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Na+ channel protein type 4 subunit alpha; Na+ channel protein type IV subunit alpha; voltage-gated Na+ channel subunit alpha Nav1.4; Na+ channel protein skeletal muscle subunit alpha; SkM1 (SCN4A)

Function: - mediates voltage-dependent Na+ permeability of excitable membranes - assumes opened or closed conformation in response to voltage difference across membrane - forms a Na+-selective channel through which Na+ ions may pass in accordance with their electrochemical gradient - muscle Na+ channels contain an alpha subunit & a smaller beta subunit - interacts with the PDZ domain of the syntrophin SNTA1, SNTB1 & SNTB2 (putative) Structure: - contains 4 internal repeats, each with 5 hydrophobic segments (S1,S2,S3,S5,S6) & one positively charged segment (S4) - segment S4 is probably the voltage-sensor & is characterized by a series of positively charged amino acids at every 3rd position - belongs to the Na+ channel family - contains 1 IQ domain Compartment: membrane Expression: - may be present in both denervated & innervated skeletal muscle Pathology: - defects in SCN4A are the cause of a) paramyotonia congenita of von Eulenburg b) familial periodic paralysis hypokalemic (HOKPP), hyperkalemic (HYPP), normokalemic (NKPP) c) myotonia SCN4A-related (MYOSCN4A) d) congenital myasthenic syndrome due to mutation in SCNA4

Related

SCN4A gene mutation voltage-dependent Na+ channel

General

glycoprotein voltage-dependent Na+ channel protein alpha subunit

Properties

SIZE: entity length = 1836 aa MW = 208 kD COMPARTMENT: cellular membrane MOTIF: consensus repeat {128-450} MOTIF: transmembrane domain {129-150} transmembrane domain {159-178} transmembrane domain {191-210} N-glycosylation site {N214} transmembrane domain {217-236} transmembrane domain {253-266} N-glycosylation site {N288} N-glycosylation site {N291} N-glycosylation site {N297} N-glycosylation site {N303} N-glycosylation site {N315} N-glycosylation site {N321} N-glycosylation site {N333} N-glycosylation site {N362} transmembrane domain {424-449} N-glycosylation site {N507} consensus repeat {571-796} MOTIF: transmembrane domain {574-597} transmembrane domain {609-632} transmembrane domain {641-660} transmembrane domain {667-686} transmembrane domain {702-724} transmembrane domain {777-802} N-glycosylation site {N961} consensus repeat {1024-1281} MOTIF: transmembrane domain {1027-1049} transmembrane domain {1064-1089} transmembrane domain {1096-1116} transmembrane domain {1122-1143} transmembrane domain {1163-1184} N-glycosylation site {N1191} N-glycosylation site {N1205} transmembrane domain {1269-1295} consensus repeat {1349-1595} MOTIF: transmembrane domain {1349-1372} transmembrane domain {1384-1407} transmembrane domain {1414-1437} transmembrane domain {1447-1469} transmembrane domain {1485-1507} transmembrane domain {1574-1598} IQ motif {1727-1756}

Database Correlations

OMIM correlations MORBIDMAP 603967 UniProt P35499 PFAM correlations Entrez Gene 6329 Kegg hsa:6329

References

  1. UniProt :accession P35499
  2. GeneReviews https://www.genecards.org/cgi-bin/carddisp.pl?gene=SCN4A
  3. Wikipedia; Note: SCN4A entry http://en.wikipedia.org/wiki/SCN4A