Proton-coupled amino acid transporter (PAT) (PAT)

Proton-coupled amino acid transporters (PATs), belonging to the SLC36 family, are membrane proteins that facilitate the movement of small neutral amino acids and their derivatives across cellular and organelle membranes. These transporters, primarily PAT1 (SLC36A1) and PAT2 (SLC36A2), function as secondary active symporters that couple the transport of substrates like glycine, alanine, and proline to the movement of protons down their electrochemical gradient (Thwaites & Anderson, 2011). PAT1 is notably expressed in the apical membrane of the small intestine for nutrient absorption and in lysosomes for amino acid efflux, while PAT2 is essential for renal reabsorption in the proximal tubule (UniProt, 2024). Beyond their transport function, PATs act as "transceptors" that sense amino acid availability to activate the mTORC1 signaling pathway, thereby regulating cell growth and proliferation (Fan & Goberdhan, 2018). This signaling role links PATs to various cancers, where their overexpression supports tumor growth and survival. PATs also play a significant role in pharmacology by mediating the intestinal absorption and renal disposition of amino acid-mimetic drugs, such as the anti-epileptic vigabatrin and the investigational sleep aid gaboxadol (NIH, 2011).

Other names

Solute carrier family 36SLC36 familyProton-assisted amino acid transporterLysosomal amino acid transporterLYAATTramdorin

Proton-coupled symport of small neutral amino acids and amino acid-mimetic drugs (PAT1 and PAT2) or facilitated diffusion (PAT4) across the plasma or lysosomal membranes (Thwaites & Anderson, 2011; Fan & Goberdhan, 2018).