Identification of an amino acid transporter associated with the cystinuria-related type II membrane glycoprotein
Identification of an amino acid transporter associated with the cystinuria-related type II membrane glycoprotein
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DOI：
10.1074/jbc.274.41.28845
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发表时间：
1999-10-08
影响因子：
4.8
通讯作者：
Kanai, Y
中科院分区：
文献类型：
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作者：
Chairoungdua, A;Segawa, H;Kanai, Y
我们发现了与胱氨酸尿相关的II型膜糖蛋白rBAT（与b（0,+）氨基酸转运蛋白相关）相关的氨基酸转运蛋白。从大鼠肾脏中发现的转运蛋白BAT1 （b(0,+)'型氨基酸转运蛋白1）在结构上与最近发现的系统L、系统y(+)L和系统x-C的氨基酸转运蛋白相关，这些转运蛋白通过二硫键连接到另一种II型膜糖蛋白4F2hc （4F2重链）。在非还原条件下，用抗BAT1抗体在大鼠肾脏中检测到一条125 kda的条带，该条带似乎与BAT1和rBAT的异二聚体复合物相对应。在还原条件下，条带移位到41 kDa，证实BAT1和rBAT是通过二硫键连接的。BAT1和rBAT蛋白被证明共定位于肾近端小管的顶膜，在那里有大量胱氨酸运输被提出。当使用rBAT而不使用4F2hc在COS-7细胞中表达时，BAT1表现出不依赖Na+的胱氨酸转运以及具有系统b特性的碱性和中性氨基酸转运（0,+）。本研究的结果被用来建立一个与II型膜糖蛋白相关的氨基酸转运蛋白家族。
We identified an amino acid transporter that is associated with the cystinuria-related type II membrane glycoprotein, rBAT (related to b(0,+) amino acid transporter). The transporter designated BAT1 (b(0,+)'-type amino acid transporter 1) from rat kidney was found to be structurally related to recently identified amino acid transporters for system L, system y(+)L, and system x-C, which are linked, via a disulfide bond, to the other type II membrane glycoprotein, 4F2hc (4F2 heavy chain). In the nonreducing condition, a 125-kDa band, which seems to correspond to the heterodimeric complex of BAT1 and rBAT, was detected in rat kidney with anti-BAT1 antibody. The band was shifted to 41 kDa in the reducing condition, confirming that BAT1 and rBAT are linked via a disulfide bond. The BAT1 and rBAT proteins were shown to be colocalized in the apical membrane of the renal proximal tubules where massive cystine transport had been proposed. When expressed in COS-7 cells with rBAT, but not with 4F2hc, BAT1 exhibited a Na+-independent transport of cystine as well as basic and neutral amino acids with the properties of system b(0,+). The results from the present investigation were used to establish a family of amino acid transporters associated with type II membrane glycoproteins.