• Nanion Technologies: Smart Tools for Ion Channel Research

    Nanion Technologies: Smart Tools for Ion Channel Research

  • SyncroPatch 384i: HTS Automated Patch Clamp

    SyncroPatch 384i: HTS Automated Patch Clamp

  • SURFE²R 96SE: Label-free HTS Transporter Screening

    SURFE²R 96SE: Label-free HTS Transporter Screening

  • Dynamic Clamp: Patchliner

    Dynamic Clamp: Patchliner

  • Bilayer recordings: Orbit product family

    Bilayer recordings: Orbit product family

  • CardioExcyte 96 SOL: Pacing Cardiomyocytes with Light

    CardioExcyte 96 SOL: Pacing Cardiomyocytes with Light

Our Product Portfolio

SyncroPatch 384i

SyncroPatch 384i

Patchliner

Patchliner

Port-a-Patch

Port-a-Patch

Port-a-Patch mini

Port-a-Patch mini

CardioExcyte 96

CardioExcyte 96

FLEXcyte 96

FLEXcyte 96

SURFE²R 96SE

SURFE²R 96SE

SURFE²R N1

SURFE²R N1

Orbit 16

Orbit 16

Orbit Mini

Orbit Mini

Vesicle Prep Pro

Vesicle Prep Pro

2018 - An allosteric mechanism of inactivation in the calcium-dependent chloride channel BEST1

icon pap   Port-a-Patch publication in Journal of General Physiology (2018)

Authors:
Vaisey G., Long S.B.

Journal:
Journal of General Physiology (2018) doi:10.1085/jgp.201812190


Abstract:

Bestrophin proteins are calcium (Ca2+)-activated chloride channels. Mutations in bestrophin 1 (BEST1) cause macular degenerative disorders. Whole-cell recordings show that ionic currents through BEST1 run down over time, but it is unclear whether this behavior is intrinsic to the channel or the result of cellular factors. Here, using planar lipid bilayer recordings of purified BEST1, we show that current rundown is an inherent property of the channel that can now be characterized as inactivation. Inactivation depends on the cytosolic concentration of Ca2+, such that higher concentrations stimulate inactivation. We identify a C-terminal inactivation peptide that is necessary for inactivation and dynamically interacts with a receptor site on the channel. Alterations of the peptide or its receptor dramatically reduce inactivation. Unlike inactivation peptides of voltage-gated channels that bind within the ion pore, the receptor for the inactivation peptide is on the cytosolic surface of the channel and separated from the pore. Biochemical, structural, and electrophysiological analyses indicate that binding of the peptide to its receptor promotes inactivation, whereas dissociation prevents it. Using additional mutational studies we find that the “neck” constriction of the pore, which we have previously shown to act as the Ca2+-dependent activation gate, also functions as the inactivation gate. Our results indicate that unlike a ball-and-chain inactivation mechanism involving physical occlusion of the pore, inactivation in BEST1 occurs through an allosteric mechanism wherein binding of a peptide to a surface-exposed receptor controls a structurally distant gate.


Download here

Back to Overview

Nanion Corporate Blog

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.