Molecular cloning and characterization of LKv1, a novel voltage-gated potassium channel in leech

We have cloned a novel voltage-gated K channel, LKv1, in two species of lee ch. The properties of LKv1 expressed in transiently transfected HEK293 cell s is that of a delayed rectifier current. LKv1 may be a major modulator of excitability in leech neurons, since antibody localization studies show tha t LKv1 is expressed in the soma and axons of all neurons in both the centra l and peripheral nervous systems. Comparison of the biophysical and pharmac ological properties of LKv1 with native voltage-gated conductances in leech neurons suggests that LKv1 may correspond to the previously characterized delayed rectifier current, I-K. Phylogenetic analysis of LKv1 shows that it is related to the Shaker subfamily of voltage-gated K channels although it occupies a separate branch from that of the monophyletic Shaker clade comp osed of the flatworm, Aplysia, Drosophila, and mammalian Shaker homologs as well as from that of two recently identified Shaker-related K channels in jellyfish. Thus, this analysis indicates that this group of voltage-gated K channels contains several evolutionarily divergent lineages, (C) 1999 John Wiley & Sons, Inc.