MOLECULAR-STRUCTURE AND EXPRESSION OF THE MURINE LYMPHOCYTE LOW-AFFINITY RECEPTOR FOR IGE (FC-EPSILON-RII)
MOLECULAR-STRUCTURE AND EXPRESSION OF THE MURINE LYMPHOCYTE LOW-AFFINITY RECEPTOR FOR IGE (FC-EPSILON-RII)
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DOI：
10.1073/pnas.86.19.7566
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发表时间：
1989-10-01
影响因子：
11.1
通讯作者：
CONRAD, DH
中科院分区：
文献类型：
--
作者：
BETTLER, B;HOFSTETTER, H;CONRAD, DH
编码IgE的鼠低亲和力受体（Fc γ RII）的cDNA已从用脂多糖和白细胞介素4活化的B细胞制备的cDNA文库中分离。它编码331个氨基酸的37-kDa蛋白质，具有两个潜在的N-连接糖基化位点。类似于其人类对应物，没有信号序列，并且推定的跨膜区靠近氨基末端，表明羧基末端在细胞外部的反向膜取向。预测的鼠Fc γ RII氨基酸序列与其人对应物具有57%的同一性。鼠序列具有21个氨基酸的额外内部重复基序，与人序列中的3个相比，其提供4个重复。此外，鼠Fc γ RII在羧基末端被截短，并且缺失了Arg-Gly-Asp序列，该序列是整联蛋白受体的常见识别位点，其在人Fc γ RII中以反向构型存在。与静息或脂多糖刺激的B细胞相比，用白介素4和脂多糖激活的B细胞具有增加量的Fc γ RII mRNA。Con A活化的正常T细胞、TH-2细胞系D10以及巨噬细胞系J774没有可检测的Fc γ RII mRNA。使用瞬时转染的COS细胞进行的表达分析显示，重组鼠Fc γ RII结合抗Fc γ RII以及小鼠和大鼠IgE，但不结合人IgE或小鼠IgG。在COS细胞中表达的Fc γ RII具有45 kDa的分子量，而来自B细胞系的Fc γ RII是49 kDa的蛋白质。
The cDNA encoding the murine low-affinity receptor for IgE (Fc.epsilon.RII) has been isolated from a cDNA library prepared from B cells activated with lipopolysaccharide and interleukin 4. It encodes a 37-kDa protein of 331 amino acids with two potential N-linked glycosylation sites. Analogous to its human counterpart, there is no signal sequence and the putative transmembrane region is close to the amino terminus, indicating an inverse membrane orientation with the carboxyl terminus at the cell exterior. The predicted murine Fc.epsilon.RII amino acid sequence demonstrates a 57% identity with its human counterpart. The murine sequence has an additional internal repeat motif of 21 amino acids giving four repeats as compared to three in the human sequence. Furthermore, the murine Fc.epsilon.RII is truncated at the carboxyl terminus and the Arg-Gly-Asp sequence, a common recognition site of integrin receptors, which is found in the reverse configuration in human Fc.epsilon.RII, is missing. B cells activated with interleukin 4 and lipopolysaccharide have an increased amount of Fc.epsilon.RII mRNA as compared with resting or lipopolysaccharide-stimulated B cells. Con A-activated normal T cells, the TH-2 cell line D10, as well as the macrophage cell line J774 have no detectable Fc.epsilon.RII mRNA. Expression analysis using transiently transfected COS cells revealed that recombinant murine Fc.epsilon.RII binds anti-Fc.epsilon.RII as well as mouse and rat IgE but does not bind human IgE or mouse IgG. Fc.epsilon.RII expressed in COS cells has a molecular mass of 45 kDa whereas the Fc.epsilon.RII from B-cell lines is a 49-kDa protein.