RGD Reference Report - Cloning and function of the rat colonic epithelial K+ channel KVLQT1. - Rat Genome Database

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Cloning and function of the rat colonic epithelial K+ channel KVLQT1.

Authors: Kunzelmann, K  Hubner, M  Schreiber, R  Levy-Holzman, R  Garty, H  Bleich, M  Warth, R  Slavik, M  Von Hahn, T  Greger, R 
Citation: Kunzelmann K, etal., J Membr Biol 2001 Jan 15,;179(2):155-64.
RGD ID: 633100
Pubmed: PMID:11220365   (View Abstract at PubMed)

KVLQT1 (KCNQ1) 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 KVLQT1 from rat colon. Overlapping clones identified by cDNA-library screening were combined to a full length cDNA that shares high sequence homology to KVLQT1 cloned from other species. RT-PCR analysis of rat colonic musoca demonstrated expression of KVLQT1 in crypt cells and surface epithelium. Expression of rKVLQT1 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 KVLQT1 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.

Gene Ontology Annotations    Click to see Annotation Detail View

Molecular Function
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
delayed rectifier potassium channel activity enablesIDA 633100PMID:11220365UniProt 
outward rectifier potassium channel activity enablesIDA 633100PMID:11220365UniProt 

Objects Annotated

Genes (Rattus norvegicus)
Kcnq1  (potassium voltage-gated channel subfamily Q member 1)


Additional Information