Abstract:
:Divergence of the Shaker superfamily of voltage-gated (Kv) ion channels early in metazoan evolution created numerous electrical phenotypes that were presumably selected to produce a wide range of excitability characteristics in neurons, myocytes, and other cells. A comparative approach that emphasizes this early radiation provides a comprehensive sampling of sequence space that is necessary to develop generally applicable models of the structure-function relationship in the Kv potassium channel family. We have cloned and characterized two Shaw-type potassium channels from a flatworm (Notoplana atomata) that is arguably a representative of early diverging bilaterians. When expressed in Xenopus oocytes, one of these cloned channels, N.at-Kv3.1, exhibits a noninactivating, outward current with slow opening kinetics that are dependent on both the holding potential and the activating potential. A second Shaw-type channel, N.at-Kv3.2, has very different properties, showing weak inward rectification. These results demonstrate that broad phylogenetic sampling of proteins of a single family will reveal unexpected properties that lead to new interpretations of structure-function relationships.
journal_name
J Neurophysioljournal_title
Journal of neurophysiologyauthors
Klassen TL,Buckingham SD,Atherton DM,Dacks JB,Gallin WJ,Spencer ANdoi
10.1152/jn.00858.2005subject
Has Abstractpub_date
2006-05-01 00:00:00pages
3035-46issue
5eissn
0022-3077issn
1522-1598pii
00858.2005journal_volume
95pub_type
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