Concatemers of brain Kv1 channel α subunits that give similar K+ currents yield pharmacologically distinguishable heteromers

Maxim V. Sokolov, Oleg Shamotienko, Sorcha Ní Dhochartaigh, Jon T Sack, J. Oliver Dolly

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

At least five subtypes of voltage-gated (Kv1) channels occur in neurons as tetrameric combinations of different α subunits. Their involvement in controlling cell excitability and synaptic transmission make them potential targets for neurotherapeutics. As a prerequisite for this, we established herein how the characteristics of hetero-oligomeric K+ channels can be influenced by α subunit composition. Since the three most prevalent Kv1 subunits in brain are Kv1.2, 1.1 and 1.6, new Kv1.6-1.2 and Kv1.1-1.2 concatenated constructs in pIRES-EGFP were stably expressed in HEK cells and the biophysical plus pharmacological properties of their K+ currents determined relative to those for the requisite homo-tetramers. These heteromers yielded delayed-rectifier type K+ currents whose activation, deactivation and inactivation parameters are fairly similar although substituting Kv1.1 with Kv1.6 led to a small negative shift in the conductance-voltage relationship, a direction unexpected from the characteristics of the parental homo-tetramers. Changes resulting from swapping Kv1.6 for Kv1.1 in the concatemers were clearly discerned with two pharmacological agents, as measured by inhibition of the K+ currents and Rb+ efflux. αDendrotoxin and 4-aminopyridine gave a similar blockade of both hetero-tetramers, as expected. Most important for pharmacological dissection of channel subtypes, dendrotoxink and tetraethylammonium readily distinguished the susceptible Kv1.1-1.2 containing oligomers from the resistant Kv1.6-1.2 channels. Moreover, the discriminating ability of dendrotoxink was further confirmed by its far greater ability to displace 125I-labelled αdendrotoxin binding to Kv1.1-1.2 than Kv1.6-1.2 channels. Thus, due to the profiles of these two channel subtypes being found to differ, it seems that only multimers corresponding to those present in the nervous system provide meaningful targets for drug development.

Original languageEnglish (US)
Pages (from-to)272-282
Number of pages11
JournalNeuropharmacology
Volume53
Issue number2
DOIs
StatePublished - Aug 2007
Externally publishedYes

Fingerprint

Pharmacology
Brain
4-Aminopyridine
Tetraethylammonium
Synaptic Transmission
Nervous System
Dissection
Neurons
Pharmaceutical Preparations
dendrotoxin
Direction compound

Keywords

  • Dendrotoxins
  • Hetero-oligomers
  • K channels
  • Kv1.1
  • Kv1.2
  • Kv1.6
  • Patch-clamp

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Drug Discovery
  • Pharmacology

Cite this

Concatemers of brain Kv1 channel α subunits that give similar K+ currents yield pharmacologically distinguishable heteromers. / Sokolov, Maxim V.; Shamotienko, Oleg; Dhochartaigh, Sorcha Ní; Sack, Jon T; Dolly, J. Oliver.

In: Neuropharmacology, Vol. 53, No. 2, 08.2007, p. 272-282.

Research output: Contribution to journalArticle

Sokolov, Maxim V. ; Shamotienko, Oleg ; Dhochartaigh, Sorcha Ní ; Sack, Jon T ; Dolly, J. Oliver. / Concatemers of brain Kv1 channel α subunits that give similar K+ currents yield pharmacologically distinguishable heteromers. In: Neuropharmacology. 2007 ; Vol. 53, No. 2. pp. 272-282.
@article{1bc077d32bdd4f659a3b72ed4b8df5af,
title = "Concatemers of brain Kv1 channel α subunits that give similar K+ currents yield pharmacologically distinguishable heteromers",
abstract = "At least five subtypes of voltage-gated (Kv1) channels occur in neurons as tetrameric combinations of different α subunits. Their involvement in controlling cell excitability and synaptic transmission make them potential targets for neurotherapeutics. As a prerequisite for this, we established herein how the characteristics of hetero-oligomeric K+ channels can be influenced by α subunit composition. Since the three most prevalent Kv1 subunits in brain are Kv1.2, 1.1 and 1.6, new Kv1.6-1.2 and Kv1.1-1.2 concatenated constructs in pIRES-EGFP were stably expressed in HEK cells and the biophysical plus pharmacological properties of their K+ currents determined relative to those for the requisite homo-tetramers. These heteromers yielded delayed-rectifier type K+ currents whose activation, deactivation and inactivation parameters are fairly similar although substituting Kv1.1 with Kv1.6 led to a small negative shift in the conductance-voltage relationship, a direction unexpected from the characteristics of the parental homo-tetramers. Changes resulting from swapping Kv1.6 for Kv1.1 in the concatemers were clearly discerned with two pharmacological agents, as measured by inhibition of the K+ currents and Rb+ efflux. αDendrotoxin and 4-aminopyridine gave a similar blockade of both hetero-tetramers, as expected. Most important for pharmacological dissection of channel subtypes, dendrotoxink and tetraethylammonium readily distinguished the susceptible Kv1.1-1.2 containing oligomers from the resistant Kv1.6-1.2 channels. Moreover, the discriminating ability of dendrotoxink was further confirmed by its far greater ability to displace 125I-labelled αdendrotoxin binding to Kv1.1-1.2 than Kv1.6-1.2 channels. Thus, due to the profiles of these two channel subtypes being found to differ, it seems that only multimers corresponding to those present in the nervous system provide meaningful targets for drug development.",
keywords = "Dendrotoxins, Hetero-oligomers, K channels, Kv1.1, Kv1.2, Kv1.6, Patch-clamp",
author = "Sokolov, {Maxim V.} and Oleg Shamotienko and Dhochartaigh, {Sorcha N{\'i}} and Sack, {Jon T} and Dolly, {J. Oliver}",
year = "2007",
month = "8",
doi = "10.1016/j.neuropharm.2007.05.008",
language = "English (US)",
volume = "53",
pages = "272--282",
journal = "Neuropharmacology",
issn = "0028-3908",
publisher = "Elsevier Limited",
number = "2",

}

TY - JOUR

T1 - Concatemers of brain Kv1 channel α subunits that give similar K+ currents yield pharmacologically distinguishable heteromers

AU - Sokolov, Maxim V.

AU - Shamotienko, Oleg

AU - Dhochartaigh, Sorcha Ní

AU - Sack, Jon T

AU - Dolly, J. Oliver

PY - 2007/8

Y1 - 2007/8

N2 - At least five subtypes of voltage-gated (Kv1) channels occur in neurons as tetrameric combinations of different α subunits. Their involvement in controlling cell excitability and synaptic transmission make them potential targets for neurotherapeutics. As a prerequisite for this, we established herein how the characteristics of hetero-oligomeric K+ channels can be influenced by α subunit composition. Since the three most prevalent Kv1 subunits in brain are Kv1.2, 1.1 and 1.6, new Kv1.6-1.2 and Kv1.1-1.2 concatenated constructs in pIRES-EGFP were stably expressed in HEK cells and the biophysical plus pharmacological properties of their K+ currents determined relative to those for the requisite homo-tetramers. These heteromers yielded delayed-rectifier type K+ currents whose activation, deactivation and inactivation parameters are fairly similar although substituting Kv1.1 with Kv1.6 led to a small negative shift in the conductance-voltage relationship, a direction unexpected from the characteristics of the parental homo-tetramers. Changes resulting from swapping Kv1.6 for Kv1.1 in the concatemers were clearly discerned with two pharmacological agents, as measured by inhibition of the K+ currents and Rb+ efflux. αDendrotoxin and 4-aminopyridine gave a similar blockade of both hetero-tetramers, as expected. Most important for pharmacological dissection of channel subtypes, dendrotoxink and tetraethylammonium readily distinguished the susceptible Kv1.1-1.2 containing oligomers from the resistant Kv1.6-1.2 channels. Moreover, the discriminating ability of dendrotoxink was further confirmed by its far greater ability to displace 125I-labelled αdendrotoxin binding to Kv1.1-1.2 than Kv1.6-1.2 channels. Thus, due to the profiles of these two channel subtypes being found to differ, it seems that only multimers corresponding to those present in the nervous system provide meaningful targets for drug development.

AB - At least five subtypes of voltage-gated (Kv1) channels occur in neurons as tetrameric combinations of different α subunits. Their involvement in controlling cell excitability and synaptic transmission make them potential targets for neurotherapeutics. As a prerequisite for this, we established herein how the characteristics of hetero-oligomeric K+ channels can be influenced by α subunit composition. Since the three most prevalent Kv1 subunits in brain are Kv1.2, 1.1 and 1.6, new Kv1.6-1.2 and Kv1.1-1.2 concatenated constructs in pIRES-EGFP were stably expressed in HEK cells and the biophysical plus pharmacological properties of their K+ currents determined relative to those for the requisite homo-tetramers. These heteromers yielded delayed-rectifier type K+ currents whose activation, deactivation and inactivation parameters are fairly similar although substituting Kv1.1 with Kv1.6 led to a small negative shift in the conductance-voltage relationship, a direction unexpected from the characteristics of the parental homo-tetramers. Changes resulting from swapping Kv1.6 for Kv1.1 in the concatemers were clearly discerned with two pharmacological agents, as measured by inhibition of the K+ currents and Rb+ efflux. αDendrotoxin and 4-aminopyridine gave a similar blockade of both hetero-tetramers, as expected. Most important for pharmacological dissection of channel subtypes, dendrotoxink and tetraethylammonium readily distinguished the susceptible Kv1.1-1.2 containing oligomers from the resistant Kv1.6-1.2 channels. Moreover, the discriminating ability of dendrotoxink was further confirmed by its far greater ability to displace 125I-labelled αdendrotoxin binding to Kv1.1-1.2 than Kv1.6-1.2 channels. Thus, due to the profiles of these two channel subtypes being found to differ, it seems that only multimers corresponding to those present in the nervous system provide meaningful targets for drug development.

KW - Dendrotoxins

KW - Hetero-oligomers

KW - K channels

KW - Kv1.1

KW - Kv1.2

KW - Kv1.6

KW - Patch-clamp

UR - http://www.scopus.com/inward/record.url?scp=34547506993&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34547506993&partnerID=8YFLogxK

U2 - 10.1016/j.neuropharm.2007.05.008

DO - 10.1016/j.neuropharm.2007.05.008

M3 - Article

C2 - 17637465

AN - SCOPUS:34547506993

VL - 53

SP - 272

EP - 282

JO - Neuropharmacology

JF - Neuropharmacology

SN - 0028-3908

IS - 2

ER -