Molecular features of the L-type amino acid transporter 2 determine different import and export profiles for thyroid hormones and amino acids.

The L-type amino acid transporter 2 (LAT2) imports amino acids (AA) and also certain thyroid hormones (TH), e.g. 3,3′-T2 and T3, but not rT3 and T4. We utilized LAT2 mutations (Y130A, N133S, F242W) that increase 3,3′-T2 import and focus here on import and export capacity for AA, T4, T3, BCH and derivatives thereof to delineate molecular features.