Requirement of the cytoplasmic portion for dimer formation of Fcα/μ receptor expressed on cell surface
Requirement of the cytoplasmic portion for dimer formation of Fcα/μ receptor expressed on cell surface
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DOI：
10.1016/j.molimm.2009.10.016
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发表时间：
2010-01-01
影响因子：
3.6
通讯作者：
Shibuya, Akira
中科院分区：
文献类型：
--
作者：
Cho, Yukiko;Honda, Shin-ichiro;Shibuya, Akira
Fc α/μ受体（Fc α/μ R）是伊加和IgM的Fc受体，是在人类和啮齿类动物造血细胞上鉴定的IgM的唯一Fc受体，也是啮齿类动物中伊加的唯一Fc受体。Fc alpha/mu R是一种1型跨膜蛋白，在细胞外部分含有一个免疫球蛋白样结构域。人和小鼠Fc α/μ R均介导配体伊加和IgM的内吞作用，Fc α/μ R的细胞质部分负责内吞作用。然而，参与功能的Fc α/μ R的分子特征尚未完全了解。在这里，我们表明，在小鼠B细胞系BCL 1-B20和BW 5147或稳定表达Fc α/μ R的Ba/F3转染子中表达单体和二聚体Fc α/μ R。我们还表明，二聚体，但不是单体，Fc α/μ R优先定位于转染子的细胞表面。表达缺乏胞质部分的突变体Fc α/μ R的BW 5147转染子仅表达单体Fc α/μ R。这些结果表明，细胞质部分是二聚体形成所需的，因此是Fc α/μ R有效细胞表面表达所需的。(C)2010爱思唯尔有限公司保留所有权利。
Fc alpha/mu receptor (Fc alpha/mu R), an Fc receptor for IgA and IgM, is the only Fc receptor for IgM identified on hematopoietic cells in human and rodents and for IgA in rodents. Fc alpha/mu R is a type 1 transmembrane protein containing one immunoglobulin-like domain in the extracellular portion. Both human and mouse Fc alpha/mu R mediate endocytosis of the ligands IgA and IgM, for which the cytoplasmic portion of Fc alpha/mu R is responsible. However, molecular characteristics of Fc alpha/mu R involved in the function have been incompletely understood. Here, we show that both monomeric and dimeric Fc alpha/mu R are expressed in a mouse B cell line BCL1-B20 and BW5147 or Ba/F3 transfectants stably expressing Fc alpha/mu R. We also show that the dimeric, but not monomeric, Fc alpha/mu R is preferentially localized to the cell Surface of the transfectants. BW5147 transfectant expressing mutant Fc alpha/mu R lacking the cytoplasmic portion expressed only the monomeric Fc alpha/mu R. These results suggest that the cytoplasmic portion is required for the dimer formation and thus for efficient cell surface expression of Fc alpha/mu R. (C) 2010 Elsevier Ltd. All rights reserved.