CANUL-TEC, Juan; KUMAR, Anand; DHENIN, Jonathan; ASSAL, Redda; LEGRAND, Pierre; REY, Martial; CHAMOT-ROOKE, Julia; REYES, Nicolas

doi:10.15252/embj.2021108341

CANUL-TEC, Juan
Microbiologie Fondamentale et Pathogénicité [MFP]

KUMAR, Anand

Microbiologie Fondamentale et Pathogénicité [MFP]

DHENIN, Jonathan

Langue

Article de revue

Ce document a été publié dans

EMBO Journal. 2022-01-04, vol. 41, n° 1, p. 377-390

EMBO Press

Résumé en anglais

Excitatory amino acid transporters (EAATs) maintain glutamate gradients in the brain essential for neurotransmission and to prevent neuronal death. They use ionic gradients as energy source and co-transport transmitter into the cytoplasm with Na+ and H+, while counter-transporting K+ to re-initiate the transport cycle. However, the molecular mechanisms underlying ion-coupled transport remain incompletely understood. Here, we present 3D X-ray crystallographic and cryo-EM structures, as well as thermodynamic analysis of human EAAT1 in different ion bound conformations, including elusive counter-transport ion bound states. Binding energies of Na+ and H+, and unexpectedly Ca2+, are coupled to neurotransmitter binding. Ca2+ competes for a conserved Na+ site, suggesting a regulatory role for Ca2+ in glutamate transport at the synapse, while H+ binds to a conserved glutamate residue stabilizing substrate occlusion. The counter-transported ion binding site overlaps with that of glutamate, revealing the K+-based mechanism to exclude the transmitter during the transport cycle and to prevent its neurotoxic release on the extracellular side.< Réduire

Mots clés en anglais

cryo-EM

neurotransmitter transport

permeation and transport

solute carrier

X-ray crystallography

URI

https://oskar-bordeaux.fr/handle/20.500.12278/182127

DOI

http://dx.doi.org/10.15252/embj.2021108341

Projet Européen

Molecular bases of human excitatory neurotransmitter transport across the plasma membrane

Project ANR

Centre d'analyse de systèmes complexes dans les environnements complexes - ANR-11-EQPX-0008

Unités de recherche

MFP (Laboratoire Microbiologie Fondamentale et Pathogénicité) - UMR 5234

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The ion‐coupling mechanism of human excitatory amino acid transporters