Cysteine is not a substrate but a specific modulator of human ASCT2 (SLC1A5) transporter.
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.
Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
Mariafrancesca
M
Scalise
Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
Lorena
L
Pochini
Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
Piero
P
Pingitore
Department of Chemistry and Molecular Biology, University of Gothenburg, PO Box 462, SE-405 30 Göteborg, Sweden.
Kristina
K
Hedfalk
Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy. Electronic address: cesare.indiveri@unical.it.
Cesare
C
Indiveri
D026962:Amino Acid Transport System ASC / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D001692:Biological Transport; D003545:Cysteine / Q000378:metabolism / Q000494:pharmacology*; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D015778:Minor Histocompatibility Antigens; D011510:Proteolipids / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism
D026962:Amino Acid Transport System ASC; D015778:Minor Histocompatibility Antigens; D011510:Proteolipids; D011994:Recombinant Proteins; C420506:SLC1A5 protein, human; C020485:proteoliposomes; D003545:Cysteine
Cysteine; Glutamine; Liposome; Plasma membrane; Redox control; Transport