SLC7A9: Solute Carrier Family 7 Member 9
Cystine and dibasic amino acid transporter, implicated in cystinuria
Gene Information Card
| Symbol | SLC7A9 |
|---|---|
| Full Name | Solute Carrier Family 7 Member 9 |
| Gene Type | protein-coding |
| Chromosomal Location | 19q13.11 |
| NCBI Gene ID | 11136 ncbi.nlm.nih.gov/gene/11136 |
| Ensembl ID | ENSG00000121488 |
| UniProt ID | P82251 |
| OMIM ID | 604144 |
| HGNC ID | 11067 |
| Aliases | b(0,+)AT1, BAT1, CSNU3 |
Description
SLC7A9 encodes the light subunit (b(0,+)AT1) of the heteromeric amino acid transporter that mediates the uptake of cystine and dibasic amino acids (ornithine, arginine, lysine) in the kidney and intestine. It associates with the heavy subunit SLC3A1 (rBAT) to form the functional transporter. Mutations in SLC7A9 cause cystinuria type B, an autosomal recessive disorder characterized by defective renal reabsorption of cystine leading to recurrent kidney stones.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cystinuria type B | Loss-of-function mutations in SLC7A9 impair cystine reabsorption in renal proximal tubule, leading to cystine stone formation | ClinVar, OMIM #604144 |
| Cystinuria (non-type I) | Dominant-negative or hypomorphic alleles cause milder, non-type I cystinuria | OMIM #600918 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Kidney | 12.5 | High |
| Small intestine | 8.3 | Medium |
| Liver | 2.1 | Low |
| Pancreas | 1.8 | Low |
| Testis | 0.9 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 5.2 | Moderate expression |
| Caco-2 | 3.8 | Intestinal epithelial model |
| HK-2 | 7.1 | Renal proximal tubule cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.614G>A (p.Arg205Gln) | Missense | Common in European populations | Impaired transport activity |
| c.649G>A (p.Gly217Arg) | Missense | Rare | Loss of function |
| c.1000C>T (p.Arg334Cys) | Missense | Found in cystinuria patients | Reduced surface expression |
| c.1195_1197del (p.Phe399del) | Deletion | Rare | Frameshift, loss of function |
Mutation functional classification
Loss of Function (LOF)
Most SLC7A9 missense and truncating mutations reduce or abolish cystine transport activity, leading to cystinuria type B.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
Some missense variants (e.g., p.Arg205Gln) can exert dominant-negative effects when co-expressed with wild-type SLC3A1, explaining non-type I cystinuria.
View complete mutation data：
Gene Ontology (GO)
| • L-cystine transmembrane transporter activity (GO:0005294) | • basic amino acid transmembrane transporter activity (GO:0015171) |
| • L-arginine transmembrane transporter activity (GO:0015187) | • L-lysine transmembrane transporter activity (GO:0015189) |
| • L-cystine transport (GO:0015825) | • L-amino acid transport (GO:0015807) |
| • apical plasma membrane (GO:0016324) | • plasma membrane (GO:0005886) |
Pathways
• Amino acid transport across the renal brush border membrane
• Cystinuria (type B) – defective reabsorption of cystine and dibasic amino acids
Protein Summary
SLC7A9 (b(0,+)AT1) is a 487-amino acid protein with 12 transmembrane domains. It functions as the catalytic light subunit of the heteromeric amino acid transporter b(0,+)AT/rBAT. The transporter exchanges extracellular cystine or dibasic amino acids for intracellular neutral amino acids. SLC7A9 is N-glycosylated and requires co-expression with SLC3A1 for trafficking to the plasma membrane. Defects in SLC7A9 cause cystinuria type B, accounting for ~50% of cystinuria cases.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SLC7A9 Knockout HEK293 Cell Line | EDJ-KQ7296 | Human | 11136 | Details Get a Quote |
| SLC7A9 Knockout HeLa Cell Line | EDJ-KQ55579 | Human | 11136 | Details Get a Quote |
| SLC7A9 Knockout A-549 Cell Line | EDJ-KQ64076 | Human | 11136 | Details Get a Quote |
| SLC7A9 Knockout HCT 116 Cell Line | EDJ-KQ72525 | Human | 11136 | Details Get a Quote |
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