K(v)2.1 and silent K-v subunits underlie the delayed rectifier K+ current in cultured small mouse DRG neurons
Bocksteins, Elke × Raes, Adam Van de Vijver, Gerda Bruyns, Tine Van Bogaert, Pierre-Paul Snyders, Dirk J #
Amer physiological soc
American Journal of Physiology. Cell Physiology vol:296 issue:6 pages:C1271-C1278
Bocksteins E, Raes AL, Van de Vijver G, Bruyns T, Van Bogaert PP, Snyders DJ. K(v)2.1 and silent K-v subunits underlie the delayed rectifier K+ current in cultured small mouse DRG neurons. Am J Physiol Cell Physiol 296: C1271-C1278, 2009. First published April 8, 2009; doi:10.1152/ajpcell.00088.2009. -Silent voltage-gated K+ (K-v) subunits interact with Kv2 subunits and primarily modulate the voltage dependence of inactivation of these heterotetrameric channels. Both K(v)2 and silent K-v subunits are expressed in the mammalian nervous system, but little is known about their expression and function in sensory neurons. This study reports the presence of K(v)2.1, K(v)2.2, and silent subunit K(v)6.1, K(v)8.1, K(v)9.1, K(v)9.2, and K(v)9.3 mRNA in mouse dorsal root ganglia (DRG). Immunocytochemistry confirmed the protein expression of K(v)2.x and K(v)9.x subunits in cultured small DRG neurons. To investigate if K(v)2 and silent K-v subunits are underlying the delayed rectifier K+ current (I-K) in these neurons, K(v)2-mediated currents were isolated by the extracellular application of rStromatoxin-1 (ScTx) or by the intracellular application of K(v)2 antibodies. Both ScTx- and anti-K(v)2.1-sensitive currents displayed two components in their voltage dependence of inactivation. Together, both components accounted for approximately two-thirds of I-K. A comparison with results obtained in heterologous expression systems suggests that one component reflects homotetrameric K(v)2.1 channels, whereas the other component represents heterotetrameric K(v)2.1/silent K-v channels. These observations support a physiological role for silent K-v subunits in small DRG neurons.