Alteration and restoration of K+ channel function by deletions at the N- and C-termini.
Voltage-dependent ion channels are thought to consist of a highly conserved repeated core of six transmembrane segments, flanked by more variable cytoplasmic domains. Significant functional differences exist among related types of K+ channels. These differences have been attributed to the variable domains, most prominently the N- and C-termini. We have therefore investigated the functional importance of both termini for the delayed rectifier K+ channel from rat brain encoded by the drk1 gene. This channel has an unusually long C-terminus. Deletions in either terminus affected both activation and inactivation, in some cases profoundly. Unexpectedly, more extensive deletions in both termini restored gating. We could therefore define a core region only slightly longer than the six transmembrane segments that is sufficient for the formation of channels with the kinetics of a delayed rectifier.
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030.
A M
AM
VanDongen
G C
GC
Frech
J A
JA
Drewe
R H
RH
Joho
A M
AM
Brown
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002872:Chromosome Deletion; D004594:Electrophysiology; D015640:Ion Channel Gating; D007700:Kinetics; D009154:Mutation; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D051381:Rats
D015221:Potassium Channels