LAT2 (SLC7A8) is a 25-30kDa transmembrane adaptor protein that functions as a neutral amino acid transporter and immune signaling mediator 1. In immune signaling, LAT2 associates with lipid rafts and undergoes tyrosine phosphorylation upon receptor activation, including FcεRI in mast cells, FcγRI in monocytes, and BCR in B cells 1. Phosphorylated LAT2 recruits signaling molecules such as Grb2, Gab1 and c-Cbl into receptor-signaling complexes 1. As an amino acid transporter, LAT2 forms heterodimeric complexes with 4F2hc and mediates cellular uptake of specific amino acids including L-leucine 2. LAT2 shows high expression in skeletal muscle where it regulates glutamine efflux and muscle proteolysis through mTORC1-dependent pathways 3. The transporter is also expressed in intestinal epithelial cells and kidney, where it facilitates L-DOPA transport 45. LAT2 knockout mice demonstrate impaired muscle proteolysis during fasting due to glutamine accumulation 3. While LAT2 can function as both positive and negative regulator of cellular activation, its precise regulatory mechanisms in different cell types remain incompletely understood 1.