Related Experiment Video
Updated: Jul 16, 2026

Measurement of Extracellular Ion Fluxes Using the Ion-selective Self-referencing Microelectrode Technique
Published on: May 3, 2015
Intracellular anions as the voltage sensor of prestin, the outer hair cell motor protein
1Department of Physiology II, University of Tübingen, 72074 Tübingen, Germany.
Abstract:
Outer hair cells (OHCs) of the mammalian cochlea actively change their cell length in response to changes in membrane potential. This electromotility, thought to be the basis of cochlear amplification, is mediated by a voltage-sensitive motor molecule recently identified as the membrane protein prestin. Here, we show that voltage sensitivity is conferred to prestin by the intracellular anions chloride and bicarbonate. Removal of these anions abolished fast voltage-dependent motility, as well as the characteristic nonlinear charge movement ("gating currents") driving the underlying structural rearrangements of the protein. The results support a model in which anions act as extrinsic voltage sensors, which bind to the prestin molecule and thus trigger the conformational changes required for motility of OHCs.
More Related Videos
Related Concept Videos
The Resting Membrane Potential
Protein Diffusion in the Membrane
Resting Membrane Potential
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
Patch Clamp
In this method, a glass micropipette containing electrolyte solution is tightly sealed against a small portion of the cell membrane. As a result, a patch of the cell...
Cell Motility through Blebbing
Blebbing Through the Matrix
In multicellular...
G-Protein Gated Ion Channels
Sensory organs,...

