Excitatory amino acid transporter 2 (EAAT2) and cystine-glutamate exchanger (System xC-) (EAAT2 and System xC-)

Excitatory amino acid transporter 2 (EAAT2), also known as SLC1A2 or GLT-1, and the cystine-glutamate exchanger (System xC-), composed of the catalytic subunit SLC7A11 (xCT), are two distinct transport systems critical for maintaining glutamate homeostasis and redox balance in the central nervous system (UniProt P43004, Q9UPY5). EAAT2 is a sodium-dependent transporter primarily expressed in astrocytes that clears over 90% of synaptic glutamate to prevent excitotoxic neuronal death (Rothstein et al., 1996, Neuron). In contrast, System xC- is a sodium-independent antiporter that exports glutamate in exchange for extracellular cystine, which is the rate-limiting precursor for the synthesis of the antioxidant glutathione (Dringen, 2000, Progress in Neurobiology). Dysregulation of these transporters is implicated in various neurological disorders, including amyotrophic lateral sclerosis (ALS), epilepsy, and Alzheimer's disease, as well as in cancer progression and ferroptosis (Dixon et al., 2012, Cell). Pharmacological strategies include the induction of EAAT2 expression by drugs like ceftriaxone to enhance glutamate clearance and the inhibition of System xC- by agents like sulfasalazine or erastin to induce oxidative stress in tumor cells (Rothstein et al., 2005, Nature; Gout et al., 2001, Leukemia). Because these are two separate molecular entities with different genes and mechanisms, they are typically considered distinct therapeutic targets.

Other names

SLC1A2GLT-1Solute carrier family 1 member 2SLC7A11xCTSystem xc-Solute carrier family 7 member 11

Mechanisms include the transcriptional upregulation of EAAT2 to enhance synaptic glutamate clearance and the pharmacological inhibition of System xC- to deplete intracellular glutathione and induce ferroptosis in cancer cells.