SLC7A9
Function
Associates with SLC3A1 to form a functional transporter complex that mediates the electrogenic exchange between cationic amino acids and neutral amino acids, with a stoichiometry of 1:1 (PubMed:16825196, PubMed:32494597, PubMed:32817565, PubMed:8663357). Has system b(0,+)-like activity with high affinity for extracellular cationic amino acids and L-cystine and lower affinity for intracellular neutral amino acids (PubMed:16825196, PubMed:32494597, PubMed:8663357). Substrate exchange is driven by high concentration of intracellular neutral amino acids and the intracellular reduction of L-cystine to L-cysteine (PubMed:8663357). Required for reabsorption of L-cystine and dibasic amino acids across the brush border membrane in renal proximal tubules.
Involvement in disease
Cystinuria
CSNU
An autosomal disorder characterized by impaired epithelial cell transport of cystine and dibasic amino acids (lysine, ornithine, and arginine) in the proximal renal tubule and gastrointestinal tract. The impaired renal reabsorption of cystine and its low solubility causes the formation of calculi in the urinary tract, resulting in obstructive uropathy, pyelonephritis, and, rarely, renal failure.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the amino acid-polyamine-organocation (APC) superfamily.
Tissue Specificity
Expressed in the brush border membrane in the kidney (at protein level). Kidney, small intestine, liver and placenta.
Cellular localization
- Apical cell membrane
- Multi-pass membrane protein
- Cell membrane
- Multi-pass membrane protein
Alternative names
BAT1, SLC7A9, Solute carrier family 7 member 9