Solute carrier family 36 member 4 (SLC36A4)

Solute carrier family 36 member 4 (SLC36A4, also known as PAT4) is a high-affinity, low-capacity transporter of neutral amino acids, with strongest specificity for proline and tryptophan but lower affinity for alanine and glycine. Unlike other members of the SLC36 family, SLC36A4 operates independently of proton gradients (non-proton-coupled), through facilitated diffusion in an electroneutral and sodium-independent manner. Its function is maximal at physiological pH 7.4, and it is ubiquitously expressed in various tissues, including several cancer cell lines, where it may contribute to nutrient sensing via regulation of mTORC1 on the Golgi apparatus. SLC36A4 is structurally predicted to have 9–11 transmembrane domains and is encoded on human chromosome 11q21. Recent research suggests SLC36A4 may act more as a nutrient sensor (“transceptor”) rather than simply a bulk transporter for amino acids, with implications for growth regulation and cancer biology due to its role in the mTOR/S6 kinase signaling pathway. No specific drugs or inhibitors are currently approved to target SLC36A4, and its direct involvement in human disease remains under investigation.

Other names

Neutral amino acid uniporter 4PAT4Proton-coupled amino acid transporter 4Solute carrier family 36 member 4FLJ38932

Null (no drugs directly target this molecule as a mechanism of action)