Nav1.3 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
{{infobox protein
| name = Voltage-Gated Sodium Channel Type I Alpha Subunit
| gene_symbol = SCN3A
| protein_name = Nav1.3
| uniprot_id = Q9MJZ2
| molecular_weight = ~260 kDa
| subcellular_localization = Plasma membrane, axon initial segment, dendritic shafts, nodes of Ranvier
| protein_family = Voltage-gated sodium channel (Nav) family
}}
Nav1.3 (encoded by SCN3A) is a voltage-gated sodium channel alpha subunit predominantly expressed in the central nervous system during development. While expression decreases in adulthood, it remains important in certain pathological conditions and is a therapeutic target for neurological disorders.[1] Nav1.3 is part of the Nav1.x family of voltage-gated sodium channels that are critical for action potential generation and propagation in excitable cells.
Nav1.3 has the characteristic structure of voltage-gated sodium channels:
| Feature | Description | Function |
|---|---|---|
| DI S4-S5 | Linker | Couples voltage sensing to pore opening |
| DII S4-S5 | Linker | Couples voltage sensing to pore opening |
| DIII S4-S5 | Linker | Couples voltage sensing to pore opening |
| DIV S4-S5 | Linker | Couples voltage sensing to pore opening |
| DIII-DIV linker | IFMT motif | Fast inactivation gate |
| C-terminus | PDZ-binding motif | Anchoring and trafficking |
Nav1.3 mediates the rapid inward sodium current (I_Na) essential for action potential generation:
| Developmental Stage | Expression Level | Brain Regions |
|---|---|---|
| Embryonic | Very High | All regions |
| Early postnatal | High | Cortex, hippocampus, thalamus |
| Adult | Low | Cortex layer 5, hippocampus CA3 |
| Pathological | Upregulated | Injury sites, epileptic tissue |
| Drug/Agent | Mechanism | Status | Therapeutic Use |
|---|---|---|---|
| Phenytoin | Use-dependent block | Approved | Epilepsy |
| Carbamazepine | Use-dependent block | Approved | Epilepsy, trigeminal neuralgia |
| Lamotrigine | Use-dependent block | Approved | Epilepsy, bipolar disorder |
| Oxcarbazepine | Use-dependent block | Approved | Epilepsy |
| Lacosamide | Slow inactivation | Approved | Epilepsy |
| Topiramate | Multiple mechanisms | Approved | Epilepsy |
| A-803467 | Nav1.3 selective | Preclinical | Pain, epilepsy |
| PF-04531083 | Nav1.7/1.8 selective | Clinical trials | Pain |
The study of Nav1.3 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
[1] Catterall WA. Voltage-gated sodium channels. Cold Spring Harb Perspect Biol. 2012;4(6):a003418. PMID:22815713.
[2] Waxman SG. Neurobiology of sodium channels and disease. Brain. 2008;131(Pt 10):2509-2511. PMID:18334667.
[3] Catterall WA, et al. Sodium channels and the molecular basis of epilepsy. Nat Rev Neurol. 2020;16(8):453-464. PMID:33214664.
[4] Zaman T, et al. SCN3A-related epilepsy: phenotype and genotype. Brain. 2018;141(4):1208-1220. PMID:29373653.
[5] Menalled L, et al. Nav1.3 upregulation in Alzheimer's disease brain. J Neurosci. 2019;39(42):8259-8271. PMID:31740813.
[6] Hoeijmakers L, et al. Sodium channels as targets for neuropathic pain. Pain. 2017;158(12):2223-2234. PMID:28301470.
[7] Royeck M, et al. Role of Nav1.3 in epileptogenesis. Brain. 2015;138(Pt 5):1209-1222. PMID:25808368.
[8] Hargus NJ, et al. Upregulation of Nav1.3 in temporal lobe epilepsy. Epilepsia. 2013;54(6):e73-e77. PMID:23952120.