Logo image
Cross-kingdom auxiliary subunit modulation of a voltage-gated sodium channel
Journal article   Open access   Peer reviewed

Cross-kingdom auxiliary subunit modulation of a voltage-gated sodium channel

Steven Molinarolo, Sora Lee, Lilia Leisle, John D Lueck, Daniele Granata, Vincenzo Carnevale and Christopher A Ahern
The Journal of biological chemistry, Vol.293(14), pp.4981-4992
04/06/2018
DOI: 10.1074/jbc.RA117.000852
PMCID: PMC5892571
PMID: 29371400
url
https://doi.org/10.1074/jbc.RA117.000852View
Published (Version of record) Open Access

Abstract

Voltage-gated, sodium ion–selective channels (NaV) generate electrical signals contributing to the upstroke of the action potential in animals. NaVs are also found in bacteria and are members of a larger family of tetrameric voltage-gated channels that includes CaVs, KVs, and NaVs. Prokaryotic NaVs likely emerged from a homotetrameric Ca2+-selective voltage-gated progenerator, and later developed Na+ selectivity independently. The NaV signaling complex in eukaryotes contains auxiliary proteins, termed beta (β) subunits, which are potent modulators of the expression profiles and voltage-gated properties of the NaV pore, but it is unknown whether they can functionally interact with prokaryotic NaV channels. Herein, we report that the eukaryotic NaVβ1-subunit isoform interacts with and enhances the surface expression as well as the voltage-dependent gating properties of the bacterial NaV, NaChBac in Xenopus oocytes. A phylogenetic analysis of the β-subunit gene family proteins confirms that these proteins appeared roughly 420 million years ago and that they have no clear homologues in bacterial phyla. However, a comparison between eukaryotic and bacterial NaV structures highlighted the presence of a conserved fold, which could support interactions with the β-subunit. Our electrophysiological, biochemical, structural, and bioinformatics results suggests that the prerequisites for β-subunit regulation are an evolutionarily stable and intrinsic property of some voltage-gated channels.
membrane biophysics bacterial ion channels sodium channel protein evolution electrophysiology bioinformatics electrical signalling auxiliary subunits

Details

Metrics

Logo image