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Characterization of TASK‐4, a novel member of the pH‐sensitive, two‐pore domain potassium channel family
Author(s) -
Decher Niels,
Maier Marcel,
Dittrich Werner,
Gassenhuber Johann,
Brüggemann Andrea,
Busch Andreas E.,
Steinmeyer Klaus
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02222-0
Subject(s) - extracellular , tetraethylammonium , chemistry , xenopus , biophysics , potassium channel , biochemistry , anatomy , potassium , biology , organic chemistry , gene
We report the primary sequence of TASK‐4, a novel member of the acid‐sensitive subfamily of tandem pore K + channels. TASK‐4 transcripts are widely expressed in humans, with highest levels in liver, lung, pancreas, placenta, aorta and heart. In Xenopus oocytes TASK‐4 generated K + currents displaying a marked outward rectification which was lost by elevation of extracellular K + . TASK‐4 currents were efficiently blocked by barium (83% inhibition at 2 mM), only weakly inhibited by 1 mM concentrations of quinine, bupivacaine and lidocaine, but not blocked by tetraethylammonium, 4‐aminopyridine and Cs + . TASK‐4 was sensitive to extracellular pH, but in contrast to other TASK channels, pH sensitivity was shifted to more alkaline pH. Thus, TASK‐4 in concert with other TASK channels might regulate cellular membrane potential over a wide range of extracellular pH.