SLC7A7
Function
Heterodimer with SLC3A2, that functions as an antiporter which operates as an efflux route by exporting cationic amino acids from inside the cells in exchange with neutral amino acids plus sodium ions and may participate in nitric oxide synthesis via the transport of L-arginine (PubMed:10080182, PubMed:10655553, PubMed:14603368, PubMed:15756301, PubMed:15776427, PubMed:17329401, PubMed:9829974, PubMed:9878049). Also mediates arginine transport in non-polarized cells, such as monocytes, and is essential for the correct function of these cells (PubMed:15280038, PubMed:31705628). The transport mechanism is electroneutral and operates with a stoichiometry of 1:1 (By similarity). In vitro, Na(+) and Li(+), but also H(+), are cotransported with the neutral amino acids (By similarity).
Involvement in disease
Lysinuric protein intolerance
LPI
A metabolic disorder characterized by increased renal excretion of cationic amino acid (CAA), reduced CAA absorption from intestine, and orotic aciduria. On a normal diet, LPI patients present poor feeding, vomiting, diarrhea, episodes of hyperammoniaemic coma and growth retardation. Hepatosplenomegaly, osteoporosis and a life-threatening pulmonary involvement (alveolar proteinosis) are also seen. Biochemically LPI is characterized by defective transport of dibasic amino acids at the basolateral membrane of epithelial cells in kidney and intestine.
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. L-type amino acid transporter (LAT) (TC 2.A.3.8) family.
Tissue Specificity
Highest expression in kidney and peripheral blood leukocytes (PubMed:9829974). Weaker expression is observed in lung, heart, placenta, spleen, testis and small intestine (PubMed:9829974). Expressed in normal fibroblasts and those from LPI patients (PubMed:10080183, PubMed:11078698). Also expressed in HUVECs, monocytes, retinal pigment epithelial cells, and various carcinoma cell lines, with highest expression in a colon-carcinoma cell line (PubMed:11742806, PubMed:15280038, PubMed:17197568, PubMed:17329401).
Cellular localization
- Basolateral cell membrane
- Multi-pass membrane protein
Alternative names
Y+L amino acid transporter 1, Monocyte amino acid permease 2, Solute carrier family 7 member 7, y(+)L-type amino acid transporter 1, MOP-2, Y+LAT1, y+LAT-1, SLC7A7