate 0.83 · 3 independent evidence families · 1 not counted as duplicate

Congenital myasthenic syndrome 16Well supported
0.93
agreement 0.811.00
Genetic81%Animal model19%Literature0%Genetic literaturedup

Open Targets aggregate 0.69 · 3 independent evidence families · 1 not counted as duplicate

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
paramyotonia congenita of Von Eulenburg0.84
Hyperkalemic periodic paralysis0.83
Potassium-aggravated myotonia0.81
Hypokalemic periodic paralysis, type 20.74
congenital myopathy 22B, severe fetal0.74
Congenital myasthenic syndromes0.70
Hypokalemic periodic paralysis0.70
Congenital myasthenic syndrome 160.69

Drug development

77 compounds recorded · 63 approved · 10 in clinical development · 4 earlier-stage

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 12 drugs that target this protein in Forefront's canonical graph (12 with a mapped approved indication, shown above): these count different sets and are not a subset relation.

View all recorded compounds (10)
RILUZOLEApproval
TOCAINIDEApproval
PHENYTOINApproval
MEXILETINEApproval
HEXYLCAINEApproval
BENOXINATE HYDROCHLORIDEPhase 3
LIDOCAINEApproval
ZONISAMIDEApproval
INDECAINIDEApproval
LEVOBUPIVACAINE HYDROCHLORIDEPhase 3

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 (8)
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 Binder

Raw Open Targets tractability assessment buckets, by modality.

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 Bupivacaine · NCT05605639

NOT_YET_RECRUITING · via Bupivacaine · NCT06293404

COMPLETED · via lidocaine · NCT05670236

UNKNOWN · via topiramate · NCT06089356

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 6 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. Regulatory approval2026-08-05

    Approval: RANOLAZINE (ANDA214551)

    fda · regulatory · fda · via ranolazine

  2. Regulatory approval2026-08-05

    Approval: ESLICARBAZEPINE ACETATE (ANDA216481)

    fda · regulatory · fda · via eslicarbazepine acetate

  3. Regulatory approval2026-07-22

    Approval: TOPIRAMATE (ANDA220943)

    fda · regulatory · fda · via topiramate

  4. Product recall2026-07-06

    Recall (Class III): TOPIRAMATE

    fda · safety · fda · via topiramate

  5. Regulatory approval2026-06-15

    Approval: LACOSAMIDE (ANDA217596)

    fda · regulatory · fda · via lacosamide

  6. Product recall2026-06-04

    Recall (Class II): LACOSAMIDE

    fda · safety · fda · via lacosamide

  7. Product recall2025-03-13

    Recall (Class II): RANOLAZINE

    fda · safety · fda · via ranolazine

  8. Safety communication2024-06-20

    Drug Safety Update: Topiramate (Topamax): introduction of new safety measures, including a Pregnancy Prevention Programme

    mhra · safety · mhra · via topiramate

  9. New publication2024-04-28
    Latest Advances in Regional Anaesthesia.

    Medicina (Kaunas, Lithuania) · 2024 · 10 citations · Europe PMC · via Bupivacaine

  10. New publication2023-01-18
    Safety and tolerability of short-term infusions of intravenous lacosamide in pediatric patients with epilepsy: An open-label, phase 2/3 trial.

    Epilepsia open · 2023 · 3 citations · Europe PMC · via lacosamide

  11. New publication2021-12-01
    Riluzole, a glutamate modulator, slows cerebral glucose metabolism decline in patients with Alzheimer's disease.

    Brain : a journal of neurology · 2021 · 71 citations · Europe PMC · via Riluzole

  12. New publication2021-06-29
    Safety and efficacy of adjunctive lacosamide in Chinese and Japanese adults with epilepsy and focal seizures: A long-term, open-label extension of a randomized, controlled trial.

    Epilepsy research · 2021 · 14 citations · Europe PMC · via lacosamide

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.