Scientists discovered that the ear mechanism turns sound into electrical activity and a protein called filaments plays a central role in hearing.
The sense of hearing is, quite literally, a molecular tightrope act. Turns out, it involves acrobatics as well. In a paper published in Nature Communications, researchers at Harvard Medical School and Boston Children's Hospital show that a dynamic and delicate connection between two pairs of diminutive protein filaments plays a central role in hearing.
The tension held by these filaments together called a tip link, is essential for the activation of sensory cells in the inner ear. The team's analyses reveal that the filaments, which are joined end-to-end, work together like trapeze artists holding hands. Their grasp on each other can be disrupted, by a loud noise, for example. But with a two-handed grip, they can quickly reconnect when one hand slips.
The findings present a new understanding of the molecular underpinnings of hearing, as well as the sense of balance, which arises from similar processes in the inner ear. Disorders of deafness and balance have been linked to mutations in tip links, and the study results could lead to new therapeutic strategies for such disorders, according to the authors.
"This tiny apparatus, made of less than a dozen proteins, is what helps change sound from a mechanical stimulus into an electrical signal that the brain can decipher," said co-corresponding author David Corey, the Bertarelli Professor of Translational Medical Science at HMS. "Understanding how these proteins work provides insights into the secrets of the sensation of sound." The dynamic connection between the filaments may also function as a circuit breaker that protects other cellular components, according to the researchers.