Structural relationship between the putative hair cell mechanotransduction channel TMC1 and TMEM16 proteins.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30063209.
- Also identified by DOI 10.7554/eLife.38433 and PMC identifier 6067890.
- Licence recorded as CC0.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The hair cell mechanotransduction (MET) channel complex is essential for hearing, yet it's molecular identity and structure remain elusive. The transmembrane channel-like 1 (TMC1) protein localizes to the site of the MET channel, interacts with the tip-link responsible for mechanical gating, and genetic alterations in TMC1 alter MET channel properties and cause deafness, supporting the hypothesis that TMC1 forms the MET channel. We generated a model of TMC1 based on X-ray and cryo-EM structures of TMEM16 proteins, revealing the presence of a large cavity near the protein-lipid interface that also harbors the Beethoven mutation, suggesting that it could function as a permeation pathway. We also find that hair cells are permeable to 3 kDa dextrans, and that dextran permeation requires TMC1/2 proteins and functional MET channels, supporting the presence of a large permeation pathway and the hypothesis that TMC1 is a pore forming subunit of the MET channel complex.
Medical subject headings
- Anoctamins
- Deafness
- Mechanotransduction, Cellular
- Membrane Proteins