Phospholipids and the origin of cationic gating charges in voltage sensors

Daniel Schmidt, Qiu Xing Jiang, Roderick MacKinnon

Research output: Contribution to journalArticlepeer-review

349 Scopus citations

Abstract

Cells communicate with their external environment through physical and chemical processes that take place in the cell-surrounding membrane. The membrane serves as a barrier as well as a special environment in which membrane proteins are able to carry out important processes. Certain membrane proteins have the ability to detect the membrane voltage and regulate ion conduction or enzyme activity. Such voltage-dependent processes rely on the action of protein domains known as voltage sensors, which are embedded inside the cell membrane and contain an excess of positively charged amino acids, which react to an electric field. How does the membrane create an environment suitable for voltage sensors? Here we show under a variety of conditions that the function of a voltage-dependent K+ channel is dependent on the negatively charged phosphodiester of phospholipid molecules. A non-voltage-dependent K+ channel does not exhibit the same dependence. The data lead us to propose that the phospholipid membrane, by providing stabilizing interactions between positively charged voltage-sensor arginine residues and negatively charged lipid phosphodiester groups, provides an appropriate environment for the energetic stability and operation of the voltage-sensing machinery. We suggest that the usage of arginine residues in voltage sensors is an adaptation to the phospholipid composition of cell membranes.

Original languageEnglish (US)
Pages (from-to)775-779
Number of pages5
JournalNature
Volume444
Issue number7120
DOIs
StatePublished - Dec 7 2006

Bibliographical note

Funding Information:
Acknowledgements We thank Y. Jiang for the MthK channel construct and A. Lee for the CTX. This work was supported by an NIH grant to R.M. R.M. is an investigator in the Howard Hughes Medical Institute.

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