Amino acid transporters of the SLC6 family mediate the Na+-dependent uptake of neutral amino acids into neurons
and epithelial cells of the intestine, kidney and other organs. They are integral parts of amino acid homeostasis in the
whole body and the brain. In the intestine they are involved in protein absorption, while in the kidney they regulate plasma
amino acid concentrations through reabsorption. The metabolic role of SLC6 amino acid transporters in the brain is less
clear and most likely related to anaplerosis of the TCA cycle. Mutations in these transporters cause rare inherited disorders
such as Hartnup disorder and iminoglycinuria. They may also play a role in complex traits such as depression, anxiety,
obesity, diabetes and cancer. The review does not cover the transport of neurotransmitter amino acids.