The molecular bases of cystinuria and lysinuric protein intolerance

Cystinuria and lysinuric protein intolerance are inherited aminoacidurias caused by defective amino-acid transport activities linked to a family of heteromeric amino-acid transporters (HATs). HATs comprise two subunits: co-expression of subunits 4F2hc and y(+)LAT-1 induces the efflux of dibasic amino acids from cells, whereas co-expression of subunits rBAT and b(o,+)AT induces the renal reabsorption and intestinal absorption of cystine and dibasic amino acids at the brush border of epithelial cells. Recently, the role of b(o,+)AT (SLC7A9) in cystinuria (non Type I) and the role of y(+)LAT-1 (SLC7A7) in lysinuric protein intolerance have been demonstrated.