Localization of the Wilson disease protein in murine intestine
Localization of the Wilson disease protein in murine intestine
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DOI：
10.1111/j.1469-7580.2008.00954.x
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发表时间：
2008-09-01
影响因子：
2.4
通讯作者：
Fuellekrug, Joachim
中科院分区：
文献类型：
--
作者：
Weiss, Karl Heinz;Wurz, Judith;Fuellekrug, Joachim
威尔逊病是一种遗传性的人类铜代谢障碍，其特征是铜在组织中逐渐积累，主要是肝脏和大脑。该基因缺陷在于Wilson病蛋白ATP 7 B，一种在肝细胞中高度活跃的铜转运ATP酶。在肝脏中，ATP 7 B是将过量的铜排泄到胆汁中和高尔基体中铜蓝蛋白的铜负载所必需的。ATP 7 B在肝外的作用尚未完全了解。我们用RT-PCR、Western blot和间接免疫荧光法分析了ATP 7 B在小鼠小肠中的表达。我们发现ATP 7 B在胃和小肠中有丰富的表达，但在结肠中没有表达。使用共聚焦显微镜，我们证明了高尔基定位的ATP 7 B在肠上皮细胞。在响应铜升高，威尔逊病蛋白显示在肠极化细胞系CaCo-2的细胞内贩运模式，远离高尔基体分散囊泡。这表明肠ATP 7 B在细胞内囊泡中螯合铜以维持肠上皮细胞中的铜稳态中的作用。总之，ATP 7 B在小肠中的表达可能代表了微调肠道铜吸收的额外调节机制。
Wilson disease is an inherited disorder of human copper metabolism, characterized by gradual accumulation of copper in tissues, predominantly liver and brain. The gene defect lies in the Wilson disease protein ATP7B, a copper transporting ATPase highly active in hepatocytes. In the liver, ATP7B is essential for excretion of excess copper into the bile and for copper loading of ceruloplasmin in the Golgi apparatus. The extrahepatic role of ATP7B is not yet completely understood. We analysed the intestinal expression of ATP7B in mice using RT-PCR, Western blot and indirect immunofluorescence. We found abundant expression of ATP7B in stomach and small intestine, but not in colon. Using confocal microscopy we demonstrate a Golgi localization of ATP7B in enterocytes. In response to elevated copper, the Wilson disease protein shows an intracellular trafficking pattern in the intestinal polarized cell line CaCo-2, moving away from the Golgi apparatus to dispersed vesicles. This suggests a role for intestinal ATP7B in sequestration of copper in intracellular vesicles for maintenance of copper homeostasis in the enterocyte. In conclusion, the expression of ATP7B in the small intestine might represent an additional regulatory mechanism to fine-tune intestinal copper absorption.