Uniport that mediates the transport of neutral amino acids such as L-leucine, L-isoleucine, L-valine, and L-phenylalanine . The transport activity is sodium ions-independent, electroneutral and mediated by a facilitated diffusion .
Subcellular locations: Cell membrane, Apical cell membrane, Endoplasmic reticulum membrane
Located in the apical plasma membrane of the podocyte foot processes . Located in the plasma membrane of liver and skeletal muscle, and in the endoplasmic reticulum and in crystalline inclusions in pancreatic acinar cells (By similarity).
Ubiquitously expressed in fetus and adult . Highest expression in adult pancreas, liver, skeletal muscle (, ). In fetus, highest expression in liver and lower levels in kidney, and lung . Exclusively expressed in the glomeruli along the glomerular capillary walls .