Journal of Biological Chemistry
Volume 286, Issue 3, 21 January 2011, Pages 2297-2307
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Molecular Biophysics
Evidence That Prestin Has at Least Two Voltage-dependent Steps*

https://doi.org/10.1074/jbc.M110.185694Get rights and content
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Prestin is a voltage-dependent membrane-spanning motor protein that confers electromotility on mammalian cochlear outer hair cells, which is essential for normal hearing of mammals. Voltage-induced charge movement in the prestin molecule is converted into mechanical work; however, little is known about the molecular mechanism of this process. For understanding the electromechanical coupling mechanism of prestin, we simultaneously measured voltage-dependent charge movement and electromotility under conditions in which the magnitudes of both charge movement and electromotility are gradually manipulated by the prestin inhibitor, salicylate. We show that the observed relationships of the charge movement and the physical displacement (q-d relations) are well represented by a three-state Boltzmann model but not by a two-state model or its previously proposed variant. Here, we suggest a molecular mechanism of prestin with at least two voltage-dependent conformational transition steps having distinct electromechanical coupling efficiencies.

Anion Transport
Cell Motility
Cell Wall
Membrane Proteins
Molecular Motors
Electrophysiology
Mechanoelectric Coupling
Prestin

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*

This work was supported, in whole or in part, by National Institutes of Health Grant DC00089 (to P. D.). This work was also supported by the Hugh Knowles Center.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1–S5 and text.