SLC38A3 Gene - SNAT3 Glutamine Transporter | Function, Expression & Disease

SLC38A3 encodes SNAT3 (sodium-coupled neutral amino acid transporter 3), a member of the SLC38 family. It mediates the sodium-dependent transport of neutral amino acids, particularly glutamine, with high affinity. SNAT3 is expressed predominantly in brain (astrocytes) and liver, where it plays a critical role in glutamine-glutamate cycling and hepatic urea synthesis. The transporter is bidirectional and can also function in efflux mode under certain conditions.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• REACT:116909 – Transport of glucose and other sugars

• bile salts and organic acids

• metal ions and amine compounds

• REACT:111045 – Amino acid transport across the plasma membrane

• WP:WP822 – Glutamine metabolism

• WP:WP364 – Urea cycle and metabolism of amino groups

SNAT3 is a 504-amino acid transmembrane protein with 11 predicted membrane-spanning domains. It functions as a sodium-coupled symporter for neutral amino acids, with highest affinity for glutamine (Km ~0.5 mM). The protein is localized to the plasma membrane and is expressed in astrocytes, hepatocytes, and renal tubules. SNAT3 plays a key role in the glutamine-glutamate cycle in the brain and in hepatic nitrogen metabolism. Its expression is regulated by ammonia and pH, and it is implicated in cancer cell metabolism.