ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
The gustatory system of channel catfish is widely studied for its sensitivity to amino acids. As a first step in identifying the molecular components that play a role in taste transduction in catfish, we cloned the full-length cDNA for Kv2-catfish, a novel K+ channel that is expressed in taste buds. The deduced amino acid sequence is 816 residues, and shares a 56–59% sequence identity with Kv2.1 and Kv2.2, the other members of the vertebrate Kv2 subfamily of voltage-gated K+ channels. The Kv2-catfish RNA was expressed in taste buds, brain, skeletal muscle, kidney, intestine and gills, and its gene is represented as a single copy in the catfish genome. Recombinant channels expressed in Xenopus oocytes were selective for K+, and were inhibited by tetraethylammonium applied to the extracellular side of the membrane during two-electrode voltage clamp analysis with a 50% inhibitory constant of 6.1 mm. The channels showed voltage-dependent activation, and did not inactivate within 200 ms. Functionally, Kv2-catfish is a voltage-gated, delayed rectifier K+ channel, and its primary structure is the most divergent sequence identified among the vertebrate members of the Kv2 subfamily of K+ channels, being related equally well to Kv2.1 and Kv2.2.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1471-4159.2001.00137.x
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