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

eLife

Stephan Kellenberger¹  Sabrina Vullo²  Nicolas Ambrosio²  Olivier Bignucolo²  Jan P Kucera³ 

[1] SIB, Swiss Institute of Bioinformatics, Lausanne, Switzerland;Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland;Department of Physiology, University of Bern, Bern, Switzerland;

关键词: conformational change;    ion channel;    voltage-clamp fluorometry;    molecular dynamics;    kinetic model;   

DOI  :  10.7554/eLife.66488

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown