アミノ酸尿症の分子遺伝学

The homologous proteins rBAT and 4F2hc have been identified as the heavy chains off amily of heteromeric amino acid transporters in mammls. Six light subunits of 4F2hc(LAT 1, LAT 2, y+LAT 1, y+LAT 2, asc 1, and xCT) and one of rBAT (BAT 1) are known.These glycoprotein-associated amino acid transporters, which follow the 12 transmembranetopology model, form heterodimers with the corresponding subunit and then are expressedin the plasma membrane. 4F2hc and y+LAT 1 express system y+L transport activity. On the other hand, rBAT and BAT 1 express system b0,+ activity. BAT 1 and y+LAT 1 have atissue distribution and a chromosomal location that made them good candidate genesfor cystinuria and lysinuric protein intolerance (LPI). Mutational analysis revealedcystinuria-associated mutations for BAT1 and LPI-associated mutations for y+LAT1. Transport defects have been shown for some of the BAT1 and y+LAT1 mutations. In addition, we focus on the animal members of the LAT cluster that form the family of glycoprotein-associated amino acid transporters.