LAT1 (L-type Amino Acid Transporter 1) is a key member of the SLC7A family, primarily functioning in the transmembrane transport of essential amino acids. LAT1 forms a heterodimer with the heavy chain 4F2hc, facilitating its localization and activity on the cell membrane. It is widely distributed across various tissues in the human body, particularly expressed at high levels in tumor cells, closely associated with the supply of amino acids and cell proliferation. The activity of LAT1 is crucial for maintaining cell metabolism and growth. Specific expression and mutations of its gene may affect the absorption and utilization of amino acids, related to the development of various diseases, including cancer and metabolic disorders.