An allosteric gating model recapitulates the biophysical properties of I<sub>K,L</sub> expressed in mouse vestibular type I hair cells

Type I and type II hair cells are the sensory receptors of the mammalian vestibular epithelia. Type I hair cells are characterized by their basolateral membrane being enveloped in a single large afferent nerve terminal, named the calyx, and by the expression of a low-voltage-activated outward rectif...

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Autores principales: Spaiardi, Pablo, Tavazzani, Elisa, Manca, Marco, Milesi, Verónica, Russo, Giancarlo, Prigioni, Ivo, Marcotti, Walter, Magistretti, Jacopo, Masetto, Sergio
Formato: Articulo
Lenguaje:Inglés
Publicado: 2017
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/87276
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id I19-R120-10915-87276
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
channel gating model
IK,L
type I vestibular hair cell
spellingShingle Ciencias Exactas
channel gating model
IK,L
type I vestibular hair cell
Spaiardi, Pablo
Tavazzani, Elisa
Manca, Marco
Milesi, Verónica
Russo, Giancarlo
Prigioni, Ivo
Marcotti, Walter
Magistretti, Jacopo
Masetto, Sergio
An allosteric gating model recapitulates the biophysical properties of I<sub>K,L</sub> expressed in mouse vestibular type I hair cells
topic_facet Ciencias Exactas
channel gating model
IK,L
type I vestibular hair cell
description Type I and type II hair cells are the sensory receptors of the mammalian vestibular epithelia. Type I hair cells are characterized by their basolateral membrane being enveloped in a single large afferent nerve terminal, named the calyx, and by the expression of a low-voltage-activated outward rectifying K<sup>+</sup> current, I<sub>K,L</sub>. The biophysical properties and molecular profile of I<sub>K,L</sub> are still largely unknown. By using the patch-clamp whole-cell technique, we examined the voltage- and time-dependent properties of I<sub>K,L</sub> in type I hair cells of the mouse semicircular canal. We found that the biophysical properties of I<sub>K,L</sub> were affected by an unstable K<sup>+</sup> equilibrium potential (V<sub>eq</sub>K<sup>+</sup>). Both the outward and inward K<sup>+</sup> currents shifted V<sub>eq</sub>K<sup>+</sup> consistent with K<sup>+</sup> accumulation or depletion, respectively, in the extracellular space, which we attributed to a residual calyx attached to the basolateral membrane of the hair cells. We therefore optimized the hair cell dissociation protocol in order to isolate mature type I hair cells without their calyx. In these cells, the uncontaminated I<sub>K,L</sub> showed a half-activation at –79.6 mV and a steep voltage dependence (2.8 mV). I<sub>K,L</sub> also showed complex activation and deactivation kinetics, which we faithfully reproduced by an allosteric channel gating scheme where the channel is able to open from all (five) closed states. The ‘early’ open states substantially contribute to I<sub>K,L</sub> activation at negative voltages. This study provides the first complete description of the ‘native’ biophysical properties of I<sub>K,L</sub> in adult mouse vestibular type I hair cells.
format Articulo
Articulo
author Spaiardi, Pablo
Tavazzani, Elisa
Manca, Marco
Milesi, Verónica
Russo, Giancarlo
Prigioni, Ivo
Marcotti, Walter
Magistretti, Jacopo
Masetto, Sergio
author_facet Spaiardi, Pablo
Tavazzani, Elisa
Manca, Marco
Milesi, Verónica
Russo, Giancarlo
Prigioni, Ivo
Marcotti, Walter
Magistretti, Jacopo
Masetto, Sergio
author_sort Spaiardi, Pablo
title An allosteric gating model recapitulates the biophysical properties of I<sub>K,L</sub> expressed in mouse vestibular type I hair cells
title_short An allosteric gating model recapitulates the biophysical properties of I<sub>K,L</sub> expressed in mouse vestibular type I hair cells
title_full An allosteric gating model recapitulates the biophysical properties of I<sub>K,L</sub> expressed in mouse vestibular type I hair cells
title_fullStr An allosteric gating model recapitulates the biophysical properties of I<sub>K,L</sub> expressed in mouse vestibular type I hair cells
title_full_unstemmed An allosteric gating model recapitulates the biophysical properties of I<sub>K,L</sub> expressed in mouse vestibular type I hair cells
title_sort allosteric gating model recapitulates the biophysical properties of i<sub>k,l</sub> expressed in mouse vestibular type i hair cells
publishDate 2017
url http://sedici.unlp.edu.ar/handle/10915/87276
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