Imperial College London
Alternate

Dr Andrei S. Kozlov

Faculty of Engineering, Department of Bioengineering

Reader in Sensory Neuroscience
 
 
 
//

Contact

 

+44 (0)20 7594 1338a.kozlov Website

 
 
//

Location

 

RSM 3.12Royal School of MinesSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@article{Gianoli:2022:10.1016/j.bpj.2022.02.016,
author = {Gianoli, F and Hogan, B and Dilly, E and Risler, T and Kozlov, A},
doi = {10.1016/j.bpj.2022.02.016},
journal = {Biophysical Journal},
pages = {897--909},
title = {Fast adaptation of cooperative channels engenders Hopf bifurcations in auditory hair cells},
url = {http://dx.doi.org/10.1016/j.bpj.2022.02.016},
volume = {121},
year = {2022}
}
Download

RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Since the pioneering work of Thomas Gold, published in 1948, it has been known that we owe our sensitive sense of hearing to a process in the inner ear that can amplify incident sounds on a cycle-by-cycle basis. Called the active process, it uses energy to counteract the viscous dissipation associated with sound-evoked vibrations of the ear’s mechanotransduction apparatus. Despite its importance, the mechanism of the active process and the proximate source of energy that powers it have remained elusive, especially at the high frequencies characteristic of amniote hearing. This is partly due to our insufficient understanding of the mechanotransduction process in hair cells, the sensory receptors and amplifiers of the inner ear. It has been proposed previously that cyclical binding of Ca2+ ions to individual mechanotransduction channels could power the active process. That model, however, relied on tailored reaction rates that structurally forced the direction of the cycle. Here we ground our study on our previous model of hair-cell mechanotransduction, which relied on cooperative gating of pairs of channels, and incorporate into it the cyclical binding of Ca2+ ions. With a single binding site per channel and reaction rates drawn from thermodynamic principles, the current model shows that hair cells behave as nonlinear oscillators that exhibit Hopf bifurcations, dynamical instabilities long understood to be signatures of the active process. Using realistic parameter values, we find bifurcations at frequencies in the kilohertz range with physiological Ca2+ concentrations. The current model relies on the electrochemical gradient of Ca2+ as the only energy source for the active process and on the relative motion of cooperative channels within the stereociliary membrane as the sole mechanical driver. Equipped with these two mechanisms, a hair bundle proves capable of operating at frequencies in the kilohertz range, characteristic of amniote hearing.
AU  - Gianoli,F
AU  - Hogan,B
AU  - Dilly,E
AU  - Risler,T
AU  - Kozlov,A
DO  - 10.1016/j.bpj.2022.02.016
EP  - 909
PY  - 2022///
SN  - 0006-3495
SP  - 897
TI  - Fast adaptation of cooperative channels engenders Hopf bifurcations in auditory hair cells
T2  - Biophysical Journal
UR  - http://dx.doi.org/10.1016/j.bpj.2022.02.016
UR  - http://hdl.handle.net/10044/1/95757
VL  - 121
ER  -
Download