A sugar transporter as a candidate for the outer hair cell motor

Forces developed by cochlear outer hair cells (OHCs) are responsible for the sharp tuning that underlies sensitivity and frequency selectivity in the ear. OHCs exhibit a voltage-dependent motility involving a 'motor' protein embedded in the basolateral membrane. The motor has so far resisted molecular identification. Here we provide evidence that it may be related to a fructose transporter. We show that OHCs are able to transport this sugar selectively and that the sugar alters electrical properties of the OHC motor. These data can be combined into an integrated model of a sugar carrier, that makes the novel prediction, demonstrated here, that such 'neutral' transporters can be voltage dependent.