The lysosomal cystine transporter (LCT) family (TC# 2.A.43) is part of the TOG Superfamily and includes secondary transport proteins that are derived from animals, plants, fungi and other eukaryotes. They exhibit 7 putative transmembrane α-helical spanners (TMSs) and vary in size between about 200 and 500 amino acyl residues, although most have between 300 and 400 residues.[1]
These proteins are found in intracellular organelles of eukaryotes, many in lysosomes. The few that have been characterized transport Cystine (TC# 2.A.43.1.1), basic amino acids such as L-lysine and L-arginine (TC# 2.A.43.2.1) and drugs such as fluconazole and caspofungin (TC# 2.A.43.2.7).