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Kinetic analysis of ASIC1a delineates conformational signaling from proton-sensing domains to the channel gate

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Vullo Sabrina, Ambrosio Nicolas, Kucera Jan P, Bignucolo Olivier, Kellenberger Stephan,
Project Understanding the roles of mechanical stretch and of sodium channel nanodomains in cardiac excitation: a multidisciplinary approach
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Original article (peer-reviewed)

Journal eLife
Volume (Issue) 10
Page(s) e66488
Title of proceedings eLife
DOI 10.7554/elife.66488

Open Access

URL http://doi.org/10.7554/eLife.66488
Type of Open Access Publisher (Gold Open Access)

Abstract

Acid-sensing ion channels (ASICs) are neuronal Na + channels that are activated by a drop in pH. Their established physiological and pathological roles, involving fear behaviors, learning, pain sensation, and neurodegeneration after stroke, make them promising targets for future drugs. Currently, the ASIC activation mechanism is not understood. Here, we used voltage-clamp fluorometry (VCF) combined with fluorophore-quencher pairing to determine the kinetics and direction of movements. We show that conformational changes with the speed of channel activation occur close to the gate and in more distant extracellular sites, where they may be driven by local protonation events. Further, we provide evidence for fast conformational changes in a pathway linking protonation sites to the channel pore, in which an extracellular interdomain loop interacts via aromatic residue interactions with the upper end of a transmembrane helix and would thereby open the gate.
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