A two-state piezoelectric model for outer hair cell motility.
Recent studies have revealed that voltage-dependent length changes of the outer hair cell are based on charge transfer across the membrane. Such a motility can be explained by an "area motor" model, which assumes two states in the motor and that conformational transitions involve transfer of motor charge across the membrane and mechanical displacements of the membrane. Here it is shown that the area motor is piezoelectric and that the hair cell that incorporates such a motor in its lateral membrane is also piezoelectric. Distinctive features of the outer hair cell are its exceptionally large piezoelectric coefficient, which exceeds the best known piezoelectric material by four orders of magnitude, and its prominent nonlinearity due to the discreteness of motor states.
Iwasa
K H
KH
Biophysics Section, Laboratory of Cellular Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892, USA. iwasa@nih.gov
D000818:Animals; D001696:Biomechanical Phenomena; D002462:Cell Membrane / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D003051:Cochlea / Q000166:cytology; D018072:Hair Cells, Auditory, Outer / Q000166:cytology / Q000502:physiology*; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000378:metabolism*; D011487:Protein Conformation; D015203:Reproducibility of Results; D055672:Static Electricity
D020409:Molecular Motor Proteins