Solute Carrier Family 7, Member 9 (SLC7A9)

The SLC7A9 cDNA is polyadenylated and contains an open reading frame encoding a 487-amino acid protein. The protein, designated b(0,+)AT for b(0,+) amino acid transporter, belongs to a family of light subunits of amino acid transporters expressed in kidney, liver, small intestine, and placenta. Northern blot analysis revealed that the SLC7A9 gene was expressed as an approximately 1.9-kb transcript in these tissues. The tissue distribution of b(0,+)AT was consistent with that of a renal basic amino acid transporter (see SLC3A1, or rBAT) light subunit. As expected, b(0,+)AT brought rBAT to the plasma membrane in cotransfected COS cells. In contrast, transfection of rBAT alone resulted in the blockage of the expressed protein in the endoplasmic reticulum.