The nonimmunoglobulin portion of lambda5 mediates cell-autonomous pre-B cell receptor signaling.
The nonimmunoglobulin portion of lambda5 mediates cell-autonomous pre-B cell receptor signaling.
复制标题
lambda5 的非免疫球蛋白部分介导细胞自主前 B 细胞受体信号传导。
作者：
K. Ohnishi;F. Melchers
前B细胞受体（preBCR）由μ免疫球蛋白（IG）和替代轻链组成，在明显缺乏配体或协作细胞的情况下向大的“preB-II”细胞发出增殖信号。我们删除了N-末端，nonimmunoglobulin（nonlg）的部分，或突变的7个精氨酸残基丝氨酸残基。具有这种突变的BCR 5蛋白质的前BCRs表现出增加的细胞表面代表性和降低的聚集和内化速率。酪氨酸磷酸化的preBCR复合物含有突变体p53蛋白被废除。这些结果表明，非免疫球蛋白的部分5，和7个精氨酸残基，需要的信号转导，信号可能是细胞自主的。我们提出了两个模型来解释明显的组成，配体独立的信号转导能力的前BCR。
The pre-B cell receptor (preBCR), composed of mu immunoglobulin (Ig) and surrogate light chains, signals large 'preB-II' cells to proliferate in the apparent absence of ligands or cooperating cells. We deleted the N-terminal, nonimmunoglobulin (nonlg) portion of lambda5, or mutated seven arginine residues in it to serine residues. PreBCRs with such mutant lambda5 proteins showed increased cell surface representation and a diminished rate of aggregation and internalization. Tyrosine phosphorylation of preBCR complexes containing mutant lambda5 proteins was abolished. These results indicate that the nonIg portion of lambda5, and the seven arginine residues in it, are needed for signal transduction, and that signaling could be cell autonomous. We propose two models to explain the apparently constitutive, ligand-independent signal-transducing capacity of the preBCR.