Sodium Channel Protein 9 Alpha

From Anvita Health Wiki

Contents 1 Function 2 Structure 3 Compartment 4 Alternative-splicing 5 Expression 6 Pathology 7 More General Terms 8 Additional Terms 9 Internet Database 10 References

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
• tetrodotoxin-sensitive Na+ channel isoform
• plays a role in pain mechanisms, especially in the development of inflammatory pain ( putative)
• ubiquitinated by NEDD4L; which may promote its endocytosis
• does not seem to be ubiquitinated by NEDD4 ( putative)
• the Na+ channel consists of a large polypeptide & 2-3 smaller ones interacts with NEDD4 & NEDD4L ( putative)

Structure

• large polypeptide contains 4 internal repeats, each with 5 hydrophobic segments (S1,S2,S3,S5,S6) & 1 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
• in neurite terminals ( putative)

Alternative-splicing

• named isoforms=3

Expression

• expressed strongly in dorsal root ganglion, with only minor levels elsewhere in the body
• expressed in smooth muscle cells, MTC cell line & C-cell carcinoma
• isoform 1 is expressed preferentially in the central & peripheral nervous system while isoform 2 is expressed preferentially in the dorsal root ganglion

Pathology

• defects in SCN9A are the cause of

• primary erythromelalgia
• autosomal recessive congenital indifference to pain
• paroxysmal extreme pain disorder

More General Terms

• transmembrane 24 protein
• voltage-dependent Na+ channel protein alpha subunit
• glycoprotein
• phosphoprotein

Additional Terms

• voltage-dependent Na+ channel

Internet Database

Entrez gene: 6335
Kegg: [1]
OMIM: 133020
OMIM: 167400
OMIM: 243000
OMIM: 603415
Prosite: [2]
UniProt: [3]

References

1. UniProt [4]
2. GeneReviews [5]
3. Wikipedia; Note: SCN9A entry [6]
4. Protein Spotlight; Silent pain - Issue 102, February 2009 [7]

Na+ channel protein type 9 subunit alpha; Na+ channel protein type IX subunit alpha; voltage-gated Na+ channel subunit alpha Nav1.7; neuroendocrine Na+ channel; hNE-Na; peripheral Na+ channel 1 (SCN9A, NENA, PN1)