L-type amino acid transporter 1 and L-type amino acid transporter 2 (LAT-1/LAT-2)

L-type amino acid transporter 1 (LAT1, SLC7A5) and L-type amino acid transporter 2 (LAT2, SLC7A8) are membrane transport proteins that mediate sodium-independent, pH-independent exchange of large neutral amino acids, as well as thyroid hormones and some drugs, across cell membranes. They operate as heterodimers with the heavy chain 4F2hc (CD98/SLC3A2), which is essential for their surface localization and function. LAT1 is highly expressed in the placenta and blood-brain barrier, and overexpressed in many cancers; it facilitates tumor growth by supplying essential amino acids and activating mTOR signaling. LAT2 is more broadly expressed, especially in the kidney, and assists in transepithelial amino acid transport. Both are pharmacologically interesting because they affect drug delivery and are implicated in disease progression, notably cancer. Few drugs specifically interact with LAT2, whereas LAT1 is under development as a drug target for cancer and as a pathway for CNS drug delivery.

Other names

SLC7A5Solute carrier family 7 member 5SLC7A8LPI-PC1Solute carrier family 7 member 8

Competitive inhibition or substrate analogs block transport, reducing amino acid uptake required for tumor growth (LAT1 inhibitors). Facilitated transport and antiport (exchange) of neutral amino acids for drug delivery or modulating amino acid homeostasis.