Characterization of TASK-4, a novel member of the pH-sensitive, two-pore domain potassium channel family

FEBS Lett. 2001 Mar 9;492(1-2):84-9. doi: 10.1016/s0014-5793(01)02222-0.


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.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Atrioventricular Node / metabolism
  • Barium / pharmacology
  • Cloning, Molecular
  • Electrophysiology
  • Heart Atria / metabolism
  • Humans
  • Hydrogen-Ion Concentration
  • Molecular Sequence Data
  • Oocytes
  • Phylogeny
  • Potassium Channel Blockers
  • Potassium Channels / genetics*
  • Potassium Channels / metabolism
  • Potassium Channels, Tandem Pore Domain*
  • Protein Conformation
  • Sequence Homology, Amino Acid
  • Tissue Distribution
  • Xenopus laevis


  • KCNK17 protein, human
  • Potassium Channel Blockers
  • Potassium Channels
  • Potassium Channels, Tandem Pore Domain
  • Barium

Associated data

  • GENBANK/AL136087