Solute carrier family 7 member 9 (SLC7A9)

Solute carrier family 7 member 9 (SLC7A9) is the light chain component of a heteromeric amino acid transporter complex, functioning primarily with the heavy chain SLC3A1 (rBAT) to form the **b(0,+)-type amino acid transporter** in the kidney and small intestine[1][2][3][4][5]. This transporter is essential for the reabsorption of cystine and dibasic amino acids (such as lysine, ornithine, and arginine) from the urine back into the bloodstream[1][2][4][5]. Mutations in SLC7A9 result in the genetic disorder cystinuria, characterized by excessive cystine excretion and the formation of cystine stones in the urinary system[4][5]. The complex operates as an **obligatory exchanger**, importing cationic amino acids and cystine in exchange for neutral amino acids, independent of sodium, and is vital for maintaining amino acid homeostasis[1][2][3][4].

Other names

b(0,+)-type amino acid transporter 1BAT1b(0,+)AT1CSNU3glycoprotein-associated amino acid transporter b0,+AT1solute carrier family 7 (amino acid transporter light chain, bo,+ system), member 9solute carrier family 7 (glycoprotein-associated amino acid transporter light chain, bo,+ system), member 9solute carrier family 7, member 9

Drugs increase cystine solubility, reduce stone formation, or promote cystine excretion. Act indirectly by altering substrate concentrations transported by SLC7A9 rather than modulating transporter function directly.