Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

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,, 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,, 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.

Original publication




Journal article


J Neurophysiol

Publication Date





3035 - 3046


Animals, Cloning, Molecular, Dose-Response Relationship, Radiation, Electric Conductivity, Electric Stimulation, Ion Channel Gating, Membrane Potentials, Microinjections, Oocytes, Patch-Clamp Techniques, Phenotype, Phylogeny, Platyhelminths, Potassium, RNA, Messenger, Reverse Transcriptase Polymerase Chain Reaction, Sequence Analysis, DNA, Sequence Analysis, Protein, Shaw Potassium Channels