Uniport that mediates the transport of neutral amino acids such as L-leucine, L-isoleucine, L-valine, and L-phenylalanine (PubMed:12930836, PubMed:26305885). The transport activity is sodium ions-independent, electroneutral and mediated by a facilitated diffusion (PubMed:12930836). Mediates the efflux of 3,3'-diiodo-L- thyronine (3,3'-T2) and 3-iodo-L-tyrosine (MIT) (PubMed:26305885). . This is the function of ENSG00000149150 (SLC43A1, solute carrier family 43 member 1).