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MGP002759

UniProt Annotations

Entry Information
Gene Namesodium channel, voltage gated, type IV alpha subunit
Protein EntrySCN4A_HUMAN
UniProt IDP35499
SpeciesHuman
Comments
Comment typeDescription
DiseaseMyasthenic syndrome, congenital, acetazolamide-responsive (CMSAR) [MIM:614198]: A congenital myasthenic syndrome associated with fatigable generalized weakness and recurrent attacks of respiratory and bulbar paralysis since birth. The fatigable weakness involves lid-elevator, external ocular, facial, limb and truncal muscles and an decremental response of the compound muscle action potential on repetitive stimulation. {ECO:0000269|PubMed:12766226}. Note=The disease is caused by mutations affecting the gene represented in this entry.
DiseaseMyotonia SCN4A-related (MYOSCN4A) [MIM:608390]: A phenotypically highly variable myotonia aggravated by potassium loading, and sometimes by cold. Myotonia is characterized by sustained muscle tensing that prevents muscles from relaxing normally. It causes muscle stiffness that can interfere with movement. In some people the stiffness is very mild, while in other cases it may be severe enough to interfere with walking, running, and other activities of daily life. Myotonia SCN4A- related includes myotonia permanens and myotonia fluctuans. In myotonia permanens, the myotonia is generalized and there is a hypertrophy of the muscle, particularly in the neck and the shoulder. Attacks of severe muscle stiffness of the thoracic muscles may be life threatening due to impaired ventilation. In myotonia fluctuans, the muscle stiffness may fluctuate from day to day, provoked by exercise. {ECO:0000269|PubMed:10218481, ECO:0000269|PubMed:16786525, ECO:0000269|PubMed:16832098, ECO:0000269|PubMed:17212350, ECO:0000269|PubMed:17998485, ECO:0000269|PubMed:18203179, ECO:0000269|PubMed:18337100, ECO:0000269|PubMed:19015483, ECO:0000269|PubMed:20076800, ECO:0000269|PubMed:8058156, ECO:0000269|PubMed:9392583}. Note=The disease is caused by mutations affecting the gene represented in this entry.
DiseaseParamyotonia congenita of von Eulenburg (PMC) [MIM:168300]: An autosomal dominant channelopathy characterized by myotonia, increased by exposure to cold, intermittent flaccid paresis, not necessarily dependent on cold or myotonia, lability of serum potassium, non-progressive nature and lack of atrophy or hypertrophy of muscles. In some patients, myotonia is not increased by cold exposure (paramyotonia without cold paralysis). Patients may have a combination phenotype of PMC and HYPP. {ECO:0000269|PubMed:10369308, ECO:0000269|PubMed:10727489, ECO:0000269|PubMed:1310898, ECO:0000269|PubMed:1316765, ECO:0000269|PubMed:1338909, ECO:0000269|PubMed:15790667, ECO:0000269|PubMed:16786525, ECO:0000269|PubMed:18166706, ECO:0000269|PubMed:19077043, ECO:0000269|PubMed:20076800, ECO:0000269|PubMed:8242056, ECO:0000269|PubMed:8308722, ECO:0000269|PubMed:8388676, ECO:0000269|PubMed:8580427}. Note=The disease is caused by mutations affecting the gene represented in this entry.
DiseasePeriodic paralysis hyperkalemic (HYPP) [MIM:170500]: An autosomal dominant channelopathy characterized by episodic flaccid generalized muscle weakness associated with high levels of serum potassium. Concurrence of myotonia is found in HYPP patients. {ECO:0000269|PubMed:1659668, ECO:0000269|PubMed:1659948, ECO:0000269|PubMed:20076800, ECO:0000269|PubMed:7695243}. Note=The disease is caused by mutations affecting the gene represented in this entry.
DiseasePeriodic paralysis hypokalemic 2 (HOKPP2) [MIM:613345]: An autosomal dominant disorder manifested by episodic flaccid generalized muscle weakness associated with falls of serum potassium levels. {ECO:0000269|PubMed:10599760, ECO:0000269|PubMed:10851391, ECO:0000269|PubMed:10944223, ECO:0000269|PubMed:11558801, ECO:0000269|PubMed:11591859, ECO:0000269|PubMed:18162704, ECO:0000269|PubMed:19118277, ECO:0000269|PubMed:20522878, ECO:0000269|PubMed:21043388}. Note=The disease is caused by mutations affecting the gene represented in this entry.
DiseasePeriodic paralysis normokalemic (NKPP) [MIM:170500]: A disorder closely related to hyperkalemic periodic paralysis, but marked by a lack of alterations in potassium levels during attacks of muscle weakness. {ECO:0000269|PubMed:15596759, ECO:0000269|PubMed:18046642, ECO:0000269|PubMed:20522878}. Note=The disease is caused by mutations affecting the gene represented in this entry.
DomainThe sequence contains 4 internal repeats, each with 5 hydrophobic segments (S1,S2,S3,S5,S6) and one positively charged segment (S4). Segments S4 are probably the voltage-sensors and are characterized by a series of positively charged amino acids at every third position.
FunctionThis protein mediates the voltage-dependent sodium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a sodium-selective channel through which Na(+) ions may pass in accordance with their electrochemical gradient. This sodium channel may be present in both denervated and innervated skeletal muscle.
PtmPhosphorylation at Ser-1328 by PKC in a highly conserved cytoplasmic loop slows inactivation of the sodium channel and reduces peak sodium currents. {ECO:0000250}.
SimilarityBelongs to the sodium channel (TC 1.A.1.10) family. Nav1.4/SCN4A subfamily. {ECO:0000305}.
SimilarityContains 1 IQ domain. {ECO:0000255|PROSITE- ProRule:PRU00116}.
Subcellular LocationMembrane; Multi-pass membrane protein.
SubunitMuscle sodium channels contain an alpha subunit and a smaller beta subunit. Interacts with the PDZ domain of the syntrophin SNTA1, SNTB1 and SNTB2 (By similarity). {ECO:0000250}.
Web ResourceName=Wikipedia; Note=SCN4A entry; URL="http://en.wikipedia.org/wiki/SCN4A";
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