Gating dependence of inner pore access in inward rectifier K+ channels

L. Revell Phillips, Decha Enkvetchakul, Colin G. Nichols

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Cation channel gating may occur either at or below the inner vestibule entrance or at the selectivity filter. To differentiate these possibilities in inward rectifier (Kir) channels, we examined cysteine accessibility in the ATP-gated Kir6.2 channel. MTSEA and MTSET both block channels and modify M2 cysteines with identical voltage dependence. If entry is restricted to open channels, modification rates will slow in ATP-closed channels, but because the reagent can be trapped in the pore following brief openings, this may not be apparent until open probability is extremely low (<0.01). When these conditions are met, modification does slow significantly, indicating gated access and highlighting an important caveat for interpretation of MTS-accessibility measurements: reagent "trapping" in nominally "closed" channels may obscure gated access.

Original languageEnglish
Pages (from-to)953-962
Number of pages10
JournalNeuron
Volume37
Issue number6
DOIs
StatePublished - Mar 27 2003

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