Fast recovery of disrupted tip links induced by mechanical displacement of hair bundles
- PMID: 33199645
- PMCID: PMC7720144
- DOI: 10.1073/pnas.2016858117
Fast recovery of disrupted tip links induced by mechanical displacement of hair bundles
Abstract
Hearing and balance rely on the capacity of mechanically sensitive hair bundles to transduce vibrations into electrical signals that are forwarded to the brain. Hair bundles possess tip links that interconnect the mechanosensitive stereocilia and convey force to the transduction channels. A dimer of dimers, each of these links comprises two molecules of protocadherin 15 (PCDH15) joined to two of cadherin 23 (CDH23). The "handshake" that conjoins the four molecules can be disrupted in vivo by intense stimulation and in vitro by exposure to Ca2+ chelators. Using hair bundles from the rat's cochlea and the bullfrog's sacculus, we observed that extensive recovery of mechanoelectrical transduction, hair bundle stiffness, and spontaneous bundle oscillation can occur within seconds after Ca2+ chelation, especially if hair bundles are deflected toward their short edges. Investigating the phenomenon in a two-compartment ionic environment that mimics natural conditions, we combined iontophoretic application of a Ca2+ chelator to selectively disrupt the tip links of individual frog hair bundles with displacement clamping to control hair bundle motion and measure forces. Our observations suggest that, after the normal Ca2+ concentration has been restored, mechanical stimulation facilitates the reconstitution of functional tip links.
Keywords: auditory system; cadherin; cochlea; hair cell; vestibular system.
Copyright © 2020 the Author(s). Published by PNAS.
Conflict of interest statement
The authors declare no competing interest.
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References
-
- Hudspeth A. J., Integrating the active process of hair cells with cochlear function. Nat. Rev. Neurosci. 15, 600–614 (2014). - PubMed
-
- Reichenbach T., Hudspeth A. J., The physics of hearing: Fluid mechanics and the active process of the inner ear. Rep. Prog. Phys. 77, 076601 (2014). - PubMed
-
- Howard J., Roberts W. M., Hudspeth A. J., Mechanoelectrical transduction by hair cells. Annu. Rev. Biophys. Biophys. Chem. 17, 99–124 (1988). - PubMed
-
- Jacobs R. A., Hudspeth A. J., Ultrastructural correlates of mechanoelectrical transduction in hair cells of the bullfrog’s internal ear. Cold Spring Harb. Symp. Quant. Biol. 55, 547–561 (1990). - PubMed
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