MOLECULAR-COMPONENTS OF THE B-CELL ANTIGEN RECEPTOR COMPLEX OF THE IGM CLASS
MOLECULAR-COMPONENTS OF THE B-CELL ANTIGEN RECEPTOR COMPLEX OF THE IGM CLASS
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DOI：
10.1038/343760a0
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发表时间：
1990-02-22
期刊：
影响因子：
64.8
通讯作者：
RETH, M
中科院分区：
文献类型：
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作者：
HOMBACH, J;TSUBATA, T;RETH, M
成熟B淋巴细胞上的抗原受体是IgM和IgD类的膜结合免疫球蛋白1,2，它们通过多价抗原交联导致B细胞增殖和分化3。这些缺乏细胞质尾部的膜结合免疫球蛋白链如何产生细胞激活信号目前尚不清楚。我们现在发现，在B细胞的细胞膜上，IgM分子与两个相对分子质量为34,000的蛋白（mr34k; IgM-α）和39k （Ig-β）非共价结合，形成二硫键异二聚体。IgM的表面表达似乎需要在IgM和异二聚体之间形成适当的复合物。转染实验表明，IgM-α是mb- 1的产物，mb- 1是一个b细胞特异性基因，编码一个与t细胞抗原受体- cd3复合物蛋白序列同源的跨膜蛋白6 - 8。
THE antigen receptors on mature B lymphocytes are membrane-bound immunoglobulins of the IgM and IgD classes1,2whose cross-linking by polyvalent antigens results in B-cell proliferation and differentiation3. How these membrane-bound immunoglobulin chains, which lack a cytoplasmic tail, generate a cell activation signal is not at present known. We now show that the IgM molecule is non-covalently associated in the membrane of B cells with two proteins of relative molecular mass 34,000 (Mr34 K; IgM-α) and 39 K (Ig-β) which form a disulphide-linked heterodimer. Surface expression of IgM seems to require the formation of an appropriate complex between IgM and the heterodimer. A transfection experiment indicates that IgM-α is the product ofmb-l, a B-cell-specific gene4encoding a transmembrane protein with sequence homology5to proteins of the T-cell antigen receptor–CD3 complex6–8.