title: Sodium channel auxiliary subunits.
abstract: Voltage-gated ion channels are well known for their functional roles in excitable tissues. Excitable tissues rely on voltage-gated ion channels and their auxiliary subunits to achieve concerted electrical activity in living cells. Auxiliary subunits are also known to provide functional diversity towards the transport and biogenesis properties of the principal subunits. Recent interests in pharmacological properties of these auxiliary subunits have prompted significant amounts of efforts in understanding their physiological roles. Some auxiliary subunits can potentially serve as drug targets for novel analgesics. Three families of sodium channel auxiliary subunits are described here: beta1 and beta3, beta2 and beta4, and temperature-induced paralytic E (TipE). While sodium channel beta-subunits are encoded in many animal genomes, TipE has only been found exclusively in insects. In this review, we present phylogenetic analyses, discuss potential evolutionary origins and functional data available for each of these subunits. For each family, we also correlate the functional specificity with the history of evolution for the individual auxiliary subunits.
authors.affiliation: Center for Biophysics and Computational Biology, University of Illinois, Urbana-Champaign, IL, USA. ttseng@vt.edu
authors.forename: Tsai-Tien
authors.initials: TT
authors.lastname: Tseng
authors.forename: Allison M
authors.initials: AM
authors.lastname: McMahon
authors.forename: Victoria T
authors.initials: VT
authors.lastname: Johnson
authors.forename: Erwin Z
authors.initials: EZ
authors.lastname: Mangubat
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Zahm
authors.forename: Mary E
authors.initials: ME
authors.lastname: Pacold
authors.forename: Eric
authors.initials: E
authors.lastname: Jakobsson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D021122:Protein Subunits / Q000235:genetics / Q000502:physiology; D016415:Sequence Alignment; D015222:Sodium Channels / Q000235:genetics* / Q000502:physiology*
chemical_list: D021122:Protein Subunits; D015222:Sodium Channels