The SCN4B protein modulates channel gating kinetics. Causes negative shifts in the voltage dependence of activation of certain alpha sodium channels, but does not affect the voltage dependence of inactivation By similarity. The protein has been found to be expressed at a high level in dorsal root ganglia, at a lower level in brain, spinal cord, skeletal muscle and heart. Defects in SCN4B are the cause of long QT syndrome type 10 (LQT10) [MIM:611819]. Long QT syndromes are heart disorders characterized by a prolonged QT interval on the ECG and polymorphic ventricular arrhythmias. They cause syncope and sudden death in response to excercise or emotional stress. They can present with a sentinel event of sudden cardiac death in infancy.
Function:
Modulates channel gating kinetics. Causes negative shifts in the voltage dependence of activation of certain alpha sodium channels, but does not affect the voltage dependence of inactivation.
Subunit:
The voltage-sensitive sodium channel consists of an ion conducting pore forming alpha-subunit regulated by one or more beta-1, beta-2, beta-3 and/or beta-4 subunits. Beta-1 and beta-3 are non-covalently associated with alpha, while beta-2 and beta-4 are covalently linked by disulfide bonds. Associates with SCN2A.
Subcellular Location:
Membrane; Single-pass type I membrane protein.
Tissue Specificity:
Expressed at a high level in dorsal root ganglia, at a lower level in brain, spinal cord, skeletal muscle and heart.
Post-translational modifications:
Contains a number of interchain disulfide bonds with SCN2A.
DISEASE:
Defects in SCN4B are the cause of long QT syndrome type 10 (LQT10) [MIM:611819]. Long QT syndromes are heart disorders characterized by a prolonged QT interval on the ECG and polymorphic ventricular arrhythmias. They cause syncope and sudden death in response to excercise or emotional stress. They can present with a sentinel event of sudden cardiac death in infancy.
Similarity:
Belongs to the sodium channel auxiliary subunit SCN4B (TC 8.A.17) family.
Contains 1 Ig-like C2-type (immunoglobulin-like) domain.
SWISS:
Q8IWT1
Gene ID:
6330
Database links:
Entrez Gene: 6330 Human
SwissProt: Q8IWT1 Human
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