Does not show transporter activity with a range of tested amino acids including proline, glutamine, glutamic acid, leucine, alanine, histidine, glycine and arginine. Interacts with CLTRN. Located in the apical brush border membrane of kidney proximal tubule cells. Detected only in kidney and lung. Belongs to the sodium:neurotransmitter symporter (SNF) (TC 2.A.22) family. SLC6A20 subfamily.