Cloning and expression of a human neutral amino acid transporter with structural similarity to the glutamate transporter gene family

• Published in: The Journal of biological chemistry 1993-07, Vol.268 (21), p.15329-15332
• Main Authors: ARRIZA, J. L, KAVANAUGH, M. P, FAIRMAN, W. A, YAN-NA WU, MURDOCH, G. H, NORTH, R. A, AMARA, S. G
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino Acid Transport System X-AG; Amino Acid Transport Systems; Amino Acids - metabolism; Analytical, structural and metabolic biochemistry; Base Sequence; Binding and carrier proteins; Biological and medical sciences; Biological Transport; brain; Carrier Proteins - chemistry; Carrier Proteins - genetics; cDNA; Cloning, Molecular; DNA; Fundamental and applied biological sciences. Psychology; genes; Glutamates - metabolism; Glutamic Acid; Glycoproteins - chemistry; Glycoproteins - genetics; Humans; man; Molecular Sequence Data; neutral amion acid transporter; nucleotide sequence; predictions; Proteins; RNA, Messenger - metabolism; Sequence Homology, Amino Acid
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)82257-8

A cDNA was isolated from human brain that encodes an amino acid sequence 34-39% identical to previously published glutamate transporter sequences. Injection of RNA transcribed from this cDNA into Xenopus oocytes resulted in expression of a transport activity with the properties of the neutral amino acid uptake system ASC. Superfusion of alanine, serine, and cysteine evoked sodium-dependent inward currents in voltage-clamped oocytes expressing the transporter. These currents were dose-dependent, stereospecific, and saturable, with Km values ranging from 29 to 88 microM. Northern blot analyses revealed ubiquitous expression of this gene, termed ASCT1, consistent with the general metabolic role ascribed to system ASC.