Nano-sized molecular motors that exist in the hair cells of the inner ear sense the vibrations of all sounds, whether loud like heavy metal being ground together or subtle and soothing sounds like those of the ocean.
Researchers at the School of Medicine, University of Pennsylvania have identified the molecular motor protein. Called myo1c, it allows an individual amino acid change to disturb the working of the cochlea of the inner ear.
The mutation, named R156W, was initially discovered in a patient who lost his cochlear hearing. This impacts the manner in which the myo1c protein interacts with the actin filaments, which is also present in the inner ear. Normal hearing depends upon this interaction between the two proteins.
A research team led by Michael Greenberg at UPenn has analyzed the biochemical and mechanical characteristics of the mutant myosin protein. The team compared the two proteins and their properties such as the kinetics and motility noting that the mutant was less sensitive to mechanical loads. This showed it stayed attached to the actin filaments for a much shorter period. The National Institutes of Health and the American Heart Association financed the research. The research paper was presented at the Biophysical society meeting held in Baltimore on March 6.