Slc7a13, also known as AGT1, is a membrane protein that functions as a cystine transporter. It is localized in the apical membrane of the S3 segment of renal proximal tubules, where it forms a heterodimer with rBAT/SLC3A1 [3]. This transporter is involved in the reabsorption of cystine and may play a role in preventing urinary loss of aspartate and glutamate [3].

Despite initial speculation, a study screening 17 cystinuria patients negative for SLC3A1 and SLC7A9 mutations found no evidence that SLC7A13 point mutations contribute to the etiology of cystinuria, suggesting other genetic factors are responsible for the phenotype in some patients [2]. In a study on urolithiasis, Slc7a13 was among the functional solute carriers used to identify distinct injured-proximal tubular cell types in calculi rats, indicating its potential role in kidney injury related to urolithiasis [1].

In conclusion, Slc7a13 is a significant cystine transporter in the renal proximal tubules. Although it has not been proven to be directly involved in cystinuria, research on animal models such as calculi rats has shown its potential association with kidney-related diseases like urolithiasis-mediated kidney injury, enhancing our understanding of renal cell biology and kidney disease mechanisms [1,2].