The Alanine Serine Cysteine Transporter 2 (ASCT2) is involved in balancing the intracellular amino acid pool. This function is allowed by the antiport mechanism and the asymmetric specificity towards different neutral amino acids, distinctive of this transporter. In the present work, the interaction of the putative substrate Cys with the human ASCT2 has been studied using the recombinant hASCT2 over-produced in Pichia pastoris and the native ASCT2 extracted from HeLa in both proteoliposomes and intact cells. It was found that Cys is a potent competitive inhibitor of hASCT2 but is not a substrate. Moreover, Cys binding to a second site, different from that of substrate, triggers a protein-mediated unidirectional Gln efflux. (C) 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Cysteine is not a substrate but a specific modulator of human ASCT2 (SLC1A5) transporter.
Scalise Mariafrancesca;POCHINI, Lorena;INDIVERI, Cesare
2015-01-01
Abstract
The Alanine Serine Cysteine Transporter 2 (ASCT2) is involved in balancing the intracellular amino acid pool. This function is allowed by the antiport mechanism and the asymmetric specificity towards different neutral amino acids, distinctive of this transporter. In the present work, the interaction of the putative substrate Cys with the human ASCT2 has been studied using the recombinant hASCT2 over-produced in Pichia pastoris and the native ASCT2 extracted from HeLa in both proteoliposomes and intact cells. It was found that Cys is a potent competitive inhibitor of hASCT2 but is not a substrate. Moreover, Cys binding to a second site, different from that of substrate, triggers a protein-mediated unidirectional Gln efflux. (C) 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
