Purpose of the assay is to determine the functionality of the SLC1A3 transporter, stably expressed in the HEK-293 JumpIn TREx cell line (SLC1A3 OverExpressing - OE - cell line). SLC1A3 (EAAT1) is a sodium-dependent, high-affinity amino acid transporter that mediates the uptake of L-glutamate, L-aspartate, and L-Cysteine. It plays an essential role in transporting these amino acids across plasma membrane in neurons, and it functions as a symporter that co-transports one amino acid together with 2 or 3 Na+ ions. The transport mediated by SLC1A3 is therefore electrogenic. For this reason, the HEK-293 JumpIn TREx/SLC1A3 OE cell line was tested using the Membrane Potential (MP) dye read-out, which is described in the section below.