Aoki Y, Isselbacher K J, Cherayil B J, Pillai S
Cancer Center, Massachusetts General Hospital, Boston 02129.
Proc Natl Acad Sci U S A. 1994 May 10;91(10):4204-8. doi: 10.1073/pnas.91.10.4204.
Proteins that bind to discrete domains of the Blk, Fyn, Lyn, and Btk protein tyrosine kinases were examined in pre-B cells that had not been subjected to any external stimulation, as well as in nonstimulated and antigen-receptor-ligated B cells. Proteins that bind to the Src homology 2 domains of Blk and Fyn were identified in B cells that had been activated with anti-IgM but were not identified in unstimulated B cells. A number of Blk and Fyn Src homology 2 domain-binding phosphoproteins were also observed in pre-B cells that had not been stimulated in vitro. The phosphoproteins seen in activated B cells potentially represent substrates that play a role in the pathway of antigen-receptor-mediated signaling. Distinct signaling pathways involving distinguishable kinase substrates may be relevant in pre-B-cell-receptor-mediated cell survival during ontogeny. These results indirectly support models that predict constitutive ligand-independent signaling by the pre-antigen receptor during lymphoid ontogeny.
在未受到任何外部刺激的前B细胞以及未受刺激和抗原受体连接的B细胞中，研究了与Blk、Fyn、Lyn和Btk蛋白酪氨酸激酶离散结构域结合的蛋白质。在经抗IgM激活的B细胞中鉴定出了与Blk和Fyn的Src同源2结构域结合的蛋白质，但在未受刺激的B细胞中未鉴定到。在体外未受刺激的前B细胞中也观察到了一些与Blk和Fyn Src同源2结构域结合的磷蛋白。在活化B细胞中看到的磷蛋白可能代表在抗原受体介导的信号通路中起作用的底物。涉及可区分激酶底物的不同信号通路可能与个体发育过程中前B细胞受体介导的细胞存活有关。这些结果间接支持了预测在淋巴细胞个体发育过程中前抗原受体进行组成型非配体依赖性信号传导的模型。
