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Reversal of rectification and alteration of selectivity and pharmacology in a mammalian Kv1.1 potassium channel by deletion of domains S1 to S4.
Author(s) -
Tytgat J,
Vereecke J,
Carmeliet E
Publication year - 1994
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1994.sp020414
Subject(s) - xenopus , transmembrane domain , mutant , potassium channel , biophysics , depolarization , chemistry , inward rectifier potassium ion channel , patch clamp , transmembrane protein , hyperpolarization (physics) , microbiology and biotechnology , biochemistry , biology , ion channel , amino acid , stereochemistry , gene , receptor , nuclear magnetic resonance spectroscopy
1. A possible relation between the family of inwardly rectifying K+ channels and the Shaker superfamily of K+ channels was investigated using a deletion mutant (DelS1‐S4) of a delayed rectifier Kv1.1 (RCK1) K+ channel. 2. The mutant DelS1‐S4 was made by eliminating the sequence coding for transmembrane domains S1 to S4 of the Kv1.1 K+ channel, and re‐ligating the sequence coding for the cytoplasmic amino terminus to transmembrane domain S5. Microelectrode voltage‐clamp and patch‐clamp experiments were performed on Xenopus laevis oocytes after injection of in vitro transcribed mRNA coding for mutant and wild‐type channels. 3. The lack of transmembrane domains S1 to S4 converts a depolarization‐activated wild‐type Kv1.1 K+ channel with outward rectification into a hyperpolarization‐activated channel with inward rectification. Although the pore region of the deletion mutant is identical to the wild‐type channel, the mutant channel is a non‐selective cation channel and is characterized by an altered pharmacology profile.