KV7.4 channels

Channel name KV7.4
Description Voltage-gated potassium channel, delayed rectifier
Other names None
Molecular information Human: 695aa, NM_004700 (transcript variant 1), chr. 1p34, KCNQ4,1 GeneID: 9132, PMID: 100254091
Mouse: 724aa, XM_143960 (predicted), chr. 4
Rat: AF249748 (partial coding sequence)
Associated subunits KCNQ32
Functional assays Voltage-clamp
Current IK,n
Conductance Not established
Ion selectivity K+
Activation Va = 10 mV
Inactivation Not established
Activators Retigabine (1 μM)3; BMS204352 (1 μM)3
Gating inhibitors None
Blockers Tetraethyammonium (3 mM),4 linopirdine (14 μM),5 XE991 (5 μM),5 bepridil (9.4 μM)5
Radioligands None
Channel distribution Cochlea (outer hair cells), placenta, vestibular organs (type 1 hair cells), brainstem auditory nuclei
Physiological functions Mediates potassium efflux from outer hair cells1,6
Mutations and pathophysiology Mutations in KCNQ4 cause autosomal dominant nonsyndromic deafness type 2 (DFNA2)1,6
Pharmacological significance Anticonvulsants (activators)
  • aa, amino acids; chr., chromosome; XE991, 10,10-bis(pyridin-4-ylmethyl)anthracen-9-one; BMS204352, 3-(5-chloro-2-methoxy-phenyl)-3-fluoro-6-(trifluoromethyl)-1H-indol-2- one.

  • 1. Kubisch C, Schroeder BC, Friedrich T, Lutjohann B, El-Amraoui A, Marlin S, Petit C, and Jentsch TJ (1999) KCNQ4, a novel potassium channel expressed in sensory outer hair cells, is mutated in dominant deafness. Cell 96:437-446

  • 2. Schroeder BC, Waldegger S, Fehr S, Bleich M, Warth R, Greger R, and Jentsch TJ (2000) A constitutively open potassium channel formed by KCNQ1 and KCNE3. Nature (Lond) 403:196-199

  • 3. Schroder RL, Jespersen T, Christophersen P, Strobaek D, Jensen BS, and Olesen SP (2001) KCNQ4 channel activation by BMS-204352 and retigabine. Neuropharmacology 40:888-898

  • 4. Hadley JK, Noda M, Selyanko AA, Wood IC, Abogadie FC, and Brown DA (2000) Differential tetraethylammonium sensitivity of KCNQ1—4 potassium channels. Br J Pharmacol 129:413-415

  • 5. Sogaard R, Ljungstrom T, Pedersen KA, Olesen SP, and Jensen BS (2001) KCNQ4 channels expressed in mammalian cells: functional characteristics and pharmacology. Am J Physiol 280:C859-C866

  • 6. Kharkovets T, Hardelin JP, Safieddine S, Schweizer M, El-Amraoui A, Petit C, and Jentsch TJ (2000) KCNQ4, a K+ channel mutated in a form of dominant deafness, is expressed in the inner ear and the central auditory pathway. Proc Natl Acad Sci USA 97:4333-4338