Referenced in: none

Automatically associated channels: Nav1.4 , Slo1

Title: Sodium channel heterologous expression in mammalian cells and the role of the endogenous beta1-subunits.

Authors: Oscar Moran, Franco Conti, Paolo Tammaro

Journal, date & volume: Neurosci. Lett., 2003 Jan 23 , 336, 175-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/12505621

Abstract
Sodium currents in cell lines transfected with the sole alpha-subunit, or constitutively expressing sodium channels, have an inactivation that is always prevalently mono-exponential. Differently, expression of alpha-subunit in Xenopus oocytes exerts slow inactivating currents with biphasic decay, while simultaneous co-transfection of alpha and beta1 restores a mono-exponential (normal) inactivation. A hypothesis for such differences is that an endogenous presence of beta1 or beta1-alternative splicing, beta1A, in cells could account for the normal inactivation. To test this hypothesis and to evaluate the role for the beta1A, we inhibited the expression of beta1/beta1A by antisense oligonucleotides on Nav1.4-transfected human embryonic cell line 293 (HEK) cells. Reduction of beta1/beta1A produces no significant functional effects in Nav1.4-HEK. This result invalidates the hypothesis that the lack of slow-mode in cell lines is simply due to a constitutive expression of beta1/beta1A.