[Molecular biological approach to mammalian amino acid transporters]

Several mammalian amino acid transporters have been purified from solubilized membranes to a single protein band with a molecular mass of 60-130 kDa. It has been demonstrated that the mammalian amino acid transporters are expressed in Xenopus oocytes following microinjection of mRNA from various cells and tissues. Using this expression system, a cDNA clone, encoding an amino acid transporter, has been isolated from a tissue cDNA library, and a topological model for the deduced protein is depicted. At present, the models for the structure of the three kinds of amino acid transporters are proposed, one of which is identical with an ecopropic retrovirus receptor.