Sodium-dependent，high-affinity amino acid transporter that mediates the uptake of L-glutamate and also L-aspartate and D-aspartate. Functions as a symporter that transports one amino acid molecule together with two or three Na+ ions and one proton，in parallel with the counter-transport of one K+ ion. Mediates Cl- flux that is not coupled to amino acid transport; this avoids the accumulation of negative charges due to aspartate and Na+ symport. Plays a redundant role in the rapid removal of released glutamate from the synaptic cleft，which is essential for terminating the postsynaptic action of glutamate.
