Differential association of CD45 Isoforms with CD4 and CD8 regulates the actions of specific pools of p56lck tyrosine kinase in T cell antigen receptor signal transduction
Differential association of CD45 Isoforms with CD4 and CD8 regulates the actions of specific pools of p56lck tyrosine kinase in T cell antigen receptor signal transduction
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DOI：
10.1074/jbc.m108386200
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发表时间：
2002-01-18
影响因子：
4.8
通讯作者：
Alexander, DR
中科院分区：
文献类型：
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作者：
Dornan, S;Sebestyen, Z;Alexander, DR
通过用CD45RO、CD45RBC和CD45RABC同种型转染CD45阴性CD4(+)CD8(+) HPB-ALL T细胞来研究CD45同种型在T细胞抗原受体信号转导中的作用。荧光共振能量转移分析表明，CD45R0 同工型（而非 CD45RBC 或 CD45RABC 同工型）被发现为同二聚体，并且还优先与细胞表面的 CD4 和 CD8 相关。因此，对表达 CD45RO 或 CD45RBC 的亚克隆之间的 T 细胞抗原受体信号传导进行了比较。在基础条件下，CD45R0(+)亚克隆中CD4相关的p56(lck)酪氨酸激酶活性和细胞蛋白酪氨酸磷酸化水平高于CD45RBC(+)亚克隆。 CD3-CD4连接后，与CD45RBC+细胞相比，CD45R0(+)细胞中的TCR-zeta磷酸化、ZAP-70募集到p21/p23 TCR-zeta磷酸异构体、ZAP-70磷酸化以及p56(lck)、c-Cb1和Slp-76磷酸化均显着增加。单独刺激 T 细胞抗原受体 (TCR) 也能促进 CD45R0(+) 细胞中的 c-Cbl 磷酸化，但不会促进 CD45RBC(+) 细胞中的 c-Cbl 磷酸化。我们的结果与 CD45RO 与 CD4 的关联产生更活跃的 CD4 相关 p56(lck) 激酶分子池的模型一致。 CD3-CD4 共连接后，活性 p56(lck) 通过促进 TCR-zeta 链磷酸化和 ZAP-70 招募来增加 T 细胞抗原受体信号转导耦合的强度。
An investigation into the role of CD45 isoforms in T cell antigen receptor signal transduction was carried out by transfecting CD45-negative CD4(+)CD8(+) HPB-ALL T cells with the CD45RO, CD45RBC, and CD45RABC isoforms. Fluorescence resonance energy transfer analysis showed that the CD45R0 isoform, but not the CD45RBC or CD45RABC isoforms, was found as homodimers and also preferentially associated with CD4 and CD8 at the cell-surface. A comparison was therefore made of T cell antigen receptor signaling between sub-clones expressing either CD45RO or CD45RBC. Under basal conditions CD4-associated p56(lck) tyrosine kinase activity and cellular protein tyrosine phosphorylation levels were higher in the CD45R0(+) than in the CD45RBC(+) sub-clones. Upon CD3-CD4 ligation, TCR-zeta phosphorylation, ZAP-70 recruitment to the p21/p23 TCR-zeta phosphoisomers, ZAP-70 phosphorylation, as well as p56(lck), c-Cb1 and Slp-76 phosphorylation, were all markedly increased in CD45R0(+) compared with CD45RBC+ cells. T cell antigen receptor (TCR) stimulation alone also promoted c-Cbl phosphorylation in CD45R0(+) but not in CD45RBC(+) cells. Our results are consistent with a model in which association of CD45RO with CD4 generates a more active pool of CD4-associated p56(lck) kinase molecules. Upon CD3-CD4 co-ligation, the active p56(lck) increases the intensity of T cell antigen receptor signal transduction coupling by promoting TCR-zeta chain phosphorylation and ZAP-70 recruitment.