SCN4A Protein is a protein that in normal physiology, nav1.4 channels are responsible for the rapid depolarization of skeletal muscle fibers during action potential generation[@jurkatrott2019]. the channel undergoes conformational changes in response to membrane depolarization, leading to sodium ion influx and muscle contraction. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
Structure and Domain Architecture
The SCN4A protein encodes the alpha subunit of the voltage-gated sodium channel Nav1.4, which is primarily expressed in skeletal muscle[@cannon2018]. The protein consists of four homologous domains (I-IV), each containing six transmembrane segments (S1-S6). The S4 segment serves as the voltage sensor, while the S5-S6 segments form the pore domain[@shen2019].
Key structural features include:
Four voltage-sensing domains (VSD): Each domain contains a positively charged S4 helix that moves in response to membrane depolarization
Pore domain: Forms the ion selectivity filter and gate
C-terminal domain: Contains binding sites for regulatory proteins and is involved in channel trafficking
Linker regions: The intracellular loops between domains contain phosphorylation sites and protein interaction motifs[@mantegazza2010]
Normal Function
In normal physiology, Nav1.4 channels are responsible for the rapid depolarization of skeletal muscle fibers during action potential generation[@jurkatrott2019]. The channel undergoes conformational changes in response to membrane depolarization, leading to sodium ion influx and muscle contraction.
SCN4A Protein (Nav1.4) is Sodium channel, voltage-gated, type IV. It plays roles in neuronal function and has been implicated in various neurological conditions.
See Also
[Neurodegeneration](/diseases/neurodegeneration)
[Ion Channels](/entities/ion-channels)
[Protein Kinases](/entities/protein-kinases)
External Links
[UniProt](https://www.uniprot.org/)
References
[Cannon SC, Sodium channelopathies of skeletal muscle (2018)](https://pubmed.ncbi.nlm.nih.gov/29500531/)
[Shen H, Liu D, Wu K, et al, Structures of human Nav1.4 channel in complex with auxiliary subunits (2019)](https://pubmed.ncbi.nlm.nih.gov/31391578/)
[Mantegazza M, Curia G, Biagini G, Ragsdale DS, Avoli M, Voltage-gated sodium channels as therapeutic targets in epilepsy and other neurological disorders (2010)](https://pubmed.ncbi.nlm.nih.gov/20298965/)
[Jurkat-Rott K, Lehmann-Horn F, Muscle channelopathies and related disorders (2019)](https://pubmed.ncbi.nlm.nih.gov/31753137/)
[Cannon SC, Pathophysiology of voltage-gated sodium channelopathies (2018)](https://pubmed.ncbi.nlm.nih.gov/29175071/)
[F奸 J, Fournier E, Sternberg D, Fontaine B, Sodium channelopathies and skeletal muscle: from channelopathies to muscle disorders (2019)](https://pubmed.ncbi.nlm.nih.gov/31778712/)
[Catterall WA, Voltage-gated sodium channels and electrical excitability (2018)](https://pubmed.ncbi.nlm.nih.gov/29440321/)
[Veeramah KR, O'Brien JE, Meisler MH, De novo pathogenic SCN8A mutation for severe infantile epilepsy and repetitive hypotonia (2012)](https://pubmed.ncbi.nlm.nih.gov/23071214/)
[Waxman SG, Sodium channels, the electrogenisome and the electrogenistat: insights from the molecular biology of sodium channelopathies (2022)](https://pubmed.ncbi.nlm.nih.gov/22952286/)