SLC1A4, also known as ASCT1, is a neutral amino acid transporter. Its other name, ASCT1, was given because it mediates obligatory exchange of alanine, serine, cysteine, and threonine. SLC1A4 mediates the efflux of glutamate from the neuron into the synaptic junction via calcium-independent release, as well as mediating the efflux of L-serine from glial cells and its uptake by neurons. SLC1A4-mediated transport is shown to involve a symmetrical potassium-independent electroneutral exchange of neutral amino acids and sodium, such that the current activated during transport is carried only by chloride ions.
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