Interactions of Cations with the Cytoplasmic Pores of Inward Rectifier K^+ Channels in the Closed State

Inanobe, Atsushi; Nakagawa, Atushi; Kurachi, Yoshihisa

Journal of Biological Chemistry, 2011, 286(48), 41801-41811

Number of Access:611（2025-09-29 10:04 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/73660

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Title
Interactions of Cations with the Cytoplasmic Pores of Inward Rectifier K^+ Channels in the Closed State
Creator
NRID
1000000270851 1000000270851
researchmap permalink
read0051668 read0051668
Scopus Author ID
7004862161 7004862161
CreatorName
Inanobe, Atsushi
NRID
1000020188890 1000020188890
ORCID
0000-0002-1700-7861 0000-0002-1700-7861
researchmap permalink
atsushi_nakagawa atsushi_nakagawa
Scopus Author ID
7202934909 7202934909
CreatorName
Nakagawa, Atushi
NRID
1000030142011 1000030142011
CreatorName
Kurachi, Yoshihisa
Description
This research was originally published in Journal of Biological Chemistry. Atsushi Inanobe, Atsushi Nakagawa, and Yoshihisa Kurachi. Interactions of Cations with the Cytoplasmic Pores of Inward Rectifier K^+ Channels in the Closed State. Journal of Biological Chemistry. 2011; 286, 41801-41811. © the American Society for Biochemistry and Molecular Biology.
Abstract
Ion channels gate at membrane-embedded domains by changing their conformation along the ion conduction pathway. Inward rectifier K^＋ (Kir) channels possess a unique extramembrane cytoplasmic domain that extends this pathway. However, the relevance and contribution of this domain to ion permeation remain unclear. By qualitative x-ray crystallographic analysis, we found that the pore in the cytoplasmic domain of Kir3.2 binds cations in a valency-dependent manner and does not allow the displacement of Mg^<2＋> by monovalent cations or spermine. Electrophysiological analyses revealed that the cytoplasmic pore of Kir3.2 selectively binds positively charged molecules and has a higher affinity for Mg^<2＋> when it has a low probability of being open. The selective blocking of chemical modification of the side chain of pore-facing residues byMg^<2＋> indicates that the mode of binding of Mg^<2＋> is likely to be similar to that observed in the crystal structure. These results indicate that the Kir3.2 crystal structure has a closed conformation with a negative electrostatic field potential at the cytoplasmic pore, the potential of which may be controlled by conformational changes in the cytoplasmic domain to regulate ion diffusion along the pore.
Publisher
American Society for Biochemistry and Molecular Biology
Source Title
Journal of Biological Chemistry
Volume (Issue)
286(48)
Page
41801-41811
Date of Issued
2011-12
Language
English
Handle URL
https://hdl.handle.net/11094/73660
eISSN
1083351X
NCID
AA1202441X
Relation.isIdenticalTo
DOI (Publisher Version)
https://doi.org/10.1074/jbc.M111.278531
PMID
21982822
Access Rights
open access
CopyRight
© the American Society for Biochemistry and Molecular Biology.
oaire:version
Version of Record
Category
学術雑誌論文 Journal Article