Takemori T, Mizuguchi J, Miyazoe I, Nakanishi M, Shigemoto K, Kimoto H, Shirasawa T, Maruyama N, Taniguchi M
Department of Cellular and Molecular Immunology, National Institute of Health, Tokyo, Japan.
EMBO J. 1990 Aug;9(8):2493-500. doi: 10.1002/j.1460-2075.1990.tb07428.x.
Immunoglobulin mu chains synthesized in murine pre-B cells are known to be associated with surrogate light chains designated as omega (omega), iota (iota) and B34. In addition to these molecules, we identified the complexes of polypeptides (50, 40, 27 and 15.5 kd) associated with surface or intracellular mu chains of pre-B cell lines. Most of these polypeptides were continuously synthesized and associated with mu chains in virgin B cells lines, although some of them scarcely bound to the mu kappa dimer or mu 2 kappa 2 tetramer concomitantly present in the same clone or population. However, in mature B cells they were no longer detectable except B34. Cross-linking of micron chains on the surface of pre-B cells resulted in an increase in intracellular free Ca2+, indicating that the micron chain complex on the surface of pre-B cell lines acted as a signal transduction molecule. However, the receptor cross-linkage of pre-B cell lines did not induce the increased inositol phospholipid metabolism usually observed in virgin and mature B cell lines. These results suggest that, during the differentiation from pre-B to mature B cells, the cells express two types of mu chain complexes which exhibit different structures as a whole and possess different signal transducing capacities.
已知在鼠前B细胞中合成的免疫球蛋白μ链与被称为ω（omega）、ι（iota）和B34的替代轻链相关。除了这些分子外，我们还鉴定出与前B细胞系的表面或细胞内μ链相关的多肽复合物（50、40、27和15.5kd）。这些多肽中的大多数在前B细胞系的原始B细胞中持续合成并与μ链相关，尽管其中一些几乎不与同一克隆或群体中同时存在的μκ二聚体或μ2κ2四聚体结合。然而，在成熟B细胞中，除了B34外，它们不再可检测到。前B细胞表面的μ链交联导致细胞内游离Ca2+增加，表明前B细胞系表面的μ链复合物作为信号转导分子起作用。然而，前B细胞系的受体交联并未诱导通常在原始和成熟B细胞系中观察到的肌醇磷脂代谢增加。这些结果表明，在前B细胞向成熟B细胞的分化过程中，细胞表达两种类型的μ链复合物，它们整体上表现出不同的结构并具有不同的信号转导能力。
