ASCT2

ASCT2 (SLC1A5) is a sodium-dependent neutral amino acid transporter that primarily mediates glutamine exchange across the plasma membrane and maintains intracellular amino acid homeostasis through an antiport mechanism^[1]. ASCT2 supports glutamine-dependent metabolic programs that regulate anabolic growth, amino acid balance, and signaling pathways linked to cellular proliferation^[1][2]. Mechanistically, glutamine transported through ASCT2 contributes to tricarboxylic acid cycle fueling and provides substrates required for nucleotide, lipid, and non-essential amino acid biosynthesis, thereby supporting metabolic reprogramming in rapidly proliferating cells and tumors^[1][3]. Increased ASCT2 expression is frequently observed in highly proliferative tissues and multiple cancers, where glutamine demand is elevated and transporter activity contributes to tumor growth and survival^[1][2][4]. In experimental cancer models, genetic deletion or inhibition of ASCT2 reduces amino acid uptake and suppresses tumor growth, supporting its value as a functional target for studying glutamine-dependent metabolism^[2][4]. Compared with the closely related isoform ASCT1 (SLC1A4), ASCT2 displays distinct substrate preferences and functions predominantly as a high-affinity glutamine transporter, highlighting its specialized role in cancer-associated nutrient utilization^[1]. A mitochondrial SLC1A5 variant further expands ASCT2-related biology by transporting glutamine into mitochondria, where it promotes ATP production, glutathione synthesis, hypoxia adaptation, and metabolic reprogramming in cancer cells^[5]. For experimental applications, pharmacological inhibitors such as GPNA and V-9302 are widely used to interrogate ASCT2-dependent glutamine transport, although inhibitor selectivity and off-target effects require careful interpretation of mechanistic studies^[6][7].