Sodium Channel Voltage Gated Type III Beta (SCN3b)

The deduced 215-amino acid SCN3B protein has an N-terminal signal sequence, an extracellular N-terminal domain, a single membrane-spanning region, and a C-terminal cytoplasmic region. The extracellular domain shows homology to proteins that adopt a V-type Ig fold, which is comprised of 10 beta strands that form 2 antiparallel sheets. Northern blot analysis of rat tissues detected a 4.0-kb transcript in brain, and RT-PCR detected expression also in rat adrenal gland and kidney. In situ hybridization of rat brain detected highest expression of Scn3b in forebrain structures and in the hippocampus. In most areas, expression of Scn3b complemented the expression of Scn1b. The exception was hippocampus, where both subunits were expressed at high levels.