Mechanism of hearing discovered!


Scientists have revealed, for the first time and in near-atomic detail, the structure of the key part of the inner ear responsible for hearing.

“This is the last sensory system in which that fundamental molecular machinery has remained unknown,” said senior author. “The molecular machinery that carries out this absolutely amazing process has been unresolved for decades.”

The researchers made the discovery by teasing out the structure through years of painstaking research to isolate the process that enables the inner ear to convert vibrations into sound, known as the mechanosensory transduction complex.

The study, which revealed the structure through cryo-electron microscopy, published in the journal Nature. The findings could point the way toward developing new treatments for hearing impairments, which affect more than 460 million people worldwide.

The discovery reveals the architecture of the inner ear complex that converts vibrations into electrical impulses that the brain translates as sound. Known as mechanosensory transduction, the process is responsible for the sensations of balance and sound.

Scientists exploited the fact that the roundworm Caenorhabditis elegans harbors a mechanosensory complex very similar to that of humans.

Resolving the basic structure is the first step, according to the senior author.

“It immediately suggests mechanisms by which one might be able to compensate for those deficits,” the author said. “If a mutation gives rise to a defect in the transduction channel that causes hearing loss, it’s possible to design a molecule that fits into that space and rescues the defect. Or it may mean we can strengthen interactions that have been weakened.”

Hearing loss can be inherited through gene mutations that alter the proteins comprising the mechanosensory transduction complex. Or it can occur from damage, including sustained exposure to loud noise. In either case, the researchers’ discovery allows scientists to visualize the complex for the first time.

The finding is an extraordinary achievement, said one leading neuroscience researcher who was not directly involved in the research.

Researchers resolved the puzzle through careful cultivation and isolation techniques involving 60 million worms over almost five years.

“We spent several years optimizing worm-growth and protein-isolation methods, and had many ‘rock-bottom’ moments when we considered giving up,” co-first author,

https://www.nature.com/articles/s41586-022-05314-8

http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Fstructures-of-the-tmc-1&filter=22

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