Identification of LAT4, a novel amino acid transporter with system L activity.

摘要: System L amino acid transporters mediate the movement of bulky neutral acids across cell membranes. Until now three proteins that induce system activity have been identified: LAT1, LAT2, and LAT3. The former two belong to solute carrier family 7 (SLC7), whereas latter belongs SLC43. In present study we a new cDNA, designated LAT4, which also mediates when expressed in Xenopus laevis oocytes. Human LAT4 exhibits 57% identity human Like LAT3, transport induced by is sodium-, chloride- pH-independent, not trans-stimulated, shows kinetic components. low affinity component sensitive sulfhydryl-specific reagent N-ethylmaleimide but with high affinity. Mutation SLC43 conserved serine 297 alanine abolishes sensitivity N-ethylmaleimide. detected at basolateral membrane PCT kidney cells. situ hybridization experiments show mRNA restricted epithelial cells distal tubule collecting duct kidney. intestine, mainly crypt.