Cloning and function of the rat colonic epithelial K+ channel K(V)LQT1

Kunzelmann, K, Hubner, M, Schreiber, R, Levy-Holzman, R, Garty, H, Bleich, M, Warth, R, Slavik, M, von Hahn, T and Greger, R (2001) Cloning and function of the rat colonic epithelial K+ channel K(V)LQT1. Journal of Membrane Biology, 179 2: 155-164. doi:10.1007/s002320010045

Author Kunzelmann, K
Hubner, M
Schreiber, R
Levy-Holzman, R
Garty, H
Bleich, M
Warth, R
Slavik, M
von Hahn, T
Greger, R
Title Cloning and function of the rat colonic epithelial K+ channel K(V)LQT1
Journal name Journal of Membrane Biology   Check publisher's open access policy
ISSN 0022-2631
Publication date 2001-01-01
Sub-type Article (original research)
DOI 10.1007/s002320010045
Open Access Status Not Open Access
Volume 179
Issue 2
Start page 155
End page 164
Total pages 10
Editor WR Loewenstein
Place of publication United States
Publisher Springer Verlag
Language eng
Subject C1
270104 Membrane Biology
730110 Respiratory system and diseases (incl. asthma)
Abstract K(V)LQT1 (K(V)LQ1) is a voltage-gated K+ channel essential for repolarization of the heart action potential that is defective in cardiac arrhythmia. The channel is inhibited by the chromanol 293B, a compound that blocks cAMP-dependent electrolyte secretion in rat and human colon, therefore suggesting expression of a similar type of K+ channel in the colonic epithelium. We now report cloning and expression of K(V)LQT1 from rat colon. Overlapping clones identified by cDNA-library screening were combined to a full length cDNA that shares high sequence homology to K(V)LQT1 cloned from other species. RT-PCR analysis of rat colonic musoca demonstrated expression of K(V)LQT1 in crypt cells and surface epithelium. Expression of rK(V)LQT1 in Xenopus oocytes induced a typical delayed activated K+ current. that was further activated by increase of intracellular cAMP but not Ca2+ and that was blocked by the chromanol 293B. The same compound blocked a basolateral cAMP-activated K+ conductance in the colonic mucosal epithelium and inhibited whole cell K+ currents in patch-clamp experiments on isolated colonic crypts. We conclude that K(V)QT1 is forming an important component of the basolateral cAMP-activated K+ conductance in the colonic epithelium and plays a crucial role in diseases like secretory diarrhea and cystic fibrosis.
Keyword Biochemistry & Molecular Biology
Cell Biology
Rat Colon
K+ Channel
Electrolyte Secretion
Ion Transport
Xenopus Oocytes
Ussing Chamber
Dogfish Squalus-acanthias
Rectal Gland Tubules
Potassium Channel
Idiopathic Epilepsy
Nacl Secretion
Cl Secretion
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biomedical Sciences Publications
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Citation counts: TR Web of Science Citation Count  Cited 63 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 15 Aug 2007, 01:11:32 EST