Scientists have finally revealed the structure of a mysterious protein complex inside the inner ear that enables humans to hear.
To solve this decades-old puzzle, researchers needed to grow 60 million roundworms (Certain types are elegant), which uses a protein complex very similar to humans to sense touch.
Since humans only have a tiny amount of this protein inside their inner ears, they turn to another source It was the only way the team was able to synthesize enough protein for the study.
“We’ve spent several years refining the worms’ growth methods and protein isolation, and we had many ‘rock bottom’ moments when we thought about giving up,” Says Co-first author Sarah Clark, a biochemist from Oregon Health & Science University (OHSU) in Portland.
Researchers have known for some time that transmembrane channel-like protein complex 1 (TMC1) plays an important role in hearing, but its exact makeup has remained elusive.
“This is the last sensory system in which the underlying molecular mechanism remains unknown,” Says Senior author Eric Guo, a biochemist at OHSU.
Thanks to this new research published in temper natureWe now know that this protein complex acts as a tension-sensitive ion channel that opens and closes according to the movement of hair within the inner ear.
Using electron microscopy, the researchers discovered that the protein complex is “accordion-like,” with subunits “balanced like knobs” on either side.
Sound waves traveling through the ear hit the eardrum (tympanic membrane), and then to the inner ear where the bones vibrate; Three of the smallest bones of the body. The ossicles strike the snail-like cochlea, which in turn sloughs off microscopic finger-like filaments called striocelli.
These stereotaxic ions are embedded in cells that contain ion channels formed by the TMC1 complex that open and close as the hair moves, sending electrical signals along the auditory nerve to the brain to be interpreted as sound.
“The field of auditory neuroscience has been waiting for these results for decades, and now that they’re here – we’re ecstatic,” Says OSHU otolaryngologist Peter Barr-Gillespie, a national leader in audiology research, was not involved in the study.
This discovery may one day help researchers develop treatments for hearing loss.
Hearing loss and deafness affect more than 460 million people worldwide. By understanding the nature of hearing, researchers can continue to find diverse ways to support, treat or prevent hearing loss in our community.
This paper was published in temper nature.