The involvement of sodium in the function of the human amino acid transporter ASCT2

FEBS Letters

article

Tiziano Mazza¹  Mariafrancesca Scalise¹  Gilda Pappacoda¹  Lorena Pochini¹  Cesare Indiveri¹ 

[1] Department DiBEST ,(Biologia, Ecologia, Scienze Della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria;CNR Institute of Biomembranes

关键词: ASCT2;    fluorometric assay;    kinetics;    membrane transport;    proteoliposomes;    SLC;   

DOI  :  10.1002/1873-3468.14224

来源: John Wiley & Sons Ltd.

【 摘 要 】

Alanine, serine, cysteine transporter 2 (ASCT2) is a membrane amino acid transporter with relevance to human physiology and pathology, such as cancer. Notwithstanding, the study on the ASCT2 transport cycle still has unknown aspects, such as the role of Na + in this process. We investigate this issue using recombinant hASCT2 reconstituted in proteoliposomes. Changes in the composition of purification buffers show the crucial role of Na + in ASCT2 functionality. The transport activity is abolished when Na + is absent or substituted by Li + or K + in purification buffers. By employing a Na + fluorometric probe, we measured an inwardly directed flux of Na + and, by combining fluorometric and radiometric assays, determined a 2Na +  : 1Gln stoichiometry. Kinetics of Na + transport suggest that pH-sensitive residues are involved in Na + binding/transport. Our results clarify the role of Na + on human ASCT2 transporter activity.

【 授权许可】

Unknown