Structural basis for anion conduction in the calcium-activated chloride channel TMEM16A.

TitleStructural basis for anion conduction in the calcium-activated chloride channel TMEM16A.
Publication TypeJournal Article
Year of Publication2017
AuthorsPaulino, C., Y. Neldner, A. Km Lam, V. Kalienkova, J. D. Brunner, S. Schenck, and R. Dutzler
JournalElife
Volume6
Date Published2017 05 31
ISSN2050-084X
KeywordsAnimals, Anions, Anoctamin-1, Cryoelectron Microscopy, Mice, Protein Conformation
Abstract

The calcium-activated chloride channel TMEM16A is a member of a conserved protein family that comprises ion channels and lipid scramblases. Although the structure of the scramblase nhTMEM16 has defined the architecture of the family, it was unknown how a channel has adapted to cope with its distinct functional properties. Here we have addressed this question by the structure determination of mouse TMEM16A by cryo-electron microscopy and a complementary functional characterization. The protein shows a similar organization to nhTMEM16, except for changes at the site of catalysis. There, the conformation of transmembrane helices constituting a membrane-spanning furrow that provides a path for lipids in scramblases has changed to form an enclosed aqueous pore that is largely shielded from the membrane. Our study thus reveals the structural basis of anion conduction in a TMEM16 channel and it defines the foundation for the diverse functional behavior in the TMEM16 family.

DOI10.7554/eLife.26232
Alternate JournalElife
PubMed ID28561733
PubMed Central IDPMC5470873
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