Heterogeneous RNA-binding protein M4 is a receptor for carcinoembryonic antigen in Kupffer cells
Heterogeneous RNA-binding protein M4 is a receptor for carcinoembryonic antigen in Kupffer cells
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DOI：
10.1074/jbc.m104093200
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发表时间：
2001-08-17
影响因子：
4.8
通讯作者：
Thomas, P
中科院分区：
文献类型：
--
作者：
Bajenova, OV;Zimmer, R;Thomas, P
在这里，我们报告的分离重组cDNA克隆从大鼠巨噬细胞，库普弗细胞（KC）编码的蛋白质与癌胚抗原（CEA）的相互作用。为了分离和鉴定CEA受体基因，我们使用了两种方法：用特异性抗体筛选KC cDNA文库和酵母双杂交系统，以编码结合位点的CEA的N-末端部分作为诱饵进行蛋白质相互作用。这两种技术导致在识别大鼠异质RNA结合蛋白（hnRNP）M4基因。大鼠直向同源物cDNA序列以前没有描述过。该基因的开放阅读框含有2351个碱基对的序列，具有多聚腺苷酸化信号AATAAA和终止聚（A）尾。mRNA显示普遍存在的组织表达作为2.4-脱氢酶转录物。推导的氨基酸序列包括一个78 kDa的膜蛋白，3个推定的RNA结合结构域，精氨酸/甲硫氨酸/谷氨酰胺丰富的C端和3个潜在的跨膜区。当hnRNP M4蛋白在大肠杆菌中以pGEX 4 T-3载体系统表达时，它以Ca 2+依赖的方式与I-125标记的CEA结合。将大鼠hnRNP M4 cDNA转染到非CEA结合的小鼠巨噬细胞系p388 D1中导致CEA结合。这些数据为hnRNP M4蛋白在枯否细胞中作为CEA结合蛋白的新功能提供了证据。
Here we report the isolation of the recombinant cDNA clone from rat macrophages, Kupffer cells (KC) that encodes a protein interacting with carcinoembryonic antigen (CEA). To isolate and identify the CEA receptor gene we used two approaches: screening of a KC cDNA library with a specific antibody and the yeast two-hybrid system for protein interaction using as a bait the N-terminal part of the CEA encoding the binding site. Both techniques resulted in the identification of the rat heterogeneous RNA-binding protein (hnRNP) M4 gene. The rat ortholog cDNA sequence has not been previously described. The open reading frame for this gene contains a 2351-base pair sequence with the polyadenylation signal AATAAA and a termination poly(A) tail. The mRNA shows ubiquitous tissue expression as a 2.4-kilobase transcript. The deduced amino acid sequence comprised a 78-kDa membrane protein with 3 putative RNA-binding domains, arginine/methionine/glutamine-rich C terminus and 3 potential membrane spanning regions. When hnRNP M4 protein is expressed in pGEX4T-3 vector system in Escherichia coli it binds I-125-labeled CEA in a Ca2+-dependent fashion. Transfection of rat hnRNP M4 cDNA into a non-CEA binding mouse macrophage cell line p388D1 resulted in CEA binding. These data provide evidence for a new function of hnRNP M4 protein as a CEA-binding protein in Kupffer cells.