Wang Y, Tate S S
Department of Biochemistry, Cornell University Medical College, New York, NY 10021, USA.
FEBS Lett. 1995 Jul 17;368(2):389-92. doi: 10.1016/0014-5793(95)00685-3.
Homologous proteins (NBAT) which mediate sodium-independent transport of neutral as well as basic amino acids and cystine when expressed in Xenopus oocytes were recently cloned from mammalian kidneys. Mutations in human NBAT have been implicated in cystinuria. Here, we show that rat kidney and jejunal brush border membrane NBAT (85 kDa) is found in association with a 50 kDa protein. The association involves one or more interprotein disulfide bonds. Rabbit kidney brush border membranes and membranes of NBAT cRNA-injected Xenopus oocytes also contain such heterodimers. Our data suggest that the heterodimer is the minimal functional unit of NBAT-mediated amino acid transport and that the NBAT-associated 50 kDa protein could play a role in cystinuria.
最近从哺乳动物肾脏中克隆出了同源蛋白（NBAT），当该蛋白在非洲爪蟾卵母细胞中表达时，可介导中性、碱性氨基酸以及胱氨酸的非钠依赖性转运。人类NBAT的突变与胱氨酸尿症有关。在此，我们发现大鼠肾脏和空肠刷状缘膜中的NBAT（85 kDa）与一种50 kDa的蛋白质相关联。这种关联涉及一个或多个蛋白质间二硫键。兔肾刷状缘膜以及注射了NBAT cRNA的非洲爪蟾卵母细胞的膜中也含有这种异二聚体。我们的数据表明，异二聚体是NBAT介导的氨基酸转运的最小功能单位，并且与NBAT相关的50 kDa蛋白质可能在胱氨酸尿症中发挥作用。
