Kv2.1 and silent Kv subunits underlie the delayed rectifier K+ current in cultured small mouse DRG neurons.
Silent voltage-gated K(+) (K(v)) subunits interact with K(v)2 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.
Laboratory for Molecular Biophysics, Physiology and Pharmacology, Department of Biomedical Sciences, University of Antwerp, Antwerpen 2610, Belgium.
Elke
E
Bocksteins
Adam L
AL
Raes
Gerda
G
Van de Vijver
Tine
T
Bruyns
Pierre-Paul
PP
Van Bogaert
Dirk J
DJ
Snyders
D000818:Animals; D002478:Cells, Cultured; D005727:Ganglia, Spinal / Q000187:drug effects / Q000196:embryology / Q000378:metabolism*; D005865:Gestational Age; D015640:Ion Channel Gating; D008564:Membrane Potentials; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D011188:Potassium / Q000378:metabolism*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D024642:Potassium Channels, Voltage-Gated / Q000378:metabolism; D021122:Protein Subunits; D012333:RNA, Messenger / Q000378:metabolism; D051669:Shab Potassium Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
C496990:Kcnb1 protein, mouse; C100581:Kcnv1 protein, mouse; D009419:Nerve Tissue Proteins; D026902:Potassium Channel Blockers; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits; D012333:RNA, Messenger; D051669:Shab Potassium Channels; D011188:Potassium