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oai:recercat.cat:2445/1771232025-12-05T09:21:23Zcom_2072_1057col_2072_478777col_2072_478781col_2072_478799col_2072_478917

Identification of a membrane protein, LAT-2, that co-expresses with 4F2 heavy chain, an L-type amino acid transport activity with broad specificity for small and large zwitterionic amino acids Pineda Riu, Marta Fernández, Esperanza Torrents Arenales, David Estévez Povedano, Raúl López Iglesias, Carmen Camps Camprubí, Marta Lloberas Cavero, Jorge Zorzano Olarte, Antonio Palacín Prieto, Manuel Antígens CD Proteïnes portadores Proteïnes de membrana CD antigens Carrier proteins Membrane proteins We have identified a new human cDNA, L-amino acid transporter-2 (LAT-2), that induces a system L transport activity with 4F2hc (the heavy chain of the surface antigen 4F2, also named CD98) in oocytes. Human LAT-2 is the fourth member of the family of amino acid transporters that are subunits of 4F2hc. The amino acid transport activity induced by the co-expression of 4F2hc and LAT-2 was sodium-independent and showed broad specificity for small and large zwitterionic amino acids, as well as bulky analogs (e.g. BCH (2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid)). This transport activity was highly trans-stimulated, suggesting an exchanger mechanism of transport. Expression of tagged N-myc-LAT-2 alone in oocytes did not induce amino acid transport, and the protein had an intracellular location. Co-expression of N-myc-LAT-2 and 4F2hc gave amino acid transport induction and expression of N-myc-LAT-2 at the plasma membrane of the oocytes. These data suggest that LAT-2 is an additional member of the family of 4F2 light chain subunits, which associates with 4F2hc to express a system L transport activity with broad specificity for zwitterionic amino acids. Human LAT-2 mRNA is expressed in kidney >>> placenta >> brain, liver > spleen, skeletal muscle, heart, small intestine, and lung. Human LAT-2 gene localizes at chromosome 14q11.2-13 (13 cR or approximately 286 kb from marker D14S1349). The high expression of LAT-2 mRNA in epithelial cells of proximal tubules, the basolateral location of 4F2hc in these cells, and the amino acid transport activity of LAT-2 suggest that this transporter contributes to the renal reabsorption of neutral amino acids in the basolateral domain of epithelial proximal tubule cells. 2021-05-10T13:27:46Z 2021-05-10T13:27:46Z 1999-07-09 2021-05-10T13:27:46Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 0021-9258 https://hdl.handle.net/2445/177123 147166 10391915 eng Reproducció del document publicat a: https://doi.org/10.1074/jbc.274.28.19738 Journal of Biological Chemistry, 1999, vol. 274, num. 28, p. 19738-19744 https://doi.org/10.1074/jbc.274.28.19738 (c) American Society for Biochemistry and Molecular Biology, 1999 info:eu-repo/semantics/openAccess 7 p. application/pdf American Society for Biochemistry and Molecular Biology Articles publicats en revistes (Ciències Fisiològiques)