期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1992
卷号：89
期号：12
页码：5596-5600
DOI：10.1073/pnas.89.12.5596
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The transport of amino acids across cell membranes is believed to be mediated by integral membrane proteins with distinct substrate specificities. Using expression cloning in Xenopus oocytes and assaying for the uptake of 14C-labeled cystine, we isolated a 2.3-kilobase cDNA (D2) from a rat kidney library. D2 is expressed specifically in kidney and intestine and induces the transport of both neutral and cationic amino acids. The deduced amino acid sequence predicts a 78-kDa protein with a single transmembrane domain, a structure not typical of the known membrane transport proteins, which generally have multiple membrane-spanning regions. The putative extracellular region is highly similar to the 4F2 heavy-chain cell surface antigen and to a family of alpha-glucosidases, which raises the possibility that D2 encodes a transport activator or regulatory subunit.
