Analysis of immature B cell activation and differentiation

为了研究未成熟B系细胞的激活和发育，我们寻找未成熟B细胞或B细胞激活过程中表达的独特信号转导分子。我们对bcr前信号转导分子进行了表征，其中PI-3激酶活性被证明参与了b细胞前阶段。我们还分离出一种名为免疫球蛋白受体结合蛋白（IGBP-1/alpha4）的分子，该分子最初被鉴定为与bcr组分MB-1分子共沉淀的磷蛋白。分离并鉴定了α 4基因。最近的研究结果还表明，α 4蛋白与蛋白磷酸酶2a相关，其关联对B细胞的增殖至关重要。alpha4/PP2A复合体被证明是雷帕霉素的新靶点。这些结果暗示了参与淋巴样细胞增殖的新的信号转导途径。

To study the activation and development of immature B lineage cells, we searched the unique signal transduction molecules expressed in the immature B cells or in the process of B cell activation.We characterized the pre-BCR signal transduction molecules, among which PI-3 kinase activity was shown to be involved in the pre-B cell stages. We also isolated a molecule named immunoglobulin-receptor binding protein (IGBP-1/alpha4) , which is originally identified as a phosphoprotein co-precipitated with the BCR-component MB-1 molecule. The alpha4 gene was isolated and characterized. The recent results also showed that the alpha4 protein is associated with the protein phosphatase 2 A,whose association is critical for the proliferation of B cells. The alpha4/PP2A complex is shown to be a novel target of rapamycin. These results implicated the novel signal transduction pathway involved in the proliferation of lymphoid cells.