Mechanoelectrical transduction by hair cells commences with hair-bundle deflection, which is postulated to tense filamentous tip links connected to transduction channels. Because direct mechanical stimulation of tip links has not been experimentally possible, this hypothesis has not been tested directly. We have engineered DNA tethers that link superparamagnetic beads to tip links and exert mechanical forces on the links when exposed to a magnetic-field gradient. By pulling directly on tip links of the bullfrog's sacculus we have evoked transduction currents from hair cells, confirming the hypothesis that tension in the tip links opens transduction channels. This demonstration of direct mechanical access to tip links additionally lays a foundation for experiments probing the mechanics of individual channels.
Animal experimentation: All procedures were approved by the University's Institutional Animal Care and Use Committee under protocol 13665. Animals were sacrificed by dual pithing after anesthesia by immersion in ethyl-3-aminobenzoate methanesulfonic acid.
- Frank Jülicher, Max Planck Institute for the Physics of Complex Systems, Germany
© 2016, Basu et al.
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