SLC1A1 encodes EAAT3 (excitatory amino acid transporter 3), a high-affinity sodium-dependent transporter that mediates cellular uptake of glutamate, aspartate, and cysteine. The protein functions as a symporter, transporting amino acids with 2-3 Na+ ions and one proton while counter-transporting K+ ions. In the nervous system, SLC1A1 plays a critical role in glutamate homeostasis and synaptic function, with loss-of-function studies demonstrating reduced dopamine signaling in basal ganglia circuits and impaired responses to amphetamine stimulation 1. The transporter contributes to metabolic reprogramming in cancer, particularly in natural killer T-cell lymphoma where SLC1A1 promotes glutamine addiction and tumor growth while modulating immune responses through PD-L1 regulation 2. In renal cell carcinoma, SLC1A1 functions as a metabolic dependency, sustaining oncogenic programs through aspartate/glutamate transport and representing a therapeutic target 3. Genetic variants in SLC1A1 show weak associations with obsessive-compulsive disorder, particularly in male patients 4, and reduced SLC1A1 protein levels have been observed in OCD patients 5. The transporter's role extends beyond neurotransmitter recycling to include metabolic support for cellular processes and pathological conditions.