論文

査読有り 国際誌
2022年7月12日

Intermolecular functional coupling between phosphoinositides and the potassium channel KcsA.

The Journal of biological chemistry
  • Takunari Kiya
  • ,
  • Kohei Takeshita
  • ,
  • Akira Kawanabe
  • ,
  • Yuichiro Fujiwara

298
8
開始ページ
102257
終了ページ
102257
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.jbc.2022.102257

Biological membranes are composed of a wide variety of lipids. Phosphoinositides (PIPns) in the membrane inner leaflet only account for a small percentage of the total membrane lipids, but modulate the functions of various membrane proteins, including ion channels, which play important roles in cell signaling. KcsA, a prototypical K+ channel that is small, simple, and easy-to-handle, has been broadly examined regarding its crystallography, in silico molecular analysis, and electrophysiology. It has been reported that KcsA activity is regulated by membrane phospholipids, such as phosphatidylglycerol. However, there has been no quantitative analysis of the correlation between direct lipid binding and the functional modification of KcsA, and it is unknown whether PIPns modulate KcsA function. Here, using contact bubble bilayer recording, we observed that the open probability of KcsA increased significantly (from about 10% to 90%) when the membrane inner leaflet contained only a small percentage of PIPns. In addition, we found an increase in the electrophysiological activity of KcsA correlated with a larger number of negative charges on PIPns. We further analyzed the affinity of the direct interaction between PIPns and KcsA using microscale thermophoresis and observed a strong correlation between direct lipid binding and the functional modification of KcsA. In conclusion, our approach was able to reconstruct the direct modification of KcsA by PIPns, and we propose that it can also be applied to elucidate the mechanism of modification of other ion channels by PIPns.

リンク情報
DOI
https://doi.org/10.1016/j.jbc.2022.102257
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/35839854
PubMed Central
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9396063
ID情報
  • DOI : 10.1016/j.jbc.2022.102257
  • PubMed ID : 35839854
  • PubMed Central 記事ID : PMC9396063

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