Neuronal and glial glycine transporters have different stoichiometries.

Michel J. Roux (1) , Stéphane Supplisson (1)

1 NEURO - Laboratoire de Neurobiologie (UMR 8544)

A neurotransmitter transporter can potentially mediate uptake or release of substrate, and its stoichiometry is a key factor that controls the driving force and thus the neurotransmitter flux direction. We have used a combination of electrophysiology and radio-tracing techniques to evaluate the stoichiometries of two glycine transporters involved in glycinergic or glutamatergic transmission. We show that GlyT2a, a transporter present in glycinergic boutons, has a stoichiometry of 3 Na+/Cl-/glycine, which predicts effective glycine accumulation in all physiological conditions. GlyT1b, a glial transporter, has a stoichiometry of 2 Na+/Cl-/ glycine, which predicts that glycine can be exported or imported, depending on physiological conditions. GlyT1b may thus modulate glutamatergic synapses by increasing or decreasing the glycine concentration around N-methyl-D-aspartate receptors (NMDARs).

Mots clés: GlyT1; GlyT2; NMDA; stoichiometries; Na+; transporter; glycine; thermodynamics; flux coupling

Domaines: Neurobiologie

Michel J. Roux, Stéphane Supplisson. Neuronal and glial glycine transporters have different stoichiometries.. Neuron, 2000, 25 (2), pp.373-83. ⟨hal-00140070⟩