SLC1A5/ASCT2 Protein, Human (sf9)

SLC1A5 is a sodium-coupled antiporter of neutral amino acids. In a tri-substrate transport cycle, it exchanges neutral amino acids between extracellular and intracellular compartments, coupled to the inward cotransport of at least one sodium ion. Its preferred substrate is the essential amino acid L-glutamine, a precursor for biosynthesis of proteins, nucleotides, and amine sugars, as well as an alternative fuel for mitochondrial oxidative phosphorylation. SLC1A5 bidirectionally exchanges L-glutamine with other neutral amino acids such as L-serine, L-threonine, and L-asparagine, supplying L-glutamine to proliferating stem and activated cells to drive the metabolic switch toward cell differentiation. The transport cycle is generally pH-independent, except for L-glutamate. In glial cells, SLC1A5 may mediate extracellular L-glutamate uptake coupled to the cotransport of one proton and one sodium ion in exchange for intracellular L-glutamine, regulating the glutamine/glutamate cycle in the nervous system. It can also transport D-amino acids and may influence NMDA receptor function in retinal neurons by mediating D-serine release from retinal glia. Additionally, SLC1A5 exhibits sodium- and amino acid-dependent but uncoupled channel-like anion conductance with a preference for SCN(-) >> NO3(-) > I(-) > Cl(-) (by similar). Through binding to the fusogenic protein syncytin-1/ERVW-1, it may mediate trophoblast syncytialization, a critical process in placental development involving spontaneous plasma membrane fusion.