title: The system N transporter SN2 doubles as a transmitter precursor furnisher and a potential regulator of NMDA receptors.
abstract: Activation of NMDA receptor requires two co-agonists, glutamate and glycine. Despite its intrinsic role in brain functions molecular mechanisms involved in glutamate replenishment and identification of the origin of glycine have eluded characterization. We have performed direct measurements of glycine flux by SN2 (Slc38a5; also known as SNAT5), executed extensive electrophysiological characterization as well as implemented ratiometric analyses to show that SN2 transport resembles SN1 in mechanism but differ in functional implications. We report that rat SN2 mediates electroneutral and bidirectional transport of glutamine and glycine at perisynaptic astroglial membranes. Sophisticated coupled and uncoupled movements of H(+) differentially associate with glutamine and glycine transport by SN2 and regulate pH(i) and the release mode of the transporter. Consequently, SN2 doubles as a transmitter precursor furnisher and a potential regulator of NMDA receptors.
authors: The Biotechnology Center and Center for Molecular Biology and Neuroscience, University of Oslo, Blindern, Oslo, Norway.
authors: El Hassan
authors: el H
authors: Hamdani
authors: Marius
authors: M
authors: Gudbrandsen
authors: Mona
authors: M
authors: Bjørkmo
authors: Farrukh Abbas
authors: FA
authors: Chaudhry
mesh_terms: D026921:Amino Acid Transport Systems, Neutral / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D005998:Glycine / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D026921:Amino Acid Transport Systems, Neutral; D026901:Membrane Transport Proteins; D016194:Receptors, N-Methyl-D-Aspartate; C442247:Slc38a5 protein, rat; D005973:Glutamine; D018698:Glutamic Acid; D005998:Glycine