SLC1A5 and neoplasm: ASCT2 mediates the Na+-coupled influx of glutamine, and LAT1 then mediates the efflux of glutamine in exchange of the influx of essential amino acids (for example, isoleucine) and mTOR activation.21, 22 In this way, ASCT2 and LAT1 are co-opted to promote metabolic reprograming and aggressive tumor progression.