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TASK-3, a NovelTandem Pore DomainAcid-sensitiveK+Channel Sindhu RajanErhard WischmeyerGong Xin Liu2000 год

TASK-3, a Novel Tandem Pore Domain Acid-sensitive K+Channel
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Аннотация: Tandem pore domain acid-sensitive K+ channel 3 (TASK-3) is a new member of the tandem pore domain potassium channel family. A cDNA encoding a 365- amino acid polypeptide with four putative transmembrane segments and two pore regions was isolated from guinea pig brain. An orthologous sequence was cloned from a human genomic library. Although TASK-3 is 62% identical to TASK-1, the cytosolic C-terminal sequence is only weakly conserved. Analysis of the gene structure identified an intron within the conserved GYG motif of the first pore region. Reverse transcriptase-polymerase chain reaction analysis showed strong expression in brain but very weak mRNA levels in other tissues. Cell-attached patch-clamp recordings of TASK-3 expressed in HEK293 cells showed that the single channel current-voltage relation was inwardly rectifying, and open probability increased markedly with depolarization. Removal of external divalent cations increased the mean single channel current measured at −100 mV from −2.3 to −5.8 pA. Expression of TASK-3 in Xenopus oocytes revealed an outwardly rectifying K+ current that was strongly decreased in the presence of lower extracellular pH. Substitution of the histidine residue His-98 by asparagine or tyrosine abolished pH sensitivity. This histidine, which is located at the outer part of the pore adjacent to the selectivity filter, may be an essential component of the extracellular pH sensor.
Год издания: 2000
Авторы: Sindhu Rajan, Erhard Wischmeyer, Gong Xin Liu, Regina Preisig‐Müller, Jürgen Daut, Andreas Karschin, Christian Derst
Издательство: Elsevier BV
Источник: Journal of Biological Chemistry
Ключевые слова: Ion channel regulation and function, Cardiac electrophysiology and arrhythmias, Ion Transport and Channel Regulation
Другие ссылки: Journal of Biological Chemistry (PDF)
Journal of Biological Chemistry (HTML)
MPG.PuRe (Max Planck Society) (PDF)
MPG.PuRe (Max Planck Society) (HTML)
PubMed (HTML)