External K activation of Kir1.1 depends on the pH gate.
The inward rectifier Kir1.1 (ROMK) family is gated by both internal pH and external K, where the putative pH gate is formed by the convergence of leucine side chains, near the inner helical bundle crossing at L160-Kir1.1. However, it is unclear whether K activation is mediated at the pH gate or by another gate in the permeation path. In this study, we used the whole-cell conductance increase during rapid K elevation as a measure of K activation, assuming that activation is inherently slower than changes in channel conduction. Results indicate that structural disruption of the Kir1.1 bundle-crossing pH gate prevents both inactivation by low external K and reactivation by high external K.
Sackin
Henry
H
Nanazashvili
Mikheil
M
Li
Hui
H
Palmer
Lawrence G
LG
Walters
D Eric
DE
D019943:Amino Acid Substitution; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D005260:Female; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects; D016297:Mutagenesis, Site-Directed; D009865:Oocytes / Q000378:metabolism; D011188:Potassium / Q000378:metabolism / Q000494:pharmacology*; D024661:Potassium Channels, Inwardly Rectifying / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D024661:Potassium Channels, Inwardly Rectifying; D011994:Recombinant Proteins; D011188:Potassium