Cytoplasmic vestibule of the weak inward rectifier Kir6.2 potassium channel

Yijun Cui, Wenxia Wang, Zheng Fan

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Intracellular application of certain charged methanethiosulfonate (MTS) reagents modified and irreversibly inhibited Kir6.2 channels when cysteine substitutions were introduced at positions Ile-210, Ile-211, or Ser-212 within the putative cytoplasmic region. Inhibition depends on the spatial dimensions of the MTS reagents. Reaction of MTS reagents, having head diameters of 7.6-8.2 Å, with cysteines introduced at position Ser-212 must occur in more than two subunits of the tetrameric Kir6.2 complex to inhibit channel activity. MTS reagents with head diameters less than 6.6 Å modified cysteines without causing channel inhibition. An MTS reagent with a head diameter of ∼10 Å could neither modify nor inhibit the channels. Channel inhibition is interpreted as blockage of the intracellular vestibule by MTS reagents that enter the channel vestibule and react with the cysteine residues at vestibule-lining positions. Data are consistent with the hypothesis that residues Ile-210-Ser-212 line a funnel-shaped vestibule of 20-25 Å in diameter, which remains unchanged during channel gating.

Original languageEnglish (US)
Pages (from-to)10523-10530
Number of pages8
JournalJournal of Biological Chemistry
Volume277
Issue number12
DOIs
StatePublished - Mar 22 2002

Fingerprint

Inwardly Rectifying Potassium Channel
Potassium Channels
Cysteine
Head
Linings
Kir6.2 channel
methanethiosulfonate
Substitution reactions

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

Cytoplasmic vestibule of the weak inward rectifier Kir6.2 potassium channel. / Cui, Yijun; Wang, Wenxia; Fan, Zheng.

In: Journal of Biological Chemistry, Vol. 277, No. 12, 22.03.2002, p. 10523-10530.

Research output: Contribution to journalArticle

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abstract = "Intracellular application of certain charged methanethiosulfonate (MTS) reagents modified and irreversibly inhibited Kir6.2 channels when cysteine substitutions were introduced at positions Ile-210, Ile-211, or Ser-212 within the putative cytoplasmic region. Inhibition depends on the spatial dimensions of the MTS reagents. Reaction of MTS reagents, having head diameters of 7.6-8.2 {\AA}, with cysteines introduced at position Ser-212 must occur in more than two subunits of the tetrameric Kir6.2 complex to inhibit channel activity. MTS reagents with head diameters less than 6.6 {\AA} modified cysteines without causing channel inhibition. An MTS reagent with a head diameter of ∼10 {\AA} could neither modify nor inhibit the channels. Channel inhibition is interpreted as blockage of the intracellular vestibule by MTS reagents that enter the channel vestibule and react with the cysteine residues at vestibule-lining positions. Data are consistent with the hypothesis that residues Ile-210-Ser-212 line a funnel-shaped vestibule of 20-25 {\AA} in diameter, which remains unchanged during channel gating.",
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N2 - Intracellular application of certain charged methanethiosulfonate (MTS) reagents modified and irreversibly inhibited Kir6.2 channels when cysteine substitutions were introduced at positions Ile-210, Ile-211, or Ser-212 within the putative cytoplasmic region. Inhibition depends on the spatial dimensions of the MTS reagents. Reaction of MTS reagents, having head diameters of 7.6-8.2 Å, with cysteines introduced at position Ser-212 must occur in more than two subunits of the tetrameric Kir6.2 complex to inhibit channel activity. MTS reagents with head diameters less than 6.6 Å modified cysteines without causing channel inhibition. An MTS reagent with a head diameter of ∼10 Å could neither modify nor inhibit the channels. Channel inhibition is interpreted as blockage of the intracellular vestibule by MTS reagents that enter the channel vestibule and react with the cysteine residues at vestibule-lining positions. Data are consistent with the hypothesis that residues Ile-210-Ser-212 line a funnel-shaped vestibule of 20-25 Å in diameter, which remains unchanged during channel gating.

AB - Intracellular application of certain charged methanethiosulfonate (MTS) reagents modified and irreversibly inhibited Kir6.2 channels when cysteine substitutions were introduced at positions Ile-210, Ile-211, or Ser-212 within the putative cytoplasmic region. Inhibition depends on the spatial dimensions of the MTS reagents. Reaction of MTS reagents, having head diameters of 7.6-8.2 Å, with cysteines introduced at position Ser-212 must occur in more than two subunits of the tetrameric Kir6.2 complex to inhibit channel activity. MTS reagents with head diameters less than 6.6 Å modified cysteines without causing channel inhibition. An MTS reagent with a head diameter of ∼10 Å could neither modify nor inhibit the channels. Channel inhibition is interpreted as blockage of the intracellular vestibule by MTS reagents that enter the channel vestibule and react with the cysteine residues at vestibule-lining positions. Data are consistent with the hypothesis that residues Ile-210-Ser-212 line a funnel-shaped vestibule of 20-25 Å in diameter, which remains unchanged during channel gating.

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